svga: implement TGSI_PROPERTY_FS_COLOR0_WRITES_ALL_CBUFS

Fixes several colorbuffer tests, including piglit "fbo-drawbuffers-none"
for "gl_FragColor" and "glDrawPixels" cases.

v2: rework patch to only avoid creating extra shader variants when
TGSI_PROPERTY_FS_COLOR0_WRITES_ALL_CBUFS is not specified.  Per Jose.
Use a write_color0_to_n_cbufs key field to replicate color0 to N
color buffers only when N > 0 and WRITES_ALL_CBUFS is set.

Reviewed-by: José Fonseca <[email protected]>

1 files changed, 29 insertions, 8 deletions

diff --git a/src/gallium/drivers/svga/svga_tgsi_decl_sm30.c b/src/gallium/drivers/svga/svga_tgsi_decl_sm30.c
index e0a30a5248e..137afd60583 100644
--- a/src/gallium/drivers/svga/svga_tgsi_decl_sm30.c
+++ b/src/gallium/drivers/svga/svga_tgsi_decl_sm30.c
@@ -327,14 +327,35 @@ ps30_output(struct svga_shader_emitter *emit,
 {
    switch (semantic.Name) {
    case TGSI_SEMANTIC_COLOR:
-      if (emit->unit == PIPE_SHADER_FRAGMENT &&
-          emit->key.fkey.white_fragments) {
-
-         emit->output_map[idx] = dst_register( SVGA3DREG_TEMP,
-                                               emit->nr_hw_temp++ );
-         emit->temp_color_output[idx] = emit->output_map[idx];
-         emit->true_color_output[idx] = dst_register(SVGA3DREG_COLOROUT, 
-                                                     semantic.Index);
+      if (emit->unit == PIPE_SHADER_FRAGMENT) {
+         if (emit->key.fkey.white_fragments) {
+            /* Used for XOR logicop mode */
+            emit->output_map[idx] = dst_register( SVGA3DREG_TEMP,
+                                                  emit->nr_hw_temp++ );
+            emit->temp_color_output[idx] = emit->output_map[idx];
+            emit->true_color_output[idx] = dst_register(SVGA3DREG_COLOROUT, 
+                                                        semantic.Index);
+         }
+         else if (emit->key.fkey.write_color0_to_n_cbufs) {
+            /* We'll write color output [0] to all render targets.
+             * Prepare all the output registers here, but only when the
+             * semantic.Index == 0 so we don't do this more than once.
+             */
+            if (semantic.Index == 0) {
+               unsigned i;
+               for (i = 0; i < emit->key.fkey.write_color0_to_n_cbufs; i++) {
+                  emit->output_map[i] = dst_register(SVGA3DREG_TEMP,
+                                                     emit->nr_hw_temp++);
+                  emit->temp_color_output[i] = emit->output_map[i];
+                  emit->true_color_output[i] = dst_register(SVGA3DREG_COLOROUT,
+                                                            i);
+               }
+            }
+         }
+         else {
+            emit->output_map[idx] =
+               dst_register(SVGA3DREG_COLOROUT, semantic.Index);
+         }
       }
       else {
          emit->output_map[idx] = dst_register( SVGA3DREG_COLOROUT,