Implement hiding backfaces

bug:3456544
Change-Id: I0e6b10e435432ddbf40085c4b3a7a7e22baed28a

4 files changed, 26 insertions, 0 deletions

diff --git a/WebCore/platform/graphics/android/GraphicsLayerAndroid.cpp b/WebCore/platform/graphics/android/GraphicsLayerAndroid.cpp
index 59f8408..e8120f9 100644
--- a/WebCore/platform/graphics/android/GraphicsLayerAndroid.cpp
+++ b/WebCore/platform/graphics/android/GraphicsLayerAndroid.cpp
@@ -337,6 +337,13 @@ void GraphicsLayerAndroid::setSize(const FloatSize& size)
     askForSync();
 }
 
+void GraphicsLayerAndroid::setBackfaceVisibility(bool b)
+{
+    GraphicsLayer::setBackfaceVisibility(b);
+    m_contentLayer->setBackfaceVisibility(b);
+    askForSync();
+}
+
 void GraphicsLayerAndroid::setTransform(const TransformationMatrix& t)
 {
     if (t == m_transform)
diff --git a/WebCore/platform/graphics/android/GraphicsLayerAndroid.h b/WebCore/platform/graphics/android/GraphicsLayerAndroid.h
index 94b828b..10db5a1 100644
--- a/WebCore/platform/graphics/android/GraphicsLayerAndroid.h
+++ b/WebCore/platform/graphics/android/GraphicsLayerAndroid.h
@@ -61,6 +61,7 @@ public:
     virtual void setAnchorPoint(const FloatPoint3D&);
     virtual void setSize(const FloatSize&);
 
+    virtual void setBackfaceVisibility(bool b);
     virtual void setTransform(const TransformationMatrix&);
 
     virtual void setChildrenTransform(const TransformationMatrix&);
diff --git a/WebCore/platform/graphics/android/LayerAndroid.cpp b/WebCore/platform/graphics/android/LayerAndroid.cpp
index 6e4b10a..7bef420 100644
--- a/WebCore/platform/graphics/android/LayerAndroid.cpp
+++ b/WebCore/platform/graphics/android/LayerAndroid.cpp
@@ -58,6 +58,8 @@ LayerAndroid::LayerAndroid(RenderLayer* owner) : SkLayer(),
     m_haveClip(false),
     m_isFixed(false),
     m_isIframe(false),
+    m_backfaceVisibility(true),
+    m_visible(true),
     m_preserves3D(false),
     m_anchorPointZ(0),
     m_recordingPicture(0),
@@ -97,6 +99,8 @@ LayerAndroid::LayerAndroid(const LayerAndroid& layer) : SkLayer(layer),
     copyBitmap(layer.m_contentsImage);
     m_renderLayerPos = layer.m_renderLayerPos;
     m_transform = layer.m_transform;
+    m_backfaceVisibility = layer.m_backfaceVisibility;
+    m_visible = layer.m_visible;
     m_backgroundColor = layer.m_backgroundColor;
 
     m_fixedLeft = layer.m_fixedLeft;
@@ -619,6 +623,14 @@ void LayerAndroid::updateGLPositions(const TransformationMatrix& parentMatrix,
         setDrawClip(clipping);
     }
 
+    if (!m_backfaceVisibility
+         && drawTransform().inverse().m33() < 0) {
+         setVisible(false);
+         return;
+    } else {
+         setVisible(true);
+    }
+
     int count = this->countChildren();
     if (!count)
         return;
@@ -933,6 +945,8 @@ static inline bool compareLayerZ(const LayerAndroid* a, const LayerAndroid* b)
 bool LayerAndroid::drawGL(GLWebViewState* glWebViewState, SkMatrix& matrix)
 {
     TilesManager::instance()->shader()->clip(m_clippingRect);
+    if (!m_visible)
+        return false;
 
     if (m_drawingTexture) {
         TextureInfo* textureInfo = m_drawingTexture->consumerLock();
diff --git a/WebCore/platform/graphics/android/LayerAndroid.h b/WebCore/platform/graphics/android/LayerAndroid.h
index 592e427..d4510c5 100644
--- a/WebCore/platform/graphics/android/LayerAndroid.h
+++ b/WebCore/platform/graphics/android/LayerAndroid.h
@@ -101,6 +101,7 @@ public:
     LayerTexture* texture() { return m_reservedTexture; }
     virtual TiledPage* page() { return 0; }
 
+    void setBackfaceVisibility(bool value) { m_backfaceVisibility = value; }
     void setTransform(const TransformationMatrix& matrix) { m_transform = matrix; }
     FloatPoint translation() const;
     SkRect bounds() const;
@@ -134,6 +135,7 @@ public:
     void updateGLPositions(const TransformationMatrix& parentMatrix,
                            const FloatRect& clip, float opacity);
     void setDrawOpacity(float opacity) { m_drawOpacity = opacity; }
+    void setVisible(bool value) { m_visible = value; }
 
     bool preserves3D() { return m_preserves3D; }
     void setPreserves3D(bool value) { m_preserves3D = value; }
@@ -289,6 +291,8 @@ private:
 
     TransformationMatrix m_transform;
     float m_zValue;
+    bool m_backfaceVisibility;
+    bool m_visible;
 
     SkColor m_backgroundColor;