[nva5] Wrong provoking vertex is selected for flat attribute interpolation (clipping?)
Submitted by alzeih
Assigned to Nouveau Project
Description
The following piglit test:
interpolation-flat-gl_BackColor-smooth-none.shader_test
appears to select the wrong provoking vertex depending on the exact value of v[0].y.
For v[0].y > -1.0, the triangle ends up red. For v[0].y = -1.0, the triangle ends up green. For v[0].y < -1.0, the triangle ends up (correctly) blue.
Hardware: nva5 (GT330M) in MacBookPro6,2 Mesa version: 1415a188 Kernel: 3.9.8-1-ARCH
Suspect the clipper doesn't respect the index of the provoking vertex in the triangle?
Version: git