src/glsl/builtin_variables.cpp

   1 /*
   2  * Copyright © 2010 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * 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 OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  21  * DEALINGS IN THE SOFTWARE.
  22  */
  23
  24 #include "ir.h"
  25 #include "glsl_parser_extras.h"
  26 #include "glsl_symbol_table.h"
  27 #include "main/core.h"
  28 #include "main/uniforms.h"
  29 #include "program/prog_parameter.h"
  30 #include "program/prog_statevars.h"
  31 #include "program/prog_instruction.h"
  32
  33 static struct gl_builtin_uniform_element gl_NumSamples_elements[] = {
  34    {NULL, {STATE_NUM_SAMPLES, 0, 0}, SWIZZLE_XXXX}
  35 };
  36
  37 static struct gl_builtin_uniform_element gl_DepthRange_elements[] = {
  38    {"near", {STATE_DEPTH_RANGE, 0, 0}, SWIZZLE_XXXX},
  39    {"far", {STATE_DEPTH_RANGE, 0, 0}, SWIZZLE_YYYY},
  40    {"diff", {STATE_DEPTH_RANGE, 0, 0}, SWIZZLE_ZZZZ},
  41 };
  42
  43 static struct gl_builtin_uniform_element gl_ClipPlane_elements[] = {
  44    {NULL, {STATE_CLIPPLANE, 0, 0}, SWIZZLE_XYZW}
  45 };
  46
  47 static struct gl_builtin_uniform_element gl_Point_elements[] = {
  48    {"size", {STATE_POINT_SIZE}, SWIZZLE_XXXX},
  49    {"sizeMin", {STATE_POINT_SIZE}, SWIZZLE_YYYY},
  50    {"sizeMax", {STATE_POINT_SIZE}, SWIZZLE_ZZZZ},
  51    {"fadeThresholdSize", {STATE_POINT_SIZE}, SWIZZLE_WWWW},
  52    {"distanceConstantAttenuation", {STATE_POINT_ATTENUATION}, SWIZZLE_XXXX},
  53    {"distanceLinearAttenuation", {STATE_POINT_ATTENUATION}, SWIZZLE_YYYY},
  54    {"distanceQuadraticAttenuation", {STATE_POINT_ATTENUATION}, SWIZZLE_ZZZZ},
  55 };
  56
  57 static struct gl_builtin_uniform_element gl_FrontMaterial_elements[] = {
  58    {"emission", {STATE_MATERIAL, 0, STATE_EMISSION}, SWIZZLE_XYZW},
  59    {"ambient", {STATE_MATERIAL, 0, STATE_AMBIENT}, SWIZZLE_XYZW},
  60    {"diffuse", {STATE_MATERIAL, 0, STATE_DIFFUSE}, SWIZZLE_XYZW},
  61    {"specular", {STATE_MATERIAL, 0, STATE_SPECULAR}, SWIZZLE_XYZW},
  62    {"shininess", {STATE_MATERIAL, 0, STATE_SHININESS}, SWIZZLE_XXXX},
  63 };
  64
  65 static struct gl_builtin_uniform_element gl_BackMaterial_elements[] = {
  66    {"emission", {STATE_MATERIAL, 1, STATE_EMISSION}, SWIZZLE_XYZW},
  67    {"ambient", {STATE_MATERIAL, 1, STATE_AMBIENT}, SWIZZLE_XYZW},
  68    {"diffuse", {STATE_MATERIAL, 1, STATE_DIFFUSE}, SWIZZLE_XYZW},
  69    {"specular", {STATE_MATERIAL, 1, STATE_SPECULAR}, SWIZZLE_XYZW},
  70    {"shininess", {STATE_MATERIAL, 1, STATE_SHININESS}, SWIZZLE_XXXX},
  71 };
  72
  73 static struct gl_builtin_uniform_element gl_LightSource_elements[] = {
  74    {"ambient", {STATE_LIGHT, 0, STATE_AMBIENT}, SWIZZLE_XYZW},
  75    {"diffuse", {STATE_LIGHT, 0, STATE_DIFFUSE}, SWIZZLE_XYZW},
  76    {"specular", {STATE_LIGHT, 0, STATE_SPECULAR}, SWIZZLE_XYZW},
  77    {"position", {STATE_LIGHT, 0, STATE_POSITION}, SWIZZLE_XYZW},
  78    {"halfVector", {STATE_LIGHT, 0, STATE_HALF_VECTOR}, SWIZZLE_XYZW},
  79    {"spotDirection", {STATE_LIGHT, 0, STATE_SPOT_DIRECTION},
  80     MAKE_SWIZZLE4(SWIZZLE_X,
  81                   SWIZZLE_Y,
  82                   SWIZZLE_Z,
  83                   SWIZZLE_Z)},
  84    {"spotCosCutoff", {STATE_LIGHT, 0, STATE_SPOT_DIRECTION}, SWIZZLE_WWWW},
  85    {"spotCutoff", {STATE_LIGHT, 0, STATE_SPOT_CUTOFF}, SWIZZLE_XXXX},
  86    {"spotExponent", {STATE_LIGHT, 0, STATE_ATTENUATION}, SWIZZLE_WWWW},
  87    {"constantAttenuation", {STATE_LIGHT, 0, STATE_ATTENUATION}, SWIZZLE_XXXX},
  88    {"linearAttenuation", {STATE_LIGHT, 0, STATE_ATTENUATION}, SWIZZLE_YYYY},
  89    {"quadraticAttenuation", {STATE_LIGHT, 0, STATE_ATTENUATION}, SWIZZLE_ZZZZ},
  90 };
  91
  92 static struct gl_builtin_uniform_element gl_LightModel_elements[] = {
  93    {"ambient", {STATE_LIGHTMODEL_AMBIENT, 0}, SWIZZLE_XYZW},
  94 };
  95
  96 static struct gl_builtin_uniform_element gl_FrontLightModelProduct_elements[] = {
  97    {"sceneColor", {STATE_LIGHTMODEL_SCENECOLOR, 0}, SWIZZLE_XYZW},
  98 };
  99
 100 static struct gl_builtin_uniform_element gl_BackLightModelProduct_elements[] = {
