This adds a new "fixed-arbfp" progend so we now have 3 distinct ways of
setting up the state of a pipeline:
» fixed; where the vertex and fragment processing are implemented
using fixed function opengl apis.
» fixed-arbfp; where vertex processing is implemented using fixed
function opengl apis but fragment processing is implemented
using the ARB Fragment Processing language.
» glsl; there vertex and fragment processing are both implemented
using glsl.
This means we avoid unusual, combinations such as glsl for vertex
processing and arbfp for fragment processing, and also avoid pairing
fixed-function vertex processing with glsl fragment processing which we
happen to know hits some awkward code paths in Mesa that lead to poor
performance.
As part of this change, the progend now implies specific vertend and
fragend choices so instead of associating a vertend and fragend with a
pipeline we now just associate a progend choice.
When flushing a pipeline and choosing what progend to use, we now call a
progend->start() method that is able to determine if the vertend and
fragend together will be able to handle the given pipeline so the
vertend and fragend ->start() methods no longer need to return a boolean
status.
Since we now don't need to support glsl used in conjunction with fixed
function this will allow us to avoid ever using OpenGL builtin attribute
names, though this patch doesn't change that yet.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit cec381f50c7a2f2186bd4a8c5f38fecd5f099075)
8f3380adc3