Modified: trunk/Source/WebCore/platform/graphics/chromium/cc/CCLayerTreeHostCommon.cpp (117644 => 117645)
--- trunk/Source/WebCore/platform/graphics/chromium/cc/CCLayerTreeHostCommon.cpp 2012-05-18 22:24:00 UTC (rev 117644)
+++ trunk/Source/WebCore/platform/graphics/chromium/cc/CCLayerTreeHostCommon.cpp 2012-05-18 22:27:18 UTC (rev 117645)
@@ -66,6 +66,14 @@
}
template<typename LayerType>
+static inline bool layerIsInExisting3DRenderingContext(LayerType* layer)
+{
+ // According to current W3C spec on CSS transforms, a layer is part of an established
+ // 3d rendering context if its parent has transform-style of preserves-3d.
+ return layer->parent() && layer->parent()->preserves3D();
+}
+
+template<typename LayerType>
static IntRect calculateVisibleLayerRect(LayerType* layer)
{
ASSERT(layer->targetRenderSurface());
@@ -211,7 +219,7 @@
// If the layer flattens its subtree (i.e. the layer doesn't preserve-3d), but it is
// treated as a 3D object by its parent (i.e. parent does preserve-3d).
- if (layer->parent() && layer->parent()->preserves3D() && !layer->preserves3D() && descendantDrawsContent)
+ if (layerIsInExisting3DRenderingContext(layer) && !layer->preserves3D() && descendantDrawsContent)
return true;
// On the main thread side, animating transforms are unknown, and may cause a RenderSurface on the impl side.
@@ -382,6 +390,14 @@
layer->setUsesLayerClipping(false);
if (subtreeShouldRenderToSeparateSurface(layer, isScaleOrTranslation(combinedTransform))) {
+
+ // We need to check back-face visibility before continuing with this surface.
+ // We cannot early exit here, however, if the transform is animating and not known on the main thread.
+ // FIXME: Also compute back-face visibility for surfaces that are not in existing 3D rendering context, using
+ // the layer's local transform. https://bugs.webkit.org/show_bug.cgi?id=84195
+ if (layerIsInExisting3DRenderingContext(layer) && transformToParentIsKnown(layer) && !layer->doubleSided() && combinedTransform.isBackFaceVisible())
+ return false;
+
if (!layer->renderSurface())
layer->createRenderSurface();
Modified: trunk/Source/WebKit/chromium/tests/CCLayerTreeHostCommonTest.cpp (117644 => 117645)
--- trunk/Source/WebKit/chromium/tests/CCLayerTreeHostCommonTest.cpp 2012-05-18 22:24:00 UTC (rev 117644)
+++ trunk/Source/WebKit/chromium/tests/CCLayerTreeHostCommonTest.cpp 2012-05-18 22:27:18 UTC (rev 117645)
@@ -1325,6 +1325,69 @@
EXPECT_TRUE(childOfAnimatingSurface->visibleLayerRect().isEmpty());
}
+TEST(CCLayerTreeHostCommonTest, verifyBackFaceCullingWithPreserves3dForFlatteningSurface)
+{
+ // Verify the behavior of back-face culling for a renderSurface that is created
+ // when it flattens its subtree, and its parent has preserves-3d.
+
+ const TransformationMatrix identityMatrix;
+ RefPtr<LayerChromium> parent = LayerChromium::create();
+ RefPtr<LayerChromiumWithForcedDrawsContent> frontFacingSurface = adoptRef(new LayerChromiumWithForcedDrawsContent());
+ RefPtr<LayerChromiumWithForcedDrawsContent> backFacingSurface = adoptRef(new LayerChromiumWithForcedDrawsContent());
+ RefPtr<LayerChromiumWithForcedDrawsContent> child1 = adoptRef(new LayerChromiumWithForcedDrawsContent());
+ RefPtr<LayerChromiumWithForcedDrawsContent> child2 = adoptRef(new LayerChromiumWithForcedDrawsContent());
+
+ parent->createRenderSurface();
+ parent->addChild(frontFacingSurface);
+ parent->addChild(backFacingSurface);
+ frontFacingSurface->addChild(child1);
+ backFacingSurface->addChild(child2);
+
+ // RenderSurfaces are not double-sided
+ frontFacingSurface->setDoubleSided(false);
+ backFacingSurface->setDoubleSided(false);
+
+ TransformationMatrix backfaceMatrix;
+ backfaceMatrix.translate(50, 50);
+ backfaceMatrix.rotate3d(0, 1, 0, 180);
+ backfaceMatrix.translate(-50, -50);
+
+ setLayerPropertiesForTesting(parent.get(), identityMatrix, identityMatrix, FloatPoint(0, 0), FloatPoint(0, 0), IntSize(100, 100), true); // parent transform style is preserve3d.
+ setLayerPropertiesForTesting(frontFacingSurface.get(), identityMatrix, identityMatrix, FloatPoint(0, 0), FloatPoint(0, 0), IntSize(100, 100), false); // surface transform style is flat.
+ setLayerPropertiesForTesting(backFacingSurface.get(), backfaceMatrix, identityMatrix, FloatPoint(0, 0), FloatPoint(0, 0), IntSize(100, 100), false); // surface transform style is flat.
+ setLayerPropertiesForTesting(child1.get(), identityMatrix, identityMatrix, FloatPoint(0, 0), FloatPoint(0, 0), IntSize(100, 100), false);
+ setLayerPropertiesForTesting(child2.get(), identityMatrix, identityMatrix, FloatPoint(0, 0), FloatPoint(0, 0), IntSize(100, 100), false);
+
+ Vector<RefPtr<LayerChromium> > renderSurfaceLayerList;
+ Vector<RefPtr<LayerChromium> > dummyLayerList;
+ int dummyMaxTextureSize = 512;
+ parent->renderSurface()->setContentRect(IntRect(IntPoint(), parent->bounds()));
+ parent->setClipRect(IntRect(IntPoint::zero(), parent->bounds()));
+ renderSurfaceLayerList.append(parent.get());
+
+ CCLayerTreeHostCommon::calculateDrawTransformsAndVisibility(parent.get(), parent.get(), identityMatrix, identityMatrix, renderSurfaceLayerList, dummyLayerList, dummyMaxTextureSize);
+
+ // Verify which renderSurfaces were created.
+ EXPECT_TRUE(frontFacingSurface->renderSurface());
+ EXPECT_FALSE(backFacingSurface->renderSurface()); // because it should be culled
+ EXPECT_FALSE(child1->renderSurface());
+ EXPECT_FALSE(child2->renderSurface());
+
+ // Verify the renderSurfaceLayerList. The back-facing surface should be culled.
+ ASSERT_EQ(2u, renderSurfaceLayerList.size());
+ EXPECT_EQ(parent->id(), renderSurfaceLayerList[0]->id());
+ EXPECT_EQ(frontFacingSurface->id(), renderSurfaceLayerList[1]->id());
+
+ // Verify root surface's layerList.
+ ASSERT_EQ(1u, renderSurfaceLayerList[0]->renderSurface()->layerList().size());
+ EXPECT_EQ(frontFacingSurface->id(), renderSurfaceLayerList[0]->renderSurface()->layerList()[0]->id());
+
+ // Verify frontFacingSurface's layerList.
+ ASSERT_EQ(2u, renderSurfaceLayerList[1]->renderSurface()->layerList().size());
+ EXPECT_EQ(frontFacingSurface->id(), renderSurfaceLayerList[1]->renderSurface()->layerList()[0]->id());
+ EXPECT_EQ(child1->id(), renderSurfaceLayerList[1]->renderSurface()->layerList()[1]->id());
+}
+
// FIXME:
// continue working on https://bugs.webkit.org/show_bug.cgi?id=68942
// - add a test to verify clipping that changes the "center point"
