tgsi: fix incorrect usage_mask for shadow tex instructions

The shadow versions of the texture targets use an extra component
(Z) to express distance from light source to the fragment.
Fixes the shadowtex demo with llvmpipe.

diff --git a/src/gallium/auxiliary/tgsi/tgsi_util.c b/src/gallium/auxiliary/tgsi/tgsi_util.c
index 3ec54964169bd528bed0407e0ef233fd74a300b3..08e7e89bd670e42fcb0a7aadd9ef50c15956316c 100644 (file)
--- a/src/gallium/auxiliary/tgsi/tgsi_util.c
+++ b/src/gallium/auxiliary/tgsi/tgsi_util.c
@@ -262,19 +262,20 @@ tgsi_util_get_inst_usage_mask(const struct tgsi_full_instruction *inst,
    case TGSI_OPCODE_TXL:
    case TGSI_OPCODE_TXP:
       if (src_idx == 0) {
+         /* Note that the SHADOW variants use the Z component too */
          switch (inst->Texture.Texture) {
          case TGSI_TEXTURE_1D:
-         case TGSI_TEXTURE_SHADOW1D:
             read_mask = TGSI_WRITEMASK_X;
             break;
-
+         case TGSI_TEXTURE_SHADOW1D:
+            read_mask = TGSI_WRITEMASK_XZ;
+            break;
          case TGSI_TEXTURE_2D:
          case TGSI_TEXTURE_RECT:
-         case TGSI_TEXTURE_SHADOW2D:
-         case TGSI_TEXTURE_SHADOWRECT:
             read_mask = TGSI_WRITEMASK_XY;
             break;
-
+         case TGSI_TEXTURE_SHADOW2D:
+         case TGSI_TEXTURE_SHADOWRECT:
          case TGSI_TEXTURE_3D:
          case TGSI_TEXTURE_CUBE:
             read_mask = TGSI_WRITEMASK_XYZ;