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, 6 insertions, 0 deletions

diff --git a/libs/hwui/Matrix.h b/libs/hwui/Matrix.h
index a76013503d5f..c1527893ee2b 100644
--- a/libs/hwui/Matrix.h
+++ b/libs/hwui/Matrix.h
@@ -134,6 +134,12 @@ public:
 
     uint8_t getType() const;
 
+    void multiplyInverse(const Matrix4& v) {
+        Matrix4 inv;
+        inv.loadInverse(v);
+        multiply(inv);
+    }
+
     void multiply(const Matrix4& v) {
         Matrix4 u;
         u.loadMultiply(*this, v);