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[Fix, Test] (MG_Util, MG_State, MG_Backend): the GL 4.3 vertex binding model - array vertex inputs, zero binding strides, instance divisors, and formats ES refuses

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swung0x48
2026-08-12 05:36:00 -04:00
parent 21b5fc2d92
commit 2fced2241b
13 changed files with 1129 additions and 29 deletions
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CMakeLists.txt
+1
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@@ -278,6 +278,7 @@ set(SOURCE_FILES
MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/DecoratePositionInvariantPass.cpp
MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/LowerDrawParametersPass.cpp
MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/PackDoubleVertexInputsPass.cpp
MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/SplitArrayVertexInputsPass.cpp
MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/RebaseInstanceIndexPass.cpp
MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/ZeroBaseVertexPass.cpp
MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/NormalizeRectCoordinatesPass.cpp
MobileGL/MG_Backend/DirectGLES/Managers.cpp
+135 -10
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@@ -1481,6 +1481,50 @@ namespace MobileGL::MG_Backend::DirectGLES {
return true;
}
// ES 3.1 core. Queried through the loader rather than the version, because the whole
// point of using it is to express something the pointer API cannot, and falling back
// silently on a driver that lacks it is better than crashing on a null entry point.
inline Bool HasVertexBindingApi() {
return g_GLESFuncs.glBindVertexBuffer != nullptr && g_GLESFuncs.glVertexAttribFormat != nullptr &&
g_GLESFuncs.glVertexAttribIFormat != nullptr && g_GLESFuncs.glVertexAttribBinding != nullptr &&
g_GLESFuncs.glVertexBindingDivisor != nullptr;
}
// Declares one attribute through the ES binding-point API, the only spelling that can
// carry a stride of zero. Returns false when the attribute has no usable buffer, in
// which case nothing was emitted.
inline Bool SyncZeroStrideAttribute(Uint attribIndex, const MG_State::GLState::VertexAttribute& attrib) {
const auto& bufferObject = attrib.Buffer;
if (!bufferObject) {
MGLOG_W("Zero-stride attribute %u has no bound buffer, skipping.", attribIndex);
return false;
}
auto* backendResource = BufferImpl::EnsureBufferResource(bufferObject);
if (!backendResource || backendResource->id == 0) {
MGLOG_E("No backend buffer for zero-stride attribute %u, cannot bind it.", attribIndex);
return false;
}
if (!attrib.IsInteger) {
const GLint glSize = attrib.IsBgra ? static_cast<GLint>(GL_BGRA) : attrib.Size;
g_GLESFuncs.glVertexAttribFormat(attribIndex, glSize,
MG_Util::ConvertDataTypeToGLEnum(attrib.Type),
attrib.Normalized ? GL_TRUE : GL_FALSE, 0);
} else {
g_GLESFuncs.glVertexAttribIFormat(attribIndex, attrib.Size,
MG_Util::ConvertDataTypeToGLEnum(attrib.Type), 0);
}
g_GLESFuncs.glVertexAttribBinding(attribIndex, attribIndex);
// The resolved offset goes on the binding point, not into a relative offset: the
// relative offset is capped by GL_MAX_VERTEX_ATTRIB_RELATIVE_OFFSET (2047 at
// minimum) while a buffer offset is not, so anything else would break on a large
// one. BindBufferId is bypassed deliberately - glBindVertexBuffer binds into the
// VAO's binding point, not the GL_ARRAY_BUFFER target that cache tracks.
g_GLESFuncs.glBindVertexBuffer(attribIndex, backendResource->id,
static_cast<GLintptr>(attrib.Offset), 0);
return true;
}
void BackendVertexArrayObject::SyncToBackend(
const SharedPtr<MG_State::GLState::VertexArrayObject>& stateVAOObject) {
#ifdef TRACY_ENABLE
@@ -1537,18 +1581,66 @@ namespace MobileGL::MG_Backend::DirectGLES {
// FormatVersion, not SwitchVersion, so the enable/disable block above will not run
// again and an already-enabled array would stay enabled with no pointer and no
// ARRAY_BUFFER binding - which ES 3.1+ makes an INVALID_OPERATION at draw.
if (attrib.IsLong) {
MGLOG_E("DirectGLES: vertex attribute %u is a 64-bit (GL_DOUBLE) array, which this "
//
// IsLong is not the only way a 64-bit array gets here: glVertexAttribFormat
// with GL_DOUBLE asks for doubles in memory CONVERTED to float, so it is not
// long, is not declined by the frontend, and still has no ES vertex format.
// Leaving that one enabled did not merely raise INVALID_ENUM - the Adreno
// driver dereferenced null inside the next draw and took the process with it
// (SIGSEGV in libGLESv2_adreno, KHR-GL43.vertex_attrib_binding.basic-input-case4),
// because the array stayed enabled with no pointer the failed call could set.
// The type test therefore covers the storage, not the spelling.
if (attrib.IsLong || attrib.Type == DataType::Float64) {
MGLOG_I("DirectGLES: vertex attribute %u is a 64-bit (GL_DOUBLE) array, which this "
"backend cannot feed - disabling the array",
attribIndex);
g_GLESFuncs.glDisableVertexAttribArray(attribIndex);
continue;
}
// A resolved stride of zero is the binding model's "never advance" (see
// VertexAttribute::Stride) and glVertexAttribPointer cannot say it - a zero
// stride argument there means "tightly packed" instead, i.e. exactly the
// opposite. ES 3.1's binding-point API can, so a zero-stride attribute takes
// that spelling: its own binding point (index == attribute index, the default
// mapping) carrying the buffer, the whole resolved offset and stride 0, with
// the format at relative offset 0. Everything the pointer call would have set
// for this attribute is set here too, so the two spellings stay interchangeable
// from one sync to the next.
if (attrib.Stride == 0 && HasVertexBindingApi()) {
if (!SyncZeroStrideAttribute(attribIndex, attrib)) {
continue;
}
if (needsSyncFormat) {
g_GLESFuncs.glVertexBindingDivisor(attribIndex, attrib.Divisor);
}
continue;
}
if (!BindAttributeBuffer(attrib)) {
continue;
}
// GL_BGRA as a vertex SIZE is desktop-only; ES has no equivalent and rejects
// it. That rejection is not benign: it leaves the array ENABLED with no
// pointer, and the Adreno driver then dereferences null inside the next draw
// and kills the process rather than reporting an error (SIGSEGV in
// libGLESv2_adreno, KHR-GL43.vertex_attrib_binding.basic-input-case5). So the
// refusal has to be observed and the array disabled.
//
// Deliberately ONLY this format. Everything else MobileGL can reach here is ES
// core - the packed 2_10_10_10 pair included, whose size the frontend has
// already pinned to the 4 that ES requires - so nothing else can be refused,
// and the per-draw sync must not grow a glGetError round trip (a driver
// pipeline stall) for the formats real applications actually use. BGRA is also
// still ATTEMPTED rather than refused up front: some ES drivers do accept it,
// and the ones that do should keep working.
const Bool formatMayBeRefused = attrib.IsBgra;
if (formatMayBeRefused) {
while (g_GLESFuncs.glGetError() != GL_NO_ERROR) {
} // start from a clean slate so the check below is about THIS call
}
if (!attrib.IsInteger) {
// GL_BGRA is passed to the driver as the size argument (the driver reorders BGRA).
const GLint glSize = attrib.IsBgra ? static_cast<GLint>(GL_BGRA) : attrib.Size;
@@ -1561,6 +1653,16 @@ namespace MobileGL::MG_Backend::DirectGLES {
(const void*)attrib.Offset);
}
if (formatMayBeRefused && g_GLESFuncs.glGetError() != GL_NO_ERROR) {
MGLOG_I("DirectGLES: the driver refused the vertex format of attribute %u "
"(size=%d bgra=%d type=%s) - disabling the array so the draw cannot "
"fetch through a pointer the driver never accepted",
attribIndex, attrib.Size, attrib.IsBgra ? 1 : 0,
MG_Util::ConvertGLEnumToString(MG_Util::ConvertDataTypeToGLEnum(attrib.Type)).c_str());
g_GLESFuncs.glDisableVertexAttribArray(attribIndex);
continue;
}
if (needsSyncFormat) {
g_GLESFuncs.glVertexAttribDivisor(attribIndex, attrib.Divisor);
}
@@ -1609,9 +1711,10 @@ namespace MobileGL::MG_Backend::DirectGLES {
continue;
}
// Same reason as SyncToBackend: there is no ES vertex format for a 64-bit array, and
// this path only ever reaches glVertexAttribPointer/IPointer.
if (attrib.IsLong) {
// Same reason as SyncToBackend, including why the test is on the storage rather
// than on IsLong: there is no ES vertex format for a 64-bit array, and this path
// only ever reaches glVertexAttribPointer/IPointer.
if (attrib.IsLong || attrib.Type == DataType::Float64) {
g_GLESFuncs.glDisableVertexAttribArray(attribIndex);
continue;
}
@@ -4366,6 +4469,21 @@ namespace MobileGL::MG_Backend::DirectGLES {
effectiveSpirv = &loweredSpirv;
}
// GLSL ES has no ARRAY vertex inputs, and SPIRV-Cross refuses the whole module
// rather than emulating them, so this has to happen before it sees the binary.
