[Mesa-dev] [PATCH] gallium: introduce GLSL based interpolation rules.

[Dave Airlie]

From: Dave Airlie <airlied at redhat.com>

This introduces an unspecified interpolation paramter that is only allowed for
color semantics, so a specified GLSL interpolation will override the ShadeModel
specified interpolation, but not vice-versa.

This fixes a lot of the interpolation tests in piglit.

Signed-off-by: Dave Airlie <airlied at redhat.com>
---
 src/gallium/auxiliary/tgsi/tgsi_exec.c          |    4 ++++
 src/gallium/auxiliary/tgsi/tgsi_exec.h          |    2 +-
 src/gallium/auxiliary/tgsi/tgsi_strings.c       |    1 +
 src/gallium/drivers/softpipe/sp_quad_fs.c       |    1 +
 src/gallium/drivers/softpipe/sp_state_derived.c |   10 ++++++++--
 src/gallium/include/pipe/p_shader_tokens.h      |    9 +++++----
 src/mesa/state_tracker/st_program.c             |    2 +-
 7 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/src/gallium/auxiliary/tgsi/tgsi_exec.c b/src/gallium/auxiliary/tgsi/tgsi_exec.c
index 61ab58a..451d84f 100644
--- a/src/gallium/auxiliary/tgsi/tgsi_exec.c
+++ b/src/gallium/auxiliary/tgsi/tgsi_exec.c
@@ -2377,6 +2377,10 @@ exec_declaration(struct tgsi_exec_machine *mach,
                eval = eval_perspective_coef;
                break;
 
+            case TGSI_INTERPOLATE_UNSPECIFIED:
+               eval = mach->flatshade_unspecified ? eval_constant_coef : eval_perspective_coef;
+               break;
+
             default:
                assert(0);
                return;
diff --git a/src/gallium/auxiliary/tgsi/tgsi_exec.h b/src/gallium/auxiliary/tgsi/tgsi_exec.h
index ac021ce..7b1e785 100644
--- a/src/gallium/auxiliary/tgsi/tgsi_exec.h
+++ b/src/gallium/auxiliary/tgsi/tgsi_exec.h
@@ -263,7 +263,7 @@ struct tgsi_exec_machine
    const struct tgsi_interp_coef *InterpCoefs;
    struct tgsi_exec_vector       QuadPos;
    float                         Face;    /**< +1 if front facing, -1 if back facing */
-
+   bool                          flatshade_unspecified;
    /* Conditional execution masks */
    uint CondMask;  /**< For IF/ELSE/ENDIF */
    uint LoopMask;  /**< For BGNLOOP/ENDLOOP */
diff --git a/src/gallium/auxiliary/tgsi/tgsi_strings.c b/src/gallium/auxiliary/tgsi/tgsi_strings.c
index 973b9fe..02d766e 100644
--- a/src/gallium/auxiliary/tgsi/tgsi_strings.c
+++ b/src/gallium/auxiliary/tgsi/tgsi_strings.c
@@ -114,6 +114,7 @@ const char *tgsi_type_names[5] =
 
 const char *tgsi_interpolate_names[TGSI_INTERPOLATE_COUNT] =
 {
+   "UNSPECIFIED",
    "CONSTANT",
    "LINEAR",
    "PERSPECTIVE"
diff --git a/src/gallium/drivers/softpipe/sp_quad_fs.c b/src/gallium/drivers/softpipe/sp_quad_fs.c
index 7b08cd0..8720947 100644
--- a/src/gallium/drivers/softpipe/sp_quad_fs.c
+++ b/src/gallium/drivers/softpipe/sp_quad_fs.c
@@ -74,6 +74,7 @@ shade_quad(struct quad_stage *qs, struct quad_header *quad)
    struct tgsi_exec_machine *machine = softpipe->fs_machine;
 
    /* run shader */
+   machine->flatshade_unspecified = softpipe->rasterizer->flatshade ? TRUE : FALSE;
    return softpipe->fs_variant->run( softpipe->fs_variant, machine, quad );
 }
 
diff --git a/src/gallium/drivers/softpipe/sp_state_derived.c b/src/gallium/drivers/softpipe/sp_state_derived.c
index 5685997..1442a7e 100644
--- a/src/gallium/drivers/softpipe/sp_state_derived.c
+++ b/src/gallium/drivers/softpipe/sp_state_derived.c
@@ -100,6 +100,9 @@ softpipe_get_vertex_info(struct softpipe_context *softpipe)
          case TGSI_INTERPOLATE_PERSPECTIVE:
             interp = INTERP_PERSPECTIVE;
             break;
+         case TGSI_INTERPOLATE_UNSPECIFIED:
+            assert(fsInfo->input_semantic_name[i] == TGSI_SEMANTIC_COLOR);
+            break;
          default:
             assert(0);
             interp = INTERP_LINEAR;
@@ -111,8 +114,11 @@ softpipe_get_vertex_info(struct softpipe_context *softpipe)
             break;
 
          case TGSI_SEMANTIC_COLOR:
-            if (softpipe->rasterizer->flatshade) {
-               interp = INTERP_CONSTANT;
+            if (fsInfo->input_interpolate[i] == TGSI_INTERPOLATE_UNSPECIFIED) {
+               if (softpipe->rasterizer->flatshade)
+                  interp = INTERP_CONSTANT;
+               else
+                  interp = INTERP_PERSPECTIVE;
             }
             break;
          }
diff --git a/src/gallium/include/pipe/p_shader_tokens.h b/src/gallium/include/pipe/p_shader_tokens.h
index 75e17a1..c9a79b4 100644
--- a/src/gallium/include/pipe/p_shader_tokens.h
+++ b/src/gallium/include/pipe/p_shader_tokens.h
@@ -97,10 +97,11 @@ enum tgsi_file_type {
 #define TGSI_WRITEMASK_YZW      0x0E
 #define TGSI_WRITEMASK_XYZW     0x0F
 
-#define TGSI_INTERPOLATE_CONSTANT      0
-#define TGSI_INTERPOLATE_LINEAR        1
-#define TGSI_INTERPOLATE_PERSPECTIVE   2
-#define TGSI_INTERPOLATE_COUNT         3
+#define TGSI_INTERPOLATE_UNSPECIFIED   0 /* only legal for colors */
+#define TGSI_INTERPOLATE_CONSTANT      1
+#define TGSI_INTERPOLATE_LINEAR        2
+#define TGSI_INTERPOLATE_PERSPECTIVE   3
+#define TGSI_INTERPOLATE_COUNT         4
 
 #define TGSI_CYLINDRICAL_WRAP_X (1 << 0)
 #define TGSI_CYLINDRICAL_WRAP_Y (1 << 1)
diff --git a/src/mesa/state_tracker/st_program.c b/src/mesa/state_tracker/st_program.c
index 8d7469d..3f6b2dd 100644
--- a/src/mesa/state_tracker/st_program.c
+++ b/src/mesa/state_tracker/st_program.c
@@ -441,7 +441,7 @@ st_translate_interp(enum glsl_interp_qualifier glsl_qual, bool is_color)
    switch (glsl_qual) {
    case INTERP_QUALIFIER_NONE:
       if (is_color)
-         return TGSI_INTERPOLATE_LINEAR;
+         return TGSI_INTERPOLATE_UNSPECIFIED;
       return TGSI_INTERPOLATE_PERSPECTIVE;
    case INTERP_QUALIFIER_SMOOTH:
       return TGSI_INTERPOLATE_PERSPECTIVE;
-- 
1.7.7.3