gallium: Replace gl_rasterization_rules with lower_left_origin and half_pixel_center.

Squashed commit of the following:

commit 04c5fa2cbb8e89d6f2fa5a75af1cca03b1f6b852
Author: José Fonseca <[email protected]>
Date:   Tue Apr 23 17:37:18 2013 +0100

    gallium: s/lower_left_origin/bottom_edge_rule/

commit 4dff4f64fa83b9737def136fffd161d55e4f1722
Author: José Fonseca <[email protected]>
Date:   Tue Apr 23 17:35:04 2013 +0100

    gallium: Move diagram to docs.

commit 442a63012c8c3c3797f45e03f2ca20ad5f399832
Author: James Benton <[email protected]>
Date:   Fri May 11 17:50:55 2012 +0100

    gallium: Replace gl_rasterization_rules with lower_left_origin and half_pixel_center.

    This change is necessary to achieve correct results when using OpenGL
    FBOs.

Reviewed-by: Marek Olšák <[email protected]>

7 files changed, 21 insertions, 38 deletions

diff --git a/src/gallium/drivers/llvmpipe/lp_setup.c b/src/gallium/drivers/llvmpipe/lp_setup.c
index c119395a9d6..6b86aae1cb1 100644
--- a/src/gallium/drivers/llvmpipe/lp_setup.c
+++ b/src/gallium/drivers/llvmpipe/lp_setup.c
@@ -491,14 +491,16 @@ lp_setup_set_triangle_state( struct lp_setup_context *setup,
                              unsigned cull_mode,
                              boolean ccw_is_frontface,
                              boolean scissor,
-                             boolean gl_rasterization_rules)
+                             boolean half_pixel_center,
+                             boolean bottom_edge_rule)
 {
    LP_DBG(DEBUG_SETUP, "%s\n", __FUNCTION__);
 
    setup->ccw_is_frontface = ccw_is_frontface;
    setup->cullmode = cull_mode;
    setup->triangle = first_triangle;
-   setup->pixel_offset = gl_rasterization_rules ? 0.5f : 0.0f;
+   setup->pixel_offset = half_pixel_center ? 0.5f : 0.0f;
+   setup->bottom_edge_rule = bottom_edge_rule;
 
    if (setup->scissor_test != scissor) {
       setup->dirty |= LP_SETUP_NEW_SCISSOR;
diff --git a/src/gallium/drivers/llvmpipe/lp_setup.h b/src/gallium/drivers/llvmpipe/lp_setup.h
index de29601329f..802ab0105e8 100644
--- a/src/gallium/drivers/llvmpipe/lp_setup.h
+++ b/src/gallium/drivers/llvmpipe/lp_setup.h
@@ -77,7 +77,8 @@ lp_setup_set_triangle_state( struct lp_setup_context *setup,
                              unsigned cullmode,
                              boolean front_is_ccw,
                              boolean scissor,
-                             boolean gl_rasterization_rules );
+                             boolean half_pixel_center,
+                             boolean bottom_edge_rule);
 
 void 
 lp_setup_set_line_state( struct lp_setup_context *setup,
diff --git a/src/gallium/drivers/llvmpipe/lp_setup_context.h b/src/gallium/drivers/llvmpipe/lp_setup_context.h
index b72831bf0e4..efc2ab76813 100644
--- a/src/gallium/drivers/llvmpipe/lp_setup_context.h
+++ b/src/gallium/drivers/llvmpipe/lp_setup_context.h
@@ -98,6 +98,7 @@ struct lp_setup_context
    boolean point_size_per_vertex;
    boolean rasterizer_discard;
    unsigned cullmode;
+   unsigned bottom_edge_rule;
    float pixel_offset;
    float line_width;
    float point_size;
diff --git a/src/gallium/drivers/llvmpipe/lp_setup_line.c b/src/gallium/drivers/llvmpipe/lp_setup_line.c
index 29c231714e1..54f19cb9f3c 100644
--- a/src/gallium/drivers/llvmpipe/lp_setup_line.c
+++ b/src/gallium/drivers/llvmpipe/lp_setup_line.c
@@ -621,17 +621,6 @@ try_setup_line( struct lp_setup_context *setup,
 
       
       /* correct for top-left vs. bottom-left fill convention.  
-       *
-       * note that we're overloading gl_rasterization_rules to mean
-       * both (0.5,0.5) pixel centers *and* bottom-left filling
-       * convention.
-       *
-       * GL actually has a top-left filling convention, but GL's
-       * notion of "top" differs from gallium's...
-       *
-       * Also, sometimes (in FBO cases) GL will render upside down
-       * to its usual method, in which case it will probably want
-       * to use the opposite, top-left convention.
        */         
       if (plane[i].dcdx < 0) {
          /* both fill conventions want this - adjust for left edges */
diff --git a/src/gallium/drivers/llvmpipe/lp_setup_tri.c b/src/gallium/drivers/llvmpipe/lp_setup_tri.c
index cf3d536eb1d..b2c8cb52500 100644
--- a/src/gallium/drivers/llvmpipe/lp_setup_tri.c
+++ b/src/gallium/drivers/llvmpipe/lp_setup_tri.c
@@ -365,7 +365,7 @@ do_triangle_ccw(struct lp_setup_context *setup,
       dcdx_zero_mask = _mm_cmpeq_epi32(dcdx, zero);
       dcdy_neg_mask = _mm_srai_epi32(dcdy, 31);
 
