Implement _mesa_append_fog_code() for fragment program fog options.

2 files changed, 178 insertions, 19 deletions

diff --git a/src/mesa/shader/programopt.c b/src/mesa/shader/programopt.c
index 199202edf77..55991dcce34 100644
--- a/src/mesa/shader/programopt.c
+++ b/src/mesa/shader/programopt.c
@@ -1,6 +1,6 @@
 /*
  * Mesa 3-D graphics library
- * Version:  6.5.1
+ * Version:  6.5.2
  *
  * Copyright (C) 1999-2006  Brian Paul   All Rights Reserved.
  *
@@ -117,31 +117,190 @@ _mesa_insert_mvp_code(GLcontext *ctx, struct gl_vertex_program *vprog)
 
 /**
  * Append extra instructions onto the given fragment program to implement
- * the fog mode specified by program->FogOption.
- * XXX incomplete.
+ * the fog mode specified by fprog->FogOption.
+ * The fragment.fogcoord input is used to compute the fog blend factor.
+ *
+ * XXX with a little work, this function could be adapted to add fog code
+ * to vertex programs too.
  */
 void
 _mesa_append_fog_code(GLcontext *ctx, struct gl_fragment_program *fprog)
 {
-   struct prog_instruction newInst[10];
-
-   switch (fprog->FogOption) {
-   case GL_LINEAR:
-      /* lerp */
-      break;
-   case GL_EXP:
-      break;
-   case GL_EXP2:
-      break;
-   case GL_NONE:
-      /* no-op */
+   static const GLint fogParamsState[] = { STATE_FOG_PARAMS, 0, 0, 0, 0 };
+   static const GLint fogColorState[] = { STATE_FOG_COLOR, 0, 0, 0, 0 };
+   struct prog_instruction *newInst, *inst;
+   const GLuint origLen = fprog->Base.NumInstructions;
+   const GLuint newLen = origLen + 6;
+   GLuint i;
+   GLint fogParamsRef, fogColorRef; /* state references */
+   GLuint colorTemp, fogFactorTemp; /* temporary registerss */
+   GLfloat fogVals[4];
+   GLuint fogConsts;                /* constant values for EXP, EXP2 mode */
+
+   if (fprog->FogOption != GL_NONE) {
+      _mesa_problem(ctx, "_mesa_append_fog_code() called for fragment program"
+                    " with FogOption == GL_NONE");
       return;
-   default:
-      _mesa_problem(ctx, "Invalid fog option");
+   }
+
+   /* Alloc storage for new instructions */
+   newInst = _mesa_alloc_instructions(newLen);
+   if (!newInst) {
+      _mesa_error(ctx, GL_OUT_OF_MEMORY,
+                  "glProgramString(inserting fog_option code)");
       return;
    }
 
+   /* Copy orig instructions into new instruction buffer */
+   _mesa_memcpy(newInst, fprog->Base.Instructions,
+                origLen * sizeof(struct prog_instruction));
+
+   /* PARAM fogParamsRef = state.fog.params; */
+   fogParamsRef
+      = _mesa_add_state_reference(fprog->Base.Parameters, fogParamsState);
+   /* PARAM fogColorRef = state.fog.color; */
+   fogColorRef
+      = _mesa_add_state_reference(fprog->Base.Parameters, fogColorState);
 
-   (void) newInst;
+   /* TEMP colorTemp; */
+   colorTemp = fprog->Base.NumTemporaries++;
+   /* TEMP fogFactorTemp; */
+   fogFactorTemp = fprog->Base.NumTemporaries++;
 