Vector<unsigned int> splitArrayInputSpirv;
if (glShaderType == GL_VERTEX_SHADER &&
MG_Util::ShaderTranspiler::ShaderCompiler::SplitArrayVertexInputsForEssl(
*effectiveSpirv, splitArrayInputSpirv) &&
!splitArrayInputSpirv.empty() && splitArrayInputSpirv != *effectiveSpirv) {
// Only when the pass ACTUALLY split something. The optimizer hands back a
// re-serialised copy either way, and adopting that copy for every vertex
// shader would put every one of them through a round trip they do not need
// - which is not free: it cost the create-indirect retrace 0.15 SSIM the
// first time this gate was missing.
effectiveSpirv = &splitArrayInputSpirv;
}
// ESSL stage-matches uniform blocks by member precision, but SPIRV-Cross prints
// a RelaxedPrecision member as explicit "mediump" in the vertex stage and as
// UNQUALIFIED (mediump-by-default) in the fragment stage; after
@@ -4447,11 +4565,18 @@ namespace MobileGL::MG_Backend::DirectGLES {
spvcSession.Compile(&result);
if (!result) {
MG_Util::ShaderTranspiler::ResultInfo r;
r.log += "Failed to compile the shader to GLSL: \n";
r.log += spvcSession.GetLastErrorString();
r.errc = -5;
MGLOG_E("%s", r.log.c_str());
// MGLOG_I, for the same reason as the compile- and link-failure diagnostics
// below: every CI, retrace and release build compiles at
// MOBILEGL_LOG_LEVEL_INFO, where MGLOG_E expands to nothing. A stage that
// never reaches the driver leaves the program short of that stage, so the
// link fails with an EMPTY driver info log - the least debuggable failure
// MobileGL can produce, and what hid the whole
// KHR-GL43.vertex_attrib_binding family behind "the draw captured zeros".
MGLOG_I("Shader transpilation to ESSL failed. State program ID: %u, stage: %s, "
"SPIRV-Cross error: %s",
stateProgramObject->GetExternalIndex(),
MG_Util::ConvertGLEnumToString(glShaderType).c_str(),
spvcSession.GetLastErrorString());
m_backendProgramUsable = false;
continue;
}
MobileGL/MG_Backend/DirectVulkan/Renderer/VertexInputStateFactory.cpp
+18 -6
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@@ -153,8 +153,14 @@ namespace MobileGL::MG_Backend::DirectVulkan {
continue;
}
const Uint32 sourceStride =
attr.Stride > 0 ? static_cast<Uint32>(attr.Stride) : static_cast<Uint32>(attribByteSize);
// Verbatim, zero included. The frontend already resolved a pointer call's
// "tightly packed" stride 0 into the element size (see VertexAttribute::Stride),
// so a zero here is the binding model's stride 0 - every vertex reads the same
// element - which is exactly what a zero VkVertexInputBindingDescription::stride
// means. Substituting the element size fetched a fresh element per vertex and ran
// off the end of the buffer (KHR-GL43.vertex_attrib_binding.basic-input-case7/8).
// Client-memory arrays cannot reach zero: they only exist on the pointer path.
const Uint32 sourceStride = static_cast<Uint32>(attr.Stride);
const Bool packedAttribute = attr.Type == DataType::Int2101010Rev ||
attr.Type == DataType::Uint2101010Rev;
const SizeT requiredAlignment = packedAttribute ? attribByteSize : GetComponentSize(attr.Type);
@@ -175,10 +181,16 @@ namespace MobileGL::MG_Backend::DirectVulkan {
}
Uint32 stride = sourceStride;
if (conversion == VertexStreamConversion::Repack) {
stride = static_cast<Uint32>(attribByteSize);
} else if (conversion == VertexStreamConversion::ScaledIntegerToFloat32) {
stride = static_cast<Uint32>(attr.Size * static_cast<Int>(sizeof(Float)));
// A converted stream is tightly packed, so its stride is the converted element
// size - unless the source stride is zero, which does not describe a packing at
// all but "never advance". That survives the conversion unchanged: the draw path
// converts exactly one element and every vertex reads it.
if (sourceStride != 0) {
if (conversion == VertexStreamConversion::Repack) {
stride = static_cast<Uint32>(attribByteSize);
} else if (conversion == VertexStreamConversion::ScaledIntegerToFloat32) {
stride = static_cast<Uint32>(attr.Size * static_cast<Int>(sizeof(Float)));
}
}
const VkVertexInputRate inputRate =
(attr.Divisor == 0) ? VK_VERTEX_INPUT_RATE_VERTEX : VK_VERTEX_INPUT_RATE_INSTANCE;
MobileGL/MG_Backend/DirectVulkan/Renderer/VulkanRenderer.cpp
+18 -5
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@@ -3546,9 +3546,11 @@ void main() {
const auto& attr = vao.GetAttribute(bindingLocation);
const SizeT elementSize =
VertexInputStateFactory::GetAttributeByteSize(attr.Type, attr.Size, attr.IsBgra);
const SizeT sourceStride =
attr.Stride > 0 ? static_cast<SizeT>(attr.Stride) : elementSize;
if (sourceBufferShared->MappedData() == nullptr || elementSize == 0 || sourceStride == 0 ||
// Zero is a legal binding stride and means "never advance" (see
// VertexAttribute::Stride), so it is NOT folded into the element size here -
// it selects the single-element conversion below instead.
const SizeT sourceStride = static_cast<SizeT>(attr.Stride);
if (sourceBufferShared->MappedData() == nullptr || elementSize == 0 ||
baseOffset > sourceSize || elementSize > sourceSize - baseOffset) {
MGLOG_E("UploadAndBindVertexStreams skipped: invalid converted source binding=%zu "
"location=%u base=%zu size=%zu element=%zu stride=%zu",
@@ -3557,7 +3559,8 @@ void main() {
}
sourceBufferShared->SyncPersistentMappedRange();
const SizeT availableElementCount = 1 + (sourceSize - baseOffset - elementSize) / sourceStride;
const SizeT availableElementCount =
sourceStride == 0 ? 1 : 1 + (sourceSize - baseOffset - elementSize) / sourceStride;
const Bool cacheable = !sourceBufferShared->IsBackendPersistentMapped();
// Convert only what this draw can fetch instead of the whole buffer tail.
