The max size of renderbuffers and texture often match by accident, but
as we always use textures, we should check for the right flag. Also
check for viewport size as this may be lower and we want to render to
almost every pixmap.
Signed-off-by: Markus Wick <markus@selfnet.de>
Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Eric Anholt <eric@anholt.net>