Define shadow casting behavior within layers

bug:15860114

Savelayers and HW layers both now support shadow casting.

For save layers, the light source should always be correct, for HW
layers, the light source position is set when the layer is created,
and updated when it is resized.

Change-Id: Ie85567dd43c2bb0a0b08fd0bd4db41efa793ac2b

1 files changed, 12 insertions, 1 deletions

diff --git a/libs/hwui/RenderNode.cpp b/libs/hwui/RenderNode.cpp
index e3732a1..0db6198 100644
--- a/libs/hwui/RenderNode.cpp
+++ b/libs/hwui/RenderNode.cpp
@@ -116,6 +116,7 @@ int RenderNode::getDebugSize() {
 
 void RenderNode::prepareTree(TreeInfo& info) {
     ATRACE_CALL();
+    LOG_ALWAYS_FATAL_IF(!info.damageAccumulator, "DamageAccumulator missing");
 
     prepareTreeImpl(info);
 }
@@ -163,16 +164,26 @@ void RenderNode::pushLayerUpdate(TreeInfo& info) {
         return;
     }
 
+    bool transformUpdateNeeded = false;
     if (!mLayer) {
         mLayer = LayerRenderer::createRenderLayer(info.renderState, getWidth(), getHeight());
         applyLayerPropertiesToLayer(info);
         damageSelf(info);
+        transformUpdateNeeded = true;
     } else if (mLayer->layer.getWidth() != getWidth() || mLayer->layer.getHeight() != getHeight()) {
         if (!LayerRenderer::resizeLayer(mLayer, getWidth(), getHeight())) {
             LayerRenderer::destroyLayer(mLayer);
             mLayer = 0;
         }
         damageSelf(info);
+        transformUpdateNeeded = true;
+    }
+
+    if (transformUpdateNeeded) {
+        // update the transform in window of the layer to reset its origin wrt light source position
+        Matrix4 windowTransform;
+        info.damageAccumulator->computeCurrentTransform(&windowTransform);
+        mLayer->setWindowTransform(windowTransform);
     }
 
     SkRect dirty;
@@ -406,7 +417,7 @@ void RenderNode::setViewProperties(OpenGLRenderer& renderer, T& handler) {
  * If true3dTransform is set to true, the transform applied to the input matrix will use true 4x4
  * matrix computation instead of the Skia 3x3 matrix + camera hackery.
  */
-void RenderNode::applyViewPropertyTransforms(mat4& matrix, bool true3dTransform) {
+void RenderNode::applyViewPropertyTransforms(mat4& matrix, bool true3dTransform) const {
     if (properties().getLeft() != 0 || properties().getTop() != 0) {
         matrix.translate(properties().getLeft(), properties().getTop());
     }