// Instance-rate bindings index by instance, not the vertex range, so they
@@ -4737,6 +4740,7 @@ void main() {
hasPatchedVertexAttributes = true;
}
VertexInputStateBuilder syntheticVertexInputBuilder;
VkPipelineVertexInputStateCreateInfo syntheticVertexInputState{};
const VkPipelineVertexInputStateCreateInfo* pipelineVertexInputState = &vis.state;
if (missingAttribMask != 0 || hasPatchedVertexAttributes) {
for (const auto& binding : vis.bindings) {
@@ -4764,7 +4768,16 @@ void main() {
syntheticVertexInputBuilder.AddAttribute(location, syntheticBinding, format, 0);
++syntheticBinding;
}
pipelineVertexInputState = &syntheticVertexInputBuilder.Build();
syntheticVertexInputState = syntheticVertexInputBuilder.Build();
// Carry the divisor chain over. The synthetic rebuild copies bindings and
// attributes only, and it keeps every real binding's INDEX, so the divisor
// descriptions built for them stay valid - but dropping the pNext silently
// demoted every instanced binding to divisor 1. This path runs whenever the
// program declares an input the VAO does not feed (which is most capture
// shaders: KHR-GL43.vertex_attrib_binding declares 16 inputs and enables three),
// so the loss was near-total rather than a corner case.
syntheticVertexInputState.pNext = vis.state.pNext;
pipelineVertexInputState = &syntheticVertexInputState;
}
auto cullFaceEnabled = MG_State::pGLContext->IsCapabilityEnabled(CapabilityInput::CullFace);
auto depthTestEnabled = MG_State::pGLContext->IsCapabilityEnabled(CapabilityInput::DepthTest);
MobileGL/MG_Impl/GLImpl/VertexArray/GL_VertexArray.cpp
+7 -4
View File
@@ -315,9 +315,10 @@ namespace MobileGL::MG_Impl::GLImpl {
auto offset = reinterpret_cast<SizeT>(pointer);
vao->SetAttributeFormat(index, size, dataType, false, stride, offset, true, false);
const int effectiveStride = EffectiveVertexStride(stride, size, type);
vao->SetAttributeFormat(index, size, dataType, false, stride, offset, true, false, effectiveStride);
vao->BindAttributeBuffer(index, vbo);
vao->MirrorPointerIntoBinding(index, vbo, offset, EffectiveVertexStride(stride, size, type));
vao->MirrorPointerIntoBinding(index, vbo, offset, effectiveStride);
}
void VertexAttribPointer_State(GLuint index, GLint size, GLenum type, GLboolean normalized, GLsizei stride,
@@ -345,9 +346,11 @@ namespace MobileGL::MG_Impl::GLImpl {
// backend can pick the reversed VkFormat / pass GL_BGRA through to a GLES driver.
const bool isBgra = (size == static_cast<GLint>(GL_BGRA));
const int effectiveSize = isBgra ? 4 : size;
vao->SetAttributeFormat(index, effectiveSize, dataType, normalized, stride, offset, false, isBgra);
const int effectiveStride = EffectiveVertexStride(stride, effectiveSize, type);
vao->SetAttributeFormat(index, effectiveSize, dataType, normalized, stride, offset, false, isBgra,
effectiveStride);
vao->BindAttributeBuffer(index, vbo);
vao->MirrorPointerIntoBinding(index, vbo, offset, EffectiveVertexStride(stride, effectiveSize, type));
vao->MirrorPointerIntoBinding(index, vbo, offset, effectiveStride);
}
void BindVertexArray_State(GLuint array) {
MobileGL/MG_IntegrationTest/CMakeLists.txt
+1
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@@ -69,6 +69,7 @@ add_executable(MobileGLIntegrationTest
Scenarios/Glsl420DeclarationScenario.cpp
Scenarios/FragmentOutputArrayIndexScenario.cpp
Scenarios/BufferTextureScenario.cpp
Scenarios/VertexAttribBindingScenario.cpp
)
target_include_directories(MobileGLIntegrationTest PRIVATE
MobileGL/MG_IntegrationTest/Scenarios/VertexAttribBindingScenario.cpp
+465
View File
@@ -0,0 +1,465 @@
// MobileGL - MobileGL/MG_IntegrationTest/Scenarios/VertexAttribBindingScenario.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
//
// ARB_vertex_attrib_binding: the separate format/binding state the GL 4.3 vertex
// input model is made of, read back out of the draw that consumed it.
//
// Every scenario here captures the vertex shader's inputs with transform feedback
// under GL_RASTERIZER_DISCARD, which is what the KHR-GL43.vertex_attrib_binding
// cases do: the captured record IS the fetched vertex, so "the binding state did
// not reach the draw" and "the draw fetched the wrong bytes" are distinguishable
// from each other and from "the capture did not run" (the buffer is pre-filled
// with a poison value).
#include <cstdio>
#include <cstring>
#include <string>
#include <vector>
#include "../Harness/HeadlessGL.h"
#include "../Harness/ScenarioFixture.h"
#ifdef GLAPI
#undef GLAPI
#endif
#define GL_GLEXT_PROTOTYPES
#include <GL/gl.h>
#include <GL/glcorearb.h>
#undef GL_GLEXT_PROTOTYPES
namespace MGITest {
namespace {
constexpr float kPoison = -1234.0f;
GLuint CompileShader(GLenum type, const std::string& source, std::string* log) {
const GLuint shader = glCreateShader(type);
const char* text = source.c_str();
glShaderSource(shader, 1, &text, nullptr);
glCompileShader(shader);
GLint status = GL_FALSE;
glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
if (status == GL_FALSE) {
GLint length = 0;
glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &length);
std::vector<char> buffer(static_cast<std::size_t>(length) + 1, '\0');
glGetShaderInfoLog(shader, length + 1, nullptr, buffer.data());
if (log != nullptr) *log = buffer.data();
glDeleteShader(shader);
return 0;
}
return shader;
}
// A vertex-only capture program, exactly how the CTS builds one: the varying
// names are declared before the link and the fragment stage is absent because
// the draw runs under GL_RASTERIZER_DISCARD.
GLuint BuildCaptureProgram(const std::string& vertexSource, const std::vector<const char*>& xfbVaryings,
std::string* log) {
const GLuint vertexShader = CompileShader(GL_VERTEX_SHADER, vertexSource, log);
if (vertexShader == 0) return 0;
const GLuint program = glCreateProgram();
glAttachShader(program, vertexShader);
if (!xfbVaryings.empty()) {
glTransformFeedbackVaryings(program, static_cast<GLsizei>(xfbVaryings.size()), xfbVaryings.data(),
GL_INTERLEAVED_ATTRIBS);
}
glLinkProgram(program);
glDeleteShader(vertexShader);
GLint status = GL_FALSE;
glGetProgramiv(program, GL_LINK_STATUS, &status);
if (status == GL_FALSE) {
GLint length = 0;
glGetProgramiv(program, GL_INFO_LOG_LENGTH, &length);
std::vector<char> buffer(static_cast<std::size_t>(length) + 1, '\0');
glGetProgramInfoLog(program, length + 1, nullptr, buffer.data());
if (log != nullptr) *log = buffer.data();
glDeleteProgram(program);
return 0;
}
return program;
}
// Four float inputs at locations 0..3, captured as four vec4s per vertex.
// Locations the test does not feed keep their current-attribute value, which
// every scenario sets to a known constant first.
std::string CaptureVertexSource() {
return R"(#version 430 core
layout(location = 0) in vec4 vs_in_attrib0;
layout(location = 1) in vec4 vs_in_attrib1;
layout(location = 2) in vec4 vs_in_attrib2;
layout(location = 3) in vec4 vs_in_attrib3;
out StageData {
vec4 attrib0;
vec4 attrib1;
vec4 attrib2;
vec4 attrib3;
} vs_out;
void main() {
vs_out.attrib0 = vs_in_attrib0;
vs_out.attrib1 = vs_in_attrib1;
vs_out.attrib2 = vs_in_attrib2;
vs_out.attrib3 = vs_in_attrib3;
}
)";
}
std::vector<const char*> CaptureVaryingNames() {
return {"StageData.attrib0", "StageData.attrib1", "StageData.attrib2", "StageData.attrib3"};
}
// Runs `vertexCount` x `instanceCount` points through the capture program and
// returns the interleaved floats (16 per point: four vec4s).