 101    {"sceneColor", {STATE_LIGHTMODEL_SCENECOLOR, 1}, SWIZZLE_XYZW},
 102 };
 103
 104 static struct gl_builtin_uniform_element gl_FrontLightProduct_elements[] = {
 105    {"ambient", {STATE_LIGHTPROD, 0, 0, STATE_AMBIENT}, SWIZZLE_XYZW},
 106    {"diffuse", {STATE_LIGHTPROD, 0, 0, STATE_DIFFUSE}, SWIZZLE_XYZW},
 107    {"specular", {STATE_LIGHTPROD, 0, 0, STATE_SPECULAR}, SWIZZLE_XYZW},
 108 };
 109
 110 static struct gl_builtin_uniform_element gl_BackLightProduct_elements[] = {
 111    {"ambient", {STATE_LIGHTPROD, 0, 1, STATE_AMBIENT}, SWIZZLE_XYZW},
 112    {"diffuse", {STATE_LIGHTPROD, 0, 1, STATE_DIFFUSE}, SWIZZLE_XYZW},
 113    {"specular", {STATE_LIGHTPROD, 0, 1, STATE_SPECULAR}, SWIZZLE_XYZW},
 114 };
 115
 116 static struct gl_builtin_uniform_element gl_TextureEnvColor_elements[] = {
 117    {NULL, {STATE_TEXENV_COLOR, 0}, SWIZZLE_XYZW},
 118 };
 119
 120 static struct gl_builtin_uniform_element gl_EyePlaneS_elements[] = {
 121    {NULL, {STATE_TEXGEN, 0, STATE_TEXGEN_EYE_S}, SWIZZLE_XYZW},
 122 };
 123
 124 static struct gl_builtin_uniform_element gl_EyePlaneT_elements[] = {
 125    {NULL, {STATE_TEXGEN, 0, STATE_TEXGEN_EYE_T}, SWIZZLE_XYZW},
 126 };
 127
 128 static struct gl_builtin_uniform_element gl_EyePlaneR_elements[] = {
 129    {NULL, {STATE_TEXGEN, 0, STATE_TEXGEN_EYE_R}, SWIZZLE_XYZW},
 130 };
 131
 132 static struct gl_builtin_uniform_element gl_EyePlaneQ_elements[] = {
 133    {NULL, {STATE_TEXGEN, 0, STATE_TEXGEN_EYE_Q}, SWIZZLE_XYZW},
 134 };
 135
 136 static struct gl_builtin_uniform_element gl_ObjectPlaneS_elements[] = {
 137    {NULL, {STATE_TEXGEN, 0, STATE_TEXGEN_OBJECT_S}, SWIZZLE_XYZW},
 138 };
 139
 140 static struct gl_builtin_uniform_element gl_ObjectPlaneT_elements[] = {
 141    {NULL, {STATE_TEXGEN, 0, STATE_TEXGEN_OBJECT_T}, SWIZZLE_XYZW},
 142 };
 143
 144 static struct gl_builtin_uniform_element gl_ObjectPlaneR_elements[] = {
 145    {NULL, {STATE_TEXGEN, 0, STATE_TEXGEN_OBJECT_R}, SWIZZLE_XYZW},
 146 };
 147
 148 static struct gl_builtin_uniform_element gl_ObjectPlaneQ_elements[] = {
 149    {NULL, {STATE_TEXGEN, 0, STATE_TEXGEN_OBJECT_Q}, SWIZZLE_XYZW},
 150 };
 151
 152 static struct gl_builtin_uniform_element gl_Fog_elements[] = {
 153    {"color", {STATE_FOG_COLOR}, SWIZZLE_XYZW},
 154    {"density", {STATE_FOG_PARAMS}, SWIZZLE_XXXX},
 155    {"start", {STATE_FOG_PARAMS}, SWIZZLE_YYYY},
 156    {"end", {STATE_FOG_PARAMS}, SWIZZLE_ZZZZ},
 157    {"scale", {STATE_FOG_PARAMS}, SWIZZLE_WWWW},
 158 };
 159
 160 static struct gl_builtin_uniform_element gl_NormalScale_elements[] = {
 161    {NULL, {STATE_NORMAL_SCALE}, SWIZZLE_XXXX},
 162 };
 163
 164 static struct gl_builtin_uniform_element gl_BumpRotMatrix0MESA_elements[] = {
 165    {NULL, {STATE_INTERNAL, STATE_ROT_MATRIX_0}, SWIZZLE_XYZW},
 166 };
 167
 168 static struct gl_builtin_uniform_element gl_BumpRotMatrix1MESA_elements[] = {
 169    {NULL, {STATE_INTERNAL, STATE_ROT_MATRIX_1}, SWIZZLE_XYZW},
 170 };
 171
 172 static struct gl_builtin_uniform_element gl_FogParamsOptimizedMESA_elements[] = {
 173    {NULL, {STATE_INTERNAL, STATE_FOG_PARAMS_OPTIMIZED}, SWIZZLE_XYZW},
 174 };
 175
 176 static struct gl_builtin_uniform_element gl_CurrentAttribVertMESA_elements[] = {
 177    {NULL, {STATE_INTERNAL, STATE_CURRENT_ATTRIB, 0}, SWIZZLE_XYZW},
 178 };
 179
 180 static struct gl_builtin_uniform_element gl_CurrentAttribFragMESA_elements[] = {
 181    {NULL, {STATE_INTERNAL, STATE_CURRENT_ATTRIB_MAYBE_VP_CLAMPED, 0}, SWIZZLE_XYZW},
 182 };
 183
 184 #define MATRIX(name, statevar, modifier)                                \
 185    static struct gl_builtin_uniform_element name ## _elements[] = {     \
 186       { NULL, { statevar, 0, 0, 0, modifier}, SWIZZLE_XYZW },           \
 187       { NULL, { statevar, 0, 1, 1, modifier}, SWIZZLE_XYZW },           \
 188       { NULL, { statevar, 0, 2, 2, modifier}, SWIZZLE_XYZW },           \
 189       { NULL, { statevar, 0, 3, 3, modifier}, SWIZZLE_XYZW },           \
 190    }
 191
 192 MATRIX(gl_ModelViewMatrix,
 193        STATE_MODELVIEW_MATRIX, STATE_MATRIX_TRANSPOSE);
 194 MATRIX(gl_ModelViewMatrixInverse,
