mesa: new gl_fragment_program fields indicating use of fog, front-facing, point coord

(cherry picked from commit d7a7b0a10dd355fbeb7a404091a42d4ab558c820)

2 files changed, 36 insertions, 19 deletions

diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 3370aa2977..19cf6f56d1 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -1932,7 +1932,10 @@ struct gl_fragment_program
 {
    struct gl_program Base;   /**< base class */
    GLenum FogOption;
-   GLboolean UsesKill;
+   GLboolean UsesKill;          /**< shader uses KIL instruction */
+   GLboolean UsesPointCoord;    /**< shader uses gl_PointCoord */
+   GLboolean UsesFrontFacing;   /**< shader used gl_FrontFacing */
+   GLboolean UsesFogFragCoord;  /**< shader used gl_FogFragCoord */
 };
 
 
diff --git a/src/mesa/shader/slang/slang_link.c b/src/mesa/shader/slang/slang_link.c
index a6390846b2..b780e87fe6 100644
--- a/src/mesa/shader/slang/slang_link.c
+++ b/src/mesa/shader/slang/slang_link.c
@@ -42,6 +42,24 @@
 #include "slang_link.h"
 
 
+/** cast wrapper */
+static struct gl_vertex_program *
+vertex_program(struct gl_program *prog)
+{
+   assert(prog->Target == GL_VERTEX_PROGRAM_ARB);
+   return (struct gl_vertex_program *) prog;
+}
+
+
+/** cast wrapper */
+static struct gl_fragment_program *
+fragment_program(struct gl_program *prog)
+{
+   assert(prog->Target == GL_FRAGMENT_PROGRAM_ARB);
+   return (struct gl_fragment_program *) prog;
+}
+
+
 /**
  * Record a linking error.
  */
@@ -373,6 +391,20 @@ _slang_update_inputs_outputs(struct gl_program *prog)
       for (j = 0; j < numSrc; j++) {
          if (inst->SrcReg[j].File == PROGRAM_INPUT) {
             prog->InputsRead |= 1 << inst->SrcReg[j].Index;
+            if (prog->Target == GL_FRAGMENT_PROGRAM_ARB &&
+                inst->SrcReg[j].Index == FRAG_ATTRIB_FOGC) {
+               /* The fragment shader FOGC input is used for fog,
+                * front-facing and sprite/point coord.
+                */
+               struct gl_fragment_program *fp = fragment_program(prog);
+               const GLint swz = GET_SWZ(inst->SrcReg[j].Swizzle, 0);
+               if (swz == SWIZZLE_X)
+                  fp->UsesFogFragCoord = GL_TRUE;
+               else if (swz == SWIZZLE_Y)
+                  fp->UsesFrontFacing = GL_TRUE;
+               else if (swz == SWIZZLE_Z || swz == SWIZZLE_W)
+                  fp->UsesPointCoord = GL_TRUE;
+            }
          }
       }
       if (inst->DstReg.File == PROGRAM_OUTPUT) {
@@ -382,24 +414,6 @@ _slang_update_inputs_outputs(struct gl_program *prog)
 }
 
 
-/** cast wrapper */
-static struct gl_vertex_program *
-vertex_program(struct gl_program *prog)
-{
-   assert(prog->Target == GL_VERTEX_PROGRAM_ARB);
-   return (struct gl_vertex_program *) prog;
-}
-
-
-/** cast wrapper */
-static struct gl_fragment_program *
-fragment_program(struct gl_program *prog)
-{
-   assert(prog->Target == GL_FRAGMENT_PROGRAM_ARB);
-   return (struct gl_fragment_program *) prog;
-}
-
-
 /**
  * Shader linker.  Currently:
  *