std::vector<float> CapturePoints(GLuint program, GLuint xfbBuffer, int vertexCount, int instanceCount) {
const std::size_t floats = static_cast<std::size_t>(vertexCount) * instanceCount * 16;
std::vector<float> poison(floats, kPoison);
glBindBufferBase(GL_TRANSFORM_FEEDBACK_BUFFER, 0, xfbBuffer);
glBufferData(GL_TRANSFORM_FEEDBACK_BUFFER, static_cast<GLsizeiptr>(floats * sizeof(float)), poison.data(),
GL_DYNAMIC_DRAW);
glEnable(GL_RASTERIZER_DISCARD);
glUseProgram(program);
glBeginTransformFeedback(GL_POINTS);
glDrawArraysInstanced(GL_POINTS, 0, vertexCount, instanceCount);
glEndTransformFeedback();
glDisable(GL_RASTERIZER_DISCARD);
std::vector<float> data(floats, kPoison);
glGetBufferSubData(GL_TRANSFORM_FEEDBACK_BUFFER, 0, static_cast<GLsizeiptr>(floats * sizeof(float)),
data.data());
glUseProgram(0);
return data;
}
// point p, attribute a, component c
float At(const std::vector<float>& data, int point, int attrib, int component) {
const std::size_t index = static_cast<std::size_t>(point) * 16 + attrib * 4 + component;
return index < data.size() ? data[index] : kPoison;
}
void ResetCurrentAttribs() {
for (GLuint i = 0; i < 4; ++i) {
glVertexAttrib4f(i, 0.0f, 0.0f, 0.0f, 0.0f);
}
}
::testing::AssertionResult Vec4Is(const std::vector<float>& data, int point, int attrib, float x, float y,
float z, float w) {
const float gx = At(data, point, attrib, 0);
const float gy = At(data, point, attrib, 1);
const float gz = At(data, point, attrib, 2);
const float gw = At(data, point, attrib, 3);
const float tolerance = 0.01f;
auto close = [tolerance](float a, float b) { return (a - b) < tolerance && (b - a) < tolerance; };
if (close(gx, x) && close(gy, y) && close(gz, z) && close(gw, w)) {
return ::testing::AssertionSuccess();
}
return ::testing::AssertionFailure()
<< "point " << point << " attribute " << attrib << " is (" << gx << ", " << gy << ", " << gz << ", "
<< gw << "), expected (" << x << ", " << y << ", " << z << ", " << w << ")";
}
} // namespace
class VertexAttribBindingScenario : public ScenarioTest {
protected:
void SetUp() override {
ScenarioTest::SetUp();
if (!Ready()) return;
m_program = BuildCaptureProgram(CaptureVertexSource(), CaptureVaryingNames(), &m_log);
ASSERT_NE(m_program, 0u) << "capture program did not link: " << m_log;
glGenVertexArrays(1, &m_vao);
glGenBuffers(1, &m_xfbo);
glBindVertexArray(m_vao);
}
void TearDown() override {
if (!Ready()) return;
glBindVertexArray(0);
glDeleteVertexArrays(1, &m_vao);
glDeleteBuffers(1, &m_xfbo);
glDeleteProgram(m_program);
}
GLuint m_program = 0;
GLuint m_vao = 0;
GLuint m_xfbo = 0;
std::string m_log;
};
// glVertexAttribFormat + glBindVertexBuffer + glVertexAttribBinding, in the order
// the CTS uses (buffer first, then format, then binding), must feed the draw.
TEST_F(VertexAttribBindingScenario, FormatAndBindingFeedTheDraw) {
if (!Ready()) GTEST_SKIP();
ResetCurrentAttribs();
const float vertices[] = {1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f};
GLuint vbo = 0;
glGenBuffers(1, &vbo);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexBuffer(0, vbo, 0, 12);
glVertexAttribFormat(1, 3, GL_FLOAT, GL_FALSE, 0);
glVertexAttribBinding(1, 0);
glEnableVertexAttribArray(1);
const std::vector<float> data = CapturePoints(m_program, m_xfbo, 2, 1);
EXPECT_TRUE(Vec4Is(data, 0, 1, 1.0f, 2.0f, 3.0f, 1.0f));
EXPECT_TRUE(Vec4Is(data, 1, 1, 4.0f, 5.0f, 6.0f, 1.0f));
// An attribute nothing configured still reports its current value.
EXPECT_TRUE(Vec4Is(data, 0, 0, 0.0f, 0.0f, 0.0f, 0.0f));
glDisableVertexAttribArray(1);
glDeleteBuffers(1, &vbo);
}
// The reverse order - format and binding declared before any buffer exists on the
// binding point - has to resolve to the same thing once glBindVertexBuffer lands.
TEST_F(VertexAttribBindingScenario, FormatBeforeBufferStillResolves) {
if (!Ready()) GTEST_SKIP();
ResetCurrentAttribs();
const float vertices[] = {1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f};
GLuint vbo = 0;
glGenBuffers(1, &vbo);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glVertexAttribBinding(2, 3);
glVertexAttribFormat(2, 2, GL_FLOAT, GL_FALSE, 4);
glEnableVertexAttribArray(2);
glBindVertexBuffer(3, vbo, 0, 12);
const std::vector<float> data = CapturePoints(m_program, m_xfbo, 2, 1);
EXPECT_TRUE(Vec4Is(data, 0, 2, 2.0f, 3.0f, 0.0f, 1.0f));
EXPECT_TRUE(Vec4Is(data, 1, 2, 5.0f, 6.0f, 0.0f, 1.0f));
glDisableVertexAttribArray(2);
glDeleteBuffers(1, &vbo);
}
// GL 4.6 core 10.3.1: a binding point's stride is the byte distance between
// consecutive elements, and zero means every vertex reads the SAME element. That
// is the opposite of glVertexAttribPointer's stride 0, which means "tightly
// packed" - the two spellings must not be collapsed into one another.
TEST_F(VertexAttribBindingScenario, BindingStrideZeroRepeatsOneElement) {
if (!Ready()) GTEST_SKIP();
ResetCurrentAttribs();
const float vertices[] = {1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f};
GLuint vbo = 0;
glGenBuffers(1, &vbo);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glVertexAttribFormat(0, 4, GL_FLOAT, GL_FALSE, 0);
glVertexAttribBinding(0, 5);
glBindVertexBuffer(5, vbo, 16, 0);
glEnableVertexAttribArray(0);
const std::vector<float> data = CapturePoints(m_program, m_xfbo, 2, 1);
EXPECT_TRUE(Vec4Is(data, 0, 0, 5.0f, 6.0f, 7.0f, 8.0f));
EXPECT_TRUE(Vec4Is(data, 1, 0, 5.0f, 6.0f, 7.0f, 8.0f));
glDisableVertexAttribArray(0);
glDeleteBuffers(1, &vbo);
}
// The pointer API keeps its own meaning of stride 0 (tightly packed) even though
// it is defined in terms of the binding model - the negative control for the
// scenario above.
TEST_F(VertexAttribBindingScenario, PointerStrideZeroStaysTightlyPacked) {
if (!Ready()) GTEST_SKIP();
ResetCurrentAttribs();
const float vertices[] = {1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f};
GLuint vbo = 0;
glGenBuffers(1, &vbo);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 0, nullptr);
glEnableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
const std::vector<float> data = CapturePoints(m_program, m_xfbo, 2, 1);
EXPECT_TRUE(Vec4Is(data, 0, 0, 1.0f, 2.0f, 3.0f, 4.0f));
EXPECT_TRUE(Vec4Is(data, 1, 0, 5.0f, 6.0f, 7.0f, 8.0f));
glDisableVertexAttribArray(0);
glDeleteBuffers(1, &vbo);
}
// glVertexBindingDivisor is per BINDING POINT: it has to reach every attribute
// pointed at that binding, and the instance step must honour the divisor rather
// than advancing once per instance.
TEST_F(VertexAttribBindingScenario, BindingDivisorAppliesToEveryAttributeOnThePoint) {
if (!Ready()) GTEST_SKIP();
ResetCurrentAttribs();
const float vertices[] = {10.0f, 20.0f, 30.0f, 40.0f};
GLuint vbo = 0;
glGenBuffers(1, &vbo);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glVertexAttribFormat(0, 1, GL_FLOAT, GL_FALSE, 0);
glVertexAttribFormat(1, 1, GL_FLOAT, GL_FALSE, 4);
glVertexAttribBinding(0, 4);
glVertexAttribBinding(1, 4);
glBindVertexBuffer(4, vbo, 0, 8);
glVertexBindingDivisor(4, 2);
glEnableVertexAttribArray(0);
glEnableVertexAttribArray(1);
// The divisor is per binding point, so it has to be visible on BOTH attributes
// pointed at it - and this query is what separates "the frontend never resolved
// it" from "the backend did not apply it".