 195        STATE_MODELVIEW_MATRIX, STATE_MATRIX_INVTRANS);
 196 MATRIX(gl_ModelViewMatrixTranspose,
 197        STATE_MODELVIEW_MATRIX, 0);
 198 MATRIX(gl_ModelViewMatrixInverseTranspose,
 199        STATE_MODELVIEW_MATRIX, STATE_MATRIX_INVERSE);
 200
 201 MATRIX(gl_ProjectionMatrix,
 202        STATE_PROJECTION_MATRIX, STATE_MATRIX_TRANSPOSE);
 203 MATRIX(gl_ProjectionMatrixInverse,
 204        STATE_PROJECTION_MATRIX, STATE_MATRIX_INVTRANS);
 205 MATRIX(gl_ProjectionMatrixTranspose,
 206        STATE_PROJECTION_MATRIX, 0);
 207 MATRIX(gl_ProjectionMatrixInverseTranspose,
 208        STATE_PROJECTION_MATRIX, STATE_MATRIX_INVERSE);
 209
 210 MATRIX(gl_ModelViewProjectionMatrix,
 211        STATE_MVP_MATRIX, STATE_MATRIX_TRANSPOSE);
 212 MATRIX(gl_ModelViewProjectionMatrixInverse,
 213        STATE_MVP_MATRIX, STATE_MATRIX_INVTRANS);
 214 MATRIX(gl_ModelViewProjectionMatrixTranspose,
 215        STATE_MVP_MATRIX, 0);
 216 MATRIX(gl_ModelViewProjectionMatrixInverseTranspose,
 217        STATE_MVP_MATRIX, STATE_MATRIX_INVERSE);
 218
 219 MATRIX(gl_TextureMatrix,
 220        STATE_TEXTURE_MATRIX, STATE_MATRIX_TRANSPOSE);
 221 MATRIX(gl_TextureMatrixInverse,
 222        STATE_TEXTURE_MATRIX, STATE_MATRIX_INVTRANS);
 223 MATRIX(gl_TextureMatrixTranspose,
 224        STATE_TEXTURE_MATRIX, 0);
 225 MATRIX(gl_TextureMatrixInverseTranspose,
 226        STATE_TEXTURE_MATRIX, STATE_MATRIX_INVERSE);
 227
 228 static struct gl_builtin_uniform_element gl_NormalMatrix_elements[] = {
 229    { NULL, { STATE_MODELVIEW_MATRIX, 0, 0, 0, STATE_MATRIX_INVERSE},
 230      MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_Z) },
 231    { NULL, { STATE_MODELVIEW_MATRIX, 0, 1, 1, STATE_MATRIX_INVERSE},
 232      MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_Z) },
 233    { NULL, { STATE_MODELVIEW_MATRIX, 0, 2, 2, STATE_MATRIX_INVERSE},
 234      MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_Z) },
 235 };
 236
 237 #undef MATRIX
 238
 239 #define STATEVAR(name) {#name, name ## _elements, Elements(name ## _elements)}
 240
 241 static const struct gl_builtin_uniform_desc _mesa_builtin_uniform_desc[] = {
 242    STATEVAR(gl_NumSamples),
 243    STATEVAR(gl_DepthRange),
 244    STATEVAR(gl_ClipPlane),
 245    STATEVAR(gl_Point),
 246    STATEVAR(gl_FrontMaterial),
 247    STATEVAR(gl_BackMaterial),
 248    STATEVAR(gl_LightSource),
 249    STATEVAR(gl_LightModel),
 250    STATEVAR(gl_FrontLightModelProduct),
 251    STATEVAR(gl_BackLightModelProduct),
 252    STATEVAR(gl_FrontLightProduct),
 253    STATEVAR(gl_BackLightProduct),
 254    STATEVAR(gl_TextureEnvColor),
 255    STATEVAR(gl_EyePlaneS),
 256    STATEVAR(gl_EyePlaneT),
 257    STATEVAR(gl_EyePlaneR),
 258    STATEVAR(gl_EyePlaneQ),
 259    STATEVAR(gl_ObjectPlaneS),
 260    STATEVAR(gl_ObjectPlaneT),
 261    STATEVAR(gl_ObjectPlaneR),
 262    STATEVAR(gl_ObjectPlaneQ),
 263    STATEVAR(gl_Fog),
 264
 265    STATEVAR(gl_ModelViewMatrix),
 266    STATEVAR(gl_ModelViewMatrixInverse),
 267    STATEVAR(gl_ModelViewMatrixTranspose),
 268    STATEVAR(gl_ModelViewMatrixInverseTranspose),
 269
 270    STATEVAR(gl_ProjectionMatrix),
 271    STATEVAR(gl_ProjectionMatrixInverse),
 272    STATEVAR(gl_ProjectionMatrixTranspose),
 273    STATEVAR(gl_ProjectionMatrixInverseTranspose),
 274
 275    STATEVAR(gl_ModelViewProjectionMatrix),
 276    STATEVAR(gl_ModelViewProjectionMatrixInverse),
 277    STATEVAR(gl_ModelViewProjectionMatrixTranspose),
 278    STATEVAR(gl_ModelViewProjectionMatrixInverseTranspose),
 279
 280    STATEVAR(gl_TextureMatrix),
 281    STATEVAR(gl_TextureMatrixInverse),
 282    STATEVAR(gl_TextureMatrixTranspose),
 283    STATEVAR(gl_TextureMatrixInverseTranspose),
 284
 285    STATEVAR(gl_NormalMatrix),
 286    STATEVAR(gl_NormalScale),
 287
 288    STATEVAR(gl_BumpRotMatrix0MESA),
 289    STATEVAR(gl_BumpRotMatrix1MESA),
 290    STATEVAR(gl_FogParamsOptimizedMESA),
 291    STATEVAR(gl_CurrentAttribVertMESA),
 292    STATEVAR(gl_CurrentAttribFragMESA),
 293
 294    {NULL, NULL, 0}
 295 };
 296
 297
 298 namespace {
 299
 300 /**
 301  * Data structure that accumulates fields for the gl_PerVertex interface
 302  * block.
