Use path intersection instead of saveLayer+mesh to mask projected ripples

bug:14297149

SaveLayer's performance cost is high, and proportional to the surface
being projected onto. Since ripples (even unbounded ones) are now
always projected to the arbitrary background content behind them, this
cost is especially important to avoid.

This removes the last semi-secret, saveLayer from the projected
ripple implementation.

Also fixes the HW test app to correctly demonstrate this projection
masking behavior.

Additionaly, alters PathTessellator to gracefully handle
counter-clockwise paths, and simplifies the work done by
ShadowTessellator to ensure all of its paths are counterclockwise.

Change-Id: Ibe9e12812bd10a774e20b1d444a140c368cbba8c

1 files changed, 5 insertions, 29 deletions

diff --git a/libs/hwui/RenderNode.cpp b/libs/hwui/RenderNode.cpp
index 9146b68..c2f7234 100644
--- a/libs/hwui/RenderNode.cpp
+++ b/libs/hwui/RenderNode.cpp
@@ -768,31 +768,9 @@ void RenderNode::issueOperationsOfProjectedChildren(OpenGLRenderer& renderer, T&
     const RenderProperties& backgroundProps = backgroundOp->mRenderNode->properties();
     renderer.translate(backgroundProps.getTranslationX(), backgroundProps.getTranslationY());
 
-    // If the projection reciever has an outline, we mask each of the projected rendernodes to it
-    // Either with clipRect, or special saveLayer masking
-    if (projectionReceiverOutline != nullptr) {
-        const SkRect& outlineBounds = projectionReceiverOutline->getBounds();
-        if (projectionReceiverOutline->isRect(nullptr)) {
-            // mask to the rect outline simply with clipRect
-            ClipRectOp* clipOp = new (alloc) ClipRectOp(
-                    outlineBounds.left(), outlineBounds.top(),
-                    outlineBounds.right(), outlineBounds.bottom(), SkRegion::kIntersect_Op);
-            handler(clipOp, PROPERTY_SAVECOUNT, properties().getClipToBounds());
-        } else {
-            // wrap the projected RenderNodes with a SaveLayer that will mask to the outline
-            SaveLayerOp* op = new (alloc) SaveLayerOp(
-                    outlineBounds.left(), outlineBounds.top(),
-                    outlineBounds.right(), outlineBounds.bottom(),
-                    255, SkCanvas::kMatrix_SaveFlag | SkCanvas::kClip_SaveFlag | SkCanvas::kARGB_ClipLayer_SaveFlag);
-            op->setMask(projectionReceiverOutline);
-            handler(op, PROPERTY_SAVECOUNT, properties().getClipToBounds());
-
-            /* TODO: add optimizations here to take advantage of placement/size of projected
-             * children (which may shrink saveLayer area significantly). This is dependent on
-             * passing actual drawing/dirtying bounds of projected content down to native.
-             */
-        }
-    }
+    // If the projection reciever has an outline, we mask projected content to it
+    // (which we know, apriori, are all tessellated paths)
+    renderer.setProjectionPathMask(alloc, projectionReceiverOutline);
 
     // draw projected nodes
     for (size_t i = 0; i < mProjectedNodes.size(); i++) {
@@ -807,10 +785,8 @@ void RenderNode::issueOperationsOfProjectedChildren(OpenGLRenderer& renderer, T&
         renderer.restoreToCount(restoreTo);
     }
 
-    if (projectionReceiverOutline != nullptr) {
-        handler(new (alloc) RestoreToCountOp(restoreTo),
-                PROPERTY_SAVECOUNT, properties().getClipToBounds());
-    }
+    handler(new (alloc) RestoreToCountOp(restoreTo),
+            PROPERTY_SAVECOUNT, properties().getClipToBounds());
 }
 
 /**