GLint divisor = -1;
glGetVertexAttribiv(0, GL_VERTEX_ATTRIB_ARRAY_DIVISOR, &divisor);
EXPECT_EQ(divisor, 2);
divisor = -1;
glGetVertexAttribiv(1, GL_VERTEX_ATTRIB_ARRAY_DIVISOR, &divisor);
EXPECT_EQ(divisor, 2);
// 1 vertex x 4 instances, divisor 2: instances 0,1 read element 0 and
// instances 2,3 read element 1.
const std::vector<float> data = CapturePoints(m_program, m_xfbo, 1, 4);
EXPECT_TRUE(Vec4Is(data, 0, 0, 10.0f, 0.0f, 0.0f, 1.0f));
EXPECT_TRUE(Vec4Is(data, 1, 0, 10.0f, 0.0f, 0.0f, 1.0f));
EXPECT_TRUE(Vec4Is(data, 2, 0, 30.0f, 0.0f, 0.0f, 1.0f));
EXPECT_TRUE(Vec4Is(data, 3, 0, 30.0f, 0.0f, 0.0f, 1.0f));
EXPECT_TRUE(Vec4Is(data, 0, 1, 20.0f, 0.0f, 0.0f, 1.0f));
EXPECT_TRUE(Vec4Is(data, 2, 1, 40.0f, 0.0f, 0.0f, 1.0f));
glDisableVertexAttribArray(0);
glDisableVertexAttribArray(1);
glDeleteBuffers(1, &vbo);
}
// Two attributes on one binding point at different relative offsets, plus a
// binding offset: the fetch address is binding offset + relative offset, and the
// relative offset must not leak into the binding's own offset.
TEST_F(VertexAttribBindingScenario, RelativeOffsetComposesWithBindingOffset) {
if (!Ready()) GTEST_SKIP();
ResetCurrentAttribs();
const float vertices[] = {0.0f, 0.0f, 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f};
GLuint vbo = 0;
glGenBuffers(1, &vbo);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glVertexAttribFormat(0, 2, GL_FLOAT, GL_FALSE, 0);
glVertexAttribFormat(1, 1, GL_FLOAT, GL_FALSE, 8);
glVertexAttribBinding(0, 1);
glVertexAttribBinding(1, 1);
glBindVertexBuffer(1, vbo, 8, 12);
glEnableVertexAttribArray(0);
glEnableVertexAttribArray(1);
const std::vector<float> data = CapturePoints(m_program, m_xfbo, 2, 1);
EXPECT_TRUE(Vec4Is(data, 0, 0, 1.0f, 2.0f, 0.0f, 1.0f));
EXPECT_TRUE(Vec4Is(data, 0, 1, 3.0f, 0.0f, 0.0f, 1.0f));
EXPECT_TRUE(Vec4Is(data, 1, 0, 4.0f, 5.0f, 0.0f, 1.0f));
EXPECT_TRUE(Vec4Is(data, 1, 1, 6.0f, 0.0f, 0.0f, 1.0f));
glDisableVertexAttribArray(0);
glDisableVertexAttribArray(1);
glDeleteBuffers(1, &vbo);
}
// The KHR-GL43.vertex_attrib_binding.basic-input* capture program verbatim: a
// 16-element vec4 input ARRAY at location 0, copied element by element into a
// 16-element array inside an output interface block, all 16 members captured.
// Every one of the 17 basic-input* cases is built on it, so a backend that cannot
// produce this program fails all of them with "the draw captured zeros" and no
// other symptom.
TEST_F(VertexAttribBindingScenario, InputArrayCaptureProgramFeedsTheDraw) {
if (!Ready()) GTEST_SKIP();
const std::string vs = R"(#version 430 core
layout(location = 0) in vec4 vs_in_attrib[16];
out StageData {
vec4 attrib[16];
} vs_out;
void main() {
for (int i = 0; i < vs_in_attrib.length(); ++i) {
vs_out.attrib[i] = vs_in_attrib[i];
}
}
)";
std::vector<std::string> names;
for (int i = 0; i < 16; ++i) names.push_back("StageData.attrib[" + std::to_string(i) + "]");
std::vector<const char*> varyings;
for (const auto& n : names) varyings.push_back(n.c_str());
std::string log;
const GLuint program = BuildCaptureProgram(vs, varyings, &log);
ASSERT_NE(program, 0u) << "capture program did not link: " << log;
for (GLuint i = 0; i < 16; ++i) glVertexAttrib4f(i, 0.0f, 0.0f, 0.0f, 0.0f);
const float vertices[] = {1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f};
GLuint vbo = 0;
glGenBuffers(1, &vbo);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexBuffer(0, vbo, 0, 12);
glVertexAttribFormat(1, 3, GL_FLOAT, GL_FALSE, 0);
glVertexAttribBinding(1, 0);
glEnableVertexAttribArray(1);
// 16 vec4s per point rather than the 4 the shared helper assumes.
constexpr std::size_t kFloatsPerPoint = 64;
std::vector<float> poison(kFloatsPerPoint * 2, kPoison);
glBindBufferBase(GL_TRANSFORM_FEEDBACK_BUFFER, 0, m_xfbo);
glBufferData(GL_TRANSFORM_FEEDBACK_BUFFER, static_cast<GLsizeiptr>(poison.size() * sizeof(float)),
poison.data(), GL_DYNAMIC_DRAW);
glEnable(GL_RASTERIZER_DISCARD);
glUseProgram(program);
glBeginTransformFeedback(GL_POINTS);
glDrawArrays(GL_POINTS, 0, 2);
glEndTransformFeedback();
glDisable(GL_RASTERIZER_DISCARD);
std::vector<float> data(poison.size(), kPoison);
glGetBufferSubData(GL_TRANSFORM_FEEDBACK_BUFFER, 0,
static_cast<GLsizeiptr>(data.size() * sizeof(float)), data.data());
glUseProgram(0);
// Element 0 of the array has no enabled array behind it, so it must deliver the
// current generic attribute value set above - including its w, which is 0 here and
// NOT the 1 an unwritten vec4 input defaults to.
EXPECT_FLOAT_EQ(data[0], 0.0f);
EXPECT_FLOAT_EQ(data[3], 0.0f);
// attribute 1 of point 0 and of point 1.
EXPECT_FLOAT_EQ(data[4], 1.0f);
EXPECT_FLOAT_EQ(data[5], 2.0f);
EXPECT_FLOAT_EQ(data[6], 3.0f);
EXPECT_FLOAT_EQ(data[7], 1.0f);
EXPECT_FLOAT_EQ(data[kFloatsPerPoint + 4], 4.0f);
EXPECT_FLOAT_EQ(data[kFloatsPerPoint + 5], 5.0f);
EXPECT_FLOAT_EQ(data[kFloatsPerPoint + 6], 6.0f);
EXPECT_FLOAT_EQ(data[kFloatsPerPoint + 7], 1.0f);
glDisableVertexAttribArray(1);
glDeleteBuffers(1, &vbo);
glDeleteProgram(program);
}
} // namespace MGITest
MobileGL/MG_State/GLState/VertexArrayState/VertexArrayObject.cpp
+7 -3
View File
@@ -61,12 +61,16 @@ namespace MobileGL::MG_State::GLState {
}
void VertexArrayObject::SetAttributeFormat(Uint index, int size, DataType type, Bool normalized, int stride,
SizeT offset, Bool isInteger, Bool isBgra) {
SizeT offset, Bool isInteger, Bool isBgra, int effectiveStride) {
if (index >= MAX_VERTEX_ATTRIBS) return;
if (size < 1 || size > 4) {
return;
}
// See VertexAttribute::Stride: the resolved field carries the effective stride so that
// a zero in it can only ever mean the binding model's "do not advance".
const int resolvedStride = effectiveStride >= 0 ? effectiveStride : stride;
// The classic pointer-style API takes back full ownership of the resolved fields.
