[Mesa-dev] [PATCH 3/5] i965/vs: Handle vertex color clamping in emit_urb_slot().

[Kenneth Graunke]

Vertex color clamping only applies to a few specific built-ins: COL0/1
and BFC0/1 (aka gl_[Secondary]{Front,Back}Color).  It seems weird to
handle special cases in a function called emit_generic_urb_slot().

emit_urb_slot() is all about handling special cases, so it makes more
sense to handle this there.

Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
---
 src/mesa/drivers/dri/i965/brw_vec4.h           |  2 +-
 src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp | 22 ++++++++++++----------
 2 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_vec4.h b/src/mesa/drivers/dri/i965/brw_vec4.h
index 066ea2e..744746e 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4.h
+++ b/src/mesa/drivers/dri/i965/brw_vec4.h
@@ -499,7 +499,7 @@ public:
    void emit_ndc_computation();
    void emit_psiz_and_flags(dst_reg reg);
    void emit_clip_distances(dst_reg reg, int offset);
-   void emit_generic_urb_slot(dst_reg reg, int varying);
+   vec4_instruction *emit_generic_urb_slot(dst_reg reg, int varying);
    void emit_urb_slot(dst_reg reg, int varying);
 
    void emit_shader_time_begin();
diff --git a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
index c1c24ac..66d68c0 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
@@ -3055,22 +3055,14 @@ vec4_visitor::emit_clip_distances(dst_reg reg, int offset)
    }
 }
 
-void
+vec4_instruction *
 vec4_visitor::emit_generic_urb_slot(dst_reg reg, int varying)
 {
    assert (varying < VARYING_SLOT_MAX);
    reg.type = output_reg[varying].type;
    current_annotation = output_reg_annotation[varying];
    /* Copy the register, saturating if necessary */
-   vec4_instruction *inst = emit(MOV(reg,
-                                     src_reg(output_reg[varying])));
-   if ((varying == VARYING_SLOT_COL0 ||
-        varying == VARYING_SLOT_COL1 ||
-        varying == VARYING_SLOT_BFC0 ||
-        varying == VARYING_SLOT_BFC1) &&
-       key->clamp_vertex_color) {
-      inst->saturate = true;
-   }
+   return emit(MOV(reg, src_reg(output_reg[varying])));
 }
 
 void
@@ -3108,6 +3100,16 @@ vec4_visitor::emit_urb_slot(dst_reg reg, int varying)
    case BRW_VARYING_SLOT_PAD:
       /* No need to write to this slot */
       break;
+   case VARYING_SLOT_COL0:
+   case VARYING_SLOT_COL1:
+   case VARYING_SLOT_BFC0:
+   case VARYING_SLOT_BFC1: {
+      vec4_instruction *inst = emit_generic_urb_slot(reg, varying);
+      if (key->clamp_vertex_color)
+         inst->saturate = true;
+      break;
+   }
+
    default:
       emit_generic_urb_slot(reg, varying);
       break;
-- 
2.1.3