Vulkan: Fix transform feedback spanning multiple render passes

src/libANGLE/renderer/vulkan/ContextVk.cpp

@@ -1121,7 +1121,7 @@ angle::Result ContextVk::handleDirtyGraphicsPipeline(const gl::Context *context,
         mGraphicsPipelineTransition.reset();
     }
 
-    resumeTransformFeedbackIfStarted();
+    pauseTransformFeedbackIfStarted({});
 
     commandBuffer->bindGraphicsPipeline(mCurrentGraphicsPipeline->getPipeline());
     // Update the queue serial for the pipeline object.
@@ -3657,12 +3657,13 @@ void ContextVk::writeAtomicCounterBufferDriverUniformOffsets(uint32_t *offsetsOu
     }
 }
 
-ANGLE_INLINE void ContextVk::resumeTransformFeedbackIfStarted()
+ANGLE_INLINE void ContextVk::pauseTransformFeedbackIfStarted(DirtyBits onResumeOps)
 {
     if (mRenderPassCommands->isTransformFeedbackStarted())
     {
         ASSERT(getFeatures().supportsTransformFeedbackExtension.enabled);
         mGraphicsDirtyBits.set(DIRTY_BIT_TRANSFORM_FEEDBACK_RESUME);
+        mGraphicsDirtyBits |= onResumeOps;
         mRenderPassCommands->pauseTransformFeedback();
     }
 }
@@ -4596,7 +4597,9 @@ angle::Result ContextVk::flushCommandsAndEndRenderPass()
 
     addOverlayUsedBuffersCount(mRenderPassCommands);
 
-    resumeTransformFeedbackIfStarted();
+    DirtyBits rebindTransformFeedbackOnResume;
+    rebindTransformFeedbackOnResume.set(DIRTY_BIT_TRANSFORM_FEEDBACK_STATE);
+    pauseTransformFeedbackIfStarted(rebindTransformFeedbackOnResume);
 
     mRenderPassCommands->endRenderPass(this);
 

src/libANGLE/renderer/vulkan/ContextVk.h

@@ -845,7 +845,7 @@ class ContextVk : public ContextImpl, public vk::Context, public MultisampleText
     void populateTransformFeedbackBufferSet(
         size_t bufferCount,
         const gl::TransformFeedbackBuffersArray<vk::BufferHelper *> &buffers);
-    void resumeTransformFeedbackIfStarted();
+    void pauseTransformFeedbackIfStarted(DirtyBits onResumeOps);
 
     // DescriptorSet writes
     template <typename T, const T *VkWriteDescriptorSet::*pInfo>

src/tests/gl_tests/TransformFeedbackTest.cpp

@@ -280,6 +280,103 @@ TEST_P(TransformFeedbackTest, RecordAndDraw)
     EXPECT_GL_NO_ERROR();
 }
 
