1/*
2 * Copyright (C) 2016 Miklós Máté
3 * Copyright (C) 2020 Google LLC
4 *
5 * Permission is hereby granted, free of charge, to any person obtaining a
6 * copy of this software and associated documentation files (the "Software"),
7 * to deal in the Software without restriction, including without limitation
8 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
9 * and/or sell copies of the Software, and to permit persons to whom the
10 * Software is furnished to do so, subject to the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be included in
13 * all copies or substantial portions of the Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
19 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
20 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
21 * OTHER DEALINGS IN THE SOFTWARE.
22 */
23
24#include "main/mtypes.h"
25#include "main/atifragshader.h"
26#include "main/errors.h"
27#include "program/prog_parameter.h"
28#include "program/prog_instruction.h"
29#include "program/prog_to_nir.h"
30
31#include "st_program.h"
32#include "st_atifs_to_nir.h"
33#include "compiler/nir/nir_builder.h"
34
35#define FOG_PARAMS_UNIFORM (MAX_NUM_FRAGMENT_CONSTANTS_ATI + 0)
36#define FOG_COLOR_UNIFORM (MAX_NUM_FRAGMENT_CONSTANTS_ATI + 1)
37
38/**
39 * Intermediate state used during shader translation.
40 */
41struct st_translate {
42   nir_builder *b;
43   struct ati_fragment_shader *atifs;
44   const struct st_fp_variant_key *key;
45
46   nir_ssa_def *temps[MAX_PROGRAM_TEMPS];
47
48   nir_variable *fragcolor;
49   nir_variable *constants;
50   nir_variable *samplers[MAX_TEXTURE_UNITS];
51
52   nir_ssa_def *inputs[VARYING_SLOT_MAX];
53
54   unsigned current_pass;
55
56   bool regs_written[MAX_NUM_PASSES_ATI][MAX_NUM_FRAGMENT_REGISTERS_ATI];
57
58   boolean error;
59};
60
61static nir_ssa_def *
62nir_channel_vec4(nir_builder *b, nir_ssa_def *src, unsigned channel)
63{
64   unsigned swizzle[4] = { channel, channel, channel, channel };
65   return nir_swizzle(b, src, swizzle, 4);
66}
67
68static nir_ssa_def *
69nir_imm_vec4_float(nir_builder *b, float f)
70{
71   return nir_channel_vec4(b, nir_imm_float(b, f), 0);
72}
73
74static nir_ssa_def *
75get_temp(struct st_translate *t, unsigned index)
76{
77   if (!t->temps[index])
78      t->temps[index] = nir_ssa_undef(t->b, 4, 32);
79   return t->temps[index];
80}
81
82static nir_ssa_def *
83apply_swizzle(struct st_translate *t,
84              struct nir_ssa_def *src, GLuint swizzle)
85{
86   /* From the ATI_fs spec:
87    *
88    *     "Table 3.20 shows the <swizzle> modes:
89    *
90    *                           Coordinates Used for 1D or      Coordinates Used for
91    *      Swizzle              2D SampleMap and PassTexCoord   3D or cubemap SampleMap
92    *      -------              -----------------------------   -----------------------
93    *      SWIZZLE_STR_ATI      (s, t, r, undefined)            (s, t, r, undefined)
94    *      SWIZZLE_STQ_ATI      (s, t, q, undefined)            (s, t, q, undefined)
95    *      SWIZZLE_STR_DR_ATI   (s/r, t/r, 1/r, undefined)      (undefined)
96    *      SWIZZLE_STQ_DQ_ATI   (s/q, t/q, 1/q, undefined)      (undefined)
97    */
98   if (swizzle == GL_SWIZZLE_STR_ATI) {
99      return src;
100   } else if (swizzle == GL_SWIZZLE_STQ_ATI) {
101      static unsigned xywz[4] = { 0, 1, 3, 2 };
102      return nir_swizzle(t->b, src, xywz, 4);
103   } else {
104      nir_ssa_def *rcp = nir_frcp(t->b, nir_channel(t->b, src,
105                                                    swizzle == GL_SWIZZLE_STR_DR_ATI ? 2 : 3));
106
107      nir_ssa_def *st_mul = nir_fmul(t->b, nir_channels(t->b, src, 0x3), rcp);
108
109      return nir_vec4(t->b,
110                      nir_channel(t->b, st_mul, 0),
111                      nir_channel(t->b, st_mul, 1),
112                      rcp,
113                      rcp);
114   }
115}
116
117static nir_ssa_def *
118load_input(struct st_translate *t, gl_varying_slot slot)
119{
120   if (!t->inputs[slot]) {
121      const char *slot_name =
122         gl_varying_slot_name_for_stage(slot, MESA_SHADER_FRAGMENT);
123      nir_variable *var = nir_variable_create(t->b->shader, nir_var_shader_in,
124                                              slot == VARYING_SLOT_FOGC ?
