No-Op draws when no active VS and/or FS is present

src/libANGLE/Context.cpp

@@ -1124,6 +1124,7 @@ void Context::bindProgramPipeline(ProgramPipelineID pipelineHandle)
     ProgramPipeline *pipeline = mState.mProgramPipelineManager->checkProgramPipelineAllocation(
         mImplementation.get(), pipelineHandle);
     ANGLE_CONTEXT_TRY(mState.setProgramPipelineBinding(this, pipeline));
+    mStateCache.onProgramExecutableChange(this);
 }
 
 void Context::beginQuery(QueryType target, QueryID query)
@@ -8491,7 +8492,8 @@ StateCache::StateCache()
       mCachedInstancedVertexElementLimit(0),
       mCachedBasicDrawStatesError(kInvalidPointer),
       mCachedBasicDrawElementsError(kInvalidPointer),
-      mCachedTransformFeedbackActiveUnpaused(false)
+      mCachedTransformFeedbackActiveUnpaused(false),
+      mCachedCanDraw(false)
 {}
 
 StateCache::~StateCache() = default;
@@ -8512,6 +8514,7 @@ void StateCache::initialize(Context *context)
     updateBasicDrawStatesError();
     updateBasicDrawElementsError();
     updateVertexAttribTypesValidation(context);
+    updateCanDraw(context);
 }
 
 void StateCache::updateActiveAttribsMask(Context *context)
@@ -8623,6 +8626,7 @@ void StateCache::onProgramExecutableChange(Context *context)
     updateBasicDrawStatesError();
     updateValidDrawModes(context);
     updateActiveShaderStorageBufferIndices(context);
+    updateCanDraw(context);
 }
 
 void StateCache::onVertexArrayFormatChange(Context *context)
@@ -8884,4 +8888,11 @@ void StateCache::updateActiveShaderStorageBufferIndices(Context *context)
         }
     }
 }
+
+void StateCache::updateCanDraw(Context *context)
+{
+    mCachedCanDraw = (context->isGLES1() ||
+                      (context->getState().getProgramExecutable() &&
+                       context->getState().getProgramExecutable()->hasVertexAndFragmentShader()));
+}
 }  // namespace gl

src/libANGLE/Context.h

@@ -257,6 +257,10 @@ class StateCache final : angle::NonCopyable
         return mCachedActiveShaderStorageBufferIndices;
     }
 
+    // Places that can trigger updateCanDraw:
+    // 1. onProgramExecutableChange.
+    bool getCanDraw() const { return mCachedCanDraw; }
+
     // State change notifications.
     void onVertexArrayBindingChange(Context *context);
     void onProgramExecutableChange(Context *context);
@@ -290,6 +294,7 @@ class StateCache final : angle::NonCopyable
     void updateTransformFeedbackActiveUnpaused(Context *context);
     void updateVertexAttribTypesValidation(Context *context);
     void updateActiveShaderStorageBufferIndices(Context *context);
+    void updateCanDraw(Context *context);
 
     void setValidDrawModes(bool pointsOK, bool linesOK, bool trisOK, bool lineAdjOK, bool triAdjOK);
 
@@ -324,6 +329,8 @@ class StateCache final : angle::NonCopyable
                          VertexAttribTypeCase,
                          angle::EnumSize<VertexAttribType>() + 1>
         mCachedIntegerVertexAttribTypesValidation;
+
+    bool mCachedCanDraw;
 };
 
 using VertexArrayMap       = ResourceMap<VertexArray, VertexArrayID>;

src/libANGLE/Context.inl.h

@@ -66,6 +66,11 @@ ANGLE_INLINE void MarkShaderStorageBufferUsage(const Context *context)
 //  have a valid primitive for this mode (0 for points, 0-1 for lines, 0-2 for tris).
 ANGLE_INLINE bool Context::noopDraw(PrimitiveMode mode, GLsizei count)
 {
+    if (!mStateCache.getCanDraw())
+    {
+        return true;
+    }
+
     return count < kMinimumPrimitiveCounts[mode];
 }
 

src/libANGLE/Program.cpp

@@ -5464,6 +5464,7 @@ angle::Result Program::deserialize(const Context *context,
     mState.mExecutable.load(&stream);
 
     postResolveLink(context);
+    mState.mExecutable.updateCanDrawWith();
 
     return angle::Result::Continue;
 }

src/libANGLE/ProgramExecutable.cpp

@@ -24,7 +24,8 @@ ProgramExecutable::ProgramExecutable()
       mAttributesMask(0),
       mActiveSamplersMask(0),
       mActiveSamplerRefCounts{},
-      mActiveImagesMask(0)
+      mActiveImagesMask(0),
+      mCanDrawWith(false)
 {
     mActiveSamplerTypes.fill(TextureType::InvalidEnum);
     mActiveSamplerFormats.fill(SamplerFormat::InvalidEnum);
@@ -458,4 +459,10 @@ bool ProgramExecutable::linkValidateGlobalNames(InfoLog &infoLog) const
     return true;
 }
 
