/*
* Mesa 3-D graphics library
*
* Copyright (C) 1999-2007 Brian Paul All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
/**
* \file programopt.c
* Vertex/Fragment program optimizations and transformations for program
* options, etc.
*
* \author Brian Paul
*/
#include "main/glheader.h"
#include "main/context.h"
#include "prog_parameter.h"
#include "prog_statevars.h"
#include "program.h"
#include "programopt.h"
#include "prog_instruction.h"
/**
* This function inserts instructions for coordinate modelview * projection
* into a vertex program.
* May be used to implement the position_invariant option.
*/
static void
_mesa_insert_mvp_dp4_code(struct gl_context *ctx, struct gl_program *vprog)
{
struct prog_instruction *newInst;
const GLuint origLen = vprog->arb.NumInstructions;
const GLuint newLen = origLen + 4;
GLuint i;
/*
* Setup state references for the modelview/projection matrix.
* XXX we should check if these state vars are already declared.
*/
static const gl_state_index mvpState[4][STATE_LENGTH] = {
{ STATE_MVP_MATRIX, 0, 0, 0, 0 }, /* state.matrix.mvp.row[0] */
{ STATE_MVP_MATRIX, 0, 1, 1, 0 }, /* state.matrix.mvp.row[1] */
{ STATE_MVP_MATRIX, 0, 2, 2, 0 }, /* state.matrix.mvp.row[2] */
{ STATE_MVP_MATRIX, 0, 3, 3, 0 }, /* state.matrix.mvp.row[3] */
};
GLint mvpRef[4];
for (i = 0; i < 4; i++) {
mvpRef[i] = _mesa_add_state_reference(vprog->Parameters, mvpState[i]);
}
/* Alloc storage for new instructions */
newInst = rzalloc_array(vprog, struct prog_instruction, newLen);
if (!newInst) {
_mesa_error(ctx, GL_OUT_OF_MEMORY,
"glProgramString(inserting position_invariant code)");
return;
}
/*
* Generated instructions:
* newInst[0] = DP4 result.position.x, mvp.row[0], vertex.position;
* newInst[1] = DP4 result.position.y, mvp.row[1], vertex.position;
* newInst[2] = DP4 result.position.z, mvp.row[2], vertex.position;
* newInst[3] = DP4 result.position.w, mvp.row[3], vertex.position;
*/
_mesa_init_instructions(newInst, 4);
for (i = 0; i < 4; i++) {
newInst[i].Opcode = OPCODE_DP4;
newInst[i].DstReg.File = PROGRAM_OUTPUT;
newInst[i].DstReg.Index = VARYING_SLOT_POS;
newInst[i].DstReg.WriteMask = (WRITEMASK_X << i);
newInst[i].SrcReg[0].File = PROGRAM_STATE_VAR;
newInst[i].SrcReg[0].Index = mvpRef[i];
newInst[i].SrcReg[0].Swizzle = SWIZZLE_NOOP;
newInst[i].SrcReg[1].File = PROGRAM_INPUT;
newInst[i].SrcReg[1].Index = VERT_ATTRIB_POS;
newInst[i].SrcReg[1].Swizzle = SWIZZLE_NOOP;
}
/* Append original instructions after new instructions */
_mesa_copy_instructions (newInst + 4, vprog->arb.Instructions, origLen);
/* free old instructions */
ralloc_free(vprog->arb.Instructions);
/* install new instructions */
vprog->arb.Instructions = newInst;
vprog->arb.NumInstructions = newLen;
vprog->info.inputs_read |= VERT_BIT_POS;
vprog->info.outputs_written |= BITFIELD64_BIT(VARYING_SLOT_POS);
}
static void
_mesa_insert_mvp_mad_code(struct gl_context *ctx, struct gl_program *vprog)
{
struct prog_instruction *newInst;
const GLuint origLen = vprog->arb.NumInstructions;
const GLuint newLen = origLen + 4;
GLuint hposTemp;
GLuint i;
/*
* Setup state references for the modelview/projection matrix.
* XXX we should check if these state vars are already declared.
