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MobileGL/MobileGL/MG_Remote/Client/EmitTables.cpp
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// MobileGL - MobileGL/MG_Remote/Client/EmitTables.cpp
// Copyright (c) 2025-2026 MobileGL-Dev
// Licensed under the GNU Lesser General Public License v3.0:
// https://www.gnu.org/licenses/gpl-3.0.txt
// https://www.gnu.org/licenses/lgpl-3.0.txt
// SPDX-License-Identifier: LGPL-3.0-only
// End of Source File Header
// P5 package c1: the 71-slot emit table.
//
// THE PARTITION IS CONTRACT-P5.md §7's AND IS NOT RE-DERIVED HERE (R-15, ID-12):
// class A 2 slots answered locally from the caps mirror, never emitted, never Fatal
// class B 54 slots emitted; class C 15 slots name their unmigrated verb.
// The three counts are static_asserted to sum to kRemoteEmitSlotCount below, so a slot that
// changes class without changing the arithmetic is a build break rather than a behaviour
// change nobody reviewed.
//
// P5b MOVES SLOTS FROM C TO B, ONE PACKAGE AT A TIME (MG_Remote/CONTRACT-P5B.md §7). The three
// numbers above are the partition AT THE P5b CONTRACT COMMIT and they are the ones the contract
// states; the arithmetic below is what the tree currently has, and the per-package ownership
// assertions say which package moved which slot. On this head t2 has landed: class B is 5 + 6
// and class C is 58.
//
// THE PRE-VERB HOOKS RUN BEFORE THE RECORD, NEVER AFTER (b1, ID-18). PushPersistentMapsBeforeVerb
// publishes the bytes an application wrote through a coherent map with no API call at all, and
// MarkGpuWritesForDraw builds the conservative GPU-write set the client now owns. Both describe
// the work the record is ABOUT TO START, so a hook deferred past its own record is the C-1
// regression re-committed at the transport layer.
#include "EmitTables.h"
#include <MG_Remote/FatalFunnel.h>
#include "ClientSession.h"
#include "GpuWritePending.h"
#include "PersistentMapTracker.h"
#include "../Server/ServerLoop.h"
#include <MG_Util/Converters/GLToMG/TextureEnumConverter.h>
#include <MG_Util/Converters/MGToGL/TextureEnumConverter.h>
#include <MG_Util/Debug/Log.h>
#include <MG_Util/Metrics/PipeStats.h>
#include <MG_Util/Metrics/TextureMetrics.h>
#include <MG_State/GLState/BufferState/BufferObject.h>
#include <MG_State/GLState/Core.h>
#include <MG_State/GLState/VertexArrayState/VertexArrayObject.h>
// P5b i1: the emitters below name a texture's, a buffer's and a program's HANDLE beside the GL
// arguments (rule D). The handle comes from the client's own slot allocator, which is
// MG_Impl/Pipe's - the same table MG_Impl/Pipe/ImageEmit.h's set_shader_images reads, so the
// two records name one identity rather than two.
#include <MG_Impl/Pipe/SlotAllocator.h>
#include <MG_State/GLState/ProgramState/ProgramObject.h>
#include <MG_State/GLState/TextureState/TextureState.h>
// P5b d1: the handle a bound buffer already has (never minted here - the validate-time
// set_index_buffer / the buffer's own constructor did that), for MGPDrawInfo::IndexResource and
// the two indirect-buffer handles.
#include <MG_Impl/Pipe/ResourceTracker.h>
#include <MG_Impl/GLImpl/Texture/MipmapGenerationPlan.h>
#include <MG_Impl/Pipe/OwnedDrawInputs.h>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <limits>
#include "WireTables.h"
#include <MG_Impl/Pipe/FramebufferEmit.h>
#include <MG_Impl/Pipe/PipeFill.h>
#include <MG_Impl/Pipe/TextureEmit.h>
#include <MG_Impl/Pipe/ProgramEmit.h>
#include <MG_Pipe/PipeMutation.h>
namespace MobileGL::MG_Remote::Client {
// The slot arithmetic, asserted rather than commented. GlobalBackendFunctionsTable is
// GLFunctionsTable plus Present plus SetSwapInterval; GLFunctionsTable is 69 function
// pointers plus one Bool (PrefersCpuXfbPrimitiveAccounting, BackendObject.h:274). A slot
// added to either without a decision here is a build break, which is the point: R-4 forbids
// a null slot, so a new slot needs an owner on the day it appears.
static_assert(sizeof(MG_Backend::GlobalBackendFunctionsTable) ==
sizeof(MG_Backend::GLFunctionsTable) + 2 * sizeof(void (*)()),
"GlobalBackendFunctionsTable is no longer GLFunctionsTable + Present + SetSwapInterval");
static_assert(sizeof(MG_Backend::GlobalBackendFunctionsTable) ==
kRemoteEmitSlotCount * sizeof(void (*)()) + sizeof(void (*)()),
"the emit table's 71 slots plus the packed Bool no longer describe the table");
[[noreturn]] void UnmigratedVerbFatal(const char* slot) {
// The same shape as MGPipeInputPoisonFatal (generated/PipeFilled.inc:407-413): names the
// slot, live at every log level, aborts. Deliberately NOT MOBILEGL_ASSERT, which is
// inert in an INFO build - and INFO is what every device lane runs.
SessionFail(MGFatalFamily::UnmigratedVerb, "MGPipe: Fatal{UnmigratedVerb, \"%s\"}", slot);
}
namespace {
Bool g_dropClearEmission = false;
Uint64 g_droppedClearEmissions = 0;
Bool g_dropDrawEmission = false;
Uint64 g_droppedDrawEmissions = 0;
Uint64 g_presentOrdinal = 0;
Uint64 g_publishedMaxRecordBytes = 0;
// E2's control has to be armable from OUTSIDE the process that runs the replay, because
// the statement it makes is about a trace lane and not about a unit case: "drop an
// emission and OpenRA's SSIM falls below 0.99". A recompile would make the control
// arm against source text, which is ID-22(a)'s defect.
//
// READ WITH getenv RATHER THAN THROUGH MG_Config, DELIBERATELY AND TEMPORARILY. Config.h
// is c0's and a new MOBILEGL_IPC_* knob goes through the integrator; these are
// NEGATIVE-CONTROL switches no operator may ever set, and they announce themselves at
// warning level every time they arm so they cannot be on by accident. Flagged for
// adoption into IpcTable if the integrator wants them there.
Bool ReadControlKnob(const char* name) {
const char* value = std::getenv(name);
return value != nullptr && value[0] == '1' && value[1] == '\0';
}
// ---- WHY THERE ARE TWO OF THESE KNOBS, measured rather than assumed -----------------
//
// MOBILEGL_IPC_E2_DROP_CLEAR came first and it does exactly what it says: every glClear
// stops at the client and no Clear record reaches the ring. It STILL COULD NOT TURN THE
// E2 RETRACE RED (joint-v1.md 3: SSIM 1.000000, mismatchPixels=0 with the knob armed and
// the arming WARN in the library's own log). That is not a broken knob, it is OpenRA:
// `apitrace dump` of openra.trace over the 31249 replayed calls counts 30 glClear, 30
// glXSwapBuffers and 788 glDrawArrays, and the final frame issues its clear at call
// 30197 and then covers the surface four times over with a terrain layer
// (`glDrawArrays(GL_TRIANGLES, first=56064, count=16128)` x4, under a scissor of
// -24,-24,688x528 over a 640x480 surface) before the snapshot at 31249. A frame that
// overdraws every pixel it clears has a picture that does not depend on the clear, so
// "drop the clear" is a control whose observable is invisible to THIS trace - R-16's
// exact defect, a gate that cannot go red for its own reason.
//
// MOBILEGL_IPC_E2_DROP_DRAW is the honest form of the same statement for a trace lane:
// drop every DrawVbo record and the picture can only be the clear colour. It is the
// control that makes "the wire carried the frame" falsifiable, because the thing it
// removes is the thing the golden is made of.
//
// DROP_CLEAR IS KEPT rather than retired: it drops a real record, it now publishes the
// count it dropped (below), and a scenario whose picture DOES depend on its clear -
// ClearThenReadPixelsScenario is the reduced path's target A - is where it is
// observable. What it is no longer allowed to be is E2's retrace control.
void ArmControlKnobs() {
g_dropClearEmission = ReadControlKnob("MOBILEGL_IPC_E2_DROP_CLEAR");
g_dropDrawEmission = ReadControlKnob("MOBILEGL_IPC_E2_DROP_DRAW");
if (g_dropClearEmission) {
MGLOG_W("MG_Remote client: MOBILEGL_IPC_E2_DROP_CLEAR=1 - a NEGATIVE CONTROL is "
"armed and every glClear will be DROPPED on the wire. It is observable "
"only where the picture depends on the clear: OpenRA overdraws its whole "
"surface every frame, so this knob does NOT redden the E2 retrace "
"(measured, joint-v1.md 3) - MOBILEGL_IPC_E2_DROP_DRAW is the one that "
"does. The dropped count is published on the 'E2 control armed' line");
}
if (g_dropDrawEmission) {
MGLOG_W("MG_Remote client: MOBILEGL_IPC_E2_DROP_DRAW=1 - E2's NEGATIVE CONTROL is "
"armed and every DrawVbo record will be DROPPED on the wire. The surface "
"can then only carry the clear colour, so this arm is expected to fail its "
"SSIM threshold; a lane that stays green with it set is not going through "
"the wire at all");
}
}
// THE CONTROL'S OWN EVIDENCE LINE, and it is emitted per frame rather than at teardown
// on purpose: a retrace that is killed by its own timeout, or whose library never runs
// MobileGL::Destroy, would leave a teardown-only line absent and the control would then
// have to accept a bare threshold failure - which is the thing R-16 forbids. One line
// per Present, only while a knob is armed, is bounded by the frame count and present
// whatever happens afterwards.
void LogE2ControlLine(Uint64 frameOrdinal) {
if (!g_dropClearEmission && !g_dropDrawEmission) return;
MGLOG_W("MGPipe: E2 control armed - drop-draw=%d drop-clear=%d, %llu records dropped "
"on the wire (draw=%llu clear=%llu), frame %llu",
g_dropDrawEmission ? 1 : 0, g_dropClearEmission ? 1 : 0,
static_cast<unsigned long long>(g_droppedDrawEmissions + g_droppedClearEmissions),
static_cast<unsigned long long>(g_droppedDrawEmissions),
static_cast<unsigned long long>(g_droppedClearEmissions),
static_cast<unsigned long long>(frameOrdinal));
}
// ID-49's two halves, in one place so the emitter and its control read the same
// arithmetic.
//
// GL 4.6 8.4.4, pack side: the destination row stride is ROW_LENGTH (or the width)
// pixels rounded UP to PACK_ALIGNMENT, the first written byte is offset by SKIP_ROWS
// whole strides plus SKIP_PIXELS pixels, and only `width * bytesPerPixel` bytes of each
// stride are written - the gaps belong to the application and are never touched. That
// last clause is what the control checks with a sentinel.
Bool ReadbackPackStateIsTight(GLsizei width, Uint64 bytesPerPixel,
const PixelStoreParameters& pack) {
// SKIP_IMAGES (and IMAGE_HEIGHT) are NOT consulted: glReadPixels is a 2-D read and GL
// ignores the image-level pack parameters for it, exactly as the monolith conversion
// path does at DirectGLES.cpp:10905 (honorPackImageParams=false). A non-zero
// SkipImages therefore does not make the layout non-tight (codex 6).
if (pack.SkipRows != 0 || pack.SkipPixels != 0) return false;
if (pack.RowLength != 0 && pack.RowLength != width) return false;
const Uint64 alignment = pack.Alignment > 0 ? static_cast<Uint64>(pack.Alignment) : 1ull;
const Uint64 rowBytes = static_cast<Uint64>(width) * bytesPerPixel;
return (rowBytes % alignment) == 0;
}
// A band's box origin (g5-readback): the read's origin plus the band's offset, summed
// wide. It can only leave Int32 for a read whose far edge was already past INT32_MAX,
// and every pixel out there is outside any framebuffer - GL leaves their values
// undefined - so it saturates instead of wrapping onto real pixels.
Int32 ReadbackBandOrigin(GLint origin, Uint64 offset) {
const Int64 at = static_cast<Int64>(origin) + static_cast<Int64>(offset);
constexpr Int64 kMax = std::numeric_limits<Int32>::max();
return static_cast<Int32>(at > kMax ? kMax : at);
}
// ---- the session, demanded rather than assumed --------------------------------
//
// Every class-B slot needs one. A null session here is NOT the monolith answer - the
// monolith answer is that this table was never installed at all, because
// MG_Backend::Init() only reaches BackendObject_Remote when the transport resolved. So
// a null one is a Fatal by name and not a fall-through to the driver: a pass-through
// slot is the "split lane ran monolith and went green" shape that every gate in this
// phase exists to prevent (R-4).
ClientSession& RequireSession(const char* slot) {
RequireClientTablesInstalled(slot);
ClientSession* session = ClientSession::Active();
if (session == nullptr) {
// @Ph-declined (ID-P7-1): returns ClientSession& and runs in the CLIENT - no
// session to hand back, no peer bytes, and the latch is a server-session idea.
SessionFail(MGFatalFamily::NoClientSession, "MGPipe: Fatal{NoClientSession, \"%s\"} - the remote emit table is "
"installed but no ClientSession is active. A slot may not fall through "
"to a driver this role does not have",
slot);
}
return *session;
}
// A verb that reads buffers but starts no shader: clear, blit, readback, present. The
// push still has to run - a coherent map is read by the GPU on any of them - but there
// is no shader that could write one, so no mark walk.
void BeforeReadOnlyVerb() {
PushPersistentMapsBeforeVerb();
MG_Pipe::MGPipeDrainDeferredDestroys();
}
// =============================================================================
// CLASS B - the five slots the verb census measured (CONTRACT-P5.md §7)
// =============================================================================
void EmitClear(GLbitfield mask) {
ClientSession& session = RequireSession("Clear");
BeforeReadOnlyVerb();
if (g_dropClearEmission) {
// A negative control. Everything above still ran, so the only difference
// between this arm and the live one is the record - which is exactly the
// statement "the picture comes from the wire" that E2 exists to prove. Its
// OBSERVABILITY is a property of the workload, not of this branch: see
// ArmControlKnobs for the measurement that took E2's retrace off this knob.