 303  */
 304 class per_vertex_accumulator
 305 {
 306 public:
 307    per_vertex_accumulator();
 308    void add_field(int slot, const glsl_type *type, const char *name);
 309    const glsl_type *construct_interface_instance() const;
 310
 311 private:
 312    glsl_struct_field fields[10];
 313    unsigned num_fields;
 314 };
 315
 316
 317 per_vertex_accumulator::per_vertex_accumulator()
 318    : fields(),
 319      num_fields(0)
 320 {
 321 }
 322
 323
 324 void
 325 per_vertex_accumulator::add_field(int slot, const glsl_type *type,
 326                                   const char *name)
 327 {
 328    assert(this->num_fields < ARRAY_SIZE(this->fields));
 329    this->fields[this->num_fields].type = type;
 330    this->fields[this->num_fields].name = name;
 331    this->fields[this->num_fields].row_major = false;
 332    this->fields[this->num_fields].location = slot;
 333    this->fields[this->num_fields].interpolation = INTERP_QUALIFIER_NONE;
 334    this->fields[this->num_fields].centroid = 0;
 335    this->num_fields++;
 336 }
 337
 338
 339 const glsl_type *
 340 per_vertex_accumulator::construct_interface_instance() const
 341 {
 342    return glsl_type::get_interface_instance(this->fields, this->num_fields,
 343                                             GLSL_INTERFACE_PACKING_STD140,
 344                                             "gl_PerVertex");
 345 }
 346
 347
 348 class builtin_variable_generator
 349 {
 350 public:
 351    builtin_variable_generator(exec_list *instructions,
 352                               struct _mesa_glsl_parse_state *state);
 353    void generate_constants();
 354    void generate_uniforms();
 355    void generate_vs_special_vars();
 356    void generate_gs_special_vars();
 357    void generate_fs_special_vars();
 358    void generate_varyings();
 359
 360 private:
 361    const glsl_type *array(const glsl_type *base, unsigned elements)
 362    {
 363       return glsl_type::get_array_instance(base, elements);
 364    }
 365
 366    const glsl_type *type(const char *name)
 367    {
 368       return symtab->get_type(name);
 369    }
 370
 371    ir_variable *add_input(int slot, const glsl_type *type, const char *name)
 372    {
 373       return add_variable(name, type, ir_var_shader_in, slot);
 374    }
 375
 376    ir_variable *add_output(int slot, const glsl_type *type, const char *name)
 377    {
 378       return add_variable(name, type, ir_var_shader_out, slot);
 379    }
 380
 381    ir_variable *add_system_value(int slot, const glsl_type *type,
 382                                  const char *name)
 383    {
 384       return add_variable(name, type, ir_var_system_value, slot);
 385    }
 386
 387    ir_variable *add_variable(const char *name, const glsl_type *type,
 388                              enum ir_variable_mode mode, int slot);
 389    ir_variable *add_uniform(const glsl_type *type, const char *name);
 390    ir_variable *add_const(const char *name, int value);
 391    void add_varying(int slot, const glsl_type *type, const char *name,
 392                     const char *name_as_gs_input);
 393
 394    exec_list * const instructions;
 395    struct _mesa_glsl_parse_state * const state;
 396    glsl_symbol_table * const symtab;
 397
 398    /**
 399     * True if compatibility-profile-only variables should be included.  (In
 400     * desktop GL, these are always included when the GLSL version is 1.30 and
 401     * or below).
 402     */
 403    const bool compatibility;
 404
 405    const glsl_type * const bool_t;
 406    const glsl_type * const int_t;
 407    const glsl_type * const float_t;
 408    const glsl_type * const vec2_t;
 409    const glsl_type * const vec3_t;
 410    const glsl_type * const vec4_t;
 411    const glsl_type * const mat3_t;
 412    const glsl_type * const mat4_t;
 413
 414    per_vertex_accumulator per_vertex_in;
 415    per_vertex_accumulator per_vertex_out;
 416 };
 417
 418
 419 builtin_variable_generator::builtin_variable_generator(
 420    exec_list *instructions, struct _mesa_glsl_parse_state *state)
 421    : instructions(instructions), state(state), symtab(state->symbols),
 422      compatibility(!state->is_version(140, 100)),
 423      bool_t(glsl_type::bool_type), int_t(glsl_type::int_type),
 424      float_t(glsl_type::float_type), vec2_t(glsl_type::vec2_type),
 425      vec3_t(glsl_type::vec3_type), vec4_t(glsl_type::vec4_type),
 426      mat3_t(glsl_type::mat3_type), mat4_t(glsl_type::mat4_type)
 427 {
 428 }
 429
 430
 431 ir_variable *
 432 builtin_variable_generator::add_variable(const char *name,
 433                                          const glsl_type *type,
 434                                          enum ir_variable_mode mode, int slot)
 435 {
 436    ir_variable *var = new(symtab) ir_variable(type, name, mode);
 437    var->how_declared = ir_var_declared_implicitly;
 438
 439    switch (var->mode) {
 440    case ir_var_auto:
 441    case ir_var_shader_in:
 442    case ir_var_uniform:
 443    case ir_var_system_value:
 444       var->read_only = true;
 445       break;
 446    case ir_var_shader_out:
 447       break;
 448    default:
 449       /* The only variables that are added using this function should be
 450        * uniforms, shader inputs, and shader outputs, constants (which use
 451        * ir_var_auto), and system values.
 452        */
 453       assert(0);
 454       break;
 455    }
 456
 457    var->location = slot;
 458    var->explicit_location = (slot >= 0);
 459    var->explicit_index = 0;
 460
 461    /* Once the variable is created an initialized, add it to the symbol table
 462     * and add the declaration to the IR stream.
