Fix problem in mapping vertex program outputs (found with "spring" game engine)

If the vertex program writes to an output that's not consumed by the
fragment program, map the vp output to an unused slot.

1 files changed, 6 insertions, 4 deletions

diff --git a/src/mesa/state_tracker/st_atom_shader.c b/src/mesa/state_tracker/st_atom_shader.c
index 1ed9333556e..91969185093 100644
--- a/src/mesa/state_tracker/st_atom_shader.c
+++ b/src/mesa/state_tracker/st_atom_shader.c
@@ -226,9 +226,11 @@ find_translated_vp(struct st_context *st,
             GLint fpInAttrib = vp_out_to_fp_in(outAttr);
             if (fpInAttrib >= 0) {
                GLuint fpInSlot = stfp->input_to_slot[fpInAttrib];
-               GLuint vpOutSlot = stfp->fs->state.input_map[fpInSlot];
-               xvp->output_to_slot[outAttr] = vpOutSlot;
-               numVpOuts++;
+               if (fpInSlot != ~0) {
+                  GLuint vpOutSlot = stfp->fs->state.input_map[fpInSlot];
+                  xvp->output_to_slot[outAttr] = vpOutSlot;
+                  numVpOuts++;
+               }
             }
             else if (outAttr == VERT_RESULT_PSIZ ||
                      outAttr == VERT_RESULT_BFC0 ||
@@ -247,7 +249,7 @@ find_translated_vp(struct st_context *st,
        * We could use this info to do dead code elimination in the
        * vertex program.
        */
-      dummySlot = stfp->num_input_slots;
+      dummySlot = numVpOuts;
 
       /* Map vert program outputs that aren't used to the dummy slot */
       for (outAttr = 0; outAttr < VERT_RESULT_MAX; outAttr++) {