++g_droppedClearEmissions;
return;
}
MG_Pipe::MGPClear record{};
// The DRAW framebuffer is whatever the server's own SyncRenderState resolves from
// gPipeInputs, which the client's MGP_FILL(Clear) at GL_Drawing.cpp:534 has just
// written and the verb barrier keeps still (R-1). Naming a handle here would be a
// SECOND statement of the binding, and the second one is the one that goes stale.
record.Fbo = MG_Pipe::kMGPipeNullHandle;
record.Kind = kRemoteClearWhole;
record.DrawBufferIndex = -1;
record.BufferMask = static_cast<Uint32>(mask);
record.ValueClass = 0;
session.EmitAndWait(MG_Pipe::MGPWireOp::Clear, &record, sizeof(record), nullptr, 0,
nullptr, 0, nullptr);
}
// ---- f1: verbatim clear/copy/mipmap records (CONTRACT-P5B §2) ----
void EmitF1Clear(const char* slot, MG_Pipe::MGPipeHandle fbo, GLenum buffer,
GLint drawbuffer, Uint8 valueClass, const void* value,
GLfloat depth = 0, GLint stencil = 0) {
auto& session = RequireSession(slot);
BeforeReadOnlyVerb();
MG_Pipe::MGPClear record{};
record.Fbo = fbo;
record.DrawBufferIndex = drawbuffer;
record.ValueClass = valueClass;
switch (buffer) {
case GL_COLOR:
record.Kind = MG_Pipe::kMGPipeClearKindColor;
std::memcpy(record.ColorValue, value, sizeof(record.ColorValue));
break;
case GL_DEPTH:
record.Kind = MG_Pipe::kMGPipeClearKindDepth;
std::memcpy(&record.DepthValue, value, sizeof(record.DepthValue));
break;
case GL_STENCIL:
record.Kind = MG_Pipe::kMGPipeClearKindStencil;
std::memcpy(&record.StencilValue, value, sizeof(record.StencilValue));
break;
case GL_DEPTH_STENCIL:
record.Kind = MG_Pipe::kMGPipeClearKindDepthStencil;
record.DepthValue = depth;
record.StencilValue = stencil;
break;
default: UnmigratedVerbFatal(slot);
}
session.EmitAndWait(MG_Pipe::MGPWireOp::Clear, &record, sizeof(record),
nullptr, 0, nullptr, 0, nullptr);
}
void EmitClearBufferfv(GLenum buffer, GLint drawbuffer, const GLfloat* value) {
EmitF1Clear("ClearBufferfv", MG_Pipe::kMGPipeNullHandle, buffer, drawbuffer,
MG_Pipe::kMGPipeClearValueClassFloat, value);
}
void EmitClearNamedFramebufferfv(const SharedPtr<MG_State::GLState::FramebufferObject>& fbo,
GLenum buffer, GLint drawbuffer, const GLfloat* value) {
EmitF1Clear("ClearNamedFramebufferfv", MG_Pipe::MGPipeFramebufferEmitter::HandleFor(*fbo),
buffer, drawbuffer, MG_Pipe::kMGPipeClearValueClassFloat, value);
}
void EmitClearBufferiv(GLenum buffer, GLint drawbuffer, const GLint* value) {
EmitF1Clear("ClearBufferiv", MG_Pipe::kMGPipeNullHandle, buffer, drawbuffer,
MG_Pipe::kMGPipeClearValueClassInt, value);
}
void EmitClearNamedFramebufferiv(const SharedPtr<MG_State::GLState::FramebufferObject>& fbo,
GLenum buffer, GLint drawbuffer, const GLint* value) {
EmitF1Clear("ClearNamedFramebufferiv", MG_Pipe::MGPipeFramebufferEmitter::HandleFor(*fbo),
buffer, drawbuffer, MG_Pipe::kMGPipeClearValueClassInt, value);
}
void EmitClearBufferuiv(GLenum buffer, GLint drawbuffer, const GLuint* value) {
EmitF1Clear("ClearBufferuiv", MG_Pipe::kMGPipeNullHandle, buffer, drawbuffer,
MG_Pipe::kMGPipeClearValueClassUint, value);
}
void EmitClearNamedFramebufferuiv(const SharedPtr<MG_State::GLState::FramebufferObject>& fbo,
GLenum buffer, GLint drawbuffer, const GLuint* value) {
EmitF1Clear("ClearNamedFramebufferuiv", MG_Pipe::MGPipeFramebufferEmitter::HandleFor(*fbo),
buffer, drawbuffer, MG_Pipe::kMGPipeClearValueClassUint, value);
}
void EmitClearBufferfi(GLenum buffer, GLint drawbuffer, GLfloat depth, GLint stencil) {
EmitF1Clear("ClearBufferfi", MG_Pipe::kMGPipeNullHandle, buffer, drawbuffer,
MG_Pipe::kMGPipeClearValueClassFloat, nullptr, depth, stencil);
}
void EmitClearNamedFramebufferfi(const SharedPtr<MG_State::GLState::FramebufferObject>& fbo,
GLenum buffer, GLint drawbuffer, GLfloat depth, GLint stencil) {
EmitF1Clear("ClearNamedFramebufferfi", MG_Pipe::MGPipeFramebufferEmitter::HandleFor(*fbo),
buffer, drawbuffer, MG_Pipe::kMGPipeClearValueClassFloat, nullptr, depth, stencil);
}
const SharedPtr<MG_State::GLState::ITextureObject>& F1BoundTexture(GLenum target) {
auto& ctx = *MG_State::pGLContext;
return ctx.GetTextureUnitObject(ctx.GetActiveTextureUnit())
.GetBindingSlot(MG_Util::ConvertGLEnumToTextureTarget(target)).GetBoundObject();
}
void EmitF1Copy(GLenum target, GLint level, GLenum format, GLint x, GLint y,
GLsizei width, GLsizei height, GLint xoffset, GLint yoffset, Bool subImage) {
auto& session = RequireSession(subImage ? "CopyTexSubImage2D" : "CopyTexImage2D");
BeforeReadOnlyVerb();
MG_Pipe::MGPCopyFromFramebuffer record{};
record.Dst = MG_Pipe::MGPipeTextureEmitterInstance().FindTexture(*F1BoundTexture(target));
record.Target = static_cast<Uint32>(target);
record.Level = level;
record.InternalFormat = format;
record.X = x; record.Y = y;
record.Width = width; record.Height = height;
record.XOffset = xoffset; record.YOffset = yoffset;
record.SubImage = subImage;
session.EmitAndWait(MG_Pipe::MGPWireOp::CopyFramebufferToTexture, &record, sizeof(record),
nullptr, 0, nullptr, 0, nullptr);
}
void EmitCopyTexImage2D(GLenum target, GLint level, GLenum format, GLint x, GLint y,
GLsizei width, GLsizei height, GLint) {
EmitF1Copy(target, level, format, x, y, width, height, 0, 0, false);
}
void EmitCopyTexSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset,
GLint x, GLint y, GLsizei width, GLsizei height) {
EmitF1Copy(target, level, 0, x, y, width, height, xoffset, yoffset, true);
}
void EmitGenerateMipmap(GLenum target) {
auto& session = RequireSession("GenerateMipmap");
BeforeReadOnlyVerb();
const auto& texture = F1BoundTexture(target);
MG_Pipe::MGPMipPlan record{};
record.Res = MG_Pipe::MGPipeTextureEmitterInstance().FindTexture(*texture);
record.Target = static_cast<Uint16>(target);
record.BaseLevel = texture->GetLevelRange().x();
const auto* mipmap = dynamic_cast<const MG_State::GLState::TextureObjectMipmap*>(texture.get());
if (mipmap && !texture->GetUploadTargets().empty()) {
const auto plan = MG_Impl::GLImpl::ComputeMipmapGenerationRange(*mipmap, texture->GetUploadTargets()[0]);
// LevelCount is the logical end-exclusive, not the number of
// levels following BaseLevel. Preserve that existing carrier.
record.LevelCount = static_cast<Uint16>(std::min<Uint>(plan.End, mipmap->GetMipmapLevelCount()));
}
session.EmitAndWait(MG_Pipe::MGPWireOp::GenerateMipmap, &record, sizeof(record),
nullptr, 0, nullptr, 0, nullptr);
}
// All draw entry points share the owned-input preparation and emission below.
[[noreturn]] void RefuseDrawByName(const char* slot, const char* qualifier);
void EmitDrawRecord(const char* slot, MG_Pipe::MGPDrawInfo& info,
const MG_Pipe::MGPDrawRange* ranges, Uint32 numDraws,
const void* clientIndices, Uint64 clientIndexBytes,
const MG_Pipe::MGPDrawIndirect* indirect);
// Does the bound VAO fetch any ENABLED attribute out of the application's own memory.
// The test is EmitVertexBuffers' own (`attrib.Enabled && !attrib.Buffer` is exactly what
// it publishes as Res == kMGPipeNullHandle), so the flag on the wire and the record the
// server applies agree by construction.
Bool BoundVaoHasClientVertexArrays(MG_State::GLState::GLContext* ctx) {
if (ctx == nullptr) return false;
const auto& vao = ctx->GetBoundVertexArray();
if (!vao) return false;
const auto& attributes = vao->GetAllAttributes();
for (SizeT i = 0; i < attributes.size(); ++i) {
if (attributes[i].Enabled && !attributes[i].Buffer) return true;
}
return false;
}
void EmitDrawArrays(GLenum mode, GLint first, GLsizei count) {
const Bool clientArrays = BoundVaoHasClientVertexArrays(MG_State::pGLContext.get());
MG_Pipe::MGPDrawInfo info{};
info.Mode = static_cast<Uint32>(mode);
info.IndexSize = 0; // arrays
// NO kDrawHasUserIndices: the reduced path draws from a VBO. kDrawClientArrays IS
// set when one is present, because the wait rule is computed from the record on
// both sides and this path publishes its own record rather than PlanDrawInfo's.
info.Flags = clientArrays ? static_cast<Uint8>(MG_Pipe::kDrawClientArrays) : 0;
info.InstanceCount = 1;
info.StartInstance = 0;
info.RestartIndex = 0;
info.DrawIdOffset = 0;
info.IndexResource = MG_Pipe::kMGPipeNullHandle;
info.MinIndex = ~0u; // "unknown", MGPipeTypes.h:1330
info.MaxIndex = ~0u;
info.XfbCpuCapturedVertices = 0;
info.NumDraws = 1;
const MG_Pipe::MGPDrawRange range{static_cast<Uint32>(first), static_cast<Uint32>(count), 0};
// One tail of exactly NumDraws entries. w1's encoder recomputes that from the
// payload and Fatals on a disagreement, on THIS side - so a NumDraws that drifted
// from the tail is a producer-side abort rather than a corrupt stream a peer has to
// diagnose.
EmitDrawRecord("DrawArrays", info, &range, 1, nullptr, 0, nullptr);
}
// =============================================================================
// P5b d1 - the nineteen indexed / instanced / multi-draw / indirect draw slots
// (MG_Remote/CONTRACT-P5B.md §2 d1). ONE ROW, draw_vbo (59): the record carries the GL
// call verbatim (rule D) beside the handle the P8 form will dispatch on, and the sink
// reproduces the backend call the monolith makes.
// =============================================================================
//
// Every entry point below is: read the bindings, plan the head and the ranges (the pure
// functions the unit cases drive), then EmitDrawRecord - which runs the SAME pre-verb
// hooks in the SAME order as EmitDrawArrays (push, then mark walk, then the record;
// ID-18), honours the E2 draw-drop control for every draw record and not only the P5
// one, stages a client index array into SEG_STAGE when there is one, and emits.
//
// Client arrays and client indices become owned ordinary buffer resources.
// Remaining invalid/unrepresentable draw shapes are named before encoding:
// +CLIENT_COMMANDS an indirect draw with no GL_DRAW_INDIRECT_BUFFER bound: `indirect`
// would be a host pointer, which rule B forbids on the wire.
// +UNBOUND_PARAMETER an *IndirectCount with no GL_PARAMETER_BUFFER (the frontend has
// already raised INVALID_OPERATION for it; stated so the emitter
// cannot send a null handle where the sink dereferences one).
// +INDEX_OFFSET an element-buffer byte offset that is not a whole number of
// indices (or past 2^32 of them): the record spells Start in
// indices, and rounding would draw from the wrong element.
[[noreturn]] void RefuseDrawByName(const char* slot, const char* qualifier) {
char name[96];
std::snprintf(name, sizeof(name), "%s+%s", slot, qualifier);
UnmigratedVerbFatal(name);
}
// The bindings the plan is made from, read ONCE per draw from the frontend context on
// the GL thread. The element buffer is the VAO's (the same slot EmitIndexBuffer read at
// validate), the two indirect buffers are the context's, and the handles are LOOKED UP,
// never minted: a push build mints in the BufferObject constructor.
RemoteDrawBindings ReadDrawBindings() {
RemoteDrawBindings b{};
MG_State::GLState::GLContext* ctx = MG_State::pGLContext.get();
if (ctx == nullptr) return b;
if (const auto& vao = ctx->GetBoundVertexArray()) {
if (const auto& bound = vao->GetIndexBufferBindingSlot().GetBoundObject()) {
b.ElementBufferBound = true;
b.ElementBuffer = MG_Pipe::MGPipeResourceTrackerInstance().Find(*bound);
}
// P5e (vi): the client-array probe, in the SAME single read of the bindings the
// rest of the plan is made from rather than in a second walk at the refusal -
// this runs on the GL thread once per draw and the refusal must not add its own
// frontend pass. The test is the emitter's own: EmitVertexBuffers publishes
// Res == kMGPipeNullHandle for exactly `attrib.Enabled && !attrib.Buffer`, so
// the flag and the record agree by construction instead of by inspection.
const auto& attributes = vao->GetAllAttributes();
for (SizeT i = 0; i < attributes.size(); ++i) {
if (attributes[i].Enabled && !attributes[i].Buffer) {
b.ClientVertexArrays = true;
break;
}
}
}
if (const auto& di = ctx->GetBufferBindingSlot(::MobileGL::BufferTarget::DrawIndirect).GetBoundObject()) {
b.DrawIndirectBuffer = MG_Pipe::MGPipeResourceTrackerInstance().Find(*di);
}
if (const auto& pb = ctx->GetBufferBindingSlot(::MobileGL::BufferTarget::Parameter).GetBoundObject()) {
b.ParameterBuffer = MG_Pipe::MGPipeResourceTrackerInstance().Find(*pb);
}
b.PrimitiveRestart = ctx->IsCapabilityEnabled(CapabilityInput::PrimitiveRestart) ||
ctx->IsCapabilityEnabled(CapabilityInput::PrimitiveRestartFixedIndex);
b.RestartIndex = ctx->GetPrimitiveRestartIndex();
return b;
}
// The one emission for all nineteen. `clientIndices`/`clientIndexBytes` name a client
// index array to stage (no element buffer bound); `indirect` is the kDrawIsIndirect
// block. The two are exclusive by construction here and by the layout on both sides.
void EmitDrawRecord(const char* slot, MG_Pipe::MGPDrawInfo& info,
const MG_Pipe::MGPDrawRange* ranges, Uint32 numDraws,
const void* clientIndices, Uint64 clientIndexBytes,
const MG_Pipe::MGPDrawIndirect* indirect) {
ClientSession& session = RequireSession(slot);
PersistentMapTracker::Instance().PushDrawConsumers();
MG_Pipe::MGPipeDrainDeferredDestroys();
// Snapshot before marking THIS draw's potential GPU writes: resolving
// a GPU-produced EBO here must not clear its pending mark for this draw.
UniquePtr<MG_Pipe::MGPipeOwnedDrawInputs> ownedInputs;
if ((info.Flags & MG_Pipe::kDrawClientArrays) != 0 || clientIndexBytes != 0) {
if (MG_State::pGLContext == nullptr) RefuseDrawByName(slot, "NO_CONTEXT");
ownedInputs = MakeUnique<MG_Pipe::MGPipeOwnedDrawInputs>(*MG_State::pGLContext);
if (!ownedInputs->Prepare(info, ranges, numDraws, clientIndices, clientIndexBytes, indirect)) {
MG_State::pGLContext->RecordError(ErrorCode::InvalidOperation,
MakeUnique<GenericErrorInfo>("MG_Remote/Client", slot,
"the client vertex/index fetch range cannot be represented by its storage"));
return;
}
}
MarkGpuWritesForDraw();
if (g_dropDrawEmission) {
// E2's negative control covers EVERY draw record, not only DrawArrays: the
// Minecraft traces are DrawElements frames, and a control that dropped only the
// one P5 entry point would leave those lanes green with the wire disarmed.
++g_droppedDrawEmissions;
return;
}
info.NumDraws = numDraws;
Wire::WireTail tails[2] = {{ranges, static_cast<Uint64>(numDraws) * sizeof(MG_Pipe::MGPDrawRange)},
{nullptr, 0}};
Uint32 tailCount = 1;
if (indirect != nullptr) {
info.Flags |= MG_Pipe::kDrawIsIndirect;
tails[1] = {indirect, sizeof(*indirect)};
tailCount = 2;
}
session.EmitAndWaitTails(MG_Pipe::MGPWireOp::DrawVbo, &info, sizeof(info), tails,
tailCount, nullptr, 0, nullptr);
}
// ---- the single-draw indexed family: DrawElements, DrawElementsBaseVertex, the two
// DrawRangeElements*, the four DrawElementsInstanced* -------------------------------
void EmitIndexedDraw(const char* slot, GLenum mode, GLsizei count, GLenum type,
const void* indices, GLint baseVertex, GLsizei instanceCount,
GLuint baseInstance, Bool hasRange, GLuint start, GLuint end) {
const RemoteDrawBindings bindings = ReadDrawBindings();
const Uint8 indexSize = RemoteIndexSizeFor(type);
if (indexSize == 0) RefuseDrawByName(slot, "INDEX_TYPE");
MG_Pipe::MGPDrawInfo info =
PlanDrawInfo(mode, indexSize, instanceCount, baseInstance, 1, bindings);
if (hasRange) {
info.Flags |= MG_Pipe::kDrawHasIndexRange;
info.MinIndex = start;
info.MaxIndex = end;
}
MG_Pipe::MGPDrawRange range{};
if (!PlanDrawRange(bindings, indexSize, indices, count, baseVertex, range)) {
RefuseDrawByName(slot, "INDEX_OFFSET");
}
// No element buffer: `indices` is the application's array and the draw's own
// range is exactly what the driver would read. A null pointer or an empty draw
// stages nothing and crosses as a zero-length range, which is what the monolith
// hands the driver too.