125                                              glsl_float_type() : glsl_vec4_type(),
126                                              slot_name);
127      var->data.location = slot;
128      var->data.interpolation = INTERP_MODE_NONE;
129
130      t->inputs[slot] = nir_load_var(t->b, var);
131   }
132
133   return t->inputs[slot];
134}
135
136static nir_ssa_def *
137atifs_load_uniform(struct st_translate *t, int index)
138{
139   nir_deref_instr *deref = nir_build_deref_array(t->b,
140                                                  nir_build_deref_var(t->b, t->constants),
141                                                  nir_imm_int(t->b, index));
142   return nir_load_deref(t->b, deref);
143}
144
145static struct nir_ssa_def *
146get_source(struct st_translate *t, GLenum src_type)
147{
148   if (src_type >= GL_REG_0_ATI && src_type <= GL_REG_5_ATI) {
149      if (t->regs_written[t->current_pass][src_type - GL_REG_0_ATI]) {
150         return get_temp(t, src_type - GL_REG_0_ATI);
151      } else {
152         return nir_imm_vec4_float(t->b, 0.0);
153      }
154   } else if (src_type >= GL_CON_0_ATI && src_type <= GL_CON_7_ATI) {
155      int index = src_type - GL_CON_0_ATI;
156      if (t->atifs->LocalConstDef & (1 << index)) {
157         return nir_imm_vec4(t->b,
158                             t->atifs->Constants[index][0],
159                             t->atifs->Constants[index][1],
160                             t->atifs->Constants[index][2],
161                             t->atifs->Constants[index][3]);
162      } else {
163         return atifs_load_uniform(t, index);
164      }
165   } else if (src_type == GL_ZERO) {
166      return nir_imm_vec4_float(t->b, 0.0);
167   } else if (src_type == GL_ONE) {
168      return nir_imm_vec4_float(t->b, 1.0);
169   } else if (src_type == GL_PRIMARY_COLOR_ARB) {
170      return load_input(t, VARYING_SLOT_COL0);
171   } else if (src_type == GL_SECONDARY_INTERPOLATOR_ATI) {
172      return load_input(t, VARYING_SLOT_COL1);
173   } else {
174      /* frontend prevents this */
175      unreachable("unknown source");
176   }
177}
178
179static nir_ssa_def *
180prepare_argument(struct st_translate *t, const struct atifs_instruction *inst,
181                 const unsigned argId, bool alpha)
182{
183   if (argId >= inst->ArgCount[alpha]) {
184      _mesa_warning(0, "Using 0 for missing argument %d\n", argId);
185      return nir_imm_vec4_float(t->b, 0.0f);
186   }
187
188   const struct atifragshader_src_register *srcReg = &inst->SrcReg[alpha][argId];
189
190   nir_ssa_def *src = get_source(t, srcReg->Index);
191
192   switch (srcReg->argRep) {
193   case GL_NONE:
194      break;
195   case GL_RED:
196      src = nir_channel_vec4(t->b, src, 0);
197      break;
198   case GL_GREEN:
199      src = nir_channel_vec4(t->b, src, 1);
200      break;
201   case GL_BLUE:
202      src = nir_channel_vec4(t->b, src, 2);
203      break;
204   case GL_ALPHA:
205      src = nir_channel_vec4(t->b, src, 3);
206      break;
207   }
208
209   t->temps[MAX_NUM_FRAGMENT_REGISTERS_ATI + argId] = src;
210
211   if (srcReg->argMod & GL_COMP_BIT_ATI)