+void ProgramExecutable::updateCanDrawWith()
+{
+    mCanDrawWith =
+        (hasLinkedShaderStage(ShaderType::Vertex) && hasLinkedShaderStage(ShaderType::Fragment));
+}
+
 }  // namespace gl

src/libANGLE/ProgramExecutable.h

@@ -94,6 +94,8 @@ class ProgramExecutable
         {
             mLinkedGraphicsShaderStages.set(shaderType);
         }
+
+        updateCanDrawWith();
     }
     bool hasLinkedShaderStage(ShaderType shaderType) const
     {
@@ -165,6 +167,9 @@ class ProgramExecutable
 
     void setIsCompute(bool isComputeIn);
 
+    void updateCanDrawWith();
+    bool hasVertexAndFragmentShader() const { return mCanDrawWith; }
+
   private:
     // TODO(timvp): http://anglebug.com/3570: Investigate removing these friend
     // class declarations and accessing the necessary members with getters/setters.
@@ -204,6 +209,8 @@ class ProgramExecutable
     // Cached mask of active images.
     ActiveTextureMask mActiveImagesMask;
     ActiveTextureArray<ShaderBitSet> mActiveImageShaderBits;
+
+    bool mCanDrawWith;
 };
 
 }  // namespace gl

src/libANGLE/ProgramPipeline.cpp

@@ -287,6 +287,8 @@ void ProgramPipeline::updateLinkedShaderStages()
             mState.mExecutable.setLinkedShaderStages(shaderType);
         }
     }
+
+    mState.mExecutable.updateCanDrawWith();
 }
 
 void ProgramPipeline::updateExecutableAttributes()

src/libANGLE/validationES.cpp

@@ -2916,16 +2916,6 @@ const char *ValidateDrawStates(const Context *context)
 
         if (program)
         {
-            // In OpenGL ES spec for UseProgram at section 7.3, trying to render without
-            // vertex shader stage or fragment shader stage is a undefined behaviour.
-            // But ANGLE should clearly generate an INVALID_OPERATION error instead of
-            // produce undefined result.
-            if (!program->getExecutable().hasLinkedShaderStage(ShaderType::Vertex) ||
-                !program->getExecutable().hasLinkedShaderStage(ShaderType::Fragment))
-            {
-                return kNoActiveGraphicsShaderStage;
-            }
-
             if (!program->validateSamplers(nullptr, context->getCaps()))
             {
                 return kTextureTypeConflict;
@@ -2939,16 +2929,6 @@ const char *ValidateDrawStates(const Context *context)
         }
         else if (programPipeline)
         {
-            // In OpenGL ES spec for UseProgram at section 7.3, trying to render without
-            // vertex shader stage or fragment shader stage is a undefined behaviour.
-            // But ANGLE should clearly generate an INVALID_OPERATION error instead of
-            // produce undefined result.
-            if (!programPipeline->getExecutable().hasLinkedShaderStage(ShaderType::Vertex) ||
-                !programPipeline->getExecutable().hasLinkedShaderStage(ShaderType::Fragment))
-            {
-                return kNoActiveGraphicsShaderStage;
-            }
-
             const char *errorMsg = ValidateProgramPipelineAttachedPrograms(programPipeline);
             if (errorMsg)
             {
@@ -2966,10 +2946,6 @@ const char *ValidateDrawStates(const Context *context)
                 return errorMsg;
             }
         }
-        else
-        {
-            return kProgramNotBound;
-        }
 
         // Do some additional WebGL-specific validation
         if (extensions.webglCompatibility)

src/tests/gl_tests/ComputeShaderTest.cpp

@@ -296,7 +296,7 @@ void main()
 
     glUseProgram(program);
     glDrawArrays(GL_POINTS, 0, 2);
-    EXPECT_GL_ERROR(GL_INVALID_OPERATION);
+    EXPECT_GL_NO_ERROR();
 }
 
 // Attach a vertex and fragment shader and link, but dispatch compute.

src/tests/gl_tests/LinkAndRelinkTest.cpp

@@ -37,8 +37,7 @@ class LinkAndRelinkTestES31 : public ANGLETest
 // or vice versa.
 