 463     */
 464    instructions->push_tail(var);
 465
 466    symtab->add_variable(var);
 467    return var;
 468 }
 469
 470
 471 ir_variable *
 472 builtin_variable_generator::add_uniform(const glsl_type *type,
 473                                         const char *name)
 474 {
 475    ir_variable *const uni = add_variable(name, type, ir_var_uniform, -1);
 476
 477    unsigned i;
 478    for (i = 0; _mesa_builtin_uniform_desc[i].name != NULL; i++) {
 479       if (strcmp(_mesa_builtin_uniform_desc[i].name, name) == 0) {
 480          break;
 481       }
 482    }
 483
 484    assert(_mesa_builtin_uniform_desc[i].name != NULL);
 485    const struct gl_builtin_uniform_desc* const statevar =
 486       &_mesa_builtin_uniform_desc[i];
 487
 488    const unsigned array_count = type->is_array() ? type->length : 1;
 489    uni->num_state_slots = array_count * statevar->num_elements;
 490
 491    ir_state_slot *slots =
 492       ralloc_array(uni, ir_state_slot, uni->num_state_slots);
 493
 494    uni->state_slots = slots;
 495
 496    for (unsigned a = 0; a < array_count; a++) {
 497       for (unsigned j = 0; j < statevar->num_elements; j++) {
 498          struct gl_builtin_uniform_element *element = &statevar->elements[j];
 499
 500          memcpy(slots->tokens, element->tokens, sizeof(element->tokens));
 501          if (type->is_array()) {
 502             if (strcmp(name, "gl_CurrentAttribVertMESA") == 0 ||
 503                 strcmp(name, "gl_CurrentAttribFragMESA") == 0) {
 504                slots->tokens[2] = a;
 505             } else {
 506                slots->tokens[1] = a;
 507             }
 508          }
 509
 510          slots->swizzle = element->swizzle;
 511          slots++;
 512       }
 513    }
 514
 515    return uni;
 516 }
 517
 518
 519 ir_variable *
 520 builtin_variable_generator::add_const(const char *name, int value)
 521 {
 522    ir_variable *const var = add_variable(name, glsl_type::int_type,
 523                                          ir_var_auto, -1);
 524    var->constant_value = new(var) ir_constant(value);
 525    var->constant_initializer = new(var) ir_constant(value);
 526    var->has_initializer = true;
 527    return var;
 528 }
 529
 530
 531 void
 532 builtin_variable_generator::generate_constants()
 533 {
 534    add_const("gl_MaxVertexAttribs", state->Const.MaxVertexAttribs);
 535    add_const("gl_MaxVertexTextureImageUnits",
 536              state->Const.MaxVertexTextureImageUnits);
 537    add_const("gl_MaxCombinedTextureImageUnits",
 538              state->Const.MaxCombinedTextureImageUnits);
 539    add_const("gl_MaxTextureImageUnits", state->Const.MaxTextureImageUnits);
 540    add_const("gl_MaxDrawBuffers", state->Const.MaxDrawBuffers);
 541
 542    /* Max uniforms/varyings: GLSL ES counts these in units of vectors; desktop
 543     * GL counts them in units of "components" or "floats".
 544     */
 545    if (state->es_shader) {
 546       add_const("gl_MaxVertexUniformVectors",
 547                 state->Const.MaxVertexUniformComponents / 4);
 548       add_const("gl_MaxFragmentUniformVectors",
 549                 state->Const.MaxFragmentUniformComponents / 4);
 550
 551       /* In GLSL ES 3.00, gl_MaxVaryingVectors was split out to separate
 552        * vertex and fragment shader constants.
 553        */
 554       if (state->is_version(0, 300)) {
 555          add_const("gl_MaxVertexOutputVectors",
 556                    state->ctx->Const.VertexProgram.MaxOutputComponents / 4);
 557          add_const("gl_MaxFragmentInputVectors",
 558                    state->ctx->Const.FragmentProgram.MaxInputComponents / 4);
 559       } else {
 560          add_const("gl_MaxVaryingVectors",
 561                    state->ctx->Const.MaxVarying);
 562       }
 563    } else {
 564       add_const("gl_MaxVertexUniformComponents",
 565                 state->Const.MaxVertexUniformComponents);
 566
 567       /* Note: gl_MaxVaryingFloats was deprecated in GLSL 1.30+, but not
 568        * removed
 569        */
 570       add_const("gl_MaxVaryingFloats", state->ctx->Const.MaxVarying * 4);
 571
 572       add_const("gl_MaxFragmentUniformComponents",
 573                 state->Const.MaxFragmentUniformComponents);
 574    }
 575
 576    /* Texel offsets were introduced in ARB_shading_language_420pack (which
 577     * requires desktop GLSL version 130), and adopted into desktop GLSL
 578     * version 4.20 and GLSL ES version 3.00.
 579     */
 580    if ((state->is_version(130, 0) &&
 581         state->ARB_shading_language_420pack_enable) ||
 582       state->is_version(420, 300)) {
 583       add_const("gl_MinProgramTexelOffset",
 584                 state->Const.MinProgramTexelOffset);
 585       add_const("gl_MaxProgramTexelOffset",
 586                 state->Const.MaxProgramTexelOffset);
 587    }
 588
 589    if (state->is_version(130, 0)) {
 590       add_const("gl_MaxClipDistances", state->Const.MaxClipPlanes);
 591       add_const("gl_MaxVaryingComponents", state->ctx->Const.MaxVarying * 4);
 592    }
 593
 594    if (state->is_version(150, 0)) {
 595       add_const("gl_MaxVertexOutputComponents",
 596                 state->Const.MaxVertexOutputComponents);
 597       add_const("gl_MaxGeometryInputComponents",
 598                 state->Const.MaxGeometryInputComponents);
 599       add_const("gl_MaxGeometryOutputComponents",
 600                 state->Const.MaxGeometryOutputComponents);
 601       add_const("gl_MaxFragmentInputComponents",
 602                 state->Const.MaxFragmentInputComponents);
 603       add_const("gl_MaxGeometryTextureImageUnits",
 604                 state->Const.MaxGeometryTextureImageUnits);
 605       add_const("gl_MaxGeometryOutputVertices",
 606                 state->Const.MaxGeometryOutputVertices);
 607       add_const("gl_MaxGeometryTotalOutputComponents",
 608                 state->Const.MaxGeometryTotalOutputComponents);
 609       add_const("gl_MaxGeometryUniformComponents",
 610                 state->Const.MaxGeometryUniformComponents);
 611
 612       /* Note: the GLSL 1.50-4.40 specs require
 613        * gl_MaxGeometryVaryingComponents to be present, and to be at least 64.
