Implement clipRect with a transform, clipRegion & clipPath

Bug #7146141

When non-rectangular clipping occurs in a layer the render buffer
used as the stencil buffer is not cached. If this happens on a
View's hardware layer the render buffer will live for as long
as the layer is bound to the view. When a stencil buffer is
required because of a call to Canvas.saveLayer() it will be allocated
on every frame. A future change will address this problem.

If "show GPU overdraw" is enabled, non-rectangular clips are not
supported anymore and we fall back to rectangular clips instead.
This is a limitation imposed by OpenGL ES that cannot be worked
around at this time.

This change also improves the Matrix4 implementation to easily
detect when a rect remains a rect after transform.

Change-Id: I0e69fb901792d38bc0c4ca1bf9fdb02d7db415b9

1 files changed, 2 insertions, 2 deletions

diff --git a/libs/hwui/Stencil.cpp b/libs/hwui/Stencil.cpp
index 84df82b7b08f..4fcd51d6a7f4 100644
--- a/libs/hwui/Stencil.cpp
+++ b/libs/hwui/Stencil.cpp
@@ -37,7 +37,7 @@ void Stencil::clear() {
 void Stencil::enableTest() {
     if (mState != kTest) {
         enable();
-        glStencilFunc(GL_EQUAL, 0x1, 0x1);
+        glStencilFunc(GL_EQUAL, 0xff, 0xff);
         // We only want to test, let's keep everything
         glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
         glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
@@ -48,7 +48,7 @@ void Stencil::enableTest() {
 void Stencil::enableWrite() {
     if (mState != kWrite) {
         enable();
-        glStencilFunc(GL_ALWAYS, 0x1, 0x1);
+        glStencilFunc(GL_ALWAYS, 0xff, 0xff);
         // The test always passes so the first two values are meaningless
         glStencilOp(GL_KEEP, GL_KEEP, GL_REPLACE);
         glColorMask(GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE);