gl_FragCoord is a shader input with location == VARYING_SLOT_POS.
ARB_fragment_programs have an equivalent input at VARYING_SLOT_POS,
but it isn't called gl_FragCoord. We do want to transform it.
Matching by location guarantees we catch both.
Fixes several fp tests on a branch which uses this pass on i965.
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Rob Clark <robdclark@gmail.com>
The Y-offset needs flipping as well, similar to ddy.
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Rob Clark <robdclark@gmail.com>
The original value might have been swizzled. That's taken care of in
the fmul source - we don't want to reswizzle it again.
Fixes validation failures in glsl-derivs-varyings on a branch of mine
which uses this pass in i965.
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Rob Clark <robdclark@gmail.com>