212      src = nir_fsub(t->b, nir_imm_vec4_float(t->b, 1.0), src);
213   if (srcReg->argMod & GL_BIAS_BIT_ATI)
214      src = nir_fadd(t->b, src, nir_imm_vec4_float(t->b, -0.5));
215   if (srcReg->argMod & GL_2X_BIT_ATI)
216      src = nir_fadd(t->b, src, src);
217   if (srcReg->argMod & GL_NEGATE_BIT_ATI)
218      src = nir_fneg(t->b, src);
219
220   return src;
221}
222
223static nir_ssa_def *
224emit_arith_inst(struct st_translate *t,
225                const struct atifs_instruction *inst,
226                bool alpha)
227{
228   nir_ssa_def *src[3] = {0};
229   for (int i = 0; i < inst->ArgCount[alpha]; i++)
230      src[i] = prepare_argument(t, inst, i, alpha);
231
232   switch (inst->Opcode[alpha]) {
233   case GL_MOV_ATI:
234      return src[0];
235
236   case GL_ADD_ATI:
237      return nir_fadd(t->b, src[0], src[1]);
238
239   case GL_SUB_ATI:
240      return nir_fsub(t->b, src[0], src[1]);
241
242   case GL_MUL_ATI:
243      return nir_fmul(t->b, src[0], src[1]);
244
245   case GL_MAD_ATI:
246      return nir_ffma(t->b, src[0], src[1], src[2]);
247
248   case GL_LERP_ATI:
249      return nir_flrp(t->b, src[2], src[1], src[0]);
250
251   case GL_CND_ATI:
252      return nir_bcsel(t->b,
253                       nir_fge(t->b, nir_imm_vec4_float(t->b, 0.5), src[2]),
254                       src[1],
255                       src[0]);
256
257   case GL_CND0_ATI:
258      return nir_bcsel(t->b,
259                       nir_fge(t->b, src[2], nir_imm_vec4_float(t->b, 0.0)),
260                       src[0],
261                       src[1]);
262
263   case GL_DOT2_ADD_ATI:
264      return nir_channel_vec4(t->b,
265                              nir_fadd(t->b,
266                                       nir_fdot2(t->b, src[0], src[1]),
267                                       nir_channel(t->b, src[1], 2)),
268                              0);
269
270   case GL_DOT3_ATI:
271      return nir_channel_vec4(t->b, nir_fdot3(t->b,src[0], src[1]), 0);
272
273   case GL_DOT4_ATI:
274      return nir_channel_vec4(t->b, nir_fdot4(t->b,src[0], src[1]), 0);
275
276   default:
277      unreachable("Unknown ATI_fs opcode");
278   }
279}
280
281static nir_ssa_def *
282emit_dstmod(struct st_translate *t,
283            struct nir_ssa_def *dst, GLuint dstMod)
284{
285   switch (dstMod & ~GL_SATURATE_BIT_ATI) {
286   case GL_2X_BIT_ATI:
287      dst = nir_fmul_imm(t->b, dst, 2.0f);
288      break;
289   case GL_4X_BIT_ATI:
290      dst = nir_fmul_imm(t->b, dst, 4.0f);
291      break;
292   case GL_8X_BIT_ATI:
293      dst = nir_fmul_imm(t->b, dst, 8.0f);
294      break;
295   case GL_HALF_BIT_ATI:
296      dst = nir_fmul_imm(t->b, dst, 0.5f);
297      break;
298   case GL_QUARTER_BIT_ATI:
299      dst = nir_fmul_imm(t->b, dst, 0.25f);
300      break;
301   case GL_EIGHTH_BIT_ATI:
302      dst = nir_fmul_imm(t->b, dst, 0.125f);
303      break;
304   default:
305      break;
306   }
307
308   if (dstMod & GL_SATURATE_BIT_ATI)
309      dst = nir_fsat(t->b, dst);
310
311   return dst;
312}
313
314/**
315 * Compile one setup instruction to NIR instructions.