m_attributeUsesBindingModel[index] = false;
@@ -77,7 +81,7 @@ namespace MobileGL::MG_State::GLState {
m_attributes[index].LegacyPointer = offset;
if (m_attributes[index].Size == size && m_attributes[index].Type == type &&
m_attributes[index].Normalized == normalized && m_attributes[index].Stride == stride &&
m_attributes[index].Normalized == normalized && m_attributes[index].Stride == resolvedStride &&
m_attributes[index].Offset == offset && m_attributes[index].IsInteger == isInteger &&
m_attributes[index].IsBgra == isBgra && !m_attributes[index].IsLong) {
return;
@@ -87,7 +91,7 @@ namespace MobileGL::MG_State::GLState {
attr.Size = size;
attr.Type = type;
attr.Normalized = normalized;
attr.Stride = stride;
attr.Stride = resolvedStride;
attr.Offset = offset;
attr.IsInteger = isInteger;
attr.IsBgra = isBgra;
MobileGL/MG_State/GLState/VertexArrayState/VertexArrayObject.h
+13 -1
View File
@@ -19,6 +19,14 @@ namespace MobileGL {
int Size = 4;
DataType Type = DataType::Float32;
Bool Normalized = false;
// The RESOLVED byte distance between consecutive elements, never the raw
// glVertexAttrib*Pointer argument: a pointer call's stride 0 means "tightly
// packed" and is resolved to the element size here, so a zero that survives
// into this field can only have come from the binding model, where a zero
// VERTEX_BINDING_STRIDE means the opposite - every vertex reads the SAME
// element and the fetch address never advances (GL 4.6 core 10.3.1). Backends
// consume this verbatim; collapsing 0 back into the element size is what made
// KHR-GL43.vertex_attrib_binding.basic-input-case7/8 read past the buffer.
int Stride = 0;
SizeT Offset = 0;
Bool IsInteger = false;
@@ -76,8 +84,12 @@ namespace MobileGL {
void DisableAttribute(Uint index);
Bool IsAttributeEnabled(Uint index) const;
// `stride` is the raw glVertexAttrib*Pointer argument, reported verbatim by
// GL_VERTEX_ATTRIB_ARRAY_STRIDE. `effectiveStride` is what the fetch actually
// advances by - the same value when the argument is non-zero, the tightly
// packed element size when it is zero. Pass -1 to say the two are the same.
void SetAttributeFormat(Uint index, int size, DataType type, Bool normalized, int stride, SizeT offset,
Bool isInteger, Bool isBgra = false);
Bool isInteger, Bool isBgra = false, int effectiveStride = -1);
void BindAttributeBuffer(Uint index, const SharedPtr<BufferObject>& buffer);
MobileGL/MG_Util/ShaderTranspiler/ShaderCompiler.cpp
+11
View File
@@ -20,6 +20,7 @@
#include "SpirvPasses/DecoratePositionInvariantPass.h"
#include "SpirvPasses/LowerDrawParametersPass.h"
#include "SpirvPasses/PackDoubleVertexInputsPass.h"
#include "SpirvPasses/SplitArrayVertexInputsPass.h"
#include "SpirvPasses/RebaseInstanceIndexPass.h"
#include "SpirvPasses/ZeroBaseVertexPass.h"
#include "SpirvPasses/NormalizeRectCoordinatesPass.h"
@@ -630,6 +631,16 @@ namespace MobileGL {
outputBinary);
}
bool ShaderCompiler::SplitArrayVertexInputsForEssl(const Vector<Uint32>& inputBinary,
Vector<uint32_t>& outputBinary) {
using namespace spvtools;
Optimizer optimizer(SPV_ENV_VULKAN_1_1);
optimizer.RegisterPass(SplitArrayVertexInputsPass::CreateSplitArrayVertexInputsPass());
return RunOptimizerChecked("SplitArrayVertexInputsForEssl", optimizer, inputBinary,
outputBinary);
}
bool ShaderCompiler::PackDoubleVertexInputsForVulkan(const Vector<Uint32>& inputBinary,
Vector<uint32_t>& outputBinary) {
using namespace spvtools;
MobileGL/MG_Util/ShaderTranspiler/ShaderCompiler.h
+7
View File
@@ -27,6 +27,13 @@ namespace MobileGL {
// Only for backends without native draw-parameter support (DirectGLES).
static bool LowerDrawParametersForEssl(const Vector<Uint32>& inputBinary,
Vector<uint32_t>& outputBinary);
// Replaces an ARRAY vertex input with one input per element at consecutive
// locations, seeding a Private copy of the array so indexed reads still work.
// GLSL ES has no array vertex inputs and SPIRV-Cross refuses the whole module
// rather than emulating them, so without this the stage never reaches the
// driver. Only for the DirectGLES transpile path.
static bool SplitArrayVertexInputsForEssl(const Vector<Uint32>& inputBinary,
Vector<uint32_t>& outputBinary);
// Drops RelaxedPrecision member decorations from uniform-block structs so
// SPIRV-Cross prints the same (highp) member precision in every stage; ES
// drivers reject cross-stage uniform blocks whose member precisions differ.
MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/SplitArrayVertexInputsPass.cpp
+394
View File
@@ -0,0 +1,394 @@
// MobileGL - MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/SplitArrayVertexInputsPass.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
#include "SplitArrayVertexInputsPass.h"
#include "spirv.hpp"
#include "source/opt/constants.h"
#include "source/opt/def_use_manager.h"
#include "source/opt/instruction.h"
#include "source/opt/ir_context.h"
#include "source/opt/module.h"
#include "source/opt/types.h"
#include "source/util/make_unique.h"
#include <memory>
#include <unordered_set>
#include <vector>
namespace MobileGL {
namespace MG_Util {
namespace ShaderTranspiler {
namespace {
using spvtools::opt::IRContext;
using spvtools::opt::Instruction;
using spvtools::opt::Operand;
namespace analysis = spvtools::opt::analysis;
// How many attribute locations one element of the array consumes. GL 4.6 core
// 11.1.1: a scalar or vector of up to four 32-bit components takes one; a
// double-precision vector wider than two takes two; a matrix takes one per
// column. Zero means "this pass will not touch it" - the module keeps its array
// input and SPIRV-Cross will say so, which is a better outcome than a silently
// mis-located split.
Uint32 LocationsPerElement(const analysis::Type* type) {
if (type == nullptr) return 0;
// Any scalar takes one location, a 64-bit one included.
if (type->AsFloat() != nullptr || type->AsInteger() != nullptr ||
type->AsBool() != nullptr) {
return 1u;
}
if (const auto* vector = type->AsVector()) {
const auto* element = vector->element_type();
const auto* elementFloat = element->AsFloat();
const Bool is64Bit = elementFloat != nullptr && elementFloat->width() == 64;
if (element->AsFloat() == nullptr && element->AsInteger() == nullptr &&
element->AsBool() == nullptr) {
return 0;
}
return (is64Bit && vector->element_count() > 2) ? 2u : 1u;
}
// Matrices, structs, images and nested arrays are left alone deliberately:
// an array of them is vanishingly rare as a vertex input and each carries its
// own location-assignment rule, so getting one wrong would corrupt every
// attribute after it rather than fail loudly.
return 0;
}
// The Location a variable is decorated with, or `false` when it carries none.
// A vertex input without an explicit location cannot be split: the split has to
// name base+i, and inventing a base would collide with whatever the linker
// assigned.
