mesa: create/use a fallback texture when bound texture is incomplete
When a GLSL sampler reads from an incomplete texture it should
return (0,0,0,1). Instead of jumping through hoops in all the drivers
to make this happen, just create/install a fallback texture with those
texel values.
Fixes piglit/fp-incomplete-tex on i965 and more importantly, fixes some
GPU lockups when trying to sample from missing surfaces. If a binding
table entry is NULL, it seems that sampling sometimes works, but not
always (lockup).
Todo: create a fallback texture for each type of texture target?
(cherry picked from commit 3f25219c7bf0f090502489928f0f018e62c4f6cf)
4 files changed