-      top_left_flag = _mm_set1_epi32((setup->pixel_offset == 0) ? ~0 : 0);
+      top_left_flag = _mm_set1_epi32((setup->bottom_edge_rule == 0) ? ~0 : 0);
 
       c_inc_mask = _mm_or_si128(dcdx_neg_mask,
                                 _mm_and_si128(dcdx_zero_mask,
@@ -417,25 +417,14 @@ do_triangle_ccw(struct lp_setup_context *setup,
           */
          plane[i].c = plane[i].dcdx * position->x[i] - plane[i].dcdy * position->y[i];
 
-         /* correct for top-left vs. bottom-left fill convention.  
-          *
-          * note that we're overloading gl_rasterization_rules to mean
-          * both (0.5,0.5) pixel centers *and* bottom-left filling
-          * convention.
-          *
-          * GL actually has a top-left filling convention, but GL's
-          * notion of "top" differs from gallium's...
-          *
-          * Also, sometimes (in FBO cases) GL will render upside down
-          * to its usual method, in which case it will probably want
-          * to use the opposite, top-left convention.
+         /* correct for top-left vs. bottom-left fill convention.
           */         
          if (plane[i].dcdx < 0) {
             /* both fill conventions want this - adjust for left edges */
             plane[i].c++;            
          }
          else if (plane[i].dcdx == 0) {
-            if (setup->pixel_offset == 0) {
+            if (setup->bottom_edge_rule == 0){
                /* correct for top-left fill convention:
                 */
                if (plane[i].dcdy > 0) plane[i].c++;
diff --git a/src/gallium/drivers/llvmpipe/lp_state_rasterizer.c b/src/gallium/drivers/llvmpipe/lp_state_rasterizer.c
index ca8df7149eb..6148337b72d 100644
--- a/src/gallium/drivers/llvmpipe/lp_state_rasterizer.c
+++ b/src/gallium/drivers/llvmpipe/lp_state_rasterizer.c
@@ -114,21 +114,22 @@ llvmpipe_bind_rasterizer_state(struct pipe_context *pipe, void *handle)
       /* XXX: just pass lp_state directly to setup.
        */
       lp_setup_set_triangle_state( llvmpipe->setup,
-				   state->lp_state.cull_face,
-				   state->lp_state.front_ccw,
-				   state->lp_state.scissor,
-				   state->lp_state.gl_rasterization_rules);
+                                  state->lp_state.cull_face,
+                                  state->lp_state.front_ccw,
+                                  state->lp_state.scissor,
+                                  state->lp_state.half_pixel_center,
+                                  state->lp_state.bottom_edge_rule);
       lp_setup_set_flatshade_first( llvmpipe->setup,
 				    state->lp_state.flatshade_first);
       lp_setup_set_rasterizer_discard( llvmpipe->setup,
 				    state->lp_state.rasterizer_discard);
       lp_setup_set_line_state( llvmpipe->setup,
-			       state->lp_state.line_width);
+                              state->lp_state.line_width);
       lp_setup_set_point_state( llvmpipe->setup,
-				state->lp_state.point_size,
-				state->lp_state.point_size_per_vertex,
-				state->lp_state.sprite_coord_enable,
-				state->lp_state.sprite_coord_mode);
+                               state->lp_state.point_size,
+                               state->lp_state.point_size_per_vertex,
+                               state->lp_state.sprite_coord_enable,
+                               state->lp_state.sprite_coord_mode);
    }
    else {
       llvmpipe->rasterizer = NULL;
diff --git a/src/gallium/drivers/llvmpipe/lp_state_setup.c b/src/gallium/drivers/llvmpipe/lp_state_setup.c
index edd5d0fb5e7..ed68b984a92 100644
--- a/src/gallium/drivers/llvmpipe/lp_state_setup.c
+++ b/src/gallium/drivers/llvmpipe/lp_state_setup.c
@@ -807,7 +807,7 @@ lp_make_setup_variant_key(struct llvmpipe_context *lp,
    
    key->num_inputs = fs->info.base.num_inputs;
    key->flatshade_first = lp->rasterizer->flatshade_first;
-   key->pixel_center_half = lp->rasterizer->gl_rasterization_rules;
+   key->pixel_center_half = lp->rasterizer->half_pixel_center;
    key->twoside = lp->rasterizer->light_twoside;
    key->size = Offset(struct lp_setup_variant_key,
 		      inputs[key->num_inputs]);