*/
static const gl_state_index mvpState[4][STATE_LENGTH] = {
{ STATE_MVP_MATRIX, 0, 0, 0, STATE_MATRIX_TRANSPOSE },
{ STATE_MVP_MATRIX, 0, 1, 1, STATE_MATRIX_TRANSPOSE },
{ STATE_MVP_MATRIX, 0, 2, 2, STATE_MATRIX_TRANSPOSE },
{ STATE_MVP_MATRIX, 0, 3, 3, STATE_MATRIX_TRANSPOSE },
};
GLint mvpRef[4];
for (i = 0; i < 4; i++) {
mvpRef[i] = _mesa_add_state_reference(vprog->Parameters, mvpState[i]);
}
/* Alloc storage for new instructions */
newInst = rzalloc_array(vprog, struct prog_instruction, newLen);
if (!newInst) {
_mesa_error(ctx, GL_OUT_OF_MEMORY,
"glProgramString(inserting position_invariant code)");
return;
}
/* TEMP hposTemp; */
hposTemp = vprog->arb.NumTemporaries++;
/*
* Generated instructions:
* emit_op2(p, OPCODE_MUL, tmp, 0, swizzle1(src,X), mat[0]);
* emit_op3(p, OPCODE_MAD, tmp, 0, swizzle1(src,Y), mat[1], tmp);
* emit_op3(p, OPCODE_MAD, tmp, 0, swizzle1(src,Z), mat[2], tmp);
* emit_op3(p, OPCODE_MAD, dest, 0, swizzle1(src,W), mat[3], tmp);
*/
_mesa_init_instructions(newInst, 4);
newInst[0].Opcode = OPCODE_MUL;
newInst[0].DstReg.File = PROGRAM_TEMPORARY;
newInst[0].DstReg.Index = hposTemp;
newInst[0].DstReg.WriteMask = WRITEMASK_XYZW;
newInst[0].SrcReg[0].File = PROGRAM_INPUT;
newInst[0].SrcReg[0].Index = VERT_ATTRIB_POS;
newInst[0].SrcReg[0].Swizzle = SWIZZLE_XXXX;
newInst[0].SrcReg[1].File = PROGRAM_STATE_VAR;
newInst[0].SrcReg[1].Index = mvpRef[0];
newInst[0].SrcReg[1].Swizzle = SWIZZLE_NOOP;
for (i = 1; i <= 2; i++) {
newInst[i].Opcode = OPCODE_MAD;
newInst[i].DstReg.File = PROGRAM_TEMPORARY;
newInst[i].DstReg.Index = hposTemp;
newInst[i].DstReg.WriteMask = WRITEMASK_XYZW;
newInst[i].SrcReg[0].File = PROGRAM_INPUT;
newInst[i].SrcReg[0].Index = VERT_ATTRIB_POS;
newInst[i].SrcReg[0].Swizzle = MAKE_SWIZZLE4(i,i,i,i);
newInst[i].SrcReg[1].File = PROGRAM_STATE_VAR;
newInst[i].SrcReg[1].Index = mvpRef[i];
newInst[i].SrcReg[1].Swizzle = SWIZZLE_NOOP;
newInst[i].SrcReg[2].File = PROGRAM_TEMPORARY;
newInst[i].SrcReg[2].Index = hposTemp;
newInst[1].SrcReg[2].Swizzle = SWIZZLE_NOOP;
}
newInst[3].Opcode = OPCODE_MAD;
newInst[3].DstReg.File = PROGRAM_OUTPUT;
newInst[3].DstReg.Index = VARYING_SLOT_POS;
newInst[3].DstReg.WriteMask = WRITEMASK_XYZW;
newInst[3].SrcReg[0].File = PROGRAM_INPUT;
newInst[3].SrcReg[0].Index = VERT_ATTRIB_POS;
newInst[3].SrcReg[0].Swizzle = SWIZZLE_WWWW;
newInst[3].SrcReg[1].File = PROGRAM_STATE_VAR;
newInst[3].SrcReg[1].Index = mvpRef[3];
newInst[3].SrcReg[1].Swizzle = SWIZZLE_NOOP;
newInst[3].SrcReg[2].File = PROGRAM_TEMPORARY;
newInst[3].SrcReg[2].Index = hposTemp;
newInst[3].SrcReg[2].Swizzle = SWIZZLE_NOOP;
/* Append original instructions after new instructions */
_mesa_copy_instructions (newInst + 4, vprog->arb.Instructions, origLen);
/* free old instructions */
ralloc_free(vprog->arb.Instructions);
/* install new instructions */
vprog->arb.Instructions = newInst;
vprog->arb.NumInstructions = newLen;
vprog->info.inputs_read |= VERT_BIT_POS;
vprog->info.outputs_written |= BITFIELD64_BIT(VARYING_SLOT_POS);
}
void
_mesa_insert_mvp_code(struct gl_context *ctx, struct gl_program *vprog)
{
if (ctx->Const.ShaderCompilerOptions[MESA_SHADER_VERTEX].OptimizeForAOS)
_mesa_insert_mvp_dp4_code( ctx, vprog );
else
_mesa_insert_mvp_mad_code( ctx, vprog );
}
/**
* Append instructions to implement fog
*
* The \c fragment.fogcoord input is used to compute the fog blend factor.
