i965/gen6+: Add support for noperspective interpolation.

This required the following changes:

- WM setup now makes the appropriate set of barycentric coordinates
  (perspective vs. noperspective) available to the fragment shader,
  based on whether the shader requires perspective interpolation,
  noperspective interpolation, both, or neither.

- The fragment shader backend now uses the appropriate set of
  barycentric coordiantes when interpolating, based on the
  interpolation mode returned by
  ir_variable::determine_interpolation_mode().

- SF setup now uses gl_fragment_program::InterpQualifier to determine
  which attributes are to be flat shaded (as opposed to the old logic,
  which only flat shaded colors).

- CLIP setup now ensures that the clipper outputs non-perspective
  barycentric coordinates when they are needed by the fragment shader.

Fixes the remaining piglit tests of interpolation qualifiers that were
failing:
- interpolation-flat-*-smooth-none
- interpolation-flat-other-flat-none
- interpolation-noperspective-*
- interpolation-smooth-gl_*Color-flat-*

Reviewed-by: Eric Anholt <eric@anholt.net>

1 files changed, 10 insertions, 11 deletions

diff --git a/src/mesa/drivers/dri/i965/gen6_sf_state.c b/src/mesa/drivers/dri/i965/gen6_sf_state.c
index 67b649e..67119d8 100644
--- a/src/mesa/drivers/dri/i965/gen6_sf_state.c
+++ b/src/mesa/drivers/dri/i965/gen6_sf_state.c
@@ -118,6 +118,8 @@ upload_sf_state(struct brw_context *brw)
    GLbitfield64 vs_outputs_written = brw->vs.prog_data->outputs_written;
    /* BRW_NEW_FRAGMENT_PROGRAM */
    uint32_t num_outputs = _mesa_bitcount_64(brw->fragment_program->Base.InputsRead);
+   /* _NEW_LIGHT */
+   bool shade_model_flat = ctx->Light.ShadeModel == GL_FLAT;
    uint32_t dw1, dw2, dw3, dw4, dw16, dw17;
    int i;
    /* _NEW_BUFFER */
@@ -263,6 +265,10 @@ upload_sf_state(struct brw_context *brw)
     * they source from.
     */
    for (; attr < FRAG_ATTRIB_MAX; attr++) {
+      enum glsl_interp_qualifier interp_qualifier =
+         brw->fragment_program->InterpQualifier[attr];
+      bool is_gl_Color = attr == FRAG_ATTRIB_COL0 || attr == FRAG_ATTRIB_COL1;
+
       if (!(brw->fragment_program->Base.InputsRead & BITFIELD64_BIT(attr)))
 	 continue;
 
@@ -277,17 +283,10 @@ upload_sf_state(struct brw_context *brw)
 	 dw16 |= (1 << input_index);
 
       /* flat shading */
-      if (ctx->Light.ShadeModel == GL_FLAT) {
-         /*
-          * Setup the Constant Interpolation Enable bit mask for each
-          * corresponding attribute(currently, we only care two attrs:
-          * FRAG_BIT_COL0 and FRAG_BIT_COL1).
-          *
-          * FIXME: should we care other attributes?
-          */
-	  if (attr == FRAG_ATTRIB_COL0 || attr == FRAG_ATTRIB_COL1)
-             dw17 |= (1 << input_index);
-      }
+      if (interp_qualifier == INTERP_QUALIFIER_FLAT ||
+          (shade_model_flat && is_gl_Color &&
+           interp_qualifier == INTERP_QUALIFIER_NONE))
+         dw17 |= (1 << input_index);
 
       /* The hardware can only do the overrides on 16 overrides at a
        * time, and the other up to 16 have to be lined up so that the