Previous patch doesn't set the offset to zero for GLESv2
path. Now fix it.
This patch also fix a minor problem in pixmap uploading
preparation. If the revert is not REVERT_NORMAL, then we
don't need to prepare a fbo for it. As current mesa i965
gles2 driver doesn't support to set a A8 texture as a fbo
target, we must fix this problem. As some A1/A8 picture
need to be uploaded, this is the only place a A8 texture
may be attached to a fbo.
This patch also enable the shader gradient for GLESv2.
The reason we disable it before is that some glsl linker
doesn't support link different objects which have cross
reference. Now we don't have that problem.
Signed-off-by: Zhigang Gong <zhigang.gong@linux.intel.com>
