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[Fix] (Query): tie the two tessellation pipeline-statistics targets to the GL_ARB_tessellation_shader advertisement

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swung0x48
2026-08-27 10:48:20 -04:00
parent d4e7378868
commit ebff4b21f7
2 changed files with 104 additions and 11 deletions
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MobileGL/MG_Impl/GLImpl/Query/GL_Query.cpp
+34 -9
View File
@@ -64,21 +64,43 @@ namespace MobileGL::MG_Impl::GLImpl {
// and none of them has any state beyond "which object is counting".
UnorderedMap<GLenum, GLuint> g_activePipelineStatisticsQueryIds;
// Whether MobileGL puts GL_ARB_tessellation_shader in its extension string. Read from the
// ADVERTISED list rather than from a capability bit for the same reason
// BackendSupportsTextureViews does (GL_Texture.cpp): it makes "MobileGL claims tessellation
// support" and "the tessellation-conditional API surface is open" the same fact by
// construction, so the day a backend starts advertising the string the surface below opens
// with it and no second edit is owed.
Bool AdvertisesTessellationShaderExtension() {
const auto& activeBackendObject = MG_Backend::pActiveBackendObject;
if (!activeBackendObject) return false;
const auto& extensions = activeBackendObject->GetRendererInfo().RendererGLInfo.Extensions;
return std::find(extensions.begin(), extensions.end(), E_GL_ARB_tessellation_shader) != extensions.end();
}
// The eleven pipeline-statistics counters (GL 4.6 core table 4.3 / ARB_pipeline_statistics_query).
// A 4.6 core context has to ACCEPT all of them at glBeginQuery - the extension is core
// since 4.6 and there is no query by which an application could learn otherwise before
// calling. MobileGL instruments none of them, and says so the way GL 4.6 core 4.2.1
// provides for: GL_QUERY_COUNTER_BITS answers zero for these targets, which is the
// spec's own signal that the counter is unsupported and its results indeterminate. That
// is an honest zero, not an advertised capability - the alternative, GL_INVALID_ENUM on a
// core entry point, is both non-conformant AND less informative.
// A 4.6 core context ACCEPTS the nine unconditional ones at glBeginQuery - there is no query
// by which an application could learn otherwise before calling. MobileGL instruments none of
// them, and says so the way GL 4.6 core 4.2.1 provides for: GL_QUERY_COUNTER_BITS answers
// zero for these targets, which is the spec's own signal that the counter is unsupported and
// its results indeterminate. That is an honest zero, not an advertised capability - the
// alternative, GL_INVALID_ENUM on a core entry point, is both non-conformant AND less
// informative.
//
// The two TESSELLATION targets are the exception, because ARB_pipeline_statistics_query
// makes them conditional on tessellation support rather than unconditional, and the only
// thing an application (or the conformance suite) can read to decide whether an
// implementation has it is the GL_ARB_tessellation_shader string. MobileGL does not emit it
// today, so these two answer GL_INVALID_ENUM: an API surface that accepts a
// tessellation-conditional token while withholding the string that announces the condition
// is self-contradictory, and it is the contradiction the suite catches
// (KHR-GL46.pipeline_statistics_query_tests_ARB.api_coverage_unsupported_calls, whose
// support probe is gl4cPipelineStatisticsQueryTests.cpp:1166-1176). The gate is the
// advertisement itself, not a hardcoded "no", so this is one switch and not two.
Bool IsPipelineStatisticsQueryTarget(GLenum target) {
switch (target) {
case GL_VERTICES_SUBMITTED:
case GL_PRIMITIVES_SUBMITTED:
case GL_VERTEX_SHADER_INVOCATIONS:
case GL_TESS_CONTROL_SHADER_PATCHES:
case GL_TESS_EVALUATION_SHADER_INVOCATIONS:
case GL_GEOMETRY_SHADER_INVOCATIONS:
case GL_GEOMETRY_SHADER_PRIMITIVES_EMITTED:
case GL_FRAGMENT_SHADER_INVOCATIONS:
@@ -86,6 +108,9 @@ namespace MobileGL::MG_Impl::GLImpl {
case GL_CLIPPING_INPUT_PRIMITIVES:
case GL_CLIPPING_OUTPUT_PRIMITIVES:
return true;
case GL_TESS_CONTROL_SHADER_PATCHES:
case GL_TESS_EVALUATION_SHADER_INVOCATIONS:
return AdvertisesTessellationShaderExtension();
default:
return false;
}
MobileGL/MG_Test/Query/QueryTest.cpp
+70 -2
View File
@@ -827,10 +827,11 @@ TEST_F(QueryTest, DisableTimerQueryFeatureMatchesEnvironment) {
// ---------------------------------------------------------------------------------------------
TEST_F(QueryTest, PipelineStatisticsTargetsAreAcceptedAndReportZeroCounterBits) {
// The NINE unconditional targets. The two tessellation ones are conditional on tessellation
// support and have their own test below.