+   /* PARAM fogVals = { 1/ln(2), 1/sqrt(ln(2), 0, 0 }; */
+   fogVals[0] = 1.0 / log(2.0);
+   fogVals[1] = 1.0 / SQRTF(log(2.0));
+   fogVals[2] = 0.0;
+   fogVals[3] = 0.0;
+   fogConsts = _mesa_add_unnamed_constant(fprog->Base.Parameters, fogVals);
+
+   /* Scan program to find where result.color is written */
+   inst = newInst;
+   for (i = 0; i < fprog->Base.NumInstructions; i++) {
+      if (inst->Opcode == OPCODE_END)
+         break;
+      if (inst->DstReg.File == PROGRAM_OUTPUT &&
+          inst->DstReg.Index == FRAG_RESULT_COLR) {
+         /* change the instruction to write to colorTemp w/ clamping */
+         inst->DstReg.File = PROGRAM_TEMPORARY;
+         inst->DstReg.Index = colorTemp;
+         inst->SaturateMode = SATURATE_ZERO_ONE;
+         /* don't break (may be several writes to result.color) */
+      }
+      inst++;
+   }
+   assert(inst->Opcode == OPCODE_END); /* we'll overwrite this inst */
+
+   for (i = 0; i < 6; i++)
+      _mesa_init_instruction(inst + i);
+
+   /* emit instructions to compute fog blending factor */
+   if (fprog->FogOption == GL_LINEAR) {
+      /* SUB fogFactorTemp.x, fogParamsRef.z, fragment.fogcoord.x; */
+      inst->Opcode = OPCODE_SUB;
+      inst->DstReg.File = PROGRAM_TEMPORARY;
+      inst->DstReg.Index = fogFactorTemp;
+      inst->DstReg.WriteMask = WRITEMASK_X;
+      inst->SrcReg[0].File = PROGRAM_STATE_VAR;
+      inst->SrcReg[0].Index = fogParamsRef;
+      inst->SrcReg[0].Swizzle = SWIZZLE_Z;
+      inst->SrcReg[1].File = PROGRAM_INPUT;
+      inst->SrcReg[1].Index = FRAG_ATTRIB_FOGC;
+      inst++;
+      /* MUL fogFactorTemp.x, fogFactorTemp, fogParamsRef.w; */
+      inst->Opcode = OPCODE_MUL;
+      inst->DstReg.File = PROGRAM_TEMPORARY;
+      inst->DstReg.Index = fogFactorTemp;
+      inst->DstReg.WriteMask = WRITEMASK_X;
+      inst->SrcReg[0].File = PROGRAM_TEMPORARY;
+      inst->SrcReg[0].Index = fogFactorTemp;
+      inst->SrcReg[1].File = PROGRAM_STATE_VAR;
+      inst->SrcReg[1].Index = fogParamsRef;
+      inst->SrcReg[1].Swizzle = SWIZZLE_W;
+      inst++;
+   }
+   else {
+      ASSERT(fprog->FogOption == GL_EXP || fprog->FogOption == GL_EXP2);
+      /* MUL fogFactorTemp.x, fogParamsRef.x, fragment.fogcoord; */
+      inst->Opcode = OPCODE_MUL;
+      inst->DstReg.File = PROGRAM_TEMPORARY;
+      inst->DstReg.Index = fogFactorTemp;
+      inst->DstReg.WriteMask = WRITEMASK_X;
+      inst->SrcReg[0].File = PROGRAM_STATE_VAR;
+      inst->SrcReg[0].Index = fogParamsRef;
+      inst->SrcReg[0].Swizzle = SWIZZLE_X; /* X=density */
+      inst->SrcReg[1].File = PROGRAM_INPUT;
+      inst->SrcReg[1].Index = FRAG_ATTRIB_FOGC;
+      inst->SrcReg[1].Swizzle = SWIZZLE_X;
+      inst++;
+      if (fprog->FogOption == GL_EXP2) {
+         /* MUL fogFactorTemp.x, fogFactorTemp.x, fogFactorTemp.x; */
+         inst->Opcode = OPCODE_MUL;
+         inst->DstReg.File = PROGRAM_TEMPORARY;
+         inst->DstReg.Index = fogFactorTemp;
