Optimize layer clears.

Don't clear the entire texture when we use textures that are bigger
than the layer itself. This will save time during the glClear() calls.

Change-Id: I06f3259ba62affb3708ba69ea41418832c7e1a65

1 files changed, 3 insertions, 4 deletions

diff --git a/libs/hwui/OpenGLRenderer.cpp b/libs/hwui/OpenGLRenderer.cpp
index 585fa53039bd..ffd0aed92d3e 100644
--- a/libs/hwui/OpenGLRenderer.cpp
+++ b/libs/hwui/OpenGLRenderer.cpp
@@ -425,8 +425,6 @@ bool OpenGLRenderer::createLayer(sp<Snapshot> snapshot, float left, float top,
         snapshot->flags |= Snapshot::kFlagDirtyOrtho;
         snapshot->orthoMatrix.load(mOrthoMatrix);
 
-        setScissorFromClip();
-
         // Bind texture to FBO
         glBindFramebuffer(GL_FRAMEBUFFER, layer->fbo);
         glBindTexture(GL_TEXTURE_2D, layer->texture);
@@ -457,10 +455,11 @@ bool OpenGLRenderer::createLayer(sp<Snapshot> snapshot, float left, float top,
 #endif
 
         // Clear the FBO
-        glDisable(GL_SCISSOR_TEST);
+        glScissor(0.0f, 0.0f, bounds.getWidth(), bounds.getHeight());
         glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
         glClear(GL_COLOR_BUFFER_BIT);
-        glEnable(GL_SCISSOR_TEST);
+
+        setScissorFromClip();
 
         // Change the ortho projection
         glViewport(0, 0, bounds.getWidth(), bounds.getHeight());