static constexpr GLenum kTargets[] = {
GL_VERTICES_SUBMITTED, GL_PRIMITIVES_SUBMITTED,
GL_VERTEX_SHADER_INVOCATIONS, GL_TESS_CONTROL_SHADER_PATCHES,
GL_TESS_EVALUATION_SHADER_INVOCATIONS, GL_GEOMETRY_SHADER_INVOCATIONS,
GL_VERTEX_SHADER_INVOCATIONS, GL_GEOMETRY_SHADER_INVOCATIONS,
GL_GEOMETRY_SHADER_PRIMITIVES_EMITTED, GL_FRAGMENT_SHADER_INVOCATIONS,
GL_COMPUTE_SHADER_INVOCATIONS, GL_CLIPPING_INPUT_PRIMITIVES,
GL_CLIPPING_OUTPUT_PRIMITIVES,
@@ -872,6 +873,73 @@ TEST_F(QueryTest, PipelineStatisticsTargetsAreAcceptedAndReportZeroCounterBits)
}
}
// GL_TESS_CONTROL_SHADER_PATCHES / GL_TESS_EVALUATION_SHADER_INVOCATIONS are the two
// pipeline-statistics targets ARB_pipeline_statistics_query makes CONDITIONAL on tessellation
// support, and the extension string is the only thing an application can read to decide whether
// an implementation has it. So the target and the string have to move together: accepting a
// tessellation-conditional token while withholding the string that announces the condition is
// self-contradictory, and the conformance suite catches exactly that contradiction
// (KHR-GL46.pipeline_statistics_query_tests_ARB.api_coverage_unsupported_calls demands
// GL_INVALID_ENUM for every target its own probe calls unsupported, and its probe for these two
// is `compatibility(4,0) || GL_ARB_tessellation_shader` - a CORE context fails the first half).
//
// Written against the advertisement rather than against today's answer on purpose: the day a
// backend starts emitting GL_ARB_tessellation_shader this test keeps passing and keeps pinning
// the coupling, and it fails loudly if only one of the two halves moves.
TEST_F(QueryTest, TessellationPipelineStatisticsTargetsFollowTheTessellationShaderAdvertisement) {
const auto* extensionsString =
reinterpret_cast<const char*>(MG_Impl::GLImpl::GetString(GL_EXTENSIONS));
ASSERT_NE(extensionsString, nullptr);
const Bool advertised = String(extensionsString).find("GL_ARB_tessellation_shader") != String::npos;
const GLenum expectedError = advertised ? GL_NO_ERROR : GL_INVALID_ENUM;
static constexpr GLenum kTessTargets[] = {
GL_TESS_CONTROL_SHADER_PATCHES,
GL_TESS_EVALUATION_SHADER_INVOCATIONS,
};
for (const GLenum target: kTessTargets) {
GLuint id = 0;
MG_Impl::GLImpl::GenQueries(1, &id);
ASSERT_NE(id, 0u);
MG_Impl::GLImpl::BeginQuery(target, id);
EXPECT_EQ(MG_Impl::GLImpl::GetError(), expectedError)
<< "glBeginQuery on tessellation pipeline-statistics target 0x" << std::hex << target
<< " must agree with the GL_ARB_tessellation_shader advertisement";
if (advertised) {
MG_Impl::GLImpl::EndQuery(target);
EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
GLint counterBits = -1;
MG_Impl::GLImpl::GetQueryiv(target, GL_QUERY_COUNTER_BITS, &counterBits);
EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
EXPECT_EQ(counterBits, 0);
} else {
// Refused at glEndQuery too, not just at glBeginQuery: a target the implementation
// does not have is not half-accepted.
MG_Impl::GLImpl::EndQuery(target);
EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_INVALID_ENUM);
// GL_QUERY_COUNTER_BITS still answers the honest zero rather than an error - the
// getter has never validated its target, and zero is what "no such counter" reads as
// (GL 4.6 core 4.2.1), so the refusal costs no information.
GLint counterBits = -1;
MG_Impl::GLImpl::GetQueryiv(target, GL_QUERY_COUNTER_BITS, &counterBits);
EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
EXPECT_EQ(counterBits, 0);
// And GL_CURRENT_QUERY reads as "no query" rather than tracking a slot that was
// never opened.
GLint current = -1;
MG_Impl::GLImpl::GetQueryiv(target, GL_CURRENT_QUERY, &current);
EXPECT_EQ(current, 0);
}
MG_Impl::GLImpl::DeleteQueries(1, &id);
while (MG_Impl::GLImpl::GetError() != GL_NO_ERROR) {
}
}
}
// The negative half the conformance case actually asserts: an object already latched onto one
// pipeline-statistics target must refuse a different one with GL_INVALID_OPERATION. This is what
// per-target active slots buy - a single shared slot would have reported "a query is already