Add reminder in the code to fix T-junctions

Change-Id: I52b112694f930e641f01fb78dc55412986023411

2 files changed, 9 insertions, 0 deletions

diff --git a/libs/hwui/LayerRenderer.cpp b/libs/hwui/LayerRenderer.cpp
index 7e8c7fd..349b9e3 100644
--- a/libs/hwui/LayerRenderer.cpp
+++ b/libs/hwui/LayerRenderer.cpp
@@ -91,6 +91,13 @@ Region* LayerRenderer::getRegion() {
 #endif
 }
 
+// TODO: This implementation is flawed and can generate T-junctions
+//       in the mesh, which will in turn produce cracks when the
+//       mesh is rotated/skewed. The easiest way to fix this would
+//       be, for each row, to add new vertices shared with the previous
+//       row when the two rows share an edge.
+//       In practice, T-junctions do not appear often so this has yet
+//       to be fixed.
 void LayerRenderer::generateMesh() {
 #if RENDER_LAYERS_AS_REGIONS
     if (mLayer->region.isRect() || mLayer->region.isEmpty()) {
diff --git a/libs/hwui/OpenGLRenderer.cpp b/libs/hwui/OpenGLRenderer.cpp
index a20a88e..24784af 100644
--- a/libs/hwui/OpenGLRenderer.cpp
+++ b/libs/hwui/OpenGLRenderer.cpp
@@ -724,6 +724,8 @@ void OpenGLRenderer::composeLayerRegion(Layer* layer, const Rect& rect) {
         return;
     }
 
+    // TODO: See LayerRenderer.cpp::generateMesh() for important
+    //       information about this implementation
     if (!layer->region.isEmpty()) {
         size_t count;
         const android::Rect* rects = layer->region.getArray(&count);