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, 16 insertions, 4 deletions

diff --git a/libs/hwui/Layer.cpp b/libs/hwui/Layer.cpp
index ee1d391daab5..1d85b704e5ad 100644
--- a/libs/hwui/Layer.cpp
+++ b/libs/hwui/Layer.cpp
@@ -41,6 +41,7 @@ Layer::Layer(const uint32_t layerWidth, const uint32_t layerHeight) {
     renderer = NULL;
     displayList = NULL;
     fbo = 0;
+    stencil = 0;
     debugDrawUpdate = false;
     Caches::getInstance().resourceCache.incrementRefcount(this);
 }
@@ -53,9 +54,22 @@ Layer::~Layer() {
     deleteTexture();
 }
 
-void Layer::removeFbo() {
+void Layer::removeFbo(bool flush) {
+    if (stencil) {
+        // TODO: recycle & cache instead of simply deleting
+        GLuint previousFbo;
+        glGetIntegerv(GL_FRAMEBUFFER_BINDING, (GLint*) &previousFbo);
+        if (fbo != previousFbo) glBindFramebuffer(GL_FRAMEBUFFER, fbo);
+        glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_RENDERBUFFER, 0);
+        if (fbo != previousFbo) glBindFramebuffer(GL_FRAMEBUFFER, previousFbo);
+
+        glDeleteRenderbuffers(1, &stencil);
+        stencil = 0;
+    }
+
     if (fbo) {
-        LayerRenderer::flushLayer(this);
+        if (flush) LayerRenderer::flushLayer(this);
+        // If put fails the cache will delete the FBO
         Caches::getInstance().fboCache.put(fbo);
         fbo = 0;
     }
@@ -75,7 +89,5 @@ void Layer::setColorFilter(SkiaColorFilter* filter) {
     }
 }
 
-
-
 }; // namespace uirenderer
 }; // namespace android