const Bool clientArray = !bindings.ElementBufferBound && indices != nullptr && count > 0;
EmitDrawRecord(slot, info, &range, 1, clientArray ? indices : nullptr,
clientArray ? static_cast<Uint64>(count) * indexSize : 0, nullptr);
}
void EmitDrawElements(GLenum mode, GLsizei count, GLenum type, const void* indices) {
EmitIndexedDraw("DrawElements", mode, count, type, indices, 0, 1, 0, false, 0, 0);
}
void EmitDrawElementsBaseVertex(GLenum mode, GLsizei count, GLenum type, const void* indices,
GLint basevertex) {
EmitIndexedDraw("DrawElementsBaseVertex", mode, count, type, indices, basevertex, 1, 0,
false, 0, 0);
}
void EmitDrawRangeElements(GLenum mode, GLuint start, GLuint end, GLsizei count, GLenum type,
const void* indices) {
EmitIndexedDraw("DrawRangeElements", mode, count, type, indices, 0, 1, 0, true, start, end);
}
void EmitDrawRangeElementsBaseVertex(GLenum mode, GLuint start, GLuint end, GLsizei count,
GLenum type, const void* indices, GLint basevertex) {
EmitIndexedDraw("DrawRangeElementsBaseVertex", mode, count, type, indices, basevertex, 1,
0, true, start, end);
}
void EmitDrawElementsInstanced(GLenum mode, GLsizei count, GLenum type, const void* indices,
GLsizei instancecount) {
EmitIndexedDraw("DrawElementsInstanced", mode, count, type, indices, 0, instancecount, 0,
false, 0, 0);
}
void EmitDrawElementsInstancedBaseVertex(GLenum mode, GLsizei count, GLenum type,
const void* indices, GLsizei instancecount,
GLint basevertex) {
EmitIndexedDraw("DrawElementsInstancedBaseVertex", mode, count, type, indices, basevertex,
instancecount, 0, false, 0, 0);
}
void EmitDrawElementsInstancedBaseInstance(GLenum mode, GLsizei count, GLenum type,
const void* indices, GLsizei instancecount,
GLuint baseinstance) {
EmitIndexedDraw("DrawElementsInstancedBaseInstance", mode, count, type, indices, 0,
instancecount, baseinstance, false, 0, 0);
}
void EmitDrawElementsInstancedBaseVertexBaseInstance(GLenum mode, GLsizei count, GLenum type,
const void* indices, GLsizei instancecount,
GLint basevertex, GLuint baseinstance) {
EmitIndexedDraw("DrawElementsInstancedBaseVertexBaseInstance", mode, count, type, indices,
basevertex, instancecount, baseinstance, false, 0, 0);
}
// ---- the instanced array draws ------------------------------------------------
void EmitArraysDraw(const char* slot, GLenum mode, GLint first, GLsizei count,
GLsizei instanceCount, GLuint baseInstance) {
const RemoteDrawBindings bindings = ReadDrawBindings();
MG_Pipe::MGPDrawInfo info = PlanDrawInfo(mode, 0, instanceCount, baseInstance, 1, bindings);
MG_Pipe::MGPDrawRange range{};
PlanDrawRange(bindings, 0, reinterpret_cast<const void*>(static_cast<std::intptr_t>(first)),
count, 0, range);
EmitDrawRecord(slot, info, &range, 1, nullptr, 0, nullptr);
}
void EmitDrawArraysInstanced(GLenum mode, GLint first, GLsizei count, GLsizei instancecount) {
EmitArraysDraw("DrawArraysInstanced", mode, first, count, instancecount, 0);
}
void EmitDrawArraysInstancedBaseInstance(GLenum mode, GLint first, GLsizei count,
GLsizei instancecount, GLuint baseinstance) {
// The vertex-FETCH base instance already crossed in set_vertex_buffers::BaseInstance
// at validate (D-H1: MGP_SET_BASE_INSTANCE runs before MGP_FILL); StartInstance is
// gl_BaseInstance's value and feeds the GL call.
EmitArraysDraw("DrawArraysInstancedBaseInstance", mode, first, count, instancecount,
baseinstance);
}
// ---- the multi-draws: MGPDrawRange[drawcount] is exactly their shape -------------
//
// The range array is built in a scratch vector owned by the GL thread (the emitter is
// single-threaded by the ring's own SPSC contract), sized by drawcount, never held past
// the emission. A drawcount of 0 is a call that draws nothing and emits nothing: the
// frontend has already refused a negative one.
Vector<MG_Pipe::MGPDrawRange>& MultiDrawScratch(Uint32 count) {
static Vector<MG_Pipe::MGPDrawRange>& scratch = *new Vector<MG_Pipe::MGPDrawRange>();
scratch.resize(count);
return scratch;
}
void EmitMultiDrawArrays(GLenum mode, const GLint* first, const GLsizei* count, GLsizei drawcount) {
if (drawcount <= 0 || first == nullptr || count == nullptr) return;
const RemoteDrawBindings bindings = ReadDrawBindings();
const auto n = static_cast<Uint32>(drawcount);
MG_Pipe::MGPDrawInfo info = PlanDrawInfo(mode, 0, 1, 0, n, bindings);
Vector<MG_Pipe::MGPDrawRange>& ranges = MultiDrawScratch(n);
for (Uint32 i = 0; i < n; ++i) {
PlanDrawRange(bindings, 0,
reinterpret_cast<const void*>(static_cast<std::intptr_t>(first[i])),
count[i], 0, ranges[i]);
}
EmitDrawRecord("MultiDrawArrays", info, ranges.data(), n, nullptr, 0, nullptr);
}
void EmitMultiIndexedDraw(const char* slot, GLenum mode, const GLsizei* count, GLenum type,
const GLvoid* const* indices, GLsizei drawcount,
const GLint* basevertex) {
if (drawcount <= 0 || count == nullptr || indices == nullptr) return;
const RemoteDrawBindings bindings = ReadDrawBindings();
const Uint8 indexSize = RemoteIndexSizeFor(type);
if (indexSize == 0) RefuseDrawByName(slot, "INDEX_TYPE");
const auto n = static_cast<Uint32>(drawcount);
MG_Pipe::MGPDrawInfo info = PlanDrawInfo(mode, indexSize, 1, 0, n, bindings);
Vector<MG_Pipe::MGPDrawRange>& ranges = MultiDrawScratch(n);
Vector<Uint8> ownedIndices;
for (Uint32 i = 0; i < n; ++i) {
if (!PlanDrawRange(bindings, indexSize, indices[i], count[i],
basevertex != nullptr ? basevertex[i] : 0, ranges[i])) {
RefuseDrawByName(slot, "INDEX_OFFSET");
}
if (!bindings.ElementBufferBound) {
const Uint64 byteCount = static_cast<Uint64>(ranges[i].Count) * indexSize;
if (byteCount > std::numeric_limits<Uint32>::max() - ownedIndices.size() ||
(byteCount != 0 && indices[i] == nullptr)) {
MG_State::pGLContext->RecordError(ErrorCode::InvalidOperation,
MakeUnique<GenericErrorInfo>("MG_Remote/Client", slot, "invalid client index span"));
return;
}
ranges[i].Start = static_cast<Uint32>(ownedIndices.size() / indexSize);
const SizeT at = ownedIndices.size();
ownedIndices.resize(at + static_cast<SizeT>(byteCount));
if (byteCount != 0) std::memcpy(ownedIndices.data() + at, indices[i], byteCount);
}
}
EmitDrawRecord(slot, info, ranges.data(), n, ownedIndices.empty() ? nullptr : ownedIndices.data(),
ownedIndices.size(), nullptr);
}
void EmitMultiDrawElements(GLenum mode, const GLsizei* count, GLenum type,
const GLvoid* const* indices, GLsizei drawcount) {
EmitMultiIndexedDraw("MultiDrawElements", mode, count, type, indices, drawcount, nullptr);
}
void EmitMultiDrawElementsBaseVertex(GLenum mode, const GLsizei* count, GLenum type,
const GLvoid* const* indices, GLsizei drawcount,
const GLint* basevertex) {
EmitMultiIndexedDraw("MultiDrawElementsBaseVertex", mode, count, type, indices, drawcount,
basevertex);
}
// ---- the indirect family: the block is the second tail, NumDraws is 0 -------------
void EmitIndirectDraw(const char* slot, GLenum mode, GLenum type, const void* indirect,
GLsizei drawcount, GLsizei stride, GLintptr parameterOffset,
Bool hasParameterBuffer) {
const RemoteDrawBindings bindings = ReadDrawBindings();
const Uint8 indexSize = type != 0 ? RemoteIndexSizeFor(type) : 0;
if (type != 0 && indexSize == 0) RefuseDrawByName(slot, "INDEX_TYPE");
if (MG_Pipe::MGPipeHandleIsNull(bindings.DrawIndirectBuffer)) {
RefuseDrawByName(slot, "CLIENT_COMMANDS");
}
if (hasParameterBuffer && MG_Pipe::MGPipeHandleIsNull(bindings.ParameterBuffer)) {
RefuseDrawByName(slot, "UNBOUND_PARAMETER");
}
MG_Pipe::MGPDrawInfo info = PlanDrawInfo(mode, indexSize, 1, 0, 0, bindings);
const MG_Pipe::MGPDrawIndirect block = PlanDrawIndirect(bindings, indirect, drawcount, stride,
parameterOffset, hasParameterBuffer);
EmitDrawRecord(slot, info, nullptr, 0, nullptr, 0, &block);
}
void EmitDrawArraysIndirect(GLenum mode, const void* indirect) {
EmitIndirectDraw("DrawArraysIndirect", mode, 0, indirect, 1, 0, 0, false);
}
void EmitDrawElementsIndirect(GLenum mode, GLenum type, const void* indirect) {
EmitIndirectDraw("DrawElementsIndirect", mode, type, indirect, 1, 0, 0, false);
}
void EmitMultiDrawArraysIndirect(GLenum mode, const void* indirect, GLsizei drawcount,
GLsizei stride) {
EmitIndirectDraw("MultiDrawArraysIndirect", mode, 0, indirect, drawcount, stride, 0, false);
}
void EmitMultiDrawElementsIndirect(GLenum mode, GLenum type, const void* indirect,
GLsizei drawcount, GLsizei stride) {
EmitIndirectDraw("MultiDrawElementsIndirect", mode, type, indirect, drawcount, stride, 0,
false);
}
void EmitMultiDrawArraysIndirectCount(GLenum mode, const void* indirect, GLintptr drawcount,
GLsizei maxdrawcount, GLsizei stride) {
EmitIndirectDraw("MultiDrawArraysIndirectCount", mode, 0, indirect, maxdrawcount, stride,
drawcount, true);
}
void EmitMultiDrawElementsIndirectCount(GLenum mode, GLenum type, const void* indirect,
GLintptr drawcount, GLsizei maxdrawcount,
GLsizei stride) {
EmitIndirectDraw("MultiDrawElementsIndirectCount", mode, type, indirect, maxdrawcount,
stride, drawcount, true);
}
void EmitBlitFramebuffer(GLint srcX0, GLint srcY0, GLint srcX1, GLint srcY1, GLint dstX0,
GLint dstY0, GLint dstX1, GLint dstY1, GLbitfield mask,
GLenum filter) {
ClientSession& session = RequireSession("BlitFramebuffer");
BeforeReadOnlyVerb();
MG_Pipe::MGPBlit record{};
// Same reasoning as Clear's Fbo: the read and draw bindings are gPipeInputs', set
// by MGP_FILL(BlitFramebuffer) at GL_Framebuffer.cpp:660 and held still by the
// barrier. The named form below carries both handles after a scoped binding override.
record.ReadFbo = MG_Pipe::kMGPipeNullHandle;
record.DrawFbo = MG_Pipe::kMGPipeNullHandle;
record.SrcX0 = srcX0;
record.SrcY0 = srcY0;
record.SrcX1 = srcX1;
record.SrcY1 = srcY1;
record.DstX0 = dstX0;
record.DstY0 = dstY0;
record.DstX1 = dstX1;
record.DstY1 = dstY1;
record.Mask = static_cast<Uint32>(mask);
record.Filter = static_cast<Uint32>(filter);
session.EmitAndWait(MG_Pipe::MGPWireOp::Blit, &record, sizeof(record), nullptr, 0,
nullptr, 0, nullptr);
}
void EmitBlitNamedFramebuffer(
const SharedPtr<MG_State::GLState::FramebufferObject>& read,
const SharedPtr<MG_State::GLState::FramebufferObject>& draw,
GLint srcX0, GLint srcY0, GLint srcX1, GLint srcY1, GLint dstX0,
GLint dstY0, GLint dstX1, GLint dstY1, GLbitfield mask, GLenum filter) {
ClientSession& session = RequireSession("BlitNamedFramebuffer");
// P5c (hd, CONTRACT-P5C §3.3): the scoped rebind of the client's own read/draw
// binding slots is DELETED. It existed only to stage values for the server's
// binding-slot read, and that read is gone: the sink resolves both framebuffers
// from the record's handles. The validate still refreshes both framebuffers'
// emitted state (their Named set_framebuffer_state records), which is now the
// only description the server syncs from. No driver call or binding change
// happens on the client.
MG_Pipe::MGPipeValidateForVerb(MG_Pipe::MGPipeVerb::BlitNamedFramebuffer);
BeforeReadOnlyVerb();
MG_Pipe::MGPBlit record{};
record.ReadFbo = MG_Pipe::MGPipeFramebufferEmitter::HandleFor(*read);
record.DrawFbo = MG_Pipe::MGPipeFramebufferEmitter::HandleFor(*draw);
record.SrcX0 = srcX0; record.SrcY0 = srcY0;
record.SrcX1 = srcX1; record.SrcY1 = srcY1;
record.DstX0 = dstX0; record.DstY0 = dstY0;
record.DstX1 = dstX1; record.DstY1 = dstY1;
record.Mask = static_cast<Uint32>(mask);
record.Filter = static_cast<Uint32>(filter);
session.EmitAndWait(MG_Pipe::MGPWireOp::Blit, &record, sizeof(record), nullptr, 0,
nullptr, 0, nullptr);
}
// How many bytes glReadPixels will pack for this rectangle, from the PACK half of the
// pixel-store state.
//
// ID-49: THE PACK STATE NEVER CROSSES FOR A READ, AND DstSize IS THE TIGHT EXTENT.
// The first version of this computed GL 4.6 8.4.4's PACKED size - row length, skips,
// alignment - and handed it over as DstSize. v1's server allocates exactly DstSize and
// the real backend honours the live pack state, so a 4x3 RGBA8 read with
// PACK_ROW_LENGTH=8, SKIP_ROWS=1, SKIP_PIXELS=2 allocated 80 bytes and the driver wrote
// to byte 120. That is the shape of the joint inproc lane's two
// DepthReadbackHonoursThePackPixelStoreParameters SEGFAULTs, on both backends.
//
// So the wire carries a RECTANGLE and not a layout: the server reads with NEUTRAL pack
// state into a tight w*h*bytesPerPixel run that IS the reply payload, and the CLIENT -
// which is the side that holds the application's pack state, and the only side that
// can - scatters those rows into the application's pointer. "OnReadPixels writes
// exactly DstSize bytes" still holds; DstSize is now a number both sides derive from
// the same three values instead of one side deriving it from state the other cannot
// see.
//
// IT IS FORMAT-AGNOSTIC ON PURPOSE. The depth and depth-stencil reads the 21 split
// entries touch take the same rule with no special case, because the rule is about the
// LAYOUT and not about the component: bytesPerPixel is whatever the format sizes to.
Uint64 ReadbackBytesPerPixel(GLenum format, GLenum type) {
const TextureInputFormat inputFormat =
MG_Util::ConvertGLEnumToTextureInputFormat(format);
const TexturePixelDataType dataType = MG_Util::ConvertGLEnumToTexturePixelDataType(type);
const SizeT bytesPerPixel = MG_Util::GetInputBytesPerPixel(inputFormat, dataType);
if (bytesPerPixel == 0) {
// NOT a guess and not a zero-length reply. A format this build cannot size is a
// readback whose answer would be silently truncated, which is the one failure a
// picture comparison cannot see.
SessionFail(MGFatalFamily::UnsizedReadback, "MGPipe: Fatal{UnsizedReadback, \"read_pixels\"} format=0x%04x type=0x%04x "
"- the client must declare MGPReadbackInfo::DstSize and cannot size this "
"pair; P5's reduced path reads RGBA/UNSIGNED_BYTE",
static_cast<unsigned>(format), static_cast<unsigned>(type));
}
return static_cast<Uint64>(bytesPerPixel);
}
Uint64 TightReadbackBytes(GLsizei width, GLsizei height, GLenum format, GLenum type) {
if (width <= 0 || height <= 0) return 0;
return static_cast<Uint64>(width) * static_cast<Uint64>(height) *
ReadbackBytesPerPixel(format, type);
}
// GL_PACK_SWAP_BYTES as the width of the byte group it reverses for `type`, 0 when there
// is nothing to reverse. One rule for both places a swap happens: the reply form swaps
// here, and the pack-buffer form (P9) carries the number to the server, which swaps there.
Uint32 ReadbackSwapGroup(GLenum type, const PixelStoreParameters& pack) {
if (!pack.SwapBytes) return 0;
const auto dataType = MG_Util::ConvertGLEnumToTexturePixelDataType(type);
SizeT group = MG_Util::GetSizedTexturePixelDataTypeSize(dataType);
if (group == 0) group = MG_Util::GetBaseTexturePixelDataTypeSize(dataType);
// This packed depth/stencil type contains two independent 32-bit words.
if (type == GL_FLOAT_32_UNSIGNED_INT_24_8_REV) group = 4;
return group <= 1 ? 0 : static_cast<Uint32>(group);
}
void ApplyReadbackByteSwap(void* pixels, Uint64 bytes, GLenum type,
const PixelStoreParameters& pack) {
const SizeT group = ReadbackSwapGroup(type, pack);
if (group == 0 || pixels == nullptr) return;
auto* data = static_cast<Uint8*>(pixels);
for (Uint64 at = 0; at + group <= bytes; at += group) {
for (SizeT i = 0; i < group / 2; ++i) {
std::swap(data[at + i], data[at + group - 1 - i]);
}
}
}
// M2 / codex 11: the reply the server posted is COMPLETE and OK. A short OK reply, and a
// DECLINED or ERROR reply with a zero payload, both leave the destination full of stale
// bytes; scattering or returning it is the silently truncated picture ID-47's own comment
// says an SSIM comparison cannot see, arriving through the status field rather than
// through truncation. `expected` is the record's own DstSize (CONTRACT-P5 row 23: the
// reply's exact extent). The predicate is at namespace scope (below) and exposed for the
// control, so R-16's "drive the production predicate" holds rather than a second copy of
// the rule in the test.
// The same predicate at the call site, with the named Fatal each failure mode owns.
// status > expected cannot reach here: EmitAndWait already aborts Fatal{ReplyTooLarge} on
// an oversize reply, so the only failures left are a wrong status or a SHORT one.
//
// A LOST DEVICE IS NOT ONE OF THOSE FAILURES. Once the session is device-lost every verb
// is declined by EmitAndWait itself, and the GL answer for a lost context is that its
// commands do nothing: the read writes no pixel and the application learns of the loss
// from glGetGraphicsResetStatus. Dying here instead turned a server-side GPU fault into a
// crash of the client (Chrome's in-process GPU thread took the browser with it). False:
// the caller leaves the destination untouched and returns.
Bool RequireReadbackReplyComplete(Int32 status, Uint64 replySize, Uint64 expected) {
if (status != Wire::ReplySink::kStatusOk && ClientSession::DeviceLost()) return false;
if (status == Wire::ReplySink::kStatusError) {
SessionFail(MGFatalFamily::ReplyError, "MGPipe: Fatal{ReplyError, \"ReadPixels\"} - the readback answered ERROR; "
"the destination is left untouched rather than filled with stale bytes");
}
if (status == Wire::ReplySink::kStatusDeclined) {
SessionFail(MGFatalFamily::ReadbackDeclined, "MGPipe: Fatal{ReadbackDeclined, \"ReadPixels\"} - the server has no "
"GL.ReadPixels and DECLINED; a decline is a real answer for an acceptance "
"row (R-5) but a blocking readback has no pixels to return, so it is a "
"Fatal here rather than a buffer of stale bytes");
}
if (status != Wire::ReplySink::kStatusOk) {
SessionFail(MGFatalFamily::ReplyStatusInvalid, "MGPipe: Fatal{ReplyStatusInvalid, \"ReadPixels\"} - unknown reply status %d", status);
}
if (replySize != expected) {
SessionFail(MGFatalFamily::ReadbackReplyShort, "MGPipe: Fatal{ReadbackReplyShort, \"ReadPixels %llu < %llu\"} - the OK "
"reply carried fewer bytes than the read's own DstSize (CONTRACT-P5 row "
"23's exact extent); the missing rows would otherwise be scattered as "
"whatever the destination held",
static_cast<unsigned long long>(replySize),
static_cast<unsigned long long>(expected));
}
return true;
}
#include "TextureReadbackEmit.inc"
void EmitReadPixels(GLint x, GLint y, GLsizei width, GLsizei height, GLenum format,
GLenum type, void* pixels) {
ClientSession& session = RequireSession("ReadPixels");
// A bound PACK buffer makes pixels an offset. The owned reply is
// packed on this thread and only the requested rows are uploaded.
const auto pbo = MG_State::pGLContext != nullptr
? MG_State::pGLContext->GetBufferBindingSlot(::MobileGL::BufferTarget::PixelPack).GetBoundObject()
: SharedPtr<MG_State::GLState::BufferObject>{};
BeforeReadOnlyVerb();
if (width <= 0 || height <= 0) return;
const Uint64 bytesPerPixel = ReadbackBytesPerPixel(format, type);
PixelStoreParameters pack{};
if (MG_State::pGLContext != nullptr) {
pack = MG_State::pGLContext->GetPixelStoreParameters(/*isUnpack=*/false);
}
ReadbackLayout layout;
const SizeT pboOffset = reinterpret_cast<SizeT>(pixels);
if (!CheckedReadbackLayout(width, height, 1, bytesPerPixel, pack, false, layout) ||
(pbo && (pboOffset > pbo->GetSize() || layout.End > pbo->GetSize() - pboOffset))) {
RecordReadbackRangeError("ReadPixels");
return;
}
// P7 GATE 5 (g5-readback): A READ LARGER THAN ONE REPLY SLOT IS BANDED, NOT REFUSED.
// KHR-GL46.direct_state_access.renderbuffers_storage reads 256x512 RGBA/FLOAT =
// 2,097,152 bytes, sixteen over MaxReplyBytes, and that used to be
// Fatal{ReplyTooLarge} on every split arm while the monolith passed. Each band below
// is an ordinary read_pixels record - its own box, and a DstSize that IS its tight
// w*h*bpp extent (ID-49) - so every answer still fits one slot (ID-47) and the
// server's PH-3 bound (its tight answer against its own LinkTerms.maxReplyBytes,
// PipeApplier.cpp OnReadPixels) holds unchanged: no reply is chunked, the READ is. The cap is the link's own, read live, exactly as
// before, so a different SEG_REPLY geometry or a stream link needs no edit here.
ReadbackBandPlan plan;
if (!PlanReadbackBands(static_cast<Uint64>(width), static_cast<Uint64>(height),
bytesPerPixel, session.MaxReplyBytes(), plan)) {
// NOT EVEN ONE PIXEL FITS (or there is no reply pool at all). That is the only
// read no banding can answer, and ID-47's named refusal is kept for it - for the
// one-pixel piece that cannot be sent, so the message names what was impossible.
session.RequireReadPixelsReplyFits(1, 1, static_cast<Uint32>(format),
static_cast<Uint32>(type), bytesPerPixel);
return;
}
// One band's source record, the same for both destinations below.
const auto bandInfo = [&](const ReadbackBand& band, Uint64 bandBytes) {
MG_Pipe::MGPReadbackInfo info{};
info.Res = MG_Pipe::kMGPipeNullHandle; // "the bound read surface answers"
info.Box = MG_Pipe::MGPBox{ReadbackBandOrigin(x, band.FirstColumn),
ReadbackBandOrigin(y, band.FirstRow), 0,
static_cast<Uint32>(band.Columns),
static_cast<Uint32>(band.Rows), 1};
info.Format = static_cast<Uint32>(format);
info.Type = static_cast<Uint32>(type);
info.Target = 0;
info.Level = 0;
info.DstOffset = 0;
info.DstSize = bandBytes;
return info;
};
// P9 (W1, CONTRACT-P9.md §1): A PACK BUFFER IS ANSWERED BY NOTHING. Each band crosses
// as read_pixels_to_buffer naming the buffer and the band's place in it - the
// layout above, per band - and the client neither waits nor copies: the server lands
// the rows, and the mark (taken first, like every producer row's) is what sends the
// next CPU read of the buffer through resource_readback. The bands are the reply
// form's for the SERVER's sake, not the wire's: the server reads each one into its
// scratch before landing it, and the reply cap is the bound it already enforces on
// that scratch (PH-3). The monolith arm is untouched - it maps the driver PBO back
// inside its own ReadPixels, as it always has.
if (pbo) {
const MG_Pipe::MGPipeHandle target = PackBufferReadbackTarget(pbo, pboOffset + layout.End);
if (!MG_Pipe::MGPipeHandleIsNull(target)) {
MarkReadPixelsPackBuffer();
const Uint32 swapGroup = ReadbackSwapGroup(type, pack);
ForEachReadbackBand(static_cast<Uint64>(width), static_cast<Uint64>(height), plan,
[&](const ReadbackBand& band) {
MG_Pipe::MGPReadbackToBuffer record{};
record.Src = bandInfo(band, TightReadbackBytes(static_cast<GLsizei>(band.Columns),
static_cast<GLsizei>(band.Rows),
format, type));
record.Dst = target;
record.DstBase = pboOffset + layout.Start + band.FirstRow * layout.RowStride +
band.FirstColumn * bytesPerPixel;
record.RowStride = layout.RowStride;
record.ImageStride = 0;
record.SwapGroup = swapGroup;
session.EmitAndWait(MG_Pipe::MGPWireOp::ReadPixelsToBuffer, &record,
sizeof(record), nullptr, 0, nullptr, 0, nullptr);
});
return;
}
}
// THE COMMON CASE KEEPS THE ZERO-COPY. A neutral pack state means the destination
// layout IS the tight layout, so each band's reply lands straight in the
// application's buffer at the band's tight offset (whole-width bands and single-row
// pieces are both contiguous there). It is a fast path for the SAME bytes, not a
// second rule: ScatterReadbackBandIntoPackState is a memcpy of the band in exactly
// this case, and the control drives that function.
const Bool direct = !pbo && ReadbackPackStateIsTight(width, bytesPerPixel, pack);
// The bounce is the price of the application having asked for a layout. It is ONE
// band - at most a reply slot - rather than the whole read, and it is freed before
// this returns: R-11's rule one level out, nothing here outlives the call.
Vector<Uint8> bounce;
Bool pboSynced = false;
ForEachReadbackBand(static_cast<Uint64>(width), static_cast<Uint64>(height), plan,
[&](const ReadbackBand& band) {
// ONE tight-size function for production AND the control (M3 / codex 10a): the
// number the server allocates and the number the test asserts come from the
// same body, per band now.
const Uint64 bandBytes = TightReadbackBytes(static_cast<GLsizei>(band.Columns),
static_cast<GLsizei>(band.Rows),
format, type);
MG_Pipe::MGPReadbackInfo info = bandInfo(band, bandBytes);
// CHECKED BEFORE THE EMISSION, not after the answer (ID-47), through S1's
// helper, for every record. The plan makes it true by construction; it stays
// because it is the one check that names the read at the call site if the plan
// and the pool ever disagree, where the server's PH-3 refusal would only answer
// ERROR on the apply thread.
session.RequireReadPixelsReplyFits(static_cast<Uint32>(band.Columns),
static_cast<Uint32>(band.Rows),
static_cast<Uint32>(format),
static_cast<Uint32>(type), bandBytes);
Int32 status = 0;
Uint64 replySize = 0;
if (direct) {
Uint8* at = pixels == nullptr
? nullptr
: static_cast<Uint8*>(pixels) +
(band.FirstRow * static_cast<Uint64>(width) + band.FirstColumn) *
bytesPerPixel;
session.EmitAndWait(MG_Pipe::MGPWireOp::ReadPixels, &info, sizeof(info),
nullptr, 0, at, bandBytes, &status, &replySize);
// M2 / codex 11: an OK reply that arrived short, or a DECLINE/ERROR, must not
// be handed back as pixels. The Fatal aborts before the application reads the
// buffer, so the bytes EmitAndWait already copied are never observed.
if (!RequireReadbackReplyComplete(status, replySize, bandBytes)) return;
ApplyReadbackByteSwap(at, bandBytes, type, pack);
return;
}
if (bounce.size() < bandBytes) bounce.resize(static_cast<SizeT>(bandBytes));
session.EmitAndWait(MG_Pipe::MGPWireOp::ReadPixels, &info, sizeof(info), nullptr,
0, bounce.data(), bandBytes, &status, &replySize);
// BEFORE THE SCATTER, so a short or non-OK reply never reaches the application's
// pointer at all (the bounce is the only thing that held the partial bytes).
if (!RequireReadbackReplyComplete(status, replySize, bandBytes)) return;
ApplyReadbackByteSwap(bounce.data(), bandBytes, type, pack);
if (pbo) {
// pixels is an offset, never a host pointer. Upload only the requested
// rows so PACK padding and untouched bytes survive; the offsets are the
// overflow-checked layout's, the same numbers the range check accepted.
if (!pboSynced) {
pbo->SyncGpuWrites();
pboSynced = true;
}
const Uint64 bandRowBytes = band.Columns * bytesPerPixel;
for (Uint64 row = 0; row < band.Rows; ++row) {
pbo->UploadSubData({bounce.data() + row * bandRowBytes,
static_cast<SizeT>(bandRowBytes)},
pboOffset + layout.Start +
(band.FirstRow + row) * layout.RowStride +
band.FirstColumn * bytesPerPixel);
}
return;
}
ScatterReadbackBandIntoPackState(bounce.data(), pixels, width, band, bytesPerPixel,
pack);
});
}
void EmitPresent() {
ClientSession& session = RequireSession("Present");
BeforeReadOnlyVerb();
// ---- R-10's and R-9's readings, published BEFORE the present record ------------
//
// THE FRAME BOUNDARY IS THE RIGHT PLACE and the per-record path is the wrong one:
// the encoder keeps all five as run totals, so this is five relaxed stores per
// frame rather than five per record. Guarded by Enabled() like every other counting
// site in the tree, so the cost with MOBILEGL_PIPE_STATS unset is a global load and
// a predicted branch.
//
// AND IT IS BEFORE THE EmitAndWait BELOW, WHICH IS NOT A DETAIL. PipeStats::OnPresent
// is called by the SERVER's Present - i.e. from inside the apply of the very record
// this function is about to emit - so a publish placed after it lands one frame
// late, and the FIRST summary line of every run then reads `maxrec=0 maxcap=0`.
// Measured that way once: a zero that means "not published yet" is printed in the
// same shape as a zero that means "nothing crossed", and the second one is a real
// defect (an emit table that fell through to the driver). The Present record is 24
// bytes and cannot be the maximum, so nothing is lost by reading one record early.
if (MG_Util::PipeStats::Enabled()) {
const Wire::PipeWireEncoder& encoder = session.Encoder();
using MG_Util::PipeStats::Gauge;
MG_Util::PipeStats::PublishGauge(Gauge::MaxRecordBytes, encoder.MaxRecordBytesSeen());
MG_Util::PipeStats::PublishGauge(Gauge::MaxRecordBytesCap, encoder.MaxRecordBytesCap());
MG_Util::PipeStats::PublishGauge(Gauge::RingWraps, encoder.CmdWraps());
MG_Util::PipeStats::PublishGauge(Gauge::RingWrapPads, encoder.CmdWrapPads());
MG_Util::PipeStats::PublishGauge(Gauge::RingWaits, encoder.StageReclaimWaits());
// P5d round 3's wait ledger, CLIENT HALF, and it rides this frame boundary for
// the same two reasons the five above it do: the producer keeps both as run
// totals, so it is two relaxed stores per frame rather than two per wait, and
// publishing before the present record means the first summary line of a run
// carries real numbers instead of two zeroes that mean "not published yet".
// The SERVER half is published by the apply thread from its own loop - rule E
// does not let this thread read ServerLoop's counters.
const Transport::SessionProducer& producer = session.Producer();
MG_Util::PipeStats::PublishGauge(Gauge::ClientWaits, producer.Waits());
MG_Util::PipeStats::PublishGauge(Gauge::ClientParks, producer.Parks());
// AND THE ROW, WHENEVER THE MAXIMUM MOVES. The summary line can carry the
// number but not the name - MG_Util is below MG_Remote and has no WireOpName -
// and the name is the actionable half: R-10 makes the integrator choose between
// a cut for that row and a bigger ring, and that is a decision about a record
// FAMILY. ClientSession::Stop prints the same pair at teardown, but a trace
// replay never reaches it (measured: the OpenRA lane's library log ends mid-run
// with no teardown line at all), so a stats-enabled run would otherwise publish
// a size with no row. Emitted only when the maximum actually grows, so it is
// bounded by the number of distinct maxima - five or six in a whole replay.
if (encoder.MaxRecordBytesSeen() > g_publishedMaxRecordBytes) {
g_publishedMaxRecordBytes = encoder.MaxRecordBytesSeen();
MGLOG_I("MGPipe: wire ledger: new maximum record - maxrec=%llu "
"maxrecop=%s cap=%llu (R-10's proof obligation; blobs are cut, a record is not)",
static_cast<unsigned long long>(g_publishedMaxRecordBytes),
encoder.MaxRecordOpName(),
static_cast<unsigned long long>(encoder.MaxRecordBytesCap()));
}
}
MG_Pipe::MGPPresent record{};
// P5e (ra, CONTRACT-P5E §1, §2.4). FrameSerial USED TO BE 0 - "the server stamps
// its own" - and that was honest while nothing paced on it. It is now minted here,
// 1-based, by AcquirePresentCredit, which also PAYS the credit: if this client
// already has MOBILEGL_IPC_PRESENT_CREDIT presents in flight it parks until the
// server's OnPresent returns one, and only then does it mint.
