i965: fix bugs in projective texture coordinates

For the TXP instruction we check if the texcoord is really a 4-component
atttibute which requires the divide by W step.  This check involved the
projtex_mask field.  However, the projtex_mask field was being miscalculated
because of some confusion between vertex program outputs and fragment
program inputs.

1. Rework the size_masks calculation so we correctly set bits corresponding
to fragment program input attributes.

2. Rename projtex_mask to proj_attrib_mask since we're interested in more
than just texcoords (generic varying vars too).

3. Simply the indexing of the size_masks and proj_attrib_mask fields.

4. The tracker::active[] array was mis-dimensioned.  Use MAX_PROGRAM_TEMPS
instead of a magic number.

5. Update comments, add new assertions.

With these changes the Lightsmark demo/benchmark renders correctly, until
we eventually hit a GPU lockup...

1 files changed, 16 insertions, 5 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_wm_fp.c b/src/mesa/drivers/dri/i965/brw_wm_fp.c
index 1798d842c7..49aad281d7 100644
--- a/src/mesa/drivers/dri/i965/brw_wm_fp.c
+++ b/src/mesa/drivers/dri/i965/brw_wm_fp.c
@@ -834,10 +834,16 @@ static void precalc_tex( struct brw_wm_compile *c,
 }
 
 
+/**
+ * Check if the given TXP instruction really needs the divide-by-W step.
+ */
 static GLboolean projtex( struct brw_wm_compile *c,
 			  const struct prog_instruction *inst )
 {
-   struct prog_src_register src = inst->SrcReg[0];
+   const struct prog_src_register src = inst->SrcReg[0];
+   GLboolean retVal;
+
+   assert(inst->Opcode == OPCODE_TXP);
 
    /* Only try to detect the simplest cases.  Could detect (later)
     * cases where we are trying to emit code like RCP {1.0}, MUL x,
@@ -847,16 +853,21 @@ static GLboolean projtex( struct brw_wm_compile *c,
     * user-provided fragment programs anyway:
     */
    if (inst->TexSrcTarget == TEXTURE_CUBE_INDEX)
-      return 0;  /* ut2004 gun rendering !?! */
+      retVal = GL_FALSE;  /* ut2004 gun rendering !?! */
    else if (src.File == PROGRAM_INPUT && 
 	    GET_SWZ(src.Swizzle, W) == W &&
-           (c->key.projtex_mask & (1<<(src.Index + FRAG_ATTRIB_WPOS - FRAG_ATTRIB_TEX0))) == 0)
-      return 0;
+            (c->key.proj_attrib_mask & (1 << src.Index)) == 0)
+      retVal = GL_FALSE;
    else
-      return 1;
+      retVal = GL_TRUE;
+
+   return retVal;
 }
 
 
+/**
+ * Emit code for TXP.
+ */
 static void precalc_txp( struct brw_wm_compile *c,
 			       const struct prog_instruction *inst )
 {