316 */
317static void
318compile_setupinst(struct st_translate *t,
319                  const unsigned r,
320                  const struct atifs_setupinst *texinst)
321{
322   if (!texinst->Opcode)
323      return;
324
325   GLuint pass_tex = texinst->src;
326
327   nir_ssa_def *coord;
328
329   if (pass_tex >= GL_TEXTURE0_ARB && pass_tex <= GL_TEXTURE7_ARB) {
330      unsigned attr = pass_tex - GL_TEXTURE0_ARB;
331
332      coord = load_input(t, VARYING_SLOT_TEX0 + attr);
333   } else if (pass_tex >= GL_REG_0_ATI && pass_tex <= GL_REG_5_ATI) {
334      unsigned reg = pass_tex - GL_REG_0_ATI;
335
336      /* the frontend already validated that REG is only allowed in second pass */
337      if (t->regs_written[0][reg]) {
338         coord = t->temps[reg];
339      } else {
340         coord = nir_imm_vec4_float(t->b, 0.0f);
341      }
342   } else {
343      coord = nir_ssa_undef(t->b, 4, 32);
344   }
345   coord = apply_swizzle(t, coord, texinst->swizzle);
346
347   if (texinst->Opcode == ATI_FRAGMENT_SHADER_SAMPLE_OP) {
348      nir_variable *tex_var = t->samplers[r];
349      if (!tex_var) {
350         bool is_array;
351         enum glsl_sampler_dim sampler_dim =
352             _mesa_texture_index_to_sampler_dim(t->key->texture_index[r], &is_array);
353         const struct glsl_type *sampler_type =
354             glsl_sampler_type(sampler_dim, false, false, GLSL_TYPE_FLOAT);
355
356         tex_var = nir_variable_create(t->b->shader, nir_var_uniform, sampler_type, "tex");
357         tex_var->data.binding = r;
358         tex_var->data.explicit_binding = true;
359         t->samplers[r] = tex_var;
360      }
361      nir_deref_instr *tex_deref = nir_build_deref_var(t->b, t->samplers[r]);
362
363      nir_tex_instr *tex = nir_tex_instr_create(t->b->shader, 3);
364      tex->op = nir_texop_tex;
365      tex->sampler_dim = glsl_get_sampler_dim(tex_var->type);
366      tex->dest_type = nir_type_float32;
367      tex->coord_components =
368         glsl_get_sampler_dim_coordinate_components(tex->sampler_dim);
369
370      tex->src[0].src_type = nir_tex_src_texture_deref;
371      tex->src[0].src = nir_src_for_ssa(&tex_deref->dest.ssa);
372      tex->src[1].src_type = nir_tex_src_sampler_deref;
373      tex->src[1].src = nir_src_for_ssa(&tex_deref->dest.ssa);
374      tex->src[2].src_type = nir_tex_src_coord;
375      tex->src[2].src =
376         nir_src_for_ssa(nir_channels(t->b, coord,
377                                    (1 << tex->coord_components) - 1));
378
379      nir_ssa_dest_init(&tex->instr, &tex->dest, 4, 32, NULL);
380      nir_builder_instr_insert(t->b, &tex->instr);
381
382      t->temps[r] = &tex->dest.ssa;
383   } else if (texinst->Opcode == ATI_FRAGMENT_SHADER_PASS_OP) {
384      t->temps[r] = coord;
385   }
386
387   t->regs_written[t->current_pass][r] = true;
388}
389
390/**
391 * Compile one arithmetic operation COLOR&ALPHA pair into NIR instructions.
392 */
393static void
394compile_instruction(struct st_translate *t,
395                    const struct atifs_instruction *inst)
396{
397   unsigned optype;
398
399   for (optype = 0; optype < 2; optype++) { /* color, alpha */
400      unsigned dstreg = inst->DstReg[optype].Index - GL_REG_0_ATI;
401
402      if (!inst->Opcode[optype])
403         continue;
404
405      /* Execute the op */
406      nir_ssa_def *result = emit_arith_inst(t, inst, optype);
407      result = emit_dstmod(t, result, inst->DstReg[optype].dstMod);
408
409      /* Do the writemask */
410      nir_const_value wrmask[4] = { 0 };
411      for (int i = 0; i < 4; i++) {
412         if (inst->DstReg[optype].dstMask & (1 << i))
413            wrmask[i].b = 1;
414      }
415
416      t->temps[dstreg] = nir_bcsel(t->b,
417                                   nir_build_imm(t->b, 4, 1, wrmask),
418                                   result,
419                                   get_temp(t, dstreg));
420      t->regs_written[t->current_pass][dstreg] = true;
421   }
422}
423
424
425/* Creates the uniform variable referencing the ATI_fragment_shader constants
426 * plus the optimized fog state.