//
// THE CREDIT WAIT IS BEFORE THE ENCODE, WHICH IS NOT A DETAIL: EmitAndWait
// reserves SEG_CMD bytes as its first act, so a client that encoded and then
// parked would hold a ring reservation across a whole frame of server time. It
// also drains SEG_EVENT on its way out, like every other wait (§2.6).
//
// With run-ahead disarmed this is a counter and nothing else, and the record below
// travels exactly as it did - the present row's own barrier is the pacing there.
record.FrameSerial = session.AcquirePresentCredit();
record.DamageCount = session.TakePendingPresentDamage(record.Damage);
session.EmitAndWait(MG_Pipe::MGPWireOp::Present, &record, sizeof(record), nullptr, 0,
nullptr, 0, nullptr);
// R-12's invalidation edge, drained at the one boundary every target crosses. A
// second CapsSnapshot IS the invalidation; nothing else on the client can see that
// the server re-ran InitCapabilities, because GLContext::GetCompileEnv()'s memo is
// keyed on pActiveBackendObject.get() (Core.cpp:34) and that pointer never changes
// under split.
session.PumpControlPlane();
++g_presentOrdinal;
LogE2ControlLine(g_presentOrdinal);
}
// =============================================================================
// CLASS B - P5b package i1: image bind, compute, barriers, copy-image, SSBO block
// (MG_Remote/CONTRACT-P5B.md §2 i1). Seven slots, five wire rows.
// =============================================================================
//
// RULE D, WHICH IS WHY THESE ARE SHORT. A P5b verb crosses AS THE CALL: the record
// carries the GL arguments verbatim - the enums as tokens, the GL names the backend
// keys on - beside the handle the P7/P8 form will dispatch on instead, and the server's
// ServerVerbSink reproduces the backend call the monolith makes. The backend keeps
// reading the frontend state it reads today through the BARRIER-PULLED fields of its
// verb class, which the record's own verb stamp is what makes legal. So a migration is
// one emitter here plus one sink body there, and nothing in the backend moves.
//
// THE HANDLES ARE LOOKED UP, NEVER MINTED, and that is a ruling (i1-v1 §4). The sinks
// below dispatch on the GL NAME - that is the whole point of carrying it - so a handle
// is carried for P7's sake only. FindByLifetimeId answers the handle the resource
// subsystem has already published for this object and kMGPipeNullHandle when it has
// published none; Acquire would MINT one here instead, at a call site that emits no
// create record, and the server would then be handed an identity it has never seen.
// A null Res/Src/Dst/ShaderCso therefore means "no handle published yet", which is a
// true statement, rather than a slot nobody allocated.
MG_Pipe::MGPipeHandle PublishedTextureHandle(
const SharedPtr<MG_State::GLState::ITextureObject>& texture) {
if (!texture) return MG_Pipe::kMGPipeNullHandle;
return MG_Pipe::MGPipeSlots().FindByLifetimeId(MG_Pipe::MGPipeKind::Texture,
texture->GetLifetimeId());
}
// glBindImageTexture. Emitted AT THE CALL, after the frontend has written the unit's
// ImageTextureBinding and MGP_FILL(BindImageTexture) has run - the record's verb
// boundary is what makes the server's read of that binding legal. set_shader_images
// (the draw-prep set) still travels at the next validate, untouched: that record
// describes a resolved unit for the draw, this one reproduces a call.
//
// NO PRE-VERB HOOK, AND THAT IS DELIBERATE. b1's two hooks describe "the work the
// record is ABOUT TO START" - PushPersistentMapsBeforeVerb publishes bytes an
// application wrote through a coherent map, MarkGpuWrites* builds the GPU-write set.
// A bind starts no shader and reads no buffer; the dispatch that later reads this image
// is the verb that carries both hooks, and running them here as well would push the
// same maps twice per dispatch and inflate b1's per-row counters.
void EmitBindImageTexture(GLuint unit, GLuint texture, GLint level, GLboolean layered,
GLint layer, GLenum access, GLenum format) {
ClientSession& session = RequireSession("BindImageTexture");
MG_Pipe::MGPImageBind record{};
// The unit's binding is the frontend's and has just been written by the caller, so
// the texture this record names is the one the server's SyncImageTextureBinding
// will pull for the same unit. Read from MG_State::pGLContext and NOT through
// MGB_CTX: on this side of a split MGB_CTX is gPipeInputs, which is the SERVER's
// view, and the client asking it a question is how the two halves come to disagree.
if (MG_State::pGLContext != nullptr) {
record.Res = PublishedTextureHandle(
MG_State::pGLContext->GetImageTextureBinding(static_cast<Int>(unit)).Texture);
}
record.Unit = static_cast<Uint32>(unit);
// The GL name the application passed, verbatim - what the ES slot is handed as
// `texture` and currently ignores. Never an identity (ARCHITECTURE 4.2.1).
record.GlName = static_cast<Uint32>(texture);
record.Level = static_cast<Int32>(level);
record.Layer = static_cast<Int32>(layer);
// THE GL ACCESS TOKEN, not MGPImageView::Access's three-value encoding (table 0's
// MGPImageBind::Access row). Two records, two jobs.
record.Access = static_cast<Uint32>(access);
record.Format = static_cast<Uint32>(format);
record.Layered = layered != GL_FALSE ? 1 : 0;
session.EmitAndWait(MG_Pipe::MGPWireOp::BindShaderImage, &record, sizeof(record),
nullptr, 0, nullptr, 0, nullptr);
}
// glDispatchCompute. THE HOOK ORDER IS b1's AND IS INHERITED FROM THE CLASS-C STUB
// VERBATIM: push the persistent maps (they produce resource_subdata records that must
// precede the verb on SEG_CMD), then the dispatch mark walk, then the record. The stub
// carried both calls before its Fatal precisely so that the package which flipped this
// slot would inherit a call site that was already correct.
void EmitDispatchCompute(GLuint numGroupsX, GLuint numGroupsY, GLuint numGroupsZ) {
ClientSession& session = RequireSession("DispatchCompute");
PersistentMapTracker::Instance().PushDrawConsumers();
MarkGpuWritesForDispatch();
MG_Pipe::MGPGridInfo record{};
record.GridX = static_cast<Uint32>(numGroupsX);
record.GridY = static_cast<Uint32>(numGroupsY);
record.GridZ = static_cast<Uint32>(numGroupsZ);
// Block* STAY 0 IN P5b (contract i1): the local size is a link artifact the backend
// reads from its own program, and a client-minted copy would be a second statement
// of it. P7's Magma may fill it from the reflection archive.
record.IndirectBuffer = MG_Pipe::kMGPipeNullHandle;
record.IndirectOffset = 0;
record.IsIndirect = 0;
session.EmitAndWait(MG_Pipe::MGPWireOp::LaunchGrid, &record, sizeof(record), nullptr, 0,
nullptr, 0, nullptr);
}
void EmitDispatchComputeIndirect(GLintptr indirect) {
ClientSession& session = RequireSession("DispatchComputeIndirect");
PersistentMapTracker::Instance().PushDrawConsumers();
MarkGpuWritesForDispatch();
MG_Pipe::MGPGridInfo record{};
// The counts come from the GL_DISPATCH_INDIRECT_BUFFER, so the three grid fields are
// 0 and IsIndirect is what says so; the sink dispatches on it and calls
// glDispatchComputeIndirect with the offset the application spelled.
record.IsIndirect = 1;
record.IndirectOffset = static_cast<Uint64>(indirect);
record.IndirectBuffer = MG_Pipe::kMGPipeNullHandle;
if (MG_State::pGLContext != nullptr) {
const auto& bound =
MG_State::pGLContext
->GetBufferBindingSlot(::MobileGL::BufferTarget::DispatchIndirect)
.GetBoundObject();
if (bound) {
record.IndirectBuffer = MG_Pipe::MGPipeSlots().FindByLifetimeId(
MG_Pipe::MGPipeKind::Buffer, bound->GetLifetimeId());
}
}
session.EmitAndWait(MG_Pipe::MGPWireOp::LaunchGrid, &record, sizeof(record), nullptr, 0,
nullptr, 0, nullptr);
}
// glMemoryBarrier / glMemoryBarrierByRegion. The bits cross VERBATIM: the frontend has
// already validated them and already folds glTextureBarrier onto the same field
// (GL_Drawing.cpp:920-937), and Espryt's atomic-counter lowering - the counter bit
// implying the storage bit - stays inside the backend where the reason for it lives
// (DirectGLES.cpp:8837). A client that pre-lowered would be answering a driver question
// from the wrong side and the two arms would stop being byte-identical.
//
// No pre-verb hook: a barrier orders memory the GPU already holds. It starts no shader
// and reads no mapped buffer.
void EmitMemoryBarrier(GLbitfield barriers) {
ClientSession& session = RequireSession("MemoryBarrier");
MG_Pipe::MGPMemoryBarrier record{};
record.Bits = static_cast<Uint32>(barriers);
record.ByRegion = 0;
session.EmitAndWait(MG_Pipe::MGPWireOp::MemoryBarrier, &record, sizeof(record), nullptr,
0, nullptr, 0, nullptr);
}
void EmitMemoryBarrierByRegion(GLbitfield barriers) {
ClientSession& session = RequireSession("MemoryBarrierByRegion");
MG_Pipe::MGPMemoryBarrier record{};
record.Bits = static_cast<Uint32>(barriers);
record.ByRegion = 1;
session.EmitAndWait(MG_Pipe::MGPWireOp::MemoryBarrier, &record, sizeof(record), nullptr,
0, nullptr, 0, nullptr);
}
// glCopyImageSubData -> resource_copy_region (53), which P5b rules is glCopyImageSubData
// ONLY (contract §6.4; the framebuffer-sourced copies are f1's row 76).
void EmitCopyImageSubData(const MG_Backend::CopyImageEndpoint& src, GLenum srcTarget,
GLint srcLevel, GLint srcX, GLint srcY, GLint srcZ,
const MG_Backend::CopyImageEndpoint& dst, GLenum dstTarget,
GLint dstLevel, GLint dstX, GLint dstY, GLint dstZ,
GLsizei srcWidth, GLsizei srcHeight, GLsizei srcDepth) {
ClientSession& session = RequireSession("CopyImageSubData");
// The GL target selects the texture or renderbuffer handle namespace.
MG_Pipe::MGPCopyRegion record{};
const auto handle = [](const MG_Backend::CopyImageEndpoint& endpoint) {
return endpoint.IsRenderbuffer()
? MG_Pipe::MGPipeSlots().FindByLifetimeId(MG_Pipe::MGPipeKind::Renderbuffer,
endpoint.Renderbuffer->GetLifetimeId())
: PublishedTextureHandle(endpoint.Texture);
};
record.Src = handle(src);
record.Dst = handle(dst);
// GL names remain diagnostic only; backend identity comes from handles.
record.SrcGlName =
src.IsRenderbuffer() ? src.Renderbuffer->GetExternalIndex() : src.Texture->GetExternalIndex();
record.DstGlName =
dst.IsRenderbuffer() ? dst.Renderbuffer->GetExternalIndex() : dst.Texture->GetExternalIndex();
// The GL targets verbatim, in a Uint16 - every GL texture target fits one. NOT
// MGPipeResourceTarget: the sink only ever forwards these to a slot that takes GL
// enums, and the tree has no resource-target -> GL-enum inverse to spend on them.
record.SrcTarget = static_cast<Uint16>(srcTarget);
record.DstTarget = static_cast<Uint16>(dstTarget);
record.SrcLevel = static_cast<Uint16>(srcLevel);
record.DstLevel = static_cast<Uint16>(dstLevel);
// SrcBox is {srcX, srcY, srcZ, w, h, d}: the source origin AND the extent, which is
// one extent for both endpoints (GL spells the copy's size once).
record.SrcBox = MG_Pipe::MGPBox{srcX, srcY, srcZ, static_cast<Uint32>(srcWidth),
static_cast<Uint32>(srcHeight),
static_cast<Uint32>(srcDepth)};
record.DstX = dstX;
record.DstY = dstY;
record.DstZ = dstZ;
session.EmitAndWait(MG_Pipe::MGPWireOp::ResourceCopyRegion, &record, sizeof(record),
nullptr, 0, nullptr, 0, nullptr);
}
// glShaderStorageBlockBinding -> set_storage_block_binding (75), the ONE content-carrying
// row P5b adds. The block is NAMED, not indexed, because the application's index is the
// frontend interface-query enumeration's and no backend shares that index space
// (BackendObject.h:216-221) - the name is the one coordinate all three agree on.
void EmitShaderStorageBlockBinding(GLuint program, const GLchar* storageBlockName,
GLuint storageBlockBinding) {
ClientSession& session = RequireSession("ShaderStorageBlockBinding");
// The backend slot's own first line (DirectGLES.cpp:9201), kept here so a null name
// never becomes a zero-size blob - which rule A forbids spelling at all.
if (storageBlockName == nullptr) return;
BeforeReadOnlyVerb();
MG_Pipe::MGPStorageBlockBinding record{};
record.GlName = static_cast<Uint32>(program);
record.Binding = static_cast<Uint32>(storageBlockBinding);
record.ShaderCso = MG_Pipe::kMGPipeNullHandle;
if (MG_State::pGLContext != nullptr) {
const auto& programObject = MG_State::pGLContext->GetProgramObject(program);
if (programObject) {
// The application may rebind a stage program before it is
// current or attached to a pipeline. A minted slot alone does
// not publish its archive; this verb must follow that birth.
programObject->JoinLinkAndSpirv();
Uint64 bytes = 0;
auto& emitter = MG_Pipe::MGPipeProgramEmitterInstance();
record.ShaderCso = emitter.AcquireShaderCso(*programObject, bytes);
emitter.EmitProgramBindings(*programObject, record.ShaderCso);
}
}
// Size = strlen + 1: THE NUL TRAVELS (contract table 0's block-name row). The
// decoder re-terminates into a bounded local and refuses a run whose last byte is
// not NUL, so the two sides agree on where the name ends.
const Uint64 nameBytes = static_cast<Uint64>(std::strlen(storageBlockName)) + 1ull;
record.Name = session.Encoder().StageBytes(storageBlockName, nameBytes);
session.EmitAndWait(MG_Pipe::MGPWireOp::SetStorageBlockBinding, &record, sizeof(record),
nullptr, 0, nullptr, 0, nullptr);
}
// CLASS B - P5b package t2: the transform-feedback spans, the XFB object bind and the
// tessellation patch parameter (MG_Remote/CONTRACT-P5B.md §2 t2).
// =============================================================================
//
// SIX SLOTS, SIX ROWS, AND NOT ONE OF THEM STARTS A SHADER. Every one of the six is a
// control call - it opens, closes, pauses, resumes or re-targets a capture span, or sets
// the patch size the next tessellation draw uses - so each takes BeforeReadOnlyVerb(),
// which is CONTRACT-P5B.md §4's rule for "a verb that reads buffers but starts no
// shader" naming the XFB and patch controls by hand. The GPU-WRITE MARK FOR THE CAPTURE
// TARGETS IS NOT TAKEN HERE and that is deliberate: it belongs at the END of the span,
// after the record and before GLContext::EndTransformFeedback clears the live bindings,
// which is exactly where b1 already put it (GL_Drawing.cpp's
// MarkEndTransformFeedbackCaptureTargets). Taking it here as well would mark the same
// buffers twice and taking it INSTEAD of there would mark nothing.
