From 542d457cc1382d5118bf01e88f4f88b3028be88c Mon Sep 17 00:00:00 2001
From: marha <marha@users.sourceforge.net>
Date: Tue, 25 Jan 2011 20:04:12 +0000
Subject: mesalib pixman git update 25/1/2011

---
 mesalib/src/mesa/state_tracker/st_mesa_to_tgsi.c | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

(limited to 'mesalib/src/mesa/state_tracker')

diff --git a/mesalib/src/mesa/state_tracker/st_mesa_to_tgsi.c b/mesalib/src/mesa/state_tracker/st_mesa_to_tgsi.c
index b24729440..87c69e4dd 100644
--- a/mesalib/src/mesa/state_tracker/st_mesa_to_tgsi.c
+++ b/mesalib/src/mesa/state_tracker/st_mesa_to_tgsi.c
@@ -751,10 +751,12 @@ compile_instruction(
 
 /**
  * Emit the TGSI instructions to adjust the WPOS pixel center convention
+ * Basically, add (adjX, adjY) to the fragment position.
  */
 static void
 emit_adjusted_wpos( struct st_translate *t,
-                    const struct gl_program *program, GLfloat value)
+                    const struct gl_program *program,
+                    GLfloat adjX, GLfloat adjY)
 {
    struct ureg_program *ureg = t->ureg;
    struct ureg_dst wpos_temp = ureg_DECL_temporary(ureg);
@@ -764,7 +766,7 @@ emit_adjusted_wpos( struct st_translate *t,
     * The shader might also use gl_FragCoord.w and .z.
     */
    ureg_ADD(ureg, wpos_temp, wpos_input,
-            ureg_imm4f(ureg, value, value, 0.0f, 0.0f));
+            ureg_imm4f(ureg, adjX, adjY, 0.0f, 0.0f));
 
    t->inputs[t->inputMapping[FRAG_ATTRIB_WPOS]] = ureg_src(wpos_temp);
 }
@@ -848,9 +850,12 @@ emit_wpos(struct st_context *st,
    boolean invert = FALSE;
 
    if (fp->OriginUpperLeft) {
+      /* Fragment shader wants origin in upper-left */
       if (pscreen->get_param(pscreen, PIPE_CAP_TGSI_FS_COORD_ORIGIN_UPPER_LEFT)) {
+         /* the driver supports upper-left origin */
       }
       else if (pscreen->get_param(pscreen, PIPE_CAP_TGSI_FS_COORD_ORIGIN_LOWER_LEFT)) {
+         /* the driver supports lower-left origin, need to invert Y */
          ureg_property_fs_coord_origin(ureg, TGSI_FS_COORD_ORIGIN_LOWER_LEFT);
          invert = TRUE;
       }
@@ -858,28 +863,37 @@ emit_wpos(struct st_context *st,
          assert(0);
    }
    else {
+      /* Fragment shader wants origin in lower-left */
       if (pscreen->get_param(pscreen, PIPE_CAP_TGSI_FS_COORD_ORIGIN_LOWER_LEFT))
+         /* the driver supports lower-left origin */
          ureg_property_fs_coord_origin(ureg, TGSI_FS_COORD_ORIGIN_LOWER_LEFT);
       else if (pscreen->get_param(pscreen, PIPE_CAP_TGSI_FS_COORD_ORIGIN_UPPER_LEFT))
+         /* the driver supports upper-left origin, need to invert Y */
          invert = TRUE;
       else
          assert(0);
    }
    
    if (fp->PixelCenterInteger) {
+      /* Fragment shader wants pixel center integer */
       if (pscreen->get_param(pscreen, PIPE_CAP_TGSI_FS_COORD_PIXEL_CENTER_INTEGER))
+         /* the driver supports pixel center integer */
          ureg_property_fs_coord_pixel_center(ureg, TGSI_FS_COORD_PIXEL_CENTER_INTEGER);
       else if (pscreen->get_param(pscreen, PIPE_CAP_TGSI_FS_COORD_PIXEL_CENTER_HALF_INTEGER))
-         emit_adjusted_wpos(t, program, invert ? 0.5f : -0.5f);
+         /* the driver supports pixel center half integer, need to bias X,Y */
+         emit_adjusted_wpos(t, program, 0.5f, invert ? 0.5f : -0.5f);
       else
          assert(0);
    }
    else {
+      /* Fragment shader wants pixel center half integer */
       if (pscreen->get_param(pscreen, PIPE_CAP_TGSI_FS_COORD_PIXEL_CENTER_HALF_INTEGER)) {
+         /* the driver supports pixel center half integer */
       }
       else if (pscreen->get_param(pscreen, PIPE_CAP_TGSI_FS_COORD_PIXEL_CENTER_INTEGER)) {
+         /* the driver supports pixel center integer, need to bias X,Y */
          ureg_property_fs_coord_pixel_center(ureg, TGSI_FS_COORD_PIXEL_CENTER_INTEGER);
-         emit_adjusted_wpos(t, program, invert ? -0.5f : 0.5f);
+         emit_adjusted_wpos(t, program, 0.5f, invert ? -0.5f : 0.5f);
       }
       else
          assert(0);
-- 
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