i965: Fix glFrontFacing in twoside GLSL demo.

This also cuts instructions by just using the existing bit in the payload
rather than computing it from the determinant in the SF unit and passing it
as a varying down to the WM.  Something still goes wrong with getting the
backface color right, but a simpler shader appears to get the right result.

1 files changed, 0 insertions, 32 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_sf_emit.c b/src/mesa/drivers/dri/i965/brw_sf_emit.c
index ffdb0ae6df..862835f157 100644
--- a/src/mesa/drivers/dri/i965/brw_sf_emit.c
+++ b/src/mesa/drivers/dri/i965/brw_sf_emit.c
@@ -59,37 +59,6 @@ static GLboolean have_attr(struct brw_sf_compile *c,
    return (c->key.attrs & (1<<attr)) ? 1 : 0;
 }
 
-/**
- * Sets VERT_RESULT_FOGC.Y  for gl_FrontFacing
- *
- * This is currently executed if the fragment program uses VERT_RESULT_FOGC
- * at all, but this could be eliminated with a scan of the FP contents.
- */
-static void
-do_front_facing( struct brw_sf_compile *c )
-{
-   struct brw_compile *p = &c->func; 
-   int i;
-
-   if (!have_attr(c, VERT_RESULT_FOGC))
-      return;
-
-   brw_push_insn_state(p);
-   brw_CMP(p, brw_null_reg(), 
-        c->key.frontface_ccw ? BRW_CONDITIONAL_G : BRW_CONDITIONAL_L,
-        c->det, brw_imm_f(0));
-   brw_set_predicate_control(p, BRW_PREDICATE_NONE);
-   for (i = 0; i < 3; i++) {
-       struct brw_reg fogc = get_vert_attr(c, c->vert[i],FRAG_ATTRIB_FOGC);
-       brw_MOV(p, get_element(fogc, 1), brw_imm_f(0));
-       brw_set_predicate_control(p, BRW_PREDICATE_NORMAL);
-       brw_MOV(p, get_element(fogc, 1), brw_imm_f(1));
-       brw_set_predicate_control(p, BRW_PREDICATE_NONE);
-   }
-   brw_pop_insn_state(p);
-}
-
-			 
 /*********************************************************************** 
  * Twoside lighting
  */
@@ -384,7 +353,6 @@ void brw_emit_tri_setup( struct brw_sf_compile *c, GLboolean allocate)
 
    invert_det(c);
    copy_z_inv_w(c);
-   do_front_facing(c);
 
    if (c->key.do_twoside_color) 
       do_twoside_color(c);