nv50/ir: make use of TGSI_INTERPOLATE_COLOR

Flat SHADE_MODEL still overrides any non-flat interpolation
qualifier, but pulling that state out of the rasterizer cso
isn't really worth the effort, is it ?

NOTE: This is a candidate for the 8.0 branch.

2 files changed, 10 insertions, 5 deletions

diff --git a/src/gallium/drivers/nv50/codegen/nv50_ir_driver.h b/src/gallium/drivers/nv50/codegen/nv50_ir_driver.h
index a37a29a99a6..84a514091c6 100644
--- a/src/gallium/drivers/nv50/codegen/nv50_ir_driver.h
+++ b/src/gallium/drivers/nv50/codegen/nv50_ir_driver.h
@@ -42,6 +42,7 @@ struct nv50_ir_varying
    unsigned mask     : 4; /* vec4 mask */
    unsigned linear   : 1; /* linearly interpolated if true (and not flat) */
    unsigned flat     : 1;
+   unsigned sc       : 1; /* special colour interpolation mode (SHADE_MODEL) */
    unsigned centroid : 1;
    unsigned patch    : 1; /* patch constant value */
    unsigned regular  : 1; /* driver-specific meaning (e.g. input in sreg) */
diff --git a/src/gallium/drivers/nv50/codegen/nv50_ir_from_tgsi.cpp b/src/gallium/drivers/nv50/codegen/nv50_ir_from_tgsi.cpp
index c104dbe9670..3fb679b29de 100644
--- a/src/gallium/drivers/nv50/codegen/nv50_ir_from_tgsi.cpp
+++ b/src/gallium/drivers/nv50/codegen/nv50_ir_from_tgsi.cpp
@@ -817,9 +817,11 @@ bool Source::scanDeclaration(const struct tgsi_full_declaration *decl)
                case TGSI_INTERPOLATE_CONSTANT:
                   info->in[i].flat = 1;
                   break;
+               case TGSI_INTERPOLATE_COLOR:
+                  info->in[i].sc = 1;
+                  break;
                case TGSI_INTERPOLATE_LINEAR:
-                  if (sn != TGSI_SEMANTIC_COLOR) // GL_NICEST
-                     info->in[i].linear = 1;
+                  info->in[i].linear = 1;
                   break;
                default:
                   break;
@@ -1141,7 +1143,7 @@ Converter::makeSym(uint tgsiFile, int fileIdx, int idx, int c, uint32_t address)
 static inline uint8_t
 translateInterpMode(const struct nv50_ir_varying *var, operation& op)
 {
-   uint8_t mode;
+   uint8_t mode = NV50_IR_INTERP_PERSPECTIVE;
 
    if (var->flat)
       mode = NV50_IR_INTERP_FLAT;
@@ -1149,9 +1151,11 @@ translateInterpMode(const struct nv50_ir_varying *var, operation& op)
    if (var->linear)
       mode = NV50_IR_INTERP_LINEAR;
    else
-      mode = NV50_IR_INTERP_PERSPECTIVE;
+   if (var->sc)
+      mode = NV50_IR_INTERP_SC;
 
-   op = (mode == NV50_IR_INTERP_PERSPECTIVE) ? OP_PINTERP : OP_LINTERP;
+   op = (mode == NV50_IR_INTERP_PERSPECTIVE || mode == NV50_IR_INTERP_SC)
+      ? OP_PINTERP : OP_LINTERP;
 
    if (var->centroid)
       mode |= NV50_IR_INTERP_CENTROID;