llvmpipe: Obey rasterization rules.

Replicates softpipe.

src/gallium/drivers/llvmpipe/lp_setup.c

@@ -337,7 +337,8 @@ void
 lp_setup_set_triangle_state( struct lp_setup_context *setup,
                              unsigned cull_mode,
                              boolean ccw_is_frontface,
-                             boolean scissor )
+                             boolean scissor,
+                             boolean gl_rasterization_rules)
 {
    LP_DBG(DEBUG_SETUP, "%s\n", __FUNCTION__);
 
@@ -345,6 +346,7 @@ lp_setup_set_triangle_state( struct lp_setup_context *setup,
    setup->cullmode = cull_mode;
    setup->triangle = first_triangle;
    setup->scissor_test = scissor;
+   setup->pixel_offset = gl_rasterization_rules ? 0.5f : 0.0f;
 }
 
 

src/gallium/drivers/llvmpipe/lp_setup.h

@@ -89,7 +89,8 @@ void
 lp_setup_set_triangle_state( struct lp_setup_context *setup,
                              unsigned cullmode,
                              boolean front_is_ccw,
-                             boolean scissor );
+                             boolean scissor,
+                             boolean gl_rasterization_rules );
 
 void
 lp_setup_set_fs_inputs( struct lp_setup_context *setup,

src/gallium/drivers/llvmpipe/lp_setup_context.h

@@ -89,6 +89,7 @@ struct lp_setup_context
    boolean ccw_is_frontface;
    boolean scissor_test;
    unsigned cullmode;
+   float pixel_offset;
 
    struct pipe_framebuffer_state fb;
 

src/gallium/drivers/llvmpipe/lp_setup_tri.c

@@ -41,7 +41,8 @@
 /**
  * Compute a0 for a constant-valued coefficient (GL_FLAT shading).
  */
-static void constant_coef( struct lp_rast_triangle *tri,
+static void constant_coef( struct lp_setup_context *setup,
+                           struct lp_rast_triangle *tri,
                            unsigned slot,
 			   const float value,
                            unsigned i )
@@ -56,7 +57,8 @@ static void constant_coef( struct lp_rast_triangle *tri,
  * Compute a0, dadx and dady for a linearly interpolated coefficient,
  * for a triangle.
  */
-static void linear_coef( struct lp_rast_triangle *tri,
+static void linear_coef( struct lp_setup_context *setup,
+                         struct lp_rast_triangle *tri,
                          float oneoverarea,
                          unsigned slot,
                          const float (*v1)[4],
@@ -90,8 +92,8 @@ static void linear_coef( struct lp_rast_triangle *tri,
     * instead - i'll switch to this later.
     */
    tri->inputs.a0[slot][i] = (a1 -
-                              (dadx * (v1[0][0] - 0.5f) +
-                               dady * (v1[0][1] - 0.5f)));
+                              (dadx * (v1[0][0] - setup->pixel_offset) +
+                               dady * (v1[0][1] - setup->pixel_offset)));
 }
 
 
@@ -103,7 +105,8 @@ static void linear_coef( struct lp_rast_triangle *tri,
  * Later, when we compute the value at a particular fragment position we'll
  * divide the interpolated value by the interpolated W at that fragment.
  */
-static void perspective_coef( struct lp_rast_triangle *tri,
+static void perspective_coef( struct lp_setup_context *setup,
+                              struct lp_rast_triangle *tri,
                               float oneoverarea,
                               unsigned slot,
 			      const float (*v1)[4],
@@ -125,8 +128,8 @@ static void perspective_coef( struct lp_rast_triangle *tri,
    tri->inputs.dadx[slot][i] = dadx;
    tri->inputs.dady[slot][i] = dady;
    tri->inputs.a0[slot][i] = (a1 -
-                              (dadx * (v1[0][0] - 0.5f) +
-                               dady * (v1[0][1] - 0.5f)));
+                              (dadx * (v1[0][0] - setup->pixel_offset) +
+                               dady * (v1[0][1] - setup->pixel_offset)));
 }
 
 
@@ -137,7 +140,8 @@ static void perspective_coef( struct lp_rast_triangle *tri,
  * We could do a bit less work if we'd examine gl_FragCoord's swizzle mask.
  */
 static void
-setup_fragcoord_coef(struct lp_rast_triangle *tri,
+setup_fragcoord_coef(struct lp_setup_context *setup,
+                     struct lp_rast_triangle *tri,
                      float oneoverarea,
                      unsigned slot,
                      const float (*v1)[4],
@@ -153,20 +157,21 @@ setup_fragcoord_coef(struct lp_rast_triangle *tri,
    tri->inputs.dadx[slot][1] = 0.0;
    tri->inputs.dady[slot][1] = 1.0;
    /*Z*/
-   linear_coef(tri, oneoverarea, slot, v1, v2, v3, 0, 2);
+   linear_coef(setup, tri, oneoverarea, slot, v1, v2, v3, 0, 2);
    /*W*/
-   linear_coef(tri, oneoverarea, slot, v1, v2, v3, 0, 3);
+   linear_coef(setup, tri, oneoverarea, slot, v1, v2, v3, 0, 3);
 }
 