*
* \param ctx The GL context
* \param fprog Fragment program that fog instructions will be appended to.
* \param fog_mode Fog mode. One of \c GL_EXP, \c GL_EXP2, or \c GL_LINEAR.
* \param saturate True if writes to color outputs should be clamped to [0, 1]
*
* \note
* This function sets \c VARYING_BIT_FOGC in \c fprog->info.inputs_read.
*
* \todo With a little work, this function could be adapted to add fog code
* to vertex programs too.
*/
void
_mesa_append_fog_code(struct gl_context *ctx, struct gl_program *fprog,
GLenum fog_mode, GLboolean saturate)
{
static const gl_state_index fogPStateOpt[STATE_LENGTH]
= { STATE_INTERNAL, STATE_FOG_PARAMS_OPTIMIZED, 0, 0, 0 };
static const gl_state_index fogColorState[STATE_LENGTH]
= { STATE_FOG_COLOR, 0, 0, 0, 0};
struct prog_instruction *newInst, *inst;
const GLuint origLen = fprog->arb.NumInstructions;
const GLuint newLen = origLen + 5;
GLuint i;
GLint fogPRefOpt, fogColorRef; /* state references */
GLuint colorTemp, fogFactorTemp; /* temporary registerss */
if (fog_mode == GL_NONE) {
_mesa_problem(ctx, "_mesa_append_fog_code() called for fragment program"
" with fog_mode == GL_NONE");
return;
}
if (!(fprog->info.outputs_written & (1 << FRAG_RESULT_COLOR))) {
/* program doesn't output color, so nothing to do */
return;
}
/* Alloc storage for new instructions */
newInst = rzalloc_array(fprog, struct prog_instruction, newLen);
if (!newInst) {
_mesa_error(ctx, GL_OUT_OF_MEMORY,
"glProgramString(inserting fog_option code)");
return;
}
/* Copy orig instructions into new instruction buffer */
_mesa_copy_instructions(newInst, fprog->arb.Instructions, origLen);
/* PARAM fogParamsRefOpt = internal optimized fog params; */
fogPRefOpt
= _mesa_add_state_reference(fprog->Parameters, fogPStateOpt);
/* PARAM fogColorRef = state.fog.color; */
fogColorRef
= _mesa_add_state_reference(fprog->Parameters, fogColorState);
/* TEMP colorTemp; */
colorTemp = fprog->arb.NumTemporaries++;
/* TEMP fogFactorTemp; */
fogFactorTemp = fprog->arb.NumTemporaries++;
/* Scan program to find where result.color is written */
inst = newInst;
for (i = 0; i < fprog->arb.NumInstructions; i++) {
if (inst->Opcode == OPCODE_END)
break;
if (inst->DstReg.File == PROGRAM_OUTPUT &&
inst->DstReg.Index == FRAG_RESULT_COLOR) {
/* change the instruction to write to colorTemp w/ clamping */
inst->DstReg.File = PROGRAM_TEMPORARY;
inst->DstReg.Index = colorTemp;
inst->Saturate = saturate;
/* don't break (may be several writes to result.color) */
}
inst++;
}
assert(inst->Opcode == OPCODE_END); /* we'll overwrite this inst */
_mesa_init_instructions(inst, 5);
/* emit instructions to compute fog blending factor */
/* this is always clamped to [0, 1] regardless of fragment clamping */
if (fog_mode == GL_LINEAR) {
/* MAD fogFactorTemp.x, fragment.fogcoord.x, fogPRefOpt.x, fogPRefOpt.y; */
inst->Opcode = OPCODE_MAD;
inst->DstReg.File = PROGRAM_TEMPORARY;
inst->DstReg.Index = fogFactorTemp;
inst->DstReg.WriteMask = WRITEMASK_X;
inst->SrcReg[0].File = PROGRAM_INPUT;
inst->SrcReg[0].Index = VARYING_SLOT_FOGC;
inst->SrcReg[0].Swizzle = SWIZZLE_XXXX;
inst->SrcReg[1].File = PROGRAM_STATE_VAR;
inst->SrcReg[1].Index = fogPRefOpt;
inst->SrcReg[1].Swizzle = SWIZZLE_XXXX;
inst->SrcReg[2].File = PROGRAM_STATE_VAR;
inst->SrcReg[2].Index = fogPRefOpt;
inst->SrcReg[2].Swizzle = SWIZZLE_YYYY;
inst->Saturate = GL_TRUE;
inst++;
}
else {
assert(fog_mode == GL_EXP || fog_mode == GL_EXP2);
/* fogPRefOpt.z = d/ln(2), fogPRefOpt.w = d/sqrt(ln(2) */
/* EXP: MUL fogFactorTemp.x, fogPRefOpt.z, fragment.fogcoord.x; */
