Mesa (radeon-rewrite): r300: fix output register allocation for vertex shaders

[Maciej Cencora]

Module: Mesa
Branch: radeon-rewrite
Commit: 28724b575d2c003d7f10f55dcb03ac969df94389
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=28724b575d2c003d7f10f55dcb03ac969df94389

Author: Maciej Cencora <m.cencora at gmail.com>
Date:   Fri Jun  5 18:14:15 2009 +0200

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.

---

 src/mesa/drivers/dri/r300/r300_vertprog.c |   28 +++++++++++++++++++---------
 1 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/src/mesa/drivers/dri/r300/r300_vertprog.c b/src/mesa/drivers/dri/r300/r300_vertprog.c
index a74b915..1cacebf 100644
--- 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++) {