softpipe: add support for explicit early depth testing

ARB_shader_image_load_store adds support for explicit early
depth testing. However we need to make sure we don't overwrite
values using the shader written values in this case.

This fixes early depth testing in softpipe to conform with
those requirements.

Reviewed-by: Brian Paul <brianp@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 10 insertions, 6 deletions

diff --git a/src/gallium/drivers/softpipe/sp_fs_exec.c b/src/gallium/drivers/softpipe/sp_fs_exec.c
index 8941177..e2d527d 100644
--- a/src/gallium/drivers/softpipe/sp_fs_exec.c
+++ b/src/gallium/drivers/softpipe/sp_fs_exec.c
@@ -116,7 +116,8 @@ setup_pos_vector(const struct tgsi_interp_coef *coef,
 static unsigned 
 exec_run( const struct sp_fragment_shader_variant *var,
 	  struct tgsi_exec_machine *machine,
-	  struct quad_header *quad )
+	  struct quad_header *quad,
+	  bool early_depth_test )
 {
    /* Compute X, Y, Z, W vals for this quad */
    setup_pos_vector(quad->posCoef, 
@@ -155,16 +156,19 @@ exec_run( const struct sp_fragment_shader_variant *var,
             {
                uint j;
 
-               for (j = 0; j < 4; j++)
-                  quad->output.depth[j] = machine->Outputs[i].xyzw[2].f[j];
+               if (!early_depth_test) {
+                  for (j = 0; j < 4; j++)
+                     quad->output.depth[j] = machine->Outputs[i].xyzw[2].f[j];
+               }
             }
             break;
          case TGSI_SEMANTIC_STENCIL:
             {
                uint j;
-
-               for (j = 0; j < 4; j++)
-                  quad->output.stencil[j] = (unsigned)machine->Outputs[i].xyzw[1].u[j];
+               if (!early_depth_test) {
+                  for (j = 0; j < 4; j++)
+                     quad->output.stencil[j] = (unsigned)machine->Outputs[i].xyzw[1].u[j];
+               }
             }
             break;
          }