tree d6aecfb32305759211c116bc654b173b524b2582
parent 27ac64eceee8d4e392983861c6bc6bd620e4c6f7
author Romain Guy <romainguy@google.com> 1306453907 -0700
committer Romain Guy <romainguy@google.com> 1306454006 -0700

DO NOT MERGE Correctly implement the CLEAR xfermode.

This bug is a regression from the software pipeline and prevents
applications from implementing an "eraser" type tool (for instance
a drawing/painting apps.) This issue affects external applications
when they turn on hardware acceleration.

The previous implementation was using glBlendFunc with the parameters
GL_ZERO/GL_ZERO which doesn't work for text, paths and other alpha
sources (anti-aliasing.) The correct implementation is GL_ZERO/
GL_ONE_MINUS_SRC_ALPHA.

Change-Id: I1446e83480e46174b880120069d76fcad14ba300