1 files changed, 10 insertions, 2 deletions
diff --git a/src/glsl/builtin_variables.cpp b/src/glsl/builtin_variables.cpp
index e82c99ee3b..221aab0043 100644
--- a/src/glsl/builtin_variables.cpp
+++ b/src/glsl/builtin_variables.cpp
@@ -1057,8 +1057,16 @@ builtin_variable_generator::generate_fs_special_vars()
 {
    ir_variable *var;
 
-   add_input(VARYING_SLOT_POS, vec4_t, "gl_FragCoord");
-   add_input(VARYING_SLOT_FACE, bool_t, "gl_FrontFacing");
+   if (this->state->ctx->Const.GLSLFragCoordIsSysVal)
+      add_system_value(SYSTEM_VALUE_FRAG_COORD, vec4_t, "gl_FragCoord");
+   else
+      add_input(VARYING_SLOT_POS, vec4_t, "gl_FragCoord");
+
+   if (this->state->ctx->Const.GLSLFrontFacingIsSysVal)
+      add_system_value(SYSTEM_VALUE_FRONT_FACE, bool_t, "gl_FrontFacing");
+   else
+      add_input(VARYING_SLOT_FACE, bool_t, "gl_FrontFacing");
+
    if (state->is_version(120, 100))
       add_input(VARYING_SLOT_PNTC, vec2_t, "gl_PointCoord");