gallium: rework handling of sprite_coord_enable state

Implement the pipe_rasterizer_state::sprite_coord_enable field
in the draw module (and softpipe) according to what's specified
in the documentation.

The draw module can now add any number of extra vertex attributes
to a post-transformed vertex and generate texcoords for those
attributes per sprite_coord_enable.  Auto-generated texcoords
for sprites only worked for one texcoord unit before.

The frag shader gl_PointCoord input is now implemented like any
other generic/texcoord attribute.

The draw module now needs to be informed about fragment shaders
since we need to look at the fragment shader's inputs to know
which ones need auto-generated texcoords.

Only softpipe has been updated so far.

2 files changed, 19 insertions, 12 deletions

diff --git a/src/mesa/state_tracker/st_atom_rasterizer.c b/src/mesa/state_tracker/st_atom_rasterizer.c
index 2599bd5ca0..0fe333ae8a 100644
--- a/src/mesa/state_tracker/st_atom_rasterizer.c
+++ b/src/mesa/state_tracker/st_atom_rasterizer.c
@@ -60,6 +60,7 @@ static void update_raster_state( struct st_context *st )
    GLcontext *ctx = st->ctx;
    struct pipe_rasterizer_state *raster = &st->state.rasterizer;
    const struct gl_vertex_program *vertProg = ctx->VertexProgram._Current;
+   const struct gl_fragment_program *fragProg = ctx->FragmentProgram._Current;
    uint i;
 
    memset(raster, 0, sizeof(*raster));
@@ -175,17 +176,30 @@ static void update_raster_state( struct st_context *st )
    if (!ctx->Point.PointSprite && ctx->Point.SmoothFlag)
       raster->point_smooth = 1;
 
+   /* _NEW_POINT | _NEW_PROGRAM
+    */
    if (ctx->Point.PointSprite) {
+      /* origin */
       if ((ctx->Point.SpriteOrigin == GL_UPPER_LEFT) ^
           (st_fb_orientation(ctx->DrawBuffer) == Y_0_BOTTOM))
          raster->sprite_coord_mode = PIPE_SPRITE_COORD_UPPER_LEFT;
       else 
          raster->sprite_coord_mode = PIPE_SPRITE_COORD_LOWER_LEFT;
+
+      /* Coord replacement flags.  If bit 'k' is set that means
+       * that we need to replace GENERIC[k] attrib with an automatically
+       * computed texture coord.
+       */
       for (i = 0; i < MAX_TEXTURE_COORD_UNITS; i++) {
          if (ctx->Point.CoordReplace[i]) {
             raster->sprite_coord_enable |= 1 << i;
          }
       }
+      if (fragProg->Base.InputsRead & FRAG_BIT_PNTC) {
+         raster->sprite_coord_enable |=
+            1 << (FRAG_ATTRIB_PNTC - FRAG_ATTRIB_TEX0);
+      }
+
       raster->point_quad_rasterization = 1;
    }
 
diff --git a/src/mesa/state_tracker/st_program.c b/src/mesa/state_tracker/st_program.c
index 8c2d8b6154..18a7bbe0f9 100644
--- a/src/mesa/state_tracker/st_program.c
+++ b/src/mesa/state_tracker/st_program.c
@@ -338,17 +338,6 @@ st_translate_fragment_program(struct st_context *st,
             input_semantic_index[slot] = 0;
             interpMode[slot] = TGSI_INTERPOLATE_CONSTANT;
             break;
-         case FRAG_ATTRIB_PNTC:
-            /* This is a hack.  We really need a new semantic label for
-             * point coord.  The draw module needs to know which fragment
-             * shader input is the point coord attribute so that it can set
-             * up the right vertex attribute values.
-             */
-            input_semantic_name[slot] = TGSI_SEMANTIC_GENERIC;
-            input_semantic_index[slot] = 0;
-            interpMode[slot] = TGSI_INTERPOLATE_PERSPECTIVE;
-            break;
-
             /* In most cases, there is nothing special about these
              * inputs, so adopt a convention to use the generic
              * semantic name and the mesa FRAG_ATTRIB_ number as the
@@ -364,6 +353,7 @@ st_translate_fragment_program(struct st_context *st,
              * zero or be restricted to a particular range -- nobody
              * should be building tables based on semantic index.
              */
+         case FRAG_ATTRIB_PNTC:
          case FRAG_ATTRIB_TEX0:
          case FRAG_ATTRIB_TEX1:
          case FRAG_ATTRIB_TEX2:
@@ -380,7 +370,10 @@ st_translate_fragment_program(struct st_context *st,
             assert(attr >= FRAG_ATTRIB_TEX0);
             input_semantic_index[slot] = (attr - FRAG_ATTRIB_TEX0);
             input_semantic_name[slot] = TGSI_SEMANTIC_GENERIC;
-            interpMode[slot] = TGSI_INTERPOLATE_PERSPECTIVE;
+            if (attr == FRAG_ATTRIB_PNTC)
+               interpMode[slot] = TGSI_INTERPOLATE_LINEAR;
+            else
+               interpMode[slot] = TGSI_INTERPOLATE_PERSPECTIVE;
             break;
          }
       }