1 files changed, 7 insertions, 0 deletions
diff --git a/mesalib/src/mesa/state_tracker/st_glsl_to_tgsi.cpp b/mesalib/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
index 6319079d5..74b3e5b58 100644
--- a/mesalib/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
+++ b/mesalib/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
@@ -4889,6 +4889,13 @@ st_translate_program(
          t->outputs[i] = ureg_DECL_output(ureg,
                                           outputSemanticName[i],
                                           outputSemanticIndex[i]);
+         if (outputSemanticName[i] == TGSI_SEMANTIC_FOG) {
+            /* force register to contain a fog coordinate in the form (F, 0, 0, 1). */
+            ureg_MOV(ureg,
+                     ureg_writemask(t->outputs[i], TGSI_WRITEMASK_XYZW & ~TGSI_WRITEMASK_X),
+                     ureg_imm4f(ureg, 0.0f, 0.0f, 0.0f, 1.0f));
+            t->outputs[i] = ureg_writemask(t->outputs[i], TGSI_WRITEMASK_X);
+	 }
       }
       if (passthrough_edgeflags)
          emit_edgeflags(t);