/* EXP2: MUL fogFactorTemp.x, fogPRefOpt.w, fragment.fogcoord.x; */
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 = fogPRefOpt;
inst->SrcReg[0].Swizzle
= (fog_mode == GL_EXP) ? SWIZZLE_ZZZZ : SWIZZLE_WWWW;
inst->SrcReg[1].File = PROGRAM_INPUT;
inst->SrcReg[1].Index = VARYING_SLOT_FOGC;
inst->SrcReg[1].Swizzle = SWIZZLE_XXXX;
inst++;
if (fog_mode == 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[0].Swizzle = SWIZZLE_XXXX;
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].Negate = NEGATE_XYZW;
inst->SrcReg[0].Swizzle = SWIZZLE_XXXX;
inst->Saturate = GL_TRUE;
inst++;
}
/* LRP result.color.xyz, fogFactorTemp.xxxx, colorTemp, fogColorRef; */
inst->Opcode = OPCODE_LRP;
inst->DstReg.File = PROGRAM_OUTPUT;
inst->DstReg.Index = FRAG_RESULT_COLOR;
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_COLOR;
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 */
ralloc_free(fprog->arb.Instructions);
/* install new instructions */
fprog->arb.Instructions = newInst;
fprog->arb.NumInstructions = inst - newInst;
fprog->info.inputs_read |= VARYING_BIT_FOGC;
assert(fprog->info.outputs_written & (1 << FRAG_RESULT_COLOR));
}
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:
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->arb.NumInstructions; i++) {
const struct prog_instruction *inst = prog->arb.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->arb.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->arb.NumTexInstructions = 0;
for (i = 0; i < prog->arb.NumInstructions; i++) {
prog->arb.NumTexInstructions +=
is_texture_instruction(prog->arb.Instructions + i);
}
}
/**
* Scan/rewrite program to remove reads of custom (output) registers.
* The passed type has to be PROGRAM_OUTPUT.
* 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, gl_register_file type)
{
GLuint i;
GLint outputMap[VARYING_SLOT_MAX];
GLuint numVaryingReads = 0;
GLboolean usedTemps[MAX_PROGRAM_TEMPS];
GLuint firstTemp = 0;
_mesa_find_used_registers(prog, PROGRAM_TEMPORARY,
usedTemps, MAX_PROGRAM_TEMPS);
assert(type == PROGRAM_OUTPUT);
for (i = 0; i < VARYING_SLOT_MAX; i++)
outputMap[i] = -1;
/* look for instructions which read from varying vars */
for (i = 0; i < prog->arb.NumInstructions; i++) {
struct prog_instruction *inst = prog->arb.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(usedTemps,
MAX_PROGRAM_TEMPS,
firstTemp);
firstTemp = outputMap[var] + 1;
}
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->arb.NumInstructions; i++) {
struct prog_instruction *inst = prog->arb.Instructions + i;
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->arb.NumInstructions; i++) {
struct prog_instruction *inst = prog->arb.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->arb.Instructions + endPos;
for (var = 0; var < VARYING_SLOT_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++;
}
}
}
}
void
_mesa_program_fragment_position_to_sysval(struct gl_program *prog)
{
GLuint i;
if (prog->Target != GL_FRAGMENT_PROGRAM_ARB ||
!(prog->info.inputs_read & BITFIELD64_BIT(VARYING_SLOT_POS)))
return;
prog->info.inputs_read &= ~BITFIELD64_BIT(VARYING_SLOT_POS);
prog->info.system_values_read |= 1 << SYSTEM_VALUE_FRAG_COORD;
for (i = 0; i < prog->arb.NumInstructions; i++) {
struct prog_instruction *inst = prog->arb.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 == PROGRAM_INPUT &&
inst->SrcReg[j].Index == VARYING_SLOT_POS) {
inst->SrcReg[j].File = PROGRAM_SYSTEM_VALUE;
inst->SrcReg[j].Index = SYSTEM_VALUE_FRAG_COORD;
}
}
}
}