 614        * But they do not define what it means (and there does not appear to be
 615        * any corresponding constant in the GL specs).  However,
 616        * ARB_geometry_shader4 defines MAX_GEOMETRY_VARYING_COMPONENTS_ARB to
 617        * be the maximum number of components available for use as geometry
 618        * outputs.  So we assume this is a synonym for
 619        * gl_MaxGeometryOutputComponents.
 620        */
 621       add_const("gl_MaxGeometryVaryingComponents",
 622                 state->Const.MaxGeometryOutputComponents);
 623    }
 624
 625    if (compatibility) {
 626       /* Note: gl_MaxLights stopped being listed as an explicit constant in
 627        * GLSL 1.30, however it continues to be referred to (as a minimum size
 628        * for compatibility-mode uniforms) all the way up through GLSL 4.30, so
 629        * this seems like it was probably an oversight.
 630        */
 631       add_const("gl_MaxLights", state->Const.MaxLights);
 632
 633       add_const("gl_MaxClipPlanes", state->Const.MaxClipPlanes);
 634
 635       /* Note: gl_MaxTextureUnits wasn't made compatibility-only until GLSL
 636        * 1.50, however this seems like it was probably an oversight.
 637        */
 638       add_const("gl_MaxTextureUnits", state->Const.MaxTextureUnits);
 639
 640       /* Note: gl_MaxTextureCoords was left out of GLSL 1.40, but it was
 641        * re-introduced in GLSL 1.50, so this seems like it was probably an
 642        * oversight.
 643        */
 644       add_const("gl_MaxTextureCoords", state->Const.MaxTextureCoords);
 645    }
 646
 647    if (state->ARB_shader_atomic_counters_enable) {
 648       add_const("gl_MaxVertexAtomicCounters",
 649                 state->Const.MaxVertexAtomicCounters);
 650       add_const("gl_MaxGeometryAtomicCounters",
 651                 state->Const.MaxGeometryAtomicCounters);
 652       add_const("gl_MaxFragmentAtomicCounters",
 653                 state->Const.MaxFragmentAtomicCounters);
 654       add_const("gl_MaxCombinedAtomicCounters",
 655                 state->Const.MaxCombinedAtomicCounters);
 656       add_const("gl_MaxAtomicCounterBindings",
 657                 state->Const.MaxAtomicBufferBindings);
 658       add_const("gl_MaxTessControlAtomicCounters", 0);
 659       add_const("gl_MaxTessEvaluationAtomicCounters", 0);
 660    }
 661 }
 662
 663
 664 /**
 665  * Generate uniform variables (which exist in all types of shaders).
 666  */
 667 void
 668 builtin_variable_generator::generate_uniforms()
 669 {
 670    add_uniform(int_t, "gl_NumSamples");
 671    add_uniform(type("gl_DepthRangeParameters"), "gl_DepthRange");
 672    add_uniform(array(vec4_t, VERT_ATTRIB_MAX), "gl_CurrentAttribVertMESA");
 673    add_uniform(array(vec4_t, VARYING_SLOT_MAX), "gl_CurrentAttribFragMESA");
 674
 675    if (compatibility) {
 676       add_uniform(mat4_t, "gl_ModelViewMatrix");
 677       add_uniform(mat4_t, "gl_ProjectionMatrix");
 678       add_uniform(mat4_t, "gl_ModelViewProjectionMatrix");
 679       add_uniform(mat3_t, "gl_NormalMatrix");
 680       add_uniform(mat4_t, "gl_ModelViewMatrixInverse");
 681       add_uniform(mat4_t, "gl_ProjectionMatrixInverse");
 682       add_uniform(mat4_t, "gl_ModelViewProjectionMatrixInverse");
 683       add_uniform(mat4_t, "gl_ModelViewMatrixTranspose");
 684       add_uniform(mat4_t, "gl_ProjectionMatrixTranspose");
 685       add_uniform(mat4_t, "gl_ModelViewProjectionMatrixTranspose");
 686       add_uniform(mat4_t, "gl_ModelViewMatrixInverseTranspose");
 687       add_uniform(mat4_t, "gl_ProjectionMatrixInverseTranspose");
 688       add_uniform(mat4_t, "gl_ModelViewProjectionMatrixInverseTranspose");
 689       add_uniform(float_t, "gl_NormalScale");
 690       add_uniform(type("gl_LightModelParameters"), "gl_LightModel");
 691       add_uniform(vec2_t, "gl_BumpRotMatrix0MESA");
 692       add_uniform(vec2_t, "gl_BumpRotMatrix1MESA");
 693       add_uniform(vec4_t, "gl_FogParamsOptimizedMESA");
 694
 695       const glsl_type *const mat4_array_type =
 696          array(mat4_t, state->Const.MaxTextureCoords);
 697       add_uniform(mat4_array_type, "gl_TextureMatrix");
 698       add_uniform(mat4_array_type, "gl_TextureMatrixInverse");
 699       add_uniform(mat4_array_type, "gl_TextureMatrixTranspose");
 700       add_uniform(mat4_array_type, "gl_TextureMatrixInverseTranspose");
 701
 702       add_uniform(array(vec4_t, state->Const.MaxClipPlanes), "gl_ClipPlane");
 703       add_uniform(type("gl_PointParameters"), "gl_Point");
 704
 705       const glsl_type *const material_parameters_type =
 706          type("gl_MaterialParameters");
 707       add_uniform(material_parameters_type, "gl_FrontMaterial");
 708       add_uniform(material_parameters_type, "gl_BackMaterial");
 709
 710       add_uniform(array(type("gl_LightSourceParameters"),
 711                         state->Const.MaxLights),
 712                   "gl_LightSource");
 713
 714       const glsl_type *const light_model_products_type =
 715          type("gl_LightModelProducts");
 716       add_uniform(light_model_products_type, "gl_FrontLightModelProduct");
 717       add_uniform(light_model_products_type, "gl_BackLightModelProduct");
 718
 719       const glsl_type *const light_products_type =
 720          array(type("gl_LightProducts"), state->Const.MaxLights);
 721       add_uniform(light_products_type, "gl_FrontLightProduct");
 722       add_uniform(light_products_type, "gl_BackLightProduct");
 723
 724       add_uniform(array(vec4_t, state->Const.MaxTextureUnits),
 725                   "gl_TextureEnvColor");
 726
 727       const glsl_type *const texcoords_vec4 =
 728          array(vec4_t, state->Const.MaxTextureCoords);
 729       add_uniform(texcoords_vec4, "gl_EyePlaneS");
 730       add_uniform(texcoords_vec4, "gl_EyePlaneT");
 731       add_uniform(texcoords_vec4, "gl_EyePlaneR");
 732       add_uniform(texcoords_vec4, "gl_EyePlaneQ");
 733       add_uniform(texcoords_vec4, "gl_ObjectPlaneS");
 734       add_uniform(texcoords_vec4, "gl_ObjectPlaneT");
 735       add_uniform(texcoords_vec4, "gl_ObjectPlaneR");
 736       add_uniform(texcoords_vec4, "gl_ObjectPlaneQ");
 737
 738       add_uniform(type("gl_FogParameters"), "gl_Fog");
 739    }
 740 }
 741
 742
 743 /**
 744  * Generate variables which only exist in vertex shaders.
