r300: fix output register allocation for vertex shaders

If the vertex program wrote secondary color without primary color, the secondary color output register index would be 0 which resulted in overwriting vertex position in some cases.

diff --git a/src/mesa/drivers/dri/r300/r300_vertprog.c b/src/mesa/drivers/dri/r300/r300_vertprog.c
index a74b9156cf9face49aef5ab4381599c2d6ade4e9..1cacebf3666f6688c08bc6e8b228cfb51b499281 100644 (file)
--- a/src/mesa/drivers/dri/r300/r300_vertprog.c
+++ b/src/mesa/drivers/dri/r300/r300_vertprog.c
@@ -955,26 +955,36 @@ static void t_inputs_outputs(struct r300_vertex_program *vp)
                vp->outputs[VERT_RESULT_PSIZ] = cur_reg++;
        }
 
+       /* If we're writing back facing colors we need to send
+        * four colors to make front/back face colors selection work.
+        * If the vertex program doesn't write all 4 colors, lets
+        * pretend it does by skipping output index reg so the colors
+        * get written into appropriate output vectors.
+        */
        if (vp->key.OutputsWritten & (1 << VERT_RESULT_COL0)) {
                vp->outputs[VERT_RESULT_COL0] = cur_reg++;
+       } else if (vp->key.OutputsWritten & (1 << VERT_RESULT_BFC0) ||
+               vp->key.OutputsWritten & (1 << VERT_RESULT_BFC1)) {
+               cur_reg++;
        }
 
        if (vp->key.OutputsWritten & (1 << VERT_RESULT_COL1)) {
-               vp->outputs[VERT_RESULT_COL1] =
-                   vp->outputs[VERT_RESULT_COL0] + 1;
-               cur_reg = vp->outputs[VERT_RESULT_COL1] + 1;
+               vp->outputs[VERT_RESULT_COL1] = cur_reg++;
+       } else if (vp->key.OutputsWritten & (1 << VERT_RESULT_BFC0) ||
+               vp->key.OutputsWritten & (1 << VERT_RESULT_BFC1)) {
+               cur_reg++;
        }
 
        if (vp->key.OutputsWritten & (1 << VERT_RESULT_BFC0)) {
-               vp->outputs[VERT_RESULT_BFC0] =
-                   vp->outputs[VERT_RESULT_COL0] + 2;
-               cur_reg = vp->outputs[VERT_RESULT_BFC0] + 2;
+               vp->outputs[VERT_RESULT_BFC0] = cur_reg++;
+       } else if (vp->key.OutputsWritten & (1 << VERT_RESULT_BFC1)) {
+               cur_reg++;
        }
 
        if (vp->key.OutputsWritten & (1 << VERT_RESULT_BFC1)) {
-               vp->outputs[VERT_RESULT_BFC1] =
-                   vp->outputs[VERT_RESULT_COL0] + 3;
-               cur_reg = vp->outputs[VERT_RESULT_BFC1] + 1;
+               vp->outputs[VERT_RESULT_BFC1] = cur_reg++;
+       } else if (vp->key.OutputsWritten & (1 << VERT_RESULT_BFC0)) {
+               cur_reg++;
        }
 
        for (i = VERT_RESULT_TEX0; i <= VERT_RESULT_TEX7; i++) {