a5e95a419e
Accelerates a few glReadPixels cases for WebGL. See https://bugs.freedesktop.org/show_bug.cgi?id=48545 v2: Per Jose, use bit twiddling for the swizzle case instead of ubyte arrays (it's about 44% faster). Note: This is a candidate for the 8.0 branch. Reviewed-by: José Fonseca <jfonseca@vmware.com>