Bool FindLocationDecoration(IRContext& irContext, Uint32 variableId, Uint32& outLocation) {
for (auto& annotation : irContext.annotations()) {
if (annotation.opcode() != spv::Op::OpDecorate) continue;
if (annotation.GetSingleWordInOperand(0) != variableId) continue;
if (static_cast<spv::Decoration>(annotation.GetSingleWordInOperand(1)) !=
spv::Decoration::Location) {
continue;
}
outLocation = annotation.GetSingleWordInOperand(2);
return true;
}
return false;
}
} // namespace
spvtools::opt::Pass::Status SplitArrayVertexInputsPass::Process() {
auto* irContext = context();
auto entryPoints = irContext->module()->entry_points();
if (entryPoints.begin() == entryPoints.end()) return Status::SuccessWithoutChange;
Instruction* entryPoint = &*entryPoints.begin();
if (static_cast<spv::ExecutionModel>(entryPoint->GetSingleWordInOperand(0)) !=
spv::ExecutionModel::Vertex) {
return Status::SuccessWithoutChange;
}
auto* defUseMgr = irContext->get_def_use_mgr();
auto* typeMgr = irContext->get_type_mgr();
auto* constMgr = irContext->get_constant_mgr();
struct Target {
Instruction* variable = nullptr;
Uint32 arrayTypeId = 0;
Uint32 elementTypeId = 0;
Uint32 elementCount = 0;
Uint32 baseLocation = 0;
Uint32 locationsPerElement = 1;
Uint32 elementInputPointerTypeId = 0;
Uint32 elementPrivatePointerTypeId = 0;
Uint32 arrayPrivatePointerTypeId = 0;
};
std::vector<Target> targets;
for (Instruction& inst : irContext->types_values()) {
if (inst.opcode() != spv::Op::OpVariable) continue;
if (static_cast<spv::StorageClass>(inst.GetSingleWordInOperand(0)) !=
spv::StorageClass::Input) {
continue;
}
Instruction* pointerType = defUseMgr->GetDef(inst.type_id());
if (pointerType == nullptr) continue;
const Uint32 pointeeTypeId = pointerType->GetSingleWordInOperand(1);
const analysis::Type* pointeeType = typeMgr->GetType(pointeeTypeId);
const auto* arrayType = pointeeType != nullptr ? pointeeType->AsArray() : nullptr;
if (arrayType == nullptr) continue;
// A builtin input array (gl_ClipDistance and friends) is not an attribute and
// has no location; SPIRV-Cross emits those itself.
Uint32 baseLocation = 0;
if (!FindLocationDecoration(*irContext, inst.result_id(), baseLocation)) continue;
const Uint32 elementTypeId = typeMgr->GetId(arrayType->element_type());
const Uint32 locationsPerElement = LocationsPerElement(arrayType->element_type());
if (elementTypeId == 0 || locationsPerElement == 0) {
MGLOG_I("SplitArrayVertexInputsPass: vertex input %%%u is an array whose element "
"type has no single-location mapping; leaving it declared as an array",
inst.result_id());
continue;
}
// OpTypeArray's length is an id of an integer constant.
Instruction* arrayTypeInst = defUseMgr->GetDef(pointeeTypeId);
if (arrayTypeInst == nullptr || arrayTypeInst->NumInOperands() < 2) continue;
const analysis::Constant* lengthConstant =
constMgr->FindDeclaredConstant(arrayTypeInst->GetSingleWordInOperand(1));
if (lengthConstant == nullptr || lengthConstant->AsIntConstant() == nullptr) continue;
const Uint32 elementCount = lengthConstant->AsIntConstant()->GetU32();
if (elementCount == 0) continue;
Target target;
target.variable = &inst;
target.arrayTypeId = pointeeTypeId;
target.elementTypeId = elementTypeId;
target.elementCount = elementCount;
target.baseLocation = baseLocation;
target.locationsPerElement = locationsPerElement;
targets.push_back(target);
}
if (targets.empty()) return Status::SuccessWithoutChange;
// Everything the demoted array's pointer flows into, in SSA order. Demoting the
// variable changes the STORAGE CLASS of every pointer derived from it, and a
// derived pointer's own result type still says Input - which is an invalid
// module ("the result pointer storage class and base pointer storage class in
// OpAccessChain do not match"), so each one has to be retyped too. Collected
// before anything is mutated so an unsupported use can still decline the whole
// rewrite rather than leave a half-converted module behind.
std::unordered_set<Uint32> derivedPointers;
for (const auto& target : targets) {
derivedPointers.insert(target.variable->result_id());
}
std::vector<Instruction*> pointersToRetype;
for (auto& function : *irContext->module()) {
for (auto& block : function) {
for (auto& inst : block) {
const spv::Op opcode = inst.opcode();
// A pointer this pass moved may only be loaded from or indexed into.
// Anything else (handing it to a function, storing THROUGH it, casting
// it) either cannot happen for a vertex input or would need the callee
// rewritten as well, and silently getting that wrong is worse than
// leaving the module for SPIRV-Cross to reject out loud.
const Bool indexes =
opcode == spv::Op::OpAccessChain ||
opcode == spv::Op::OpInBoundsAccessChain ||
opcode == spv::Op::OpCopyObject;
if (indexes) {
if (inst.NumInOperands() > 0 &&
derivedPointers.count(inst.GetSingleWordInOperand(0)) != 0) {
derivedPointers.insert(inst.result_id());
pointersToRetype.push_back(&inst);
}
continue;
}
if (opcode == spv::Op::OpLoad) continue; // reads are always fine
for (Uint32 i = 0; i < inst.NumInOperands(); ++i) {
const Operand& operand = inst.GetInOperand(i);
if (operand.type != SPV_OPERAND_TYPE_ID || operand.words.size() != 1) {
continue;
}
if (derivedPointers.count(operand.words[0]) == 0) continue;
MGLOG_I("SplitArrayVertexInputsPass: array vertex input %%%u reaches a "
"SPIR-V opcode %u that this pass cannot follow; leaving it "
"declared as an "
"array",
operand.words[0], static_cast<Uint32>(opcode));
return Status::SuccessWithoutChange;
}
}
}
}
// Entry block insertion point: after the block's leading OpVariable run, which
// SPIR-V requires to stay at the top of a function's first block.
const Uint32 entryFunctionId = entryPoint->GetSingleWordInOperand(1);
spvtools::opt::Function* entryFunction = nullptr;
for (auto& function : *irContext->module()) {
if (function.result_id() == entryFunctionId) {
entryFunction = &function;
break;
}
}
if (entryFunction == nullptr || entryFunction->begin() == entryFunction->end()) {
return Status::SuccessWithoutChange;
}
auto& entryBlock = *entryFunction->begin();
auto insertPoint = entryBlock.begin();
while (insertPoint != entryBlock.end() && insertPoint->opcode() == spv::Op::OpVariable) {
++insertPoint;
}
if (insertPoint == entryBlock.end()) return Status::SuccessWithoutChange;
// Every type this pass names has to exist before the variables that name it: the
// types-and-variables section is emitted in order and a forward reference to a
// type is invalid SPIR-V. Same staging as PackDoubleVertexInputsPass.
for (auto& target : targets) {
target.elementInputPointerTypeId =
typeMgr->FindPointerToType(target.elementTypeId, spv::StorageClass::Input);
target.elementPrivatePointerTypeId =
typeMgr->FindPointerToType(target.elementTypeId, spv::StorageClass::Private);
target.arrayPrivatePointerTypeId =
typeMgr->FindPointerToType(target.arrayTypeId, spv::StorageClass::Private);
}
// Index constants for the seeding access chains, all of them before any variable.
Uint32 maxElementCount = 0;
for (const auto& target : targets) {
maxElementCount = std::max(maxElementCount, target.elementCount);
}
std::vector<Uint32> indexConstantIds(maxElementCount, 0);
for (Uint32 index = 0; index < maxElementCount; ++index) {
indexConstantIds[index] = constMgr->GetUIntConstId(index);
}
std::vector<Operand> interfaceOperands;
for (Uint32 i = 0; i < entryPoint->NumInOperands(); ++i) {
interfaceOperands.push_back(entryPoint->GetInOperand(i));
}
for (const auto& target : targets) {
Instruction* variable = target.variable;
const Uint32 oldVariableId = variable->result_id();
// Collected, never added inline: AddAnnotationInst mutates the annotation
// list this function is still walking below.
std::vector<std::unique_ptr<Instruction>> newDecorations;
std::vector<Uint32> elementVariableIds(target.elementCount, 0);
for (Uint32 element = 0; element < target.elementCount; ++element) {
const Uint32 elementVariableId = irContext->TakeNextId();
elementVariableIds[element] = elementVariableId;
irContext->AddGlobalValue(spvtools::MakeUnique<Instruction>(
irContext, spv::Op::OpVariable, target.elementInputPointerTypeId,
elementVariableId,
std::initializer_list<Operand>{
{SPV_OPERAND_TYPE_STORAGE_CLASS,
{static_cast<Uint32>(spv::StorageClass::Input)}}}));
newDecorations.push_back(spvtools::MakeUnique<Instruction>(
irContext, spv::Op::OpDecorate, 0, 0,
std::initializer_list<Operand>{
{SPV_OPERAND_TYPE_ID, {elementVariableId}},
{SPV_OPERAND_TYPE_DECORATION,
{static_cast<Uint32>(spv::Decoration::Location)}},
{SPV_OPERAND_TYPE_LITERAL_INTEGER,
{target.baseLocation + element * target.locationsPerElement}}}));
}
// The array's own decorations move to the elements, except Location (each
// element got its own above) and anything that only described the aggregate.
