+
+ /* special case: scan fragment shaders for use of the fog
+ * input/attribute. The X component is fog, the Y component
+ * is the front/back-face flag.
+ */
+ if (procType == TGSI_PROCESSOR_FRAGMENT) {
+ uint i;
+ for (i = 0; i < fullinst->Instruction.NumSrcRegs; i++) {
+ const struct tgsi_full_src_register *src =
+ &fullinst->FullSrcRegisters[i];
+ if (src->SrcRegister.File == TGSI_FILE_INPUT) {
+ const int ind = src->SrcRegister.Index;
+ if (info->input_semantic_name[ind] == TGSI_SEMANTIC_FOG) {
+ if (src->SrcRegister.SwizzleX == TGSI_SWIZZLE_X) {
+ info->uses_fogcoord = TRUE;
+ }
+ else if (src->SrcRegister.SwizzleX == TGSI_SWIZZLE_Y) {
+ info->uses_frontfacing = TRUE;
+ }
+ }
+ }
+ }
+ }