//
// P5f fe extends Begin with the immutable capture snapshot: program CSO handle,
// XFB object lifetime id, and four buffer handle/range pairs. Buffer resource records
// precede this verb through BeforeReadOnlyVerb; AcquireShaderCso below publishes the
// program archive before Begin. Deferred driver Begin and End therefore need no
// frontend program or binding-point lookup. set_stream_output_targets stays unused:
// this state changes at the capture-span boundary, so it rides Begin itself.
void EmitBeginTransformFeedback(GLenum primitiveMode) {
ClientSession& session = RequireSession("BeginTransformFeedback");
BeforeReadOnlyVerb();
MG_Pipe::MGPStreamOutputBegin record{};
// The GL token verbatim (contract table 0's "GL enums on the wire"): the sink hands
// it to the backend slot that takes it, and nothing between here and there reads it.
record.PrimitiveMode = static_cast<Uint32>(primitiveMode);
auto& context = *MG_State::pGLContext;
record.LifetimeId = context.GetBoundTransformFeedbackLifetimeId();
const auto& program = context.GetTransformFeedbackProgram();
if (program) {
Uint64 bytes = 0;
record.CaptureProgram = MG_Pipe::MGPipeProgramEmitterInstance().AcquireShaderCso(*program, bytes);
}
static_assert(MG_State::GLState::GLContext::MAX_TRANSFORM_FEEDBACK_BUFFERS == 4);
for (Uint i = 0; i < 4; ++i) {
const auto& point = context.GetBufferBindingPoint(BufferTarget::TransformFeedback, i);
const auto& buffer = point.GetBoundObject();
if (!buffer) continue;
const auto range = point.GetRange();
const SizeT start = std::min(range.start, buffer->GetSize());
const SizeT end = std::min(range.end, buffer->GetSize());
record.Targets[i] = {MG_Pipe::MGPipeResourceTrackerInstance().Find(*buffer), start,
end > start ? end - start : 0};
}
session.EmitAndWait(MG_Pipe::MGPWireOp::BeginStreamOutput, &record, sizeof(record),
nullptr, 0, nullptr, 0, nullptr);
}
void EmitEndTransformFeedback() {
ClientSession& session = RequireSession("EndTransformFeedback");
BeforeReadOnlyVerb();
MG_Pipe::MGPXfbAccounting record{};
// THE ACCOUNTING IS THE CLIENT'S OWN AND IT IS INFORMATIONAL ON THIS SIDE OF THE
// WIRE: end_stream_output's backend call takes no arguments, and the three numbers
// are what the frontend has counted over this span (CONTRACT-P5B.md §2 t2, the
// companions row). They travel because the row has carried them since P4a and
// because they are what a server-side scatter would need when P9 lands one; the
// sink today calls GL.EndTransformFeedback() and reads none of them. Read here,
// BEFORE GLContext::EndTransformFeedback resets the counters at the call site.
const auto& context = *MG_State::pGLContext;
record.CapturedVertices = context.GetTransformFeedbackCapturedVertices();
record.PrimitivesWritten = context.GetTransformFeedbackPrimitiveCounter();
record.PrimitiveMode = static_cast<Uint32>(context.GetTransformFeedbackPrimitiveMode());
session.EmitAndWait(MG_Pipe::MGPWireOp::EndStreamOutput, &record, sizeof(record),
nullptr, 0, nullptr, 0, nullptr);
}
void EmitPauseTransformFeedback() {
ClientSession& session = RequireSession("PauseTransformFeedback");
BeforeReadOnlyVerb();
// Reserved IS zero and the contract says so (MGPStreamOutputControl{Reserved = 0}).
// The row exists to BE the verb boundary - the stamp the server puts up before the
// sink runs - not to carry anything.
MG_Pipe::MGPStreamOutputControl record{};
record.Reserved = 0;
session.EmitAndWait(MG_Pipe::MGPWireOp::PauseStreamOutput, &record, sizeof(record),
nullptr, 0, nullptr, 0, nullptr);
}
void EmitResumeTransformFeedback() {
ClientSession& session = RequireSession("ResumeTransformFeedback");
BeforeReadOnlyVerb();
MG_Pipe::MGPStreamOutputControl record{};
record.Reserved = 0;
session.EmitAndWait(MG_Pipe::MGPWireOp::ResumeStreamOutput, &record, sizeof(record),
nullptr, 0, nullptr, 0, nullptr);
}
void EmitBindTransformFeedback(GLuint name) {
ClientSession& session = RequireSession("BindTransformFeedback");
BeforeReadOnlyVerb();
MG_Pipe::MGPStreamOutputBind record{};
// THE GL NAME IS NOT AN IDENTITY (ARCHITECTURE 4.2.1) and is carried anyway, because
// it is the key the backend has always used: Espryt indexes its driver objects by it
// (XfbImpl::g_xfbObjects[name], DirectGLES.cpp:1401) and generates the ES object on
// first bind. Name 0 is the default object, which is why the field is not a handle.
record.GlName = static_cast<Uint32>(name);
// Beside it, the identity that WILL dispatch: the frontend's per-object lifetime id,
// process-wide and never reused, which is what survives glGenTransformFeedbacks
// recycling a name. Read AFTER GLContext::BindTransformFeedbackObject at the call
// site, so it is the id of the object being bound and not of the previous one.
record.LifetimeId = MG_State::pGLContext->GetBoundTransformFeedbackLifetimeId();
session.EmitAndWait(MG_Pipe::MGPWireOp::BindStreamOutput, &record, sizeof(record),
nullptr, 0, nullptr, 0, nullptr);
}
void EmitPatchParameteri(GLenum pname, GLint value) {
ClientSession& session = RequireSession("PatchParameteri");
BeforeReadOnlyVerb();
MG_Pipe::MGPPatchParameter record{};
// GL_PATCH_VERTICES is the only pname that reaches a backend slot - the frontend
// answers GL_PATCH_DEFAULT_*_LEVEL itself and bakes those into the synthesized
// control stage - and the frontend has already rejected every other pname with
// INVALID_ENUM before this call (GL_Drawing.cpp's PatchParameteri). Carried verbatim
// so the sink reproduces the call rather than a reading of it.
record.Pname = static_cast<Uint32>(pname);
record.Value = static_cast<Int32>(value);
// set_patch_state (43) STILL TRAVELS, at the next validate, and that is not a
// duplicate: it is the applier's working-block copy, this is the driver push Espryt
// does AT THE CALL (DirectGLES.cpp:8760), and both pushes happen today on the
// monolith path too (CONTRACT-P5B.md §2 t2).
session.EmitAndWait(MG_Pipe::MGPWireOp::PatchParameter, &record, sizeof(record),
nullptr, 0, nullptr, 0, nullptr);
}
// =============================================================================
// CLASS A - answered locally from the caps mirror (R-15). NO RECORD, EVER.
// =============================================================================
void AnswerGetIntegeri_v(GLenum target, GLuint index, GLint* data) {
if (data == nullptr) return;
const MG_Backend::DynamicBackendParameters& dynamic = CapsMirrorInstance().Dynamic();
// The ONLY two indexed pnames the device owns; every other indexed pname names
// frontend state and is answered in GL_Getter::GetIntegeri_v before any table is
// consulted (BackendObject.h:196-205). The existing gate is
// AdvertisedLimitsScenario.ComputeWorkGroupLimitsAreTheCapsBlocksAnswer, which pins
// that this answer and the caps copy are ONE number.
switch (target) {
case GL_MAX_COMPUTE_WORK_GROUP_COUNT:
if (index < 3) *data = static_cast<GLint>(dynamic.MaxComputeWorkGroupCount[index]);
return;
case GL_MAX_COMPUTE_WORK_GROUP_SIZE:
if (index < 3) *data = static_cast<GLint>(dynamic.MaxComputeWorkGroupSize[index]);
return;
default:
// Not a Fatal: the slot's own contract is "whatever pname the frontend has no
// case for at all", and the monolith backends answer such a pname by leaving
// the driver's own default in place. Answering a wrong number would be worse
// than answering none.
MGLOG_W_ONCE("MG_Remote client: GetIntegeri_v(0x%04x, %u) is not one of the two "
"device-owned indexed pnames and has no caps-mirror answer",
static_cast<unsigned>(target), static_cast<unsigned>(index));
return;
}
}
Bool AnswerIsTimerQuerySupported() {
// A capability predicate, not a call. Today a null slot means COUNTER_BITS == 0
// (GL_Query.cpp:792) - which is precisely the null check R-4 forbids, so it moves
// here, to the bit the server published.
return CapsMirrorInstance().HasCap(MG_Pipe::kCapTimerQuery);
}
// =============================================================================
// The frontend sees a local opaque token; neither this address nor the driver's
// BackendSyncHandle is serialized. The Fence-kind slot allocator supplies wire identity.
struct RemoteFenceProxy {
MG_Pipe::MGPipeHandle Handle;
// P10: zero-timeout polls answered "not yet" in a row since the last escalation.
Uint32 Unanswered = 0;
};
std::mutex g_fenceMutex;
UnorderedMap<MG_Backend::BackendSyncHandle, UniquePtr<RemoteFenceProxy>> g_fenceProxies;
RemoteFenceProxy& FenceProxy(MG_Backend::BackendSyncHandle proxy) {
const auto it = g_fenceProxies.find(proxy);
if (it == g_fenceProxies.end())
Wire::WireProtocolFatal("Fence.proxy", "unknown client fence proxy");
return *it->second;
}
MG_Pipe::MGPipeHandle FenceHandle(MG_Backend::BackendSyncHandle proxy) { return FenceProxy(proxy).Handle; }
// ---- P10 (CONTRACT-P10.md §1): WHAT THE SERVER HAS SAID IS SIGNALED -----------------
//
// {slot -> gen} of every fence a kEventFenceSignaled named, or a round trip answered
// signaled. ITS OWN MUTEX, NOT g_fenceMutex: the report arrives in the event drain, and
// the drain runs INSIDE the emitters below while they hold g_fenceMutex (EmitAndWait and
// PollEntry both drain), so taking g_fenceMutex there would deadlock the GL thread on
// itself. A report for a fence already deleted leaves a {slot, old gen} entry that no live
// handle matches; the slot's next occupant overwrites it.
std::mutex g_signaledFenceMutex;
UnorderedMap<Uint32, Uint32> g_signaledFences;
std::atomic<Uint64> g_fenceLocalAnswers{0};
std::atomic<Uint64> g_fenceEscalations{0};
std::atomic<Uint64> g_fenceRoundTrips{0};
std::atomic<Uint64> g_fenceServerReports{0};
Bool FenceKnownSignaled(MG_Pipe::MGPipeHandle handle) {
const std::lock_guard<std::mutex> lock(g_signaledFenceMutex);
const auto it = g_signaledFences.find(handle.Slot);
return it != g_signaledFences.end() && it->second == handle.Gen;
}
void RememberFenceSignaled(MG_Pipe::MGPipeHandle handle) {
const std::lock_guard<std::mutex> lock(g_signaledFenceMutex);
g_signaledFences[handle.Slot] = handle.Gen;
}
void ForgetFence(MG_Pipe::MGPipeHandle handle) {
const std::lock_guard<std::mutex> lock(g_signaledFenceMutex);
const auto it = g_signaledFences.find(handle.Slot);
if (it != g_signaledFences.end() && it->second == handle.Gen) g_signaledFences.erase(it);
}
// MOBILEGL_IPC_POLL_ESCALATE=0 is the A/B control: every poll crosses, as before P10. A lost
// device takes the round-trip arm too, whose DECLINED answer is the no-op a dead fence gets.
Bool FencePollsAnswerLocally() {
return MG_Config::Ipc.PollEscalate != 0 && !ClientSession::DeviceLost();
}
// THE LOCAL ANSWER, OR "CROSS". A poll is a doorbell point first (PollEntry: flush what is
// published, drain the reverse channel), so the fence's own create record has reached the
// server and every report it has posted is in. Known signaled -> answered here. Not known
// and the call may not wait (a zero timeout, glGetSynciv) -> answered "not yet" here,
// unless this fence has had POLL_ESCALATE such answers in a row, in which case the poll
// takes one real round trip: the server's own reports are what make a local "not yet"
// eventually true, and the escalation is the bound that holds even if one is late. A call
// that may wait (a non-zero timeout) is never answered "not yet" here - it crosses and
// waits on the server, as the GL call asks.
enum class FencePollAnswer { Signaled, NotYet, Cross };
FencePollAnswer AnswerFencePollLocally(ClientSession& session, RemoteFenceProxy& fence, Bool mayWait) {
if (!FencePollsAnswerLocally()) return FencePollAnswer::Cross;
session.PollEntry();
if (FenceKnownSignaled(fence.Handle)) {
fence.Unanswered = 0;
g_fenceLocalAnswers.fetch_add(1, std::memory_order_relaxed);
return FencePollAnswer::Signaled;
}
if (mayWait) return FencePollAnswer::Cross;
if (++fence.Unanswered < MG_Config::Ipc.PollEscalate) {
g_fenceLocalAnswers.fetch_add(1, std::memory_order_relaxed);
return FencePollAnswer::NotYet;
}
fence.Unanswered = 0;
g_fenceEscalations.fetch_add(1, std::memory_order_relaxed);
return FencePollAnswer::Cross;
}
MG_Backend::BackendSyncHandle EmitFenceSync() {
ClientSession& session = RequireSession("FenceSync");
const std::lock_guard<std::mutex> lock(g_fenceMutex);
BeforeReadOnlyVerb();
auto proxy = MakeUnique<RemoteFenceProxy>();
proxy->Handle = MG_Pipe::MGPipeSlots().Allocate(MG_Pipe::MGPipeKind::Fence);
const MG_Pipe::MGPHandleOnly desc{proxy->Handle, static_cast<Uint32>(MG_Pipe::MGPipeKind::Fence), 0};
session.EmitAndWait(MG_Pipe::MGPWireOp::FenceCreate, &desc, sizeof(desc),
nullptr, 0, nullptr, 0, nullptr);
auto* local = proxy.get();
g_fenceProxies.emplace(local, std::move(proxy));
return local;
}
Uint32 ReadFenceReply(ClientSession& session, MG_Pipe::MGPWireOp op,
const void* payload, Uint64 bytes) {
Uint32 result = 0;
Int32 status = Wire::ReplySink::kStatusError;
Uint64 replyBytes = 0;
session.EmitAndWait(op, payload, bytes, nullptr, 0, &result, sizeof(result),
&status, &replyBytes);
// A DECLINED SYNC REPLY IS AN ANSWER, NOT A CORRUPTION (P12). ReplySink opens the
// three-value space with "DECLINED IS A REAL ANSWER, not a failure"
// (PipeWireCodec.h:457-460) and the escape rows are held to it the other way round -
// "ERROR IS NOT A DECLINE", an escape may not fold 2 into false
// (WireTables.cpp:446-450). This site folded 1 AND 2 into one abort.
//
// BOTH VALUES OF 1 ARE REACHABLE WITHOUT A BYTE OF CORRUPTION:
// - the SERVER declines these two rows by design whenever it cannot answer them -
// PostReply(op, seq, ok ? kStatusOk : kStatusDeclined, ok ? &result : nullptr,
// ok ? sizeof(result) : 0) at PipeWireCodec.cpp:1820-1830, which is a legitimate
// zero-length answer to a kWaitReply row (R-5);
// - the CLIENT produces the same status itself once the session stops carrying
// records: the device-lost latch (ClientSession.cpp:1837) and a doorbell that died
// during teardown (ClientSession.cpp:2025, where the comment says outright that
// "the verb did not happen" is reported as DECLINED and not as ERROR).
//
// AND THE NO-OP IS THE ONE THIS FRONTEND ALREADY GIVES for a fence it cannot wait on:
// GL_Sync.cpp:103-106 answers GL_ALREADY_SIGNALED for a sync with no backend handle,
// PipeApplier.cpp:175-177 answers GL_ALREADY_SIGNALED for a fence with no native
// object (a fence that provably did no work), and DirectGLES.cpp:16489 does the same
// for an absent sync. A lost device is that same class of fact.
