Don't always declare frag shader INPUT[0] as fragment position.

We were doing this for the sake of softpipe and the tgsi intergrepter since
we always need the fragment position and W-coordinate information in order
to compute fragment interpolants.
But that's not appropriate for hardware drivers.
The tgsi interpreter now get x,y,w information from a separate tgsi_exec_vector
variable setup by softpipe.
The new pipe_shader_state->input_map[] defines how vert shader outputs map
to frag shader inputs.  It may go away though, since one can also examine
the semantic label on frag shader input[0] to figure things out.

1 files changed, 14 insertions, 11 deletions

diff --git a/src/mesa/state_tracker/st_program.c b/src/mesa/state_tracker/st_program.c
index e64bf14d56a..fe22233c937 100644
--- a/src/mesa/state_tracker/st_program.c
+++ b/src/mesa/state_tracker/st_program.c
@@ -47,7 +47,7 @@
 #include "st_mesa_to_tgsi.h"
 
 
-#define TGSI_DEBUG 0
+#define TGSI_DEBUG 01
 
 
 /**
@@ -283,16 +283,17 @@ st_translate_fragment_program(struct st_context *st,
    const struct cso_fragment_shader *cso;
    GLuint interpMode[16];  /* XXX size? */
    GLuint attr;
-   GLbitfield inputsRead = stfp->Base.Base.InputsRead;
-
-   /* For software rendering, we always need the fragment input position
-    * in order to calculate interpolated values.
-    * For i915, we always want to emit the semantic info for position.
-    */
-   inputsRead |= FRAG_BIT_WPOS;
+   const GLbitfield inputsRead = stfp->Base.Base.InputsRead;
+   GLuint vslot = 0;
 
    memset(&fs, 0, sizeof(fs));
 
+   /* which vertex output goes to the first fragment input: */
+   if (inputsRead & FRAG_BIT_WPOS)
+      vslot = 0;
+   else
+      vslot = 1;
+
    /*
     * Convert Mesa program inputs to TGSI input register semantics.
     */
@@ -300,15 +301,17 @@ st_translate_fragment_program(struct st_context *st,
       if (inputsRead & (1 << attr)) {
          const GLuint slot = fs.num_inputs;
 
-         fs.num_inputs++;
-
          defaultInputMapping[attr] = slot;
 
+         fs.input_map[slot] = vslot++;
+
+         fs.num_inputs++;
+
          switch (attr) {
          case FRAG_ATTRIB_WPOS:
             fs.input_semantic_name[slot] = TGSI_SEMANTIC_POSITION;
             fs.input_semantic_index[slot] = 0;
-            interpMode[slot] = TGSI_INTERPOLATE_CONSTANT;
+            interpMode[slot] = TGSI_INTERPOLATE_LINEAR;
             break;
          case FRAG_ATTRIB_COL0:
             fs.input_semantic_name[slot] = TGSI_SEMANTIC_COLOR;