 745  */
 746 void
 747 builtin_variable_generator::generate_vs_special_vars()
 748 {
 749    if (state->is_version(130, 300))
 750       add_system_value(SYSTEM_VALUE_VERTEX_ID, int_t, "gl_VertexID");
 751    if (state->ARB_draw_instanced_enable)
 752       add_system_value(SYSTEM_VALUE_INSTANCE_ID, int_t, "gl_InstanceIDARB");
 753    if (state->ARB_draw_instanced_enable || state->is_version(140, 300))
 754       add_system_value(SYSTEM_VALUE_INSTANCE_ID, int_t, "gl_InstanceID");
 755    if (state->AMD_vertex_shader_layer_enable)
 756       add_output(VARYING_SLOT_LAYER, int_t, "gl_Layer");
 757    if (compatibility) {
 758       add_input(VERT_ATTRIB_POS, vec4_t, "gl_Vertex");
 759       add_input(VERT_ATTRIB_NORMAL, vec3_t, "gl_Normal");
 760       add_input(VERT_ATTRIB_COLOR0, vec4_t, "gl_Color");
 761       add_input(VERT_ATTRIB_COLOR1, vec4_t, "gl_SecondaryColor");
 762       add_input(VERT_ATTRIB_TEX0, vec4_t, "gl_MultiTexCoord0");
 763       add_input(VERT_ATTRIB_TEX1, vec4_t, "gl_MultiTexCoord1");
 764       add_input(VERT_ATTRIB_TEX2, vec4_t, "gl_MultiTexCoord2");
 765       add_input(VERT_ATTRIB_TEX3, vec4_t, "gl_MultiTexCoord3");
 766       add_input(VERT_ATTRIB_TEX4, vec4_t, "gl_MultiTexCoord4");
 767       add_input(VERT_ATTRIB_TEX5, vec4_t, "gl_MultiTexCoord5");
 768       add_input(VERT_ATTRIB_TEX6, vec4_t, "gl_MultiTexCoord6");
 769       add_input(VERT_ATTRIB_TEX7, vec4_t, "gl_MultiTexCoord7");
 770       add_input(VERT_ATTRIB_FOG, float_t, "gl_FogCoord");
 771    }
 772 }
 773
 774
 775 /**
 776  * Generate variables which only exist in geometry shaders.
 777  */
 778 void
 779 builtin_variable_generator::generate_gs_special_vars()
 780 {
 781    add_output(VARYING_SLOT_LAYER, int_t, "gl_Layer");
 782
 783    /* Although gl_PrimitiveID appears in tessellation control and tessellation
 784     * evaluation shaders, it has a different function there than it has in
 785     * geometry shaders, so we treat it (and its counterpart gl_PrimitiveIDIn)
 786     * as special geometry shader variables.
 787     *
 788     * Note that although the general convention of suffixing geometry shader
 789     * input varyings with "In" was not adopted into GLSL 1.50, it is used in
 790     * the specific case of gl_PrimitiveIDIn.  So we don't need to treat
 791     * gl_PrimitiveIDIn as an {ARB,EXT}_geometry_shader4-only variable.
 792     */
 793    ir_variable *var;
 794    var = add_input(VARYING_SLOT_PRIMITIVE_ID, int_t, "gl_PrimitiveIDIn");
 795    var->interpolation = INTERP_QUALIFIER_FLAT;
 796    var = add_output(VARYING_SLOT_PRIMITIVE_ID, int_t, "gl_PrimitiveID");
 797    var->interpolation = INTERP_QUALIFIER_FLAT;
 798 }
 799
 800
 801 /**
 802  * Generate variables which only exist in fragment shaders.
 803  */
 804 void
 805 builtin_variable_generator::generate_fs_special_vars()
 806 {
 807    add_input(VARYING_SLOT_POS, vec4_t, "gl_FragCoord");
 808    add_input(VARYING_SLOT_FACE, bool_t, "gl_FrontFacing");
 809    if (state->is_version(120, 100))
 810       add_input(VARYING_SLOT_PNTC, vec2_t, "gl_PointCoord");
 811
 812    if (state->is_version(150, 0)) {
 813       ir_variable *var =
 814          add_input(VARYING_SLOT_PRIMITIVE_ID, int_t, "gl_PrimitiveID");
 815       var->interpolation = INTERP_QUALIFIER_FLAT;
 816    }
 817
 818    /* gl_FragColor and gl_FragData were deprecated starting in desktop GLSL
 819     * 1.30, and were relegated to the compatibility profile in GLSL 4.20.
 820     * They were removed from GLSL ES 3.00.
 821     */
 822    if (compatibility || !state->is_version(420, 300)) {
 823       add_output(FRAG_RESULT_COLOR, vec4_t, "gl_FragColor");
 824       add_output(FRAG_RESULT_DATA0,
 825                  array(vec4_t, state->Const.MaxDrawBuffers), "gl_FragData");
 826    }
 827
 828    /* gl_FragDepth has always been in desktop GLSL, but did not appear in GLSL
 829     * ES 1.00.
