Metal: Clear visibility result buffer before use

Ensured that the current visibility pool buffer does
not contain previous results if it was used before.

Fixed: angleproject:348206830
Change-Id: I8dbc36626ef8267d5466c96405dac0da2754cb6d
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5643453
Commit-Queue: Alexey Knyazev <[email protected]>
Reviewed-by: Quyen Le <[email protected]>
Reviewed-by: Geoff Lang <[email protected]>

src/libANGLE/renderer/metal/ContextMtl.mm

@@ -1824,6 +1824,8 @@ GLint GetOwnershipIdentity(const egl::AttributeMap &attribs)
  mBlitEncoder.endEncoding();
  }
 
+ mOcclusionQueryPool.prepareRenderPassVisibilityPoolBuffer(this);
+
  encoder->endEncoding();
 
  // Resolve visibility results

src/libANGLE/renderer/metal/mtl_occlusion_query_pool.h

@@ -48,6 +48,8 @@ class OcclusionQueryPool
  size_t getNumRenderPassAllocatedQueries() const { return mAllocatedQueries.size(); }
  // This function is called at the end of render pass
  void resolveVisibilityResults(ContextMtl *contextMtl);
+ // Clear visibility pool buffer to drop previous results
+ void prepareRenderPassVisibilityPoolBuffer(ContextMtl *contextMtl);
 
  private:
  // Buffer to hold the visibility results for current render pass
@@ -57,6 +59,7 @@ class OcclusionQueryPool
  std::vector<QueryMtl *> mAllocatedQueries;
 
  bool mResetFirstQuery = false;
+ bool mUsed = false;
 };
 
 } // namespace mtl

src/libANGLE/renderer/metal/mtl_occlusion_query_pool.mm

@@ -50,6 +50,7 @@
  static_cast<uint32_t>(mAllocatedQueries.size()) * kOcclusionQueryResultSize;
  if (!mRenderPassResultsPool)
  {
+ ASSERT(!mUsed);
  // First allocation
  ANGLE_TRY(Buffer::MakeBufferWithStorageMode(contextMtl, MTLStorageModePrivate,
  kOcclusionQueryResultSize, nullptr,
@@ -62,6 +63,7 @@
  ANGLE_TRY(Buffer::MakeBufferWithStorageMode(contextMtl, MTLStorageModePrivate,
  mRenderPassResultsPool->size() * 2, nullptr,
  &mRenderPassResultsPool));
+ mUsed = false;
  mRenderPassResultsPool->get().label = @"OcclusionQueryPool";
  }
 
@@ -180,5 +182,29 @@
  mAllocatedQueries.clear();
 }
 
+void OcclusionQueryPool::prepareRenderPassVisibilityPoolBuffer(ContextMtl *contextMtl)
+{
+ if (mAllocatedQueries.empty())
+ {
+ return;
+ }
+
+ // If the current visibility pool buffer was not used before,
+ // ensure that it will be cleared next time.
+ if (!mUsed)
+ {
+ mUsed = true;
+ return;
+ }
+
+ // If the current visibility pool buffer was used before,
+ // ensure that it does not contain previous results.
+ auto blitEncoder = contextMtl->getBlitCommandEncoderWithoutEndingRenderEncoder();
+ blitEncoder->fillBuffer(mRenderPassResultsPool,
+ NSMakeRange(0, mAllocatedQueries.size() * kOcclusionQueryResultSize),
+ 0);
+ blitEncoder->endEncoding();
+}
+
 } // namespace mtl
 } // namespace rx

src/tests/gl_tests/OcclusionQueriesTest.cpp

@@ -524,6 +524,43 @@ TEST_P(OcclusionQueriesTest, EmptyQueryAfterCompletedQuery)
  EXPECT_FALSE(result);
 }
 
+// Some Metal drivers do not automatically clear visibility buffer
+// at the beginning of a render pass. This test makes two queries
+// that would use the same internal visibility buffer at the same
+// offset and checks the query results.
+TEST_P(OcclusionQueriesTest, EmptyQueryAfterCompletedQueryInterleaved)
+{
+ ANGLE_SKIP_TEST_IF(getClientMajorVersion() < 3 &&
+ !IsGLExtensionEnabled("GL_EXT_occlusion_query_boolean"));
+
+ GLQueryEXT query;
+
+ // Make a draw call to start a new render pass
+ drawQuad(mProgram, essl1_shaders::PositionAttrib(), 0.0f);
+
+ // Begin a query and make another draw call
+ glBeginQueryEXT(GL_ANY_SAMPLES_PASSED_EXT, query);
+ drawQuad(mProgram, essl1_shaders::PositionAttrib(), 0.0f);
+ glEndQueryEXT(GL_ANY_SAMPLES_PASSED_EXT);
+
+ // Check the query result to end command encoding
+ GLuint result = GL_FALSE;
+ glGetQueryObjectuivEXT(query, GL_QUERY_RESULT_EXT, &result);
+ EXPECT_TRUE(result);
+ ASSERT_GL_NO_ERROR();
+
+ // Make a draw call to start a new render pass
+ drawQuad(mProgram, essl1_shaders::PositionAttrib(), 0.0f);
+
+ // Begin and immediately resolve a new query; it must return false
+ result = GL_FALSE;
+ glBeginQueryEXT(GL_ANY_SAMPLES_PASSED_EXT, query);
+ glEndQueryEXT(GL_ANY_SAMPLES_PASSED_EXT);
+ glGetQueryObjectuivEXT(query, GL_QUERY_RESULT_EXT, &result);
+ EXPECT_FALSE(result);
+ ASSERT_GL_NO_ERROR();
+}
+
 // Test multiple occlusion queries.
 TEST_P(OcclusionQueriesTest, MultiQueries)
 {