427 */
428static void
429st_atifs_setup_uniforms(struct st_translate *t, struct gl_program *program)
430{
431   const struct glsl_type *type =
432      glsl_array_type(glsl_vec4_type(), program->Parameters->NumParameters, 0);
433   t->constants =
434      nir_variable_create(t->b->shader, nir_var_uniform, type,
435                          "gl_ATI_fragment_shader_constants");
436}
437
438/**
439 * Called when a new variant is needed, we need to translate
440 * the ATI fragment shader to NIR
441 */
442nir_shader *
443st_translate_atifs_program(struct ati_fragment_shader *atifs,
444                           const struct st_fp_variant_key *key,
445                           struct gl_program *program,
446                           const nir_shader_compiler_options *options)
447{
448   nir_builder b = nir_builder_init_simple_shader(MESA_SHADER_FRAGMENT, options, "ATI_fs");
449
450   struct st_translate translate = {
451      .atifs = atifs,
452      .b = &b,
453      .key = key,
454   };
455   struct st_translate *t = &translate;
456
457   /* Copy the shader_info from the gl_program */
458   t->b->shader->info = program->info;
459
460   nir_shader *s = t->b->shader;
461   s->info.name = ralloc_asprintf(s, "ATIFS%d", program->Id);
462
463   t->fragcolor = nir_variable_create(b.shader, nir_var_shader_out,
464                                      glsl_vec4_type(), "gl_FragColor");
465   t->fragcolor->data.location = FRAG_RESULT_COLOR;
466
467   st_atifs_setup_uniforms(t, program);
468
469   /* emit instructions */
470   for (unsigned pass = 0; pass < atifs->NumPasses; pass++) {
471      t->current_pass = pass;
472      for (unsigned r = 0; r < MAX_NUM_FRAGMENT_REGISTERS_ATI; r++) {
473         struct atifs_setupinst *texinst = &atifs->SetupInst[pass][r];
474         compile_setupinst(t, r, texinst);
475      }
476      for (unsigned i = 0; i < atifs->numArithInstr[pass]; i++) {
477         struct atifs_instruction *inst = &atifs->Instructions[pass][i];
478         compile_instruction(t, inst);
479      }
480   }
481
482   if (t->regs_written[atifs->NumPasses-1][0]) {
483      nir_ssa_def *color = t->temps[0];
484
485      if (key->fog) {
486         nir_ssa_def *fogc = load_input(t, VARYING_SLOT_FOGC);
487
488         nir_ssa_def *params = atifs_load_uniform(t, FOG_PARAMS_UNIFORM);
489
490         /* compute the 1 component fog factor f */
491         nir_ssa_def *f = NULL;
492         if (key->fog == FOG_LINEAR) {
493            f = nir_ffma(t->b, fogc,
494                         nir_channel(t->b, params, 0),
495                         nir_channel(t->b, params, 1));
496         } else if (key->fog == FOG_EXP) {
497            /* EXP formula: f = exp(-dens * z)
498             * with optimized parameters:
499             *    f = MUL(fogcoord, oparams.z); f= EX2(-f)
500             */
501            f = nir_fmul(t->b, fogc, nir_channel(t->b, params, 2));
502            f = nir_fexp2(t->b, nir_fneg(t->b, f));
503         } else if (key->fog == FOG_EXP2) {
504            /* EXP2 formula: f = exp(-(dens * z)^2)
505             * with optimized parameters:
506             *    f = MUL(fogcoord, oparams.w); f=MUL(f, f); f= EX2(-f)
507             */
508            f = nir_fmul(t->b, fogc, nir_channel(t->b, params, 3));
509            f = nir_fmul(t->b, f, f);
510            f = nir_fexp2(t->b, nir_fneg(t->b, f));
511         }
512         f = nir_fsat(t->b, f);
513
514         nir_ssa_def *fog_color = nir_flrp(t->b,
515                                           atifs_load_uniform(t, FOG_COLOR_UNIFORM),
516                                           color,
517                                           f);
518         color = nir_vec4(t->b,
519                          nir_channel(t->b, fog_color, 0),
520                          nir_channel(t->b, fog_color, 1),
521                          nir_channel(t->b, fog_color, 2),