 830     */
 831    if (state->is_version(110, 300))
 832       add_output(FRAG_RESULT_DEPTH, float_t, "gl_FragDepth");
 833
 834    if (state->ARB_shader_stencil_export_enable) {
 835       ir_variable *const var =
 836          add_output(FRAG_RESULT_STENCIL, int_t, "gl_FragStencilRefARB");
 837       if (state->ARB_shader_stencil_export_warn)
 838          var->warn_extension = "GL_ARB_shader_stencil_export";
 839    }
 840
 841    if (state->AMD_shader_stencil_export_enable) {
 842       ir_variable *const var =
 843          add_output(FRAG_RESULT_STENCIL, int_t, "gl_FragStencilRefAMD");
 844       if (state->AMD_shader_stencil_export_warn)
 845          var->warn_extension = "GL_AMD_shader_stencil_export";
 846    }
 847
 848    if (state->ARB_sample_shading_enable) {
 849       add_system_value(SYSTEM_VALUE_SAMPLE_ID, int_t, "gl_SampleID");
 850       add_system_value(SYSTEM_VALUE_SAMPLE_POS, vec2_t, "gl_SamplePosition");
 851       /* From the ARB_sample_shading specification:
 852        *    "The number of elements in the array is ceil(<s>/32), where
 853        *    <s> is the maximum number of color samples supported by the
 854        *    implementation."
 855        * Since no drivers expose more than 32x MSAA, we can simply set
 856        * the array size to 1 rather than computing it.
 857        */
 858       add_output(FRAG_RESULT_SAMPLE_MASK, array(int_t, 1), "gl_SampleMask");
 859    }
 860 }
 861
 862
 863 /**
 864  * Add a single "varying" variable.  The variable's type and direction (input
 865  * or output) are adjusted as appropriate for the type of shader being
 866  * compiled.  For geometry shaders using {ARB,EXT}_geometry_shader4,
 867  * name_as_gs_input is used for the input (to avoid ambiguity).
 868  */
 869 void
 870 builtin_variable_generator::add_varying(int slot, const glsl_type *type,
 871                                         const char *name,
 872                                         const char *name_as_gs_input)
 873 {
 874    switch (state->target) {
 875    case geometry_shader:
 876       this->per_vertex_in.add_field(slot, type, name);
 877       /* FALLTHROUGH */
 878    case vertex_shader:
 879       this->per_vertex_out.add_field(slot, type, name);
 880       break;
 881    case fragment_shader:
 882       add_input(slot, type, name);
 883       break;
 884    }
 885 }
 886
 887
 888 /**
 889  * Generate variables that are used to communicate data from one shader stage
 890  * to the next ("varyings").
 891  */
 892 void
 893 builtin_variable_generator::generate_varyings()
 894 {
 895 #define ADD_VARYING(loc, type, name) \
 896    add_varying(loc, type, name, name "In")
 897
 898    /* gl_Position and gl_PointSize are not visible from fragment shaders. */
 899    if (state->target != fragment_shader) {
 900       ADD_VARYING(VARYING_SLOT_POS, vec4_t, "gl_Position");
 901       ADD_VARYING(VARYING_SLOT_PSIZ, float_t, "gl_PointSize");
 902    }
 903
 904    if (state->is_version(130, 0)) {
 905        ADD_VARYING(VARYING_SLOT_CLIP_DIST0, array(float_t, 0),
 906                    "gl_ClipDistance");
 907    }
 908
 909    if (compatibility) {
 910       ADD_VARYING(VARYING_SLOT_TEX0, array(vec4_t, 0), "gl_TexCoord");
 911       ADD_VARYING(VARYING_SLOT_FOGC, float_t, "gl_FogFragCoord");
 912       if (state->target == fragment_shader) {
 913          ADD_VARYING(VARYING_SLOT_COL0, vec4_t, "gl_Color");
 914          ADD_VARYING(VARYING_SLOT_COL1, vec4_t, "gl_SecondaryColor");
 915       } else {
 916          ADD_VARYING(VARYING_SLOT_CLIP_VERTEX, vec4_t, "gl_ClipVertex");
 917          ADD_VARYING(VARYING_SLOT_COL0, vec4_t, "gl_FrontColor");
 918          ADD_VARYING(VARYING_SLOT_BFC0, vec4_t, "gl_BackColor");
 919          ADD_VARYING(VARYING_SLOT_COL1, vec4_t, "gl_FrontSecondaryColor");
 920          ADD_VARYING(VARYING_SLOT_BFC1, vec4_t, "gl_BackSecondaryColor");
 921       }
 922    }
 923
 924    if (state->target == geometry_shader) {
 925       const glsl_type *per_vertex_in_type =
 926          this->per_vertex_in.construct_interface_instance();
 927       add_variable("gl_in", array(per_vertex_in_type, 0),
 928                    ir_var_shader_in, -1);
 929    }
 930    if (state->target == vertex_shader || state->target == geometry_shader) {
 931       const glsl_type *per_vertex_out_type =
 932          this->per_vertex_out.construct_interface_instance();
 933       const glsl_struct_field *fields = per_vertex_out_type->fields.structure;
 934       for (unsigned i = 0; i < per_vertex_out_type->length; i++) {
 935          ir_variable *var =
 936             add_variable(fields[i].name, fields[i].type, ir_var_shader_out,
 937                          fields[i].location);
 938          var->interpolation = fields[i].interpolation;
 939          var->centroid = fields[i].centroid;
 940          var->init_interface_type(per_vertex_out_type);
 941       }
 942    }
 943 }
 944
 945
 946 }; /* Anonymous namespace */
 947
 948
 949 void
 950 _mesa_glsl_initialize_variables(exec_list *instructions,
 951                                 struct _mesa_glsl_parse_state *state)
 952 {
 953    builtin_variable_generator gen(instructions, state);
 954
 955    gen.generate_constants();
 956    gen.generate_uniforms();
 957
 958    gen.generate_varyings();
 959
 960    switch (state->target) {
 961    case vertex_shader:
 962       gen.generate_vs_special_vars();
 963       break;
 964    case geometry_shader:
 965       gen.generate_gs_special_vars();
 966       break;
 967    case fragment_shader:
 968       gen.generate_fs_special_vars();
 969       break;
 970    }
 971 }