 // When program link fails and no valid rendering program is installed in the GL
-// state before the link, it should report an error for UseProgram and
-// DrawArrays/DrawElements.
+// state before the link, it should report an error for UseProgram
 TEST_P(LinkAndRelinkTest, RenderingProgramFailsWithoutProgramInstalled)
 {
     glUseProgram(0);
@@ -53,7 +52,7 @@ TEST_P(LinkAndRelinkTest, RenderingProgramFailsWithoutProgramInstalled)
     EXPECT_GL_ERROR(GL_INVALID_OPERATION);
 
     glDrawArrays(GL_POINTS, 0, 1);
-    EXPECT_GL_ERROR(GL_INVALID_OPERATION);
+    EXPECT_GL_NO_ERROR();
 }
 
 // When program link or relink fails and a valid rendering program is installed
@@ -219,7 +218,6 @@ TEST_P(LinkAndRelinkTestES31, ComputeProgramFailsWithoutProgramInstalled)
 // When program link or relink fails and a valid compute program is installed in
 // the GL state before the link, using the failed program via UseProgram should
 // report an error, but dispatching compute should succeed.
-// However, starting rendering always fails.
 TEST_P(LinkAndRelinkTestES31, ComputeProgramFailsWithProgramInstalled)
 {
     // Install a compute program in the GL state via UseProgram, then dispatch
@@ -252,7 +250,7 @@ TEST_P(LinkAndRelinkTestES31, ComputeProgramFailsWithProgramInstalled)
     EXPECT_GL_NO_ERROR();
 
     glDrawArrays(GL_POINTS, 0, 1);
-    EXPECT_GL_ERROR(GL_INVALID_OPERATION);
+    EXPECT_GL_NO_ERROR();
 
     // Link failure, and a valid program has been installed in the GL state.
     GLuint programNull = glCreateProgram();
@@ -266,7 +264,7 @@ TEST_P(LinkAndRelinkTestES31, ComputeProgramFailsWithProgramInstalled)
     EXPECT_GL_NO_ERROR();
 
     glDrawArrays(GL_POINTS, 0, 1);
-    EXPECT_GL_ERROR(GL_INVALID_OPERATION);
+    EXPECT_GL_NO_ERROR();
 
     // Using the unsuccessfully linked program should report an error.
     glUseProgram(programNull);
@@ -280,7 +278,7 @@ TEST_P(LinkAndRelinkTestES31, ComputeProgramFailsWithProgramInstalled)
     EXPECT_GL_NO_ERROR();
 
     glDrawArrays(GL_POINTS, 0, 1);
-    EXPECT_GL_ERROR(GL_INVALID_OPERATION);
+    EXPECT_GL_NO_ERROR();
 
     // We try to relink the installed program, but make it fail.
 
@@ -296,7 +294,7 @@ TEST_P(LinkAndRelinkTestES31, ComputeProgramFailsWithProgramInstalled)
     EXPECT_GL_NO_ERROR();
 
     glDrawArrays(GL_POINTS, 0, 1);
-    EXPECT_GL_ERROR(GL_INVALID_OPERATION);
+    EXPECT_GL_NO_ERROR();
 
     // Using the unsuccessfully relinked program should report an error.
     glUseProgram(program);
@@ -310,11 +308,11 @@ TEST_P(LinkAndRelinkTestES31, ComputeProgramFailsWithProgramInstalled)
     EXPECT_GL_NO_ERROR();
 
     glDrawArrays(GL_POINTS, 0, 1);
-    EXPECT_GL_ERROR(GL_INVALID_OPERATION);
+    EXPECT_GL_NO_ERROR();
 }
 
 // If you compile and link a compute program successfully and use the program,
-// then dispatching compute can succeed, while starting rendering will fail.
+// then dispatching compute and rendering can succeed (with undefined behavior).
 // If you relink the compute program to a rendering program when it is in use,
 // then dispatching compute will fail, but starting rendering can succeed.
 TEST_P(LinkAndRelinkTestES31, RelinkProgramSucceedsFromComputeToRendering)
@@ -347,7 +345,7 @@ void main()
     EXPECT_GL_NO_ERROR();
 
     glDrawArrays(GL_POINTS, 0, 1);
-    EXPECT_GL_ERROR(GL_INVALID_OPERATION);
+    EXPECT_GL_NO_ERROR();
 
     constexpr char kVS[] = "void main() {}";
     constexpr char kFS[] = "void main() {}";
@@ -441,7 +439,7 @@ void main()
     EXPECT_GL_NO_ERROR();
 
     glDrawArrays(GL_POINTS, 0, 1);
-    EXPECT_GL_ERROR(GL_INVALID_OPERATION);
+    EXPECT_GL_NO_ERROR();
 }
 
 ANGLE_INSTANTIATE_TEST_ES2_AND_ES3(LinkAndRelinkTest);