programopt.c

Mesa is an open-source implementation of the OpenGL specification - a system for rendering interacti

         inst->SrcReg[1].File = PROGRAM_TEMPORARY;
         inst->SrcReg[1].Index = fogFactorTemp;
         inst->SrcReg[1].Swizzle = SWIZZLE_XXXX;
         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 = NEGATE_XYZW;
      inst->SrcReg[0].Swizzle = SWIZZLE_XXXX;
      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 = SWIZZLE_XXXX;
   inst->SrcReg[1].File = PROGRAM_TEMPORARY;
   inst->SrcReg[1].Index = colorTemp;
   inst->SrcReg[1].Swizzle = SWIZZLE_NOOP;
   inst->SrcReg[2].File = PROGRAM_STATE_VAR;
   inst->SrcReg[2].Index = fogColorRef;
   inst->SrcReg[2].Swizzle = SWIZZLE_NOOP;
   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->SrcReg[0].Swizzle = SWIZZLE_NOOP;
   inst++;
   /* END; */
   inst->Opcode = OPCODE_END;
   inst++;

   /* free old instructions */
   _mesa_free_instructions(fprog->Base.Instructions, origLen);

   /* 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; */
}



static GLboolean
is_texture_instruction(const struct prog_instruction *inst)
{
   switch (inst->Opcode) {
   case OPCODE_TEX:
   case OPCODE_TXB:
   case OPCODE_TXD:
   case OPCODE_TXL:
   case OPCODE_TXP:
   case OPCODE_TXP_NV:
      return GL_TRUE;
   default:
      return GL_FALSE;
   }
}
      

/**
 * Count the number of texure indirections in the given program.
 * The program's NumTexIndirections field will be updated.
 * See the GL_ARB_fragment_program spec (issue 24) for details.
 * XXX we count texture indirections in texenvprogram.c (maybe use this code
 * instead and elsewhere).
 */
void
_mesa_count_texture_indirections(struct gl_program *prog)
{
   GLuint indirections = 1;
   GLbitfield tempsOutput = 0x0;
   GLbitfield aluTemps = 0x0;
   GLuint i;

   for (i = 0; i < prog->NumInstructions; i++) {
      const struct prog_instruction *inst = prog->Instructions + i;

      if (is_texture_instruction(inst)) {
         if (((inst->SrcReg[0].File == PROGRAM_TEMPORARY) && 
              (tempsOutput & (1 << inst->SrcReg[0].Index))) ||
             ((inst->Opcode != OPCODE_KIL) &&
              (inst->DstReg.File == PROGRAM_TEMPORARY) && 
              (aluTemps & (1 << inst->DstReg.Index)))) 
            {
               indirections++;
               tempsOutput = 0x0;
               aluTemps = 0x0;
            }
      }
      else {
         GLuint j;
         for (j = 0; j < 3; j++) {
            if (inst->SrcReg[j].File == PROGRAM_TEMPORARY)
               aluTemps |= (1 << inst->SrcReg[j].Index);
         }
         if (inst->DstReg.File == PROGRAM_TEMPORARY)
            aluTemps |= (1 << inst->DstReg.Index);
      }

      if ((inst->Opcode != OPCODE_KIL) && (inst->DstReg.File == PROGRAM_TEMPORARY))
         tempsOutput |= (1 << inst->DstReg.Index);
   }

   prog->NumTexIndirections = indirections;
}


/**
 * Count number of texture instructions in given program and update the
 * program's NumTexInstructions field.
 */
void
_mesa_count_texture_instructions(struct gl_program *prog)
{
   GLuint i;
   prog->NumTexInstructions = 0;
   for (i = 0; i < prog->NumInstructions; i++) {
      prog->NumTexInstructions += is_texture_instruction(prog->Instructions + i);
   }
}


/**
 * Scan/rewrite program to remove reads of custom (output) registers.
 * The passed type has to be either PROGRAM_OUTPUT or PROGRAM_VARYING
 * (for vertex shaders).
 * In GLSL shaders, varying vars can be read and written.
 * On some hardware, trying to read an output register causes trouble.
 * So, rewrite the program to use a temporary register in this case.
 */
void
_mesa_remove_output_reads(struct gl_program *prog, enum register_file type)
{
   GLuint i;
   GLint outputMap[VERT_RESULT_MAX];
   GLuint numVaryingReads = 0;

   assert(type == PROGRAM_VARYING || type == PROGRAM_OUTPUT);
   assert(prog->Target == GL_VERTEX_PROGRAM_ARB || type != PROGRAM_VARYING);

   for (i = 0; i < VERT_RESULT_MAX; i++)
      outputMap[i] = -1;

   /* look for instructions which read from varying vars */
   for (i = 0; i < prog->NumInstructions; i++) {
      struct prog_instruction *inst = prog->Instructions + i;
      const GLuint numSrc = _mesa_num_inst_src_regs(inst->Opcode);
      GLuint j;
      for (j = 0; j < numSrc; j++) {
         if (inst->SrcReg[j].File == type) {
            /* replace the read with a temp reg */
            const GLuint var = inst->SrcReg[j].Index;
            if (outputMap[var] == -1) {
               numVaryingReads++;
               outputMap[var] = _mesa_find_free_register(prog,
                                                         PROGRAM_TEMPORARY);
            }
            inst->SrcReg[j].File = PROGRAM_TEMPORARY;
            inst->SrcReg[j].Index = outputMap[var];
         }
      }
   }

   if (numVaryingReads == 0)
      return; /* nothing to be done */

   /* look for instructions which write to the varying vars identified above */
   for (i = 0; i < prog->NumInstructions; i++) {
      struct prog_instruction *inst = prog->Instructions + i;
      const GLuint numSrc = _mesa_num_inst_src_regs(inst->Opcode);
      GLuint j;
      for (j = 0; j < numSrc; j++) {
         if (inst->DstReg.File == type &&
             outputMap[inst->DstReg.Index] >= 0) {
            /* change inst to write to the temp reg, instead of the varying */
            inst->DstReg.File = PROGRAM_TEMPORARY;
            inst->DstReg.Index = outputMap[inst->DstReg.Index];
         }
      }
   }

   /* insert new instructions to copy the temp vars to the varying vars */
   {
      struct prog_instruction *inst;
      GLint endPos, var;

      /* Look for END instruction and insert the new varying writes */
      endPos = -1;
      for (i = 0; i < prog->NumInstructions; i++) {
         struct prog_instruction *inst = prog->Instructions + i;
         if (inst->Opcode == OPCODE_END) {
            endPos = i;
            _mesa_insert_instructions(prog, i, numVaryingReads);
            break;
         }
      }

      assert(endPos >= 0);

      /* insert new MOV instructions here */
      inst = prog->Instructions + endPos;
      for (var = 0; var < VERT_RESULT_MAX; var++) {
         if (outputMap[var] >= 0) {
            /* MOV VAR[var], TEMP[tmp]; */
            inst->Opcode = OPCODE_MOV;
            inst->DstReg.File = type;
            inst->DstReg.Index = var;
            inst->SrcReg[0].File = PROGRAM_TEMPORARY;
            inst->SrcReg[0].Index = outputMap[var];
            inst++;
         }
      }
   }
}