+         inst->DstReg.WriteMask = WRITEMASK_X;
+         inst->SrcReg[0].File = PROGRAM_TEMPORARY;
+         inst->SrcReg[0].Index = fogFactorTemp;
+         inst->SrcReg[1].File = PROGRAM_TEMPORARY;
+         inst->SrcReg[1].Index = fogFactorTemp;
+         inst++;
+      }
+      /* EXP:  MUL fogFactorTemp.x, fogFactorTemp.x, {1/ln(2)}; */
+      /* EXP2: MUL fogFactorTemp.x, fogFactorTemp.x, {1/sqrt(ln(2))}; */
+      inst->Opcode = OPCODE_MUL;
+      inst->DstReg.File = PROGRAM_TEMPORARY;
+      inst->DstReg.Index = fogFactorTemp;
+      inst->DstReg.WriteMask = WRITEMASK_X;
+      inst->SrcReg[0].File = PROGRAM_TEMPORARY;
+      inst->SrcReg[0].Index = fogFactorTemp;
+      inst->SrcReg[1].File = PROGRAM_CONSTANT;
+      inst->SrcReg[1].Index = fogConsts;
+      inst->SrcReg[1].Swizzle
+         = (fprog->FogOption == GL_EXP) ? SWIZZLE_X : SWIZZLE_Y;
+      inst++;
+      /* EX2_SAT fogFactorTemp.x, -fogFactorTemp.x; */
+      inst->Opcode = OPCODE_EX2;
+      inst->DstReg.File = PROGRAM_TEMPORARY;
+      inst->DstReg.Index = fogFactorTemp;
+      inst->DstReg.WriteMask = WRITEMASK_X;
+      inst->SrcReg[0].File = PROGRAM_TEMPORARY;
+      inst->SrcReg[0].Index = fogFactorTemp;
+      inst->SrcReg[0].NegateBase = GL_TRUE;
+      inst->SaturateMode = SATURATE_ZERO_ONE;
+      inst++;
+   }
+   /* LRP result.color.xyz, fogFactorTemp.xxxx, colorTemp, fogColorRef; */
+   inst->Opcode = OPCODE_LRP;
+   inst->DstReg.File = PROGRAM_OUTPUT;
+   inst->DstReg.Index = FRAG_RESULT_COLR;
+   inst->DstReg.WriteMask = WRITEMASK_XYZ;
+   inst->SrcReg[0].File = PROGRAM_TEMPORARY;
+   inst->SrcReg[0].Index = fogFactorTemp;
+   inst->SrcReg[0].Swizzle
+      = MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_X, SWIZZLE_X, SWIZZLE_X);
+   inst->SrcReg[1].File = PROGRAM_TEMPORARY;
+   inst->SrcReg[1].Index = colorTemp;
+   inst->SrcReg[2].File = PROGRAM_STATE_VAR;
+   inst->SrcReg[2].Index = fogColorRef;
+   inst++;
+   /* MOV result.color.w, colorTemp.x;  # copy alpha */
+   inst->Opcode = OPCODE_MOV;
+   inst->DstReg.File = PROGRAM_OUTPUT;
+   inst->DstReg.Index = FRAG_RESULT_COLR;
+   inst->DstReg.WriteMask = WRITEMASK_W;
+   inst->SrcReg[0].File = PROGRAM_TEMPORARY;
+   inst->SrcReg[0].Index = colorTemp;
+   inst++;
+   /* END; */
+   inst->Opcode = OPCODE_END;
+   inst++;
+
+   /* free old instructions */
+   _mesa_free(fprog->Base.Instructions);
+
+   /* install new instructions */
+   fprog->Base.Instructions = newInst;
+   fprog->Base.NumInstructions = inst - newInst;
+   fprog->Base.InputsRead |= FRAG_BIT_FOGC;
+   /* XXX do this?  fprog->FogOption = GL_NONE; */
 }
diff --git a/src/mesa/shader/programopt.h b/src/mesa/shader/programopt.h
index 8799da435b3..efaf29b9374 100644
--- a/src/mesa/shader/programopt.h
+++ b/src/mesa/shader/programopt.h
@@ -1,6 +1,6 @@
 /*
  * Mesa 3-D graphics library
- * Version:  6.5.1
+ * Version:  6.5.2
  *
  * Copyright (C) 1999-2006  Brian Paul   All Rights Reserved.
  *