//
// WHAT ABORTING HERE COSTS, MEASURED: after a clean device loss Minecraft 26.2's next
// glClientWaitSync - the chunk-upload fences - reached this line with DECLINED and died
// of Fatal{ProtocolCorruption, "Fence.reply"}, rc=134, instead of the no-op the design
// promises ("GL calls become no-ops", design/08-runtime-and-platform.md:33).
if (status == Wire::ReplySink::kStatusDeclined) {
MGLOG_E_ONCE("MG_Remote client: the peer DECLINED a %s reply - the verb did not "
"happen (a lost device, or a teardown); answering the no-op the "
"frontend uses for a fence it cannot wait on",
Wire::WireOpName(op));
return op == MG_Pipe::MGPWireOp::FenceWait ? static_cast<Uint32>(GL_ALREADY_SIGNALED)
: 1u;
}
// ERROR AND A SHORT OK ARE STILL THE PROTOCOL CORRUPTIONS THEY ALWAYS WERE: a
// transport fault is not the server saying no, and an OK answer that arrived empty is
// a reply nobody can read.
if (status != Wire::ReplySink::kStatusOk || replyBytes != sizeof(result))
Wire::WireProtocolFatal("Fence.reply", "missing or malformed sync result");
return result;
}
GLenum EmitClientWaitSync(MG_Backend::BackendSyncHandle proxy, GLbitfield flags, GLuint64 timeout) {
ClientSession& session = RequireSession("ClientWaitSync");
const std::lock_guard<std::mutex> lock(g_fenceMutex);
RemoteFenceProxy& fence = FenceProxy(proxy);
switch (AnswerFencePollLocally(session, fence, /*mayWait=*/timeout != 0)) {
case FencePollAnswer::Signaled: return GL_ALREADY_SIGNALED;
case FencePollAnswer::NotYet: return GL_TIMEOUT_EXPIRED;
case FencePollAnswer::Cross: break;
}
g_fenceRoundTrips.fetch_add(1, std::memory_order_relaxed);
const MG_Pipe::MGPFenceWait request{fence.Handle, timeout, flags, 0};
const Uint32 result = ReadFenceReply(session, MG_Pipe::MGPWireOp::FenceWait, &request, sizeof(request));
if (result == GL_ALREADY_SIGNALED || result == GL_CONDITION_SATISFIED) RememberFenceSignaled(fence.Handle);
return result;
}
Bool EmitGetSyncStatus(MG_Backend::BackendSyncHandle proxy) {
ClientSession& session = RequireSession("GetSyncStatus");
const std::lock_guard<std::mutex> lock(g_fenceMutex);
RemoteFenceProxy& fence = FenceProxy(proxy);
switch (AnswerFencePollLocally(session, fence, /*mayWait=*/false)) {
case FencePollAnswer::Signaled: return true;
case FencePollAnswer::NotYet: return false;
case FencePollAnswer::Cross: break;
}
g_fenceRoundTrips.fetch_add(1, std::memory_order_relaxed);
const MG_Pipe::MGPHandleOnly desc{fence.Handle, static_cast<Uint32>(MG_Pipe::MGPipeKind::Fence), 0};
const Uint32 result = ReadFenceReply(session, MG_Pipe::MGPWireOp::FenceStatus, &desc, sizeof(desc));
if (result > 1) Wire::WireProtocolFatal("FenceStatus.reply", "status must be boolean");
if (result != 0) RememberFenceSignaled(fence.Handle);
return result != 0;
}
void EmitWaitSync(MG_Backend::BackendSyncHandle proxy, GLbitfield flags, GLuint64 timeout) {
ClientSession& session = RequireSession("WaitSync");
const std::lock_guard<std::mutex> lock(g_fenceMutex);
const MG_Pipe::MGPFenceWait request{FenceHandle(proxy), timeout, flags, 0};
session.EmitAndWait(MG_Pipe::MGPWireOp::FenceWaitServer, &request, sizeof(request),
nullptr, 0, nullptr, 0, nullptr);
}
void EmitDeleteSync(MG_Backend::BackendSyncHandle proxy) {
const std::lock_guard<std::mutex> lock(g_fenceMutex);
const auto handle = FenceHandle(proxy);
// MobileGL::Destroy stops the server BEFORE DestroyAllSyncObjects. Detach already
// released those native objects on the apply thread; only the local proxy remains.
if (auto* session = ClientSession::Active(); session != nullptr && session->Started()) {
const MG_Pipe::MGPHandleOnly desc{handle, static_cast<Uint32>(MG_Pipe::MGPipeKind::Fence), 0};
session->EmitAndWait(MG_Pipe::MGPWireOp::FenceDestroy, &desc, sizeof(desc),
nullptr, 0, nullptr, 0, nullptr);
}
MG_Pipe::MGPipeSlots().Free(MG_Pipe::MGPipeKind::Fence, handle);
ForgetFence(handle);
g_fenceProxies.erase(proxy);
}
#include "QueryEmit.inc"
// CLASS C - each remaining slot names its first blocker.
// =============================================================================
//
// PARTITIONED BY THE P5b PACKAGE THAT OWNS THE FLIP (MG_Remote/CONTRACT-P5B.md,
// ~/w7/notes/p5b/BRIEF-P5B.md), so that four packages migrating in parallel edit four
// DISJOINT lists and four DISJOINT counts rather than one list and one number. To flip a
// slot a package (1) removes its X row from ITS list, (2) assigns the real emitter in
// BuildRemoteEmitTable's class-B block, (3) raises ITS kEmittedSlots* by one. The
// per-package ownership assertions below then still hold, the totals stay arithmetic,
// and a slot that changes class without changing the arithmetic is a build break. The
// X-macro shape is kept so the DEFINITION and the ASSIGNMENT cannot drift apart. Three
// slots carried a body the macro cannot (DispatchCompute, DispatchComputeIndirect,
// SetSwapInterval) and were written out by hand below; all three are class B now.
//
// d1 indexed / instanced / multi-draw / indirect draws -> draw_vbo (59), its
// kDrawIsIndirect tail and its kDrawHasUserIndices span
// i1 image bind, compute, barriers, copy-image, storage block -> bind_shader_image
// (72), launch_grid (60), memory_barrier (61), resource_copy_region (53),
// set_storage_block_binding (75)
// t2 the XFB spans and object bind, the patch parameter -> begin/end/pause/resume_
// stream_output (62..65), bind_stream_output (74), patch_parameter (73)
// f1 the clear family, the framebuffer-sourced copies, mips -> clear (57),
// copy_framebuffer_to_texture (76), generate_mipmap (54)
// tail the wave-3 remainder nothing measured: queries, syncs, the texture readbacks,
// the DSA blit, the swap interval (census-classC.md "static cross")
// d1 v1 flipped all nineteen (DrawElements, DrawElementsBaseVertex, MultiDrawArrays,
// MultiDrawElements, MultiDrawElementsBaseVertex, MultiDrawElementsIndirect,
// MultiDrawArraysIndirect, MultiDrawElementsIndirectCount, MultiDrawArraysIndirectCount,
// DrawRangeElementsBaseVertex, DrawRangeElements, the four DrawElementsInstanced*,
// DrawArraysInstancedBaseInstance, DrawArraysInstanced, DrawElementsIndirect,
// DrawArraysIndirect) to class B; the list is kept, empty, so the ownership assertion
// below still reads 0 + 19 = 19 and a slot that fell back in would have to be added here.
#define MGR_UNMIGRATED_D1_SLOTS(X)
// i1 HAS LANDED: the list is EMPTY and all seven slots are class B (the five emitters
// above plus the two compute ones). It is kept as an empty macro rather than deleted so
// that MGR_UNMIGRATED_GL_SLOTS' union, kUnmigratedI1's arithmetic and the ownership
// static_assert below all keep their shape - and so the next package to need a row here
// (a P5b wave-3 image/compute slot) has the partition to put it in.
#define MGR_UNMIGRATED_I1_SLOTS(X)
// t2 LANDED (CONTRACT-P5B.md §2 t2): the three measured slots - BeginTransformFeedback
// (95 lane entries), PatchParameteri (43), BindTransformFeedback (2) - and the three
// companions that share their rows are class B now and live in the block above.
// DeleteTransformFeedback is the one that stays: it has NO ROW in P5b, by ruling and
// not by omission (unmeasured; the driver object leaks on the server until P9's XFB
// namespace work, and a bind of name 0 is what the backend does on delete of the bound
// one, DirectGLES.cpp:1422). It therefore still aborts by its own name.
#define MGR_UNMIGRATED_T2_SLOTS(X)
#define MGR_UNMIGRATED_F1_SLOTS(X)
// The wave-3 tail. Empty since P10 B retired SetSwapInterval (it was not a GL.* slot and
// was never a row here).
#define MGR_UNMIGRATED_TAIL_SLOTS(X)
// The non-void ones, kept apart only because the macro body differs: a [[noreturn]]
// call is a complete body for a void slot and for a value-returning one alike, but a
// compiler that does not see UnmigratedVerbFatal's attribute through the macro would
// warn on the second. It does see it; they are split for readability. All ten are the
// wave-3 tail.
#define MGR_UNMIGRATED_TAIL_VALUE_SLOTS(X)
// The union, for the places that want every class-C row at once (the definitions and
// the assignments). A package never edits THIS; it edits its own list above.
#define MGR_UNMIGRATED_GL_SLOTS(X) \
MGR_UNMIGRATED_D1_SLOTS(X) \
MGR_UNMIGRATED_I1_SLOTS(X) \
MGR_UNMIGRATED_T2_SLOTS(X) \
MGR_UNMIGRATED_F1_SLOTS(X) \
MGR_UNMIGRATED_TAIL_SLOTS(X)
#define MGR_UNMIGRATED_GL_VALUE_SLOTS(X) MGR_UNMIGRATED_TAIL_VALUE_SLOTS(X)
#define MGR_DEFINE_UNMIGRATED(Name, Ret, Sig) \
Ret Name##_Unmigrated Sig { UnmigratedVerbFatal(#Name); }
MGR_UNMIGRATED_GL_SLOTS(MGR_DEFINE_UNMIGRATED)
MGR_UNMIGRATED_GL_VALUE_SLOTS(MGR_DEFINE_UNMIGRATED)
#undef MGR_DEFINE_UNMIGRATED
// THE TWO COMPUTE SLOTS' class-C stubs are GONE (P5b i1): they carried b1's dispatch
// hook before their Fatal so that the package flipping them would inherit a call site
// that was already correct, and EmitDispatchCompute / EmitDispatchComputeIndirect above
// are that inheritance - same two calls, same order, the record where the Fatal was.
//
// THE LAST HAND-WRITTEN STUB, SetSwapInterval_Unmigrated, IS GONE TOO (P10 B), and class C
// is empty. It was never reachable: eglSwapInterval reaches the table only through
// BackendObject::SetEGLSwapInterval, and BackendObject_Remote overrode that to call
// Server::ServerSetEGLSwapInterval - a SurfaceControlFrame on the control channel, which
// crosses processes. The slot now IS that forwarder (assigned in the class-B block), the
// override is deleted, and there is one route from eglSwapInterval to the server.
// The counts, as arithmetic. MGR_COUNT_ONE expands to `+ 1` per row.
#define MGR_COUNT_ONE(Name, Ret, Sig) +1
constexpr Uint32 kUnmigratedD1 = 0 MGR_UNMIGRATED_D1_SLOTS(MGR_COUNT_ONE);
// i1 landed: the list is empty and the two hand-written compute stubs are gone with it.
constexpr Uint32 kUnmigratedI1 = 0 MGR_UNMIGRATED_I1_SLOTS(MGR_COUNT_ONE);
constexpr Uint32 kUnmigratedT2 = 0 MGR_UNMIGRATED_T2_SLOTS(MGR_COUNT_ONE);
constexpr Uint32 kUnmigratedF1 = 0 MGR_UNMIGRATED_F1_SLOTS(MGR_COUNT_ONE);
constexpr Uint32 kUnmigratedTail =
0 MGR_UNMIGRATED_TAIL_SLOTS(MGR_COUNT_ONE) MGR_UNMIGRATED_TAIL_VALUE_SLOTS(MGR_COUNT_ONE);
#undef MGR_COUNT_ONE
constexpr Uint32 kUnmigratedSlots =
kUnmigratedD1 + kUnmigratedI1 + kUnmigratedT2 + kUnmigratedF1 + kUnmigratedTail;
// The emitted counts, PER OWNER. P5's five are c1's; each P5b package raises its own.
constexpr Uint32 kEmittedSlotsP5 = 5; // Clear, DrawArrays, ReadPixels, Blit, Present
constexpr Uint32 kEmittedSlotsD1 = 19;
constexpr Uint32 kEmittedSlotsI1 = 7;
constexpr Uint32 kEmittedSlotsT2 = 7;
constexpr Uint32 kEmittedSlotsF1 = 11;
// BlitNamedFramebuffer, both texture readbacks, and SetSwapInterval (P10 B) - the one
// class-B slot that crosses as a surface control frame rather than a SEG_CMD record.
constexpr Uint32 kEmittedSlotsTail = 4;
constexpr Uint32 kEmittedSlotsSync = 5;
constexpr Uint32 kEmittedSlotsQueries = 11;
constexpr Uint32 kEmittedSlots =
kEmittedSlotsP5 + kEmittedSlotsD1 + kEmittedSlotsI1 + kEmittedSlotsT2 + kEmittedSlotsF1 +
kEmittedSlotsTail + kEmittedSlotsSync + kEmittedSlotsQueries;
constexpr Uint32 kLocallyAnsweredSlots = 2; // GetIntegeri_v, IsTimerQuerySupported
// EACH PACKAGE'S OWNERSHIP, PINNED. A package that flips a slot removes one row and
// adds one to its emitted count; a package that touches another's list breaks the
// other's line, not its own. The four numbers are the census's package tables plus the
// unmeasured companions that share a wire row (BRIEF-P5B.md file-ownership table).
static_assert(kUnmigratedD1 + kEmittedSlotsD1 == 19, "d1 owns the 19 draw slots");
static_assert(kUnmigratedI1 + kEmittedSlotsI1 == 7, "i1 owns the 7 image/compute/barrier/copy/SSBO slots");
static_assert(kUnmigratedT2 + kEmittedSlotsT2 == 7, "t2 owns the 7 XFB/tessellation slots");
static_assert(kUnmigratedF1 + kEmittedSlotsF1 == 11, "f1 owns the 11 clear/copy/mip slots");
static_assert(kUnmigratedTail + kEmittedSlotsTail + kEmittedSlotsSync + kEmittedSlotsQueries == 20,
"the original wave-3 tail owns 20 slots");
static_assert(kUnmigratedSlots + kEmittedSlots == 69, "class B and C own 69 slots");
static_assert(kLocallyAnsweredSlots + kEmittedSlots + kUnmigratedSlots == kRemoteEmitSlotCount,
"the three classes no longer partition the 71 slots");
MG_Backend::GlobalBackendFunctionsTable BuildRemoteEmitTable() {
ArmControlKnobs();
MG_Backend::GlobalBackendFunctionsTable table{};
// ---- class C first, so that a slot forgotten below stays Fatal rather than null.
// Order matters for exactly this reason: if class B's assignment were first, a
// typo in class C would leave a NULL slot, and a null slot is 91 potential null
// calls with no diagnostic. This way the worst a mistake can do is name a verb
// that was supposed to be emitted, loudly.
#define MGR_ASSIGN_UNMIGRATED(Name, Ret, Sig) table.GL.Name = &Name##_Unmigrated;
MGR_UNMIGRATED_GL_SLOTS(MGR_ASSIGN_UNMIGRATED)
MGR_UNMIGRATED_GL_VALUE_SLOTS(MGR_ASSIGN_UNMIGRATED)
#undef MGR_ASSIGN_UNMIGRATED
table.GL.FenceSync = &EmitFenceSync;
table.GL.ClientWaitSync = &EmitClientWaitSync;
table.GL.GetSyncStatus = &EmitGetSyncStatus;
table.GL.WaitSync = &EmitWaitSync;
table.GL.DeleteSync = &EmitDeleteSync;
table.GL.BeginTimeElapsedQuery = &EmitBeginTimeElapsedQuery;
table.GL.EndTimeElapsedQuery = &EmitEndQuery;
table.GL.QueryCounterTimestamp = &EmitQueryCounterTimestamp;
table.GL.BeginOcclusionQuery = &EmitBeginOcclusionQuery;
table.GL.EndOcclusionQuery = &EmitEndQuery;
table.GL.BeginXfbPrimitivesQuery = &EmitBeginXfbPrimitivesQuery;
table.GL.EndXfbPrimitivesQuery = &EmitEndQuery;
table.GL.IsQueryResultAvailable = &EmitIsQueryResultAvailable;
table.GL.GetQueryResult64 = &EmitGetQueryResult64;
table.GL.DeleteBackendQuery = &EmitDeleteBackendQuery;
table.GL.GetGpuTimestampNs = &EmitGetGpuTimestampNs;
table.GL.DeleteTransformFeedback = &EmitDeleteTransformFeedback;
// ---- class A
table.GL.GetIntegeri_v = &AnswerGetIntegeri_v;
table.GL.IsTimerQuerySupported = &AnswerIsTimerQuerySupported;
// NOT A SLOT and not a verb: a Bool member of the table, whose one non-test client
// reader is GL_Query.cpp:221. It does NOT ride inside MGPCaps::Dynamic - it is a
// member of GLFunctionsTable, which is exactly the thing a split client never
// receives - so it is answered from kCapCpuXfbPrimitiveAccounting.