 
-static void setup_facing_coef( struct lp_rast_triangle *tri,
+static void setup_facing_coef( struct lp_setup_context *setup,
+                               struct lp_rast_triangle *tri,
                                unsigned slot,
                                boolean frontface )
 {
-   constant_coef( tri, slot, 1.0f - frontface, 0 );
-   constant_coef( tri, slot, 0.0f, 1 ); /* wasted */
-   constant_coef( tri, slot, 0.0f, 2 ); /* wasted */
-   constant_coef( tri, slot, 0.0f, 3 ); /* wasted */
+   constant_coef( setup, tri, slot, 1.0f - frontface, 0 );
+   constant_coef( setup, tri, slot, 0.0f, 1 ); /* wasted */
+   constant_coef( setup, tri, slot, 0.0f, 2 ); /* wasted */
+   constant_coef( setup, tri, slot, 0.0f, 3 ); /* wasted */
 }
 
 
@@ -185,7 +190,7 @@ static void setup_tri_coefficients( struct lp_setup_context *setup,
 
    /* The internal position input is in slot zero:
     */
-   setup_fragcoord_coef(tri, oneoverarea, 0, v1, v2, v3);
+   setup_fragcoord_coef(setup, tri, oneoverarea, 0, v1, v2, v3);
 
    /* setup interpolation for all the remaining attributes:
     */
@@ -196,27 +201,27 @@ static void setup_tri_coefficients( struct lp_setup_context *setup,
       switch (setup->fs.input[slot].interp) {
       case LP_INTERP_CONSTANT:
          for (i = 0; i < NUM_CHANNELS; i++)
-            constant_coef(tri, slot+1, v3[vert_attr][i], i);
+            constant_coef(setup, tri, slot+1, v3[vert_attr][i], i);
          break;
 
       case LP_INTERP_LINEAR:
          for (i = 0; i < NUM_CHANNELS; i++)
-            linear_coef(tri, oneoverarea, slot+1, v1, v2, v3, vert_attr, i);
+            linear_coef(setup, tri, oneoverarea, slot+1, v1, v2, v3, vert_attr, i);
          break;
 
       case LP_INTERP_PERSPECTIVE:
          for (i = 0; i < NUM_CHANNELS; i++)
-            perspective_coef(tri, oneoverarea, slot+1, v1, v2, v3, vert_attr, i);
+            perspective_coef(setup, tri, oneoverarea, slot+1, v1, v2, v3, vert_attr, i);
          break;
 
       case LP_INTERP_POSITION:
          /* XXX: fix me - duplicates the values in slot zero.
           */
-         setup_fragcoord_coef(tri, oneoverarea, slot+1, v1, v2, v3);
+         setup_fragcoord_coef(setup, tri, oneoverarea, slot+1, v1, v2, v3);
          break;
 
       case LP_INTERP_FACING:
-         setup_facing_coef(tri, slot+1, frontface);
+         setup_facing_coef(setup, tri, slot+1, frontface);
          break;
 
       default:
@@ -281,12 +286,12 @@ do_triangle_ccw(struct lp_setup_context *setup,
 		boolean frontfacing )
 {
    /* x/y positions in fixed point */
-   const int x1 = subpixel_snap(v1[0][0]);
-   const int x2 = subpixel_snap(v2[0][0]);
-   const int x3 = subpixel_snap(v3[0][0]);
-   const int y1 = subpixel_snap(v1[0][1]);
-   const int y2 = subpixel_snap(v2[0][1]);
-   const int y3 = subpixel_snap(v3[0][1]);
+   const int x1 = subpixel_snap(v1[0][0] + 0.5 - setup->pixel_offset);
+   const int x2 = subpixel_snap(v2[0][0] + 0.5 - setup->pixel_offset);
+   const int x3 = subpixel_snap(v3[0][0] + 0.5 - setup->pixel_offset);
+   const int y1 = subpixel_snap(v1[0][1] + 0.5 - setup->pixel_offset);
+   const int y2 = subpixel_snap(v2[0][1] + 0.5 - setup->pixel_offset);
+   const int y3 = subpixel_snap(v3[0][1] + 0.5 - setup->pixel_offset);
 
    struct lp_scene *scene = lp_setup_get_current_scene(setup);
    struct lp_rast_triangle *tri;

src/gallium/drivers/llvmpipe/lp_state_rasterizer.c

@@ -62,7 +62,8 @@ void llvmpipe_bind_rasterizer_state(struct pipe_context *pipe,
       lp_setup_set_triangle_state( llvmpipe->setup,
                    llvmpipe->rasterizer->cull_mode,
                    llvmpipe->rasterizer->front_winding == PIPE_WINDING_CCW,
-                   llvmpipe->rasterizer->scissor);
+                   llvmpipe->rasterizer->scissor,
+                   llvmpipe->rasterizer->gl_rasterization_rules);
    }
 
    llvmpipe->dirty |= LP_NEW_RASTERIZER;