+// Test that transform feedback can cover multiple render passes.
+TEST_P(TransformFeedbackTest, SpanMultipleRenderPasses)
+{
+    // TODO(anglebug.com/4533) This fails after the upgrade to the 26.20.100.7870 driver.
+    ANGLE_SKIP_TEST_IF(IsWindows() && IsIntel() && IsVulkan());
+
+    // Fails on Mac GL drivers. http://anglebug.com/4992
+    ANGLE_SKIP_TEST_IF(IsOpenGL() && IsOSX());
+
+    // anglebug.com/5428
+    ANGLE_SKIP_TEST_IF(IsLinux() && IsIntel() && IsVulkan());
+
+    // anglebug.com/5429
+    ANGLE_SKIP_TEST_IF(IsAndroid() && IsOpenGLES());
+
+    glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
+    glClear(GL_COLOR_BUFFER_BIT);
+
+    // Set the program's transform feedback varyings (just gl_Position)
+    std::vector<std::string> tfVaryings;
+    tfVaryings.push_back("gl_Position");
+    compileDefaultProgram(tfVaryings, GL_INTERLEAVED_ATTRIBS);
+
+    glUseProgram(mProgram);
+
+    GLint positionLocation = glGetAttribLocation(mProgram, essl1_shaders::PositionAttrib());
+
+    const GLfloat vertices[] = {
+        -0.5f, 0.5f, 0.5f, -0.5f, -0.5f, 0.5f, 0.5f, -0.5f, 0.5f,
+        -0.5f, 0.5f, 0.5f, 0.5f,  -0.5f, 0.5f, 0.5f, 0.5f,  0.5f,
+    };
+
+    glVertexAttribPointer(positionLocation, 3, GL_FLOAT, GL_FALSE, 0, vertices);
+    glEnableVertexAttribArray(positionLocation);
+
+    // Bind the buffer for transform feedback output and start transform feedback
+    glBindBufferBase(GL_TRANSFORM_FEEDBACK_BUFFER, 0, mTransformFeedbackBuffer);
+    glBeginTransformFeedback(GL_POINTS);
+
+    // Create a query to check how many primitives were written
+    GLuint primitivesWrittenQuery = 0;
+    glGenQueries(1, &primitivesWrittenQuery);
+    glBeginQuery(GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN, primitivesWrittenQuery);
+
+    // Draw the first set of three points
+    glDrawArrays(GL_POINTS, 0, 3);
+
+    // Break the render pass
+    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::black);
+
+    // Draw the second set of three points
+    glVertexAttribPointer(positionLocation, 3, GL_FLOAT, GL_FALSE, 0, vertices + 9);
+    glDrawArrays(GL_POINTS, 0, 3);
+
+    glDisableVertexAttribArray(positionLocation);
+    glVertexAttribPointer(positionLocation, 4, GL_FLOAT, GL_FALSE, 0, nullptr);
+    // End the query and transform feedback
+    glEndQuery(GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN);
+    glEndTransformFeedback();
+
+    glBindBufferBase(GL_TRANSFORM_FEEDBACK_BUFFER, 0, 0);
+
+    // Verify the number of primitives written
+    GLuint primitivesWritten = 0;
+    glGetQueryObjectuiv(primitivesWrittenQuery, GL_QUERY_RESULT_EXT, &primitivesWritten);
+    EXPECT_GL_NO_ERROR();
+
+    EXPECT_EQ(6u, primitivesWritten);
+
+    // Verify the captured buffer.
+
+    glBindBuffer(GL_ARRAY_BUFFER, mTransformFeedbackBuffer);
+    glVertexAttribPointer(positionLocation, 4, GL_FLOAT, GL_FALSE, 0, 0);
+    glEnableVertexAttribArray(positionLocation);
+
+    glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
+    glClear(GL_COLOR_BUFFER_BIT);
+    glDrawArrays(GL_TRIANGLES, 0, 6);
+
+    const int w = getWindowWidth();
+    const int h = getWindowHeight();
+
+    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::black);
+    EXPECT_PIXEL_COLOR_EQ(w - 1, 0, GLColor::black);
+    EXPECT_PIXEL_COLOR_EQ(0, h - 1, GLColor::black);
+    EXPECT_PIXEL_COLOR_EQ(w - 1, h - 1, GLColor::black);
+
+    EXPECT_PIXEL_COLOR_EQ(w / 4 + 1, h / 4 + 1, GLColor::red);
+    EXPECT_PIXEL_COLOR_EQ(3 * w / 4 - 1, h / 4 + 1, GLColor::red);
+    EXPECT_PIXEL_COLOR_EQ(w / 4 + 1, 3 * h / 4 - 1, GLColor::red);
+    EXPECT_PIXEL_COLOR_EQ(3 * w / 4 - 1, 3 * h / 4 - 1, GLColor::red);
+
+    EXPECT_PIXEL_COLOR_EQ(w / 2, h / 2, GLColor::red);
+
+    EXPECT_GL_NO_ERROR();
+}
+
 // Test that XFB does not allow writing more vertices than fit in the bound buffers.
 // TODO(jmadill): Enable this test after fixing the last case where the buffer size changes after
 // calling glBeginTransformFeedback.