table.GL.PrefersCpuXfbPrimitiveAccounting =
CapsMirrorInstance().PrefersCpuXfbPrimitiveAccounting();
// ---- class B
table.GL.Clear = &EmitClear;
table.GL.DrawArrays = &EmitDrawArrays;
// ---- P5b d1: the nineteen draw slots, all on draw_vbo (CONTRACT-P5B.md §2 d1)
table.GL.DrawElements = &EmitDrawElements;
table.GL.DrawElementsBaseVertex = &EmitDrawElementsBaseVertex;
table.GL.DrawRangeElements = &EmitDrawRangeElements;
table.GL.DrawRangeElementsBaseVertex = &EmitDrawRangeElementsBaseVertex;
table.GL.DrawElementsInstanced = &EmitDrawElementsInstanced;
table.GL.DrawElementsInstancedBaseVertex = &EmitDrawElementsInstancedBaseVertex;
table.GL.DrawElementsInstancedBaseInstance = &EmitDrawElementsInstancedBaseInstance;
table.GL.DrawElementsInstancedBaseVertexBaseInstance =
&EmitDrawElementsInstancedBaseVertexBaseInstance;
table.GL.DrawArraysInstanced = &EmitDrawArraysInstanced;
table.GL.DrawArraysInstancedBaseInstance = &EmitDrawArraysInstancedBaseInstance;
table.GL.MultiDrawArrays = &EmitMultiDrawArrays;
table.GL.MultiDrawElements = &EmitMultiDrawElements;
table.GL.MultiDrawElementsBaseVertex = &EmitMultiDrawElementsBaseVertex;
table.GL.DrawArraysIndirect = &EmitDrawArraysIndirect;
table.GL.DrawElementsIndirect = &EmitDrawElementsIndirect;
table.GL.MultiDrawArraysIndirect = &EmitMultiDrawArraysIndirect;
table.GL.MultiDrawElementsIndirect = &EmitMultiDrawElementsIndirect;
table.GL.MultiDrawArraysIndirectCount = &EmitMultiDrawArraysIndirectCount;
table.GL.MultiDrawElementsIndirectCount = &EmitMultiDrawElementsIndirectCount;
table.GL.ReadPixels = &EmitReadPixels;
table.GL.BlitFramebuffer = &EmitBlitFramebuffer;
table.GL.BlitNamedFramebuffer = &EmitBlitNamedFramebuffer;
table.Present = &EmitPresent;
// P10 B: the swap interval is the server's presentation-path question, so the slot
// forwards it there as a SurfaceControlFrame (ServerLoop.cpp's SetSwapInterval arm),
// across processes on spawn and tcp - the forwarder BackendObject_Remote's deleted
// SetEGLSwapInterval override used to call.
table.SetSwapInterval = &Server::ServerSetEGLSwapInterval;
// ---- class B, P5b t2. Assigned AFTER the class-C block above, which is what makes
// the flip a single-line change per slot: the Fatal thunk is overwritten, and a slot
// whose row is removed from MGR_UNMIGRATED_T2_SLOTS but not assigned here would be
// NULL and caught by RemoteEmitTable.NoSlotIsNull rather than silently skipped.
table.GL.BeginTransformFeedback = &EmitBeginTransformFeedback;
table.GL.EndTransformFeedback = &EmitEndTransformFeedback;
table.GL.PauseTransformFeedback = &EmitPauseTransformFeedback;
table.GL.ResumeTransformFeedback = &EmitResumeTransformFeedback;
table.GL.BindTransformFeedback = &EmitBindTransformFeedback;
table.GL.PatchParameteri = &EmitPatchParameteri;
// ---- f1 ----
table.GL.ClearBufferfi = &EmitClearBufferfi;
table.GL.ClearBufferfv = &EmitClearBufferfv;
table.GL.ClearBufferiv = &EmitClearBufferiv;
table.GL.ClearBufferuiv = &EmitClearBufferuiv;
table.GL.ClearNamedFramebufferfi = &EmitClearNamedFramebufferfi;
table.GL.ClearNamedFramebufferfv = &EmitClearNamedFramebufferfv;
table.GL.ClearNamedFramebufferiv = &EmitClearNamedFramebufferiv;
table.GL.ClearNamedFramebufferuiv = &EmitClearNamedFramebufferuiv;
table.GL.CopyTexImage2D = &EmitCopyTexImage2D;
table.GL.CopyTexSubImage2D = &EmitCopyTexSubImage2D;
table.GL.GenerateMipmap = &EmitGenerateMipmap;
table.GL.GetTexImage = &EmitGetTexImage;
table.GL.GetTextureImage = &EmitGetTextureImage;
// ---- class B, P5b package i1 (kEmittedSlotsI1 = 7)
table.GL.BindImageTexture = &EmitBindImageTexture;
table.GL.DispatchCompute = &EmitDispatchCompute;
table.GL.DispatchComputeIndirect = &EmitDispatchComputeIndirect;
table.GL.MemoryBarrier = &EmitMemoryBarrier;
table.GL.MemoryBarrierByRegion = &EmitMemoryBarrierByRegion;
table.GL.CopyImageSubData = &EmitCopyImageSubData;
table.GL.ShaderStorageBlockBinding = &EmitShaderStorageBlockBinding;
return table;
}
} // namespace
void NoteFenceSignaledByServer(MG_Pipe::MGPipeHandle fence) {
RememberFenceSignaled(fence);
g_fenceServerReports.fetch_add(1, std::memory_order_relaxed);
}
FencePollCounters ReadFencePollCounters() {
FencePollCounters counters;
counters.LocalAnswers = g_fenceLocalAnswers.load(std::memory_order_relaxed);
counters.Escalations = g_fenceEscalations.load(std::memory_order_relaxed);
counters.RoundTrips = g_fenceRoundTrips.load(std::memory_order_relaxed);
counters.ServerReports = g_fenceServerReports.load(std::memory_order_relaxed);
return counters;
}
const MG_Backend::GlobalBackendFunctionsTable& RemoteEmitTable() {
// Leaked at exit like every other MG_Remote singleton (ID-8): MG_Backend::Init()
// copies it into gBackendFunctionsTable and MobileGL::Destroy() clears that copy from
// an exit handler, by which point a static destructor here would already have run.
static const MG_Backend::GlobalBackendFunctionsTable& table =
*new MG_Backend::GlobalBackendFunctionsTable{BuildRemoteEmitTable()};
return table;
}
Uint32 ImplementedVerbCount() { return kEmittedSlots; }
Uint32 LocallyAnsweredSlotCount() { return kLocallyAnsweredSlots; }
Uint32 UnmigratedSlotCount() { return kUnmigratedSlots; }
void SetDropClearEmissionForNegativeControl(Bool drop) { g_dropClearEmission = drop; }
Uint64 DroppedClearEmissions() { return g_droppedClearEmissions; }
void SetDropDrawEmissionForNegativeControl(Bool drop) { g_dropDrawEmission = drop; }
Uint64 DroppedDrawEmissions() { return g_droppedDrawEmissions; }
Bool ReadbackPackStateIsTightForTest(GLsizei width, Uint64 bytesPerPixel,
const PixelStoreParameters& pack) {
return ReadbackPackStateIsTight(width, bytesPerPixel, pack);
}
Uint64 TightReadbackByteCount(GLsizei width, GLsizei height, GLenum format, GLenum type) {
return TightReadbackBytes(width, height, format, type);
}
// M2 / codex 11's predicate at namespace scope: the one RequireReadbackReplyComplete decides
// on and the one the control drives. 0=OK / 1=DECLINED / 2=ERROR.
Bool ReadbackReplyIsComplete(Int32 status, Uint64 replySize, Uint64 expected) {
return status == Wire::ReplySink::kStatusOk && replySize == expected;
}
// g5-readback's plan (EmitTables.h, ReadbackBand). Pixels-per-reply first and the row test
// against it, so no product here can overflow whatever the inputs: a unit control drives
// this with Uint64 extremes, and the emitter with a GLsizei width.
Bool PlanReadbackBands(Uint64 width, Uint64 height, Uint64 bytesPerPixel, Uint64 maxReplyBytes,
ReadbackBandPlan& plan) {
if (width == 0 || height == 0 || bytesPerPixel == 0 || maxReplyBytes < bytesPerPixel) {
return false;
}
const Uint64 pixelsPerReply = maxReplyBytes / bytesPerPixel; // >= 1
if (width <= pixelsPerReply) {
// floor(floor(cap / bpp) / width) == floor(cap / (bpp * width)): the most whole rows
// one reply holds, and at least one because a row fits.
plan.RowsPerBand = pixelsPerReply / width;
plan.ColumnsPerBand = width;
} else {
// A SINGLE ROW IS LARGER THAN A REPLY (a >131071-pixel RGBA/FLOAT row at the 2 MiB
// slot - wider than any attachment, but a legal glReadPixels whose in-bounds pixels
// GL still defines). Each row is cut into pieces; one row per band keeps every piece
// contiguous in the tight layout.
plan.RowsPerBand = 1;
plan.ColumnsPerBand = pixelsPerReply;
}
return true;
}
// ID-49's scatter, for one band of a banded read (g5-readback). The whole-read scatter below
// is this function over the single band {0, height, 0, width}, so there is one copy of
// 8.4.4's arithmetic and the control drives it.
void ScatterReadbackBandIntoPackState(const void* band, void* destination, GLsizei width,
const ReadbackBand& where, Uint64 bytesPerPixel,
const PixelStoreParameters& pack) {
if (band == nullptr || destination == nullptr || width <= 0 || where.Rows == 0 ||
where.Columns == 0) {
return;
}
const Uint64 rowPixels =
pack.RowLength > 0 ? static_cast<Uint64>(pack.RowLength) : static_cast<Uint64>(width);
const Uint64 alignment = pack.Alignment > 0 ? static_cast<Uint64>(pack.Alignment) : 1ull;
const Uint64 strideBytes =
((rowPixels * bytesPerPixel + alignment - 1) / alignment) * alignment;
// m6: the client re-derives GL 4.6 8.4.4's pack layout, so it honours GL_PACK_ROW_LENGTH
// VERBATIM - including the ill-formed 0 < ROW_LENGTH < width, where the row stride is
// narrower than a written row and consecutive rows overlap. GL leaves that case to the
// implementation; the client reproduces exactly what the monolith backend's own scatter
// would do with the same state rather than clamping, so the two arms stay byte-identical.
// The fast path (ReadbackPackStateIsTight) already rejects any ROW_LENGTH != width, so
// this only runs on the scatter path the application asked for.
const Uint64 writtenPerRow = where.Columns * bytesPerPixel;
// SKIP_IMAGES and IMAGE_HEIGHT ARE IGNORED (codex 6). glReadPixels is a 2-D read; GL
// does not apply the image-level pack parameters to it, and the monolith conversion path
// says so explicitly with honorPackImageParams=false (DirectGLES.cpp:10905). Applying
// SKIP_IMAGES here shifted a read with SKIP_IMAGES=1 by a whole image and overran an
// application buffer sized for exactly `height` rows. Only SKIP_ROWS and SKIP_PIXELS -
// the 2-D skips - offset the first written byte; the band's own row and column then
// offset it within the read, on the SAME stride, so a banded read writes exactly the
// bytes the whole-read scatter would have, in the same row order.
auto* out = static_cast<Uint8*>(destination) +
(static_cast<Uint64>(pack.SkipRows) + where.FirstRow) * strideBytes +
(static_cast<Uint64>(pack.SkipPixels) + where.FirstColumn) * bytesPerPixel;
const auto* in = static_cast<const Uint8*>(band);
for (Uint64 row = 0; row < where.Rows; ++row) {
std::memcpy(out + row * strideBytes, in + row * writtenPerRow,
static_cast<SizeT>(writtenPerRow));
}
}
// ID-49's scatter. Exported for the same reason as the refusal above: the control drives
// THIS, which is what the emitter calls, rather than a second copy of 8.4.4's arithmetic.
void ScatterTightReadbackIntoPackState(const void* tight, void* destination, GLsizei width,
GLsizei height, Uint64 bytesPerPixel,
const PixelStoreParameters& pack) {
if (tight == nullptr || destination == nullptr || width <= 0 || height <= 0) return;
ScatterReadbackBandIntoPackState(
tight, destination, width,
ReadbackBand{0, static_cast<Uint64>(height), 0, static_cast<Uint64>(width)},
bytesPerPixel, pack);
}
// =============================================================================
// P5b d1 - the draw family's record plan, at namespace scope so the unit cases drive
// exactly what the emitters above call (R-16).
// =============================================================================
Uint8 RemoteIndexSizeFor(GLenum indexType) {
switch (indexType) {
case GL_UNSIGNED_BYTE: return 1;
case GL_UNSIGNED_SHORT: return 2;
case GL_UNSIGNED_INT: return 4;
default: return 0;
}
}
MG_Pipe::MGPDrawInfo PlanDrawInfo(GLenum mode, Uint8 indexSize, GLsizei instanceCount,
GLuint baseInstance, Uint32 numDraws,
const RemoteDrawBindings& bindings) {
MG_Pipe::MGPDrawInfo info{};
info.Mode = static_cast<Uint32>(mode);
info.IndexSize = indexSize;
// The restart state rides verbatim (informational in P5b: the backend's
// ScopedRestartIndexSubstitution reads its own barrier-pulled copy and the index bytes
// on its side). kDrawHasUserIndices / kDrawIsIndirect are added by the emission itself,
// kDrawHasIndexRange by the two DrawRangeElements* callers.
info.Flags = bindings.PrimitiveRestart ? static_cast<Uint8>(MG_Pipe::kDrawPrimitiveRestart) : 0;
// P5e (vi), CONTRACT-P5E §2.1 (ii) / §5.1. On the wire BECAUSE the server needs it: the
// barriered predicate is computed identically by both roles from the record alone, and
// "does this draw fetch from client memory" is not derivable from anything else in it -
// a null Res inside the vertex-buffer window is also what a DISABLED attribute below
// the high-water mark publishes. Set for every draw shape, not just the array ones: a
// glDrawElements can fetch its VERTICES from client memory too.
if (bindings.ClientVertexArrays) info.Flags |= static_cast<Uint8>(MG_Pipe::kDrawClientArrays);
// A negative count has already been refused by the frontend (INVALID_VALUE); 0 crosses
// as 0 and draws nothing, which is what the driver does with it.
info.InstanceCount = instanceCount > 0 ? static_cast<Uint32>(instanceCount) : 0u;
info.StartInstance = baseInstance;
info.RestartIndex = bindings.RestartIndex;
info.DrawIdOffset = 0;
// The handle beside the call (rule D): the VAO's element buffer for an indexed draw,
// the same handle set_index_buffer (32) carried at validate; null for arrays and for a
// client index array.
info.IndexResource = (indexSize != 0 && bindings.ElementBufferBound) ? bindings.ElementBuffer
: MG_Pipe::kMGPipeNullHandle;
info.MinIndex = ~0u; // "unknown" (MGPipeTypes.h); the DrawRangeElements* callers fill it
info.MaxIndex = ~0u;
info.XfbCpuCapturedVertices = 0;
info.NumDraws = numDraws;
return info;
}
Bool PlanDrawRange(const RemoteDrawBindings& bindings, Uint8 indexSize, const void* indicesOrFirst,
GLsizei count, GLint baseVertex, MG_Pipe::MGPDrawRange& out) {
out = MG_Pipe::MGPDrawRange{};
out.Count = count > 0 ? static_cast<Uint32>(count) : 0u;
if (indexSize == 0) {
// Arrays: `first`, spelled through the pointer parameter so one function serves
// both shapes. A negative first has already been refused by the frontend.
const auto first = static_cast<std::intptr_t>(reinterpret_cast<std::uintptr_t>(indicesOrFirst));
out.Start = first > 0 ? static_cast<Uint32>(first) : 0u;
out.IndexBias = 0;
return true;
}
out.IndexBias = baseVertex;
if (!bindings.ElementBufferBound) {
// A client index array: the emitter stages the bytes and the run starts at its
// first index.
out.Start = 0;
return true;
}
// An element buffer: `indices` is a byte offset into it, and Start is that offset in
// INDICES - the same arithmetic OnDrawVbo inverts (offset = Start * IndexSize). An
// offset that is not a whole number of indices cannot be spelled and is the caller's
// refusal, not a rounding.
const auto offset = reinterpret_cast<std::uintptr_t>(indicesOrFirst);
if (offset % indexSize != 0) return false;
const std::uintptr_t start = offset / indexSize;
if (start > 0xFFFFFFFFull) return false;
out.Start = static_cast<Uint32>(start);
return true;
}
MG_Pipe::MGPDrawIndirect PlanDrawIndirect(const RemoteDrawBindings& bindings, const void* indirect,
GLsizei drawCount, GLsizei stride,
GLintptr parameterOffset, Bool hasParameterBuffer) {
MG_Pipe::MGPDrawIndirect block{};
block.Buffer = bindings.DrawIndirectBuffer;
block.ParameterBuffer = hasParameterBuffer ? bindings.ParameterBuffer : MG_Pipe::kMGPipeNullHandle;
// The command byte offset the call passed as `indirect` (a bound GL_DRAW_INDIRECT_BUFFER
// makes it an offset, never an address - the emitter refused the other case by name).
block.Offset = static_cast<Uint64>(reinterpret_cast<std::uintptr_t>(indirect));
block.ParameterOffset = hasParameterBuffer ? static_cast<Uint64>(parameterOffset) : 0u;
// 0 = tightly packed, as GL spells it; the backend normalises. Negative counts and
// strides have already been refused by the frontend.
block.Stride = stride > 0 ? static_cast<Uint32>(stride) : 0u;
block.DrawCount = drawCount > 0 ? static_cast<Uint32>(drawCount) : 0u;
return block;
}
} // namespace MobileGL::MG_Remote::Client
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