522                          nir_channel(t->b, color, 3));
523      }
524
525      nir_store_var(t->b, t->fragcolor, color, 0xf);
526   }
527
528   return b.shader;
529}
530
531/**
532 * Called in ProgramStringNotify, we need to fill the metadata of the
533 * gl_program attached to the ati_fragment_shader
534 */
535void
536st_init_atifs_prog(struct gl_context *ctx, struct gl_program *prog)
537{
538   /* we know this is st_fragment_program, because of st_new_ati_fs() */
539   struct st_program *stfp = (struct st_program *) prog;
540   struct ati_fragment_shader *atifs = stfp->ati_fs;
541
542   unsigned pass, i, r, optype, arg;
543
544   static const gl_state_index16 fog_params_state[STATE_LENGTH] =
545      {STATE_FOG_PARAMS_OPTIMIZED, 0, 0};
546   static const gl_state_index16 fog_color[STATE_LENGTH] =
547      {STATE_FOG_COLOR, 0, 0, 0};
548
549   prog->info.inputs_read = 0;
550   prog->info.outputs_written = BITFIELD64_BIT(FRAG_RESULT_COLOR);
551   prog->SamplersUsed = 0;
552   prog->Parameters = _mesa_new_parameter_list();
553
554   /* fill in inputs_read, SamplersUsed, TexturesUsed */
555   for (pass = 0; pass < atifs->NumPasses; pass++) {
556      for (r = 0; r < MAX_NUM_FRAGMENT_REGISTERS_ATI; r++) {
557         struct atifs_setupinst *texinst = &atifs->SetupInst[pass][r];
558         GLuint pass_tex = texinst->src;
559
560         if (texinst->Opcode == ATI_FRAGMENT_SHADER_SAMPLE_OP) {
561            /* mark which texcoords are used */
562            prog->info.inputs_read |= BITFIELD64_BIT(VARYING_SLOT_TEX0 + pass_tex - GL_TEXTURE0_ARB);
563            /* by default there is 1:1 mapping between samplers and textures */
564            prog->SamplersUsed |= (1 << r);
565            /* the target is unknown here, it will be fixed in the draw call */
566            prog->TexturesUsed[r] = TEXTURE_2D_BIT;
567         } else if (texinst->Opcode == ATI_FRAGMENT_SHADER_PASS_OP) {
568            if (pass_tex >= GL_TEXTURE0_ARB && pass_tex <= GL_TEXTURE7_ARB) {
569               prog->info.inputs_read |= BITFIELD64_BIT(VARYING_SLOT_TEX0 + pass_tex - GL_TEXTURE0_ARB);
570            }
571         }
572      }
573   }
574   for (pass = 0; pass < atifs->NumPasses; pass++) {
575      for (i = 0; i < atifs->numArithInstr[pass]; i++) {
576         struct atifs_instruction *inst = &atifs->Instructions[pass][i];
577
578         for (optype = 0; optype < 2; optype++) { /* color, alpha */
579            if (inst->Opcode[optype]) {
580               for (arg = 0; arg < inst->ArgCount[optype]; arg++) {
581                  GLint index = inst->SrcReg[optype][arg].Index;
582                  if (index == GL_PRIMARY_COLOR_EXT) {
583                     prog->info.inputs_read |= BITFIELD64_BIT(VARYING_SLOT_COL0);
584                  } else if (index == GL_SECONDARY_INTERPOLATOR_ATI) {
585                     /* note: ATI_fragment_shader.txt never specifies what
586                      * GL_SECONDARY_INTERPOLATOR_ATI is, swrast uses
587                      * VARYING_SLOT_COL1 for this input */
588                     prog->info.inputs_read |= BITFIELD64_BIT(VARYING_SLOT_COL1);
589                  }
590               }
591            }
592         }
593      }
594   }
595   /* we may need fog */
596   prog->info.inputs_read |= BITFIELD64_BIT(VARYING_SLOT_FOGC);
597
598   /* we always have the ATI_fs constants, and the fog params */
599   for (i = 0; i < MAX_NUM_FRAGMENT_CONSTANTS_ATI; i++) {
600      _mesa_add_parameter(prog->Parameters, PROGRAM_UNIFORM,
601                          NULL, 4, GL_FLOAT, NULL, NULL, true);
602   }
603   ASSERTED uint32_t ref;
604   ref = _mesa_add_state_reference(prog->Parameters, fog_params_state);
605   assert(ref == FOG_PARAMS_UNIFORM);
606   ref = _mesa_add_state_reference(prog->Parameters, fog_color);
607   assert(ref == FOG_COLOR_UNIFORM);
608}
609