// RelaxedPrecision is the one that MUST travel: dropping it changes the
// declared precision of the input in the emitted ESSL.
std::vector<Instruction*> deadDecorations;
for (auto& annotation : irContext->annotations()) {
if (annotation.opcode() != spv::Op::OpDecorate) continue;
if (annotation.GetSingleWordInOperand(0) != oldVariableId) continue;
const auto decoration =
static_cast<spv::Decoration>(annotation.GetSingleWordInOperand(1));
if (decoration == spv::Decoration::RelaxedPrecision ||
decoration == spv::Decoration::Flat ||
decoration == spv::Decoration::NoPerspective ||
decoration == spv::Decoration::Centroid ||
decoration == spv::Decoration::Sample) {
for (const Uint32 elementVariableId : elementVariableIds) {
std::vector<Operand> operands;
operands.push_back({SPV_OPERAND_TYPE_ID, {elementVariableId}});
for (Uint32 i = 1; i < annotation.NumInOperands(); ++i) {
operands.push_back(annotation.GetInOperand(i));
}
newDecorations.push_back(spvtools::MakeUnique<Instruction>(
irContext, spv::Op::OpDecorate, 0, 0, operands));
}
}
deadDecorations.push_back(&annotation);
}
for (auto* annotation : deadDecorations) {
irContext->KillInst(annotation);
}
for (auto& decoration : newDecorations) {
irContext->AddAnnotationInst(std::move(decoration));
}
// Demote the original to a Private global: every existing OpLoad and
// OpAccessChain on it stays valid and keeps its array type, dynamic indices
// included. Moved to the end of the section for the same reason as in
// PackDoubleVertexInputsPass - a variable may not forward-reference its type.
variable->SetResultType(target.arrayPrivatePointerTypeId);
variable->SetInOperand(0, {static_cast<Uint32>(spv::StorageClass::Private)});
variable->RemoveFromList();
irContext->AddGlobalValue(std::unique_ptr<Instruction>(variable));
// SPIR-V 1.3 lists only Input/Output in the entry-point interface, and the
// array is no longer an Input: replace it with the elements in place, so the
// interface keeps one entry per live interface variable.
std::vector<Operand> rebuilt;
for (Uint32 i = 0; i < interfaceOperands.size(); ++i) {
const Operand& operand = interfaceOperands[i];
if (i >= 3 && operand.type == SPV_OPERAND_TYPE_ID &&
operand.words.size() == 1 && operand.words[0] == oldVariableId) {
for (const Uint32 elementVariableId : elementVariableIds) {
rebuilt.push_back({SPV_OPERAND_TYPE_ID, {elementVariableId}});
}
continue;
}
rebuilt.push_back(operand);
}
interfaceOperands = std::move(rebuilt);
// Seed the Private array once, at the top of the entry point, before any of
// the code that reads it.
for (Uint32 element = 0; element < target.elementCount; ++element) {
const Uint32 loadedId = irContext->TakeNextId();
const Uint32 elementPointerId = irContext->TakeNextId();
insertPoint = insertPoint.InsertBefore(spvtools::MakeUnique<Instruction>(
irContext, spv::Op::OpLoad, target.elementTypeId, loadedId,
std::initializer_list<Operand>{
{SPV_OPERAND_TYPE_ID, {elementVariableIds[element]}}}));
++insertPoint;
insertPoint = insertPoint.InsertBefore(spvtools::MakeUnique<Instruction>(
irContext, spv::Op::OpAccessChain, target.elementPrivatePointerTypeId,
elementPointerId,
std::initializer_list<Operand>{
{SPV_OPERAND_TYPE_ID, {oldVariableId}},
{SPV_OPERAND_TYPE_ID, {indexConstantIds[element]}}}));
++insertPoint;
insertPoint = insertPoint.InsertBefore(spvtools::MakeUnique<Instruction>(
irContext, spv::Op::OpStore, 0, 0,
std::initializer_list<Operand>{{SPV_OPERAND_TYPE_ID, {elementPointerId}},
{SPV_OPERAND_TYPE_ID, {loadedId}}}));
++insertPoint;
}
}
entryPoint->SetInOperands(std::move(interfaceOperands));
// Retype the derived pointers collected above. Done last, so the pointer types
// it appends land after the variables (nothing in the types-and-variables
// section names them - they are only ever the result type of an instruction in
// a function body).
for (Instruction* pointer : pointersToRetype) {
Instruction* resultType = defUseMgr->GetDef(pointer->type_id());
if (resultType == nullptr || resultType->opcode() != spv::Op::OpTypePointer) continue;
if (static_cast<spv::StorageClass>(resultType->GetSingleWordInOperand(0)) ==
spv::StorageClass::Private) {
continue;
}
pointer->SetResultType(typeMgr->FindPointerToType(resultType->GetSingleWordInOperand(1),
spv::StorageClass::Private));
}
irContext->InvalidateAnalysesExceptFor(IRContext::kAnalysisNone);
return Status::SuccessWithChange;
}
spvtools::Optimizer::PassToken SplitArrayVertexInputsPass::CreateSplitArrayVertexInputsPass() {
return spvtools::Optimizer::PassToken(MakeUnique<SplitArrayVertexInputsPass>());
}
} // namespace ShaderTranspiler
} // namespace MG_Util
} // namespace MobileGL
MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/SplitArrayVertexInputsPass.h
+52
View File
@@ -0,0 +1,52 @@
// MobileGL - MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/SplitArrayVertexInputsPass.h
// 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
#pragma once
#include "source/opt/pass.h"
#include "spirv-tools/optimizer.hpp"
#include <Includes.h>
namespace MobileGL {
namespace MG_Util {
namespace ShaderTranspiler {
// Replaces an ARRAY vertex input with one input variable per element, at
// consecutive locations, and demotes the original array to a Private global
// seeded once at the top of the entry point.
//
// GLSL ES has no array vertex inputs at all (GLSL ES 3.20 4.3.4: a vertex shader
// input "cannot be ... arrays"), and SPIRV-Cross does not emulate the difference:
// it refuses the whole module with "OpenGL ES doesn't support array input
// variables in vertex shader". The stage then never reaches the driver, the
// program links without a vertex shader, and every draw using it is a silent
// no-op - which is how the entire KHR-GL43.vertex_attrib_binding.basic-input*
// family (its capture program declares `in vec4 vs_in_attrib[16]`) failed on
// DirectGLES with no symptom other than "the draw captured zeros".
//
// Desktop GL DOES allow the declaration, and it means exactly what the split
// produces: element i of an input array consumes location base+i (GL 4.6 core
// 11.1.1). So the split is a spelling change, not a semantic one - the same
// vertex attributes feed the same components, and the frontend's reflection
// (which the backends bind attributes from) is not involved.
//
// Downstream code is untouched on purpose: the original variable keeps its id and
// its array type, so every OpAccessChain into it - including the DYNAMICALLY
// indexed ones a `for` loop produces, which is precisely what an input array is
// usually written for - stays valid against the Private copy.
//
// DirectGLES only. Vulkan takes array vertex inputs as they are.
class SplitArrayVertexInputsPass : public spvtools::opt::Pass {
public:
const char* name() const override { return "mobilegl-split-array-vertex-inputs"; }
Status Process() override;
static spvtools::Optimizer::PassToken CreateSplitArrayVertexInputsPass();
};
} // namespace ShaderTranspiler
} // namespace MG_Util
} // namespace MobileGL