src/mesa/main/state.c

   1 /*
   2  * Mesa 3-D graphics library
   3  *
   4  * Copyright (C) 1999-2008  Brian Paul   All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the "Software"),
   8  * to deal in the Software without restriction, including without limitation
   9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  10  * and/or sell copies of the Software, and to permit persons to whom the
  11  * Software is furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included
  14  * in all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  17  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  20  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  21  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  22  * OTHER DEALINGS IN THE SOFTWARE.
  23  */
  24
  25
  26 /**
  27  * \file state.c
  28  * State management.
  29  *
  30  * This file manages recalculation of derived values in struct gl_context.
  31  */
  32
  33
  34 #include "glheader.h"
  35 #include "mtypes.h"
  36 #include "arrayobj.h"
  37 #include "context.h"
  38 #include "debug.h"
  39 #include "macros.h"
  40 #include "ffvertex_prog.h"
  41 #include "framebuffer.h"
  42 #include "light.h"
  43 #include "matrix.h"
  44 #include "pixel.h"
  45 #include "program/program.h"
  46 #include "program/prog_parameter.h"
  47 #include "shaderobj.h"
  48 #include "state.h"
  49 #include "stencil.h"
  50 #include "texenvprogram.h"
  51 #include "texobj.h"
  52 #include "texstate.h"
  53 #include "varray.h"
  54 #include "viewport.h"
  55 #include "blend.h"
  56
  57
  58 /**
  59  * Update the following fields:
  60  *   ctx->VertexProgram._Enabled
  61  *   ctx->FragmentProgram._Enabled
  62  *   ctx->ATIFragmentShader._Enabled
  63  * This needs to be done before texture state validation.
  64  */
  65 static void
  66 update_program_enables(struct gl_context *ctx)
  67 {
  68    /* These _Enabled flags indicate if the user-defined ARB/NV vertex/fragment
  69     * program is enabled AND valid.  Similarly for ATI fragment shaders.
  70     * GLSL shaders not relevant here.
  71     */
  72    ctx->VertexProgram._Enabled = ctx->VertexProgram.Enabled
  73       && ctx->VertexProgram.Current->Base.Instructions;
  74    ctx->FragmentProgram._Enabled = ctx->FragmentProgram.Enabled
  75       && ctx->FragmentProgram.Current->Base.Instructions;
  76    ctx->ATIFragmentShader._Enabled = ctx->ATIFragmentShader.Enabled
  77       && ctx->ATIFragmentShader.Current->Instructions[0];
  78 }
  79
  80
  81 /**
  82  * Update the ctx->*Program._Current pointers to point to the
  83  * current/active programs.  Then call ctx->Driver.BindProgram() to
  84  * tell the driver which programs to use.
  85  *
  86  * Programs may come from 3 sources: GLSL shaders, ARB/NV_vertex/fragment
  87  * programs or programs derived from fixed-function state.
  88  *
  89  * This function needs to be called after texture state validation in case
  90  * we're generating a fragment program from fixed-function texture state.
  91  *
  92  * \return bitfield which will indicate _NEW_PROGRAM state if a new vertex
  93  * or fragment program is being used.
  94  */
  95 static GLbitfield
  96 update_program(struct gl_context *ctx)
  97 {
  98    const struct gl_shader_program *vsProg =
  99       ctx->_Shader->CurrentProgram[MESA_SHADER_VERTEX];
 100    const struct gl_shader_program *tcsProg =
 101       ctx->_Shader->CurrentProgram[MESA_SHADER_TESS_CTRL];
 102    const struct gl_shader_program *tesProg =
 103       ctx->_Shader->CurrentProgram[MESA_SHADER_TESS_EVAL];
 104    const struct gl_shader_program *gsProg =
 105       ctx->_Shader->CurrentProgram[MESA_SHADER_GEOMETRY];
 106    struct gl_shader_program *fsProg =
 107       ctx->_Shader->CurrentProgram[MESA_SHADER_FRAGMENT];
 108    const struct gl_shader_program *csProg =
 109       ctx->_Shader->CurrentProgram[MESA_SHADER_COMPUTE];
 110    const struct gl_vertex_program *prevVP = ctx->VertexProgram._Current;
 111    const struct gl_fragment_program *prevFP = ctx->FragmentProgram._Current;
 112    const struct gl_program *prevGP = ctx->GeometryProgram._Current;
 113    const struct gl_program *prevTCP = ctx->TessCtrlProgram._Current;
 114    const struct gl_program *prevTEP = ctx->TessEvalProgram._Current;
 115    const struct gl_compute_program *prevCP = ctx->ComputeProgram._Current;
 116    GLbitfield new_state = 0x0;
 117
 118    /*
 119     * Set the ctx->VertexProgram._Current and ctx->FragmentProgram._Current
 120     * pointers to the programs that should be used for rendering.  If either
 121     * is NULL, use fixed-function code paths.
 122     *
 123     * These programs may come from several sources.  The priority is as
 124     * follows:
 125     *   1. OpenGL 2.0/ARB vertex/fragment shaders
 126     *   2. ARB/NV vertex/fragment programs
 127     *   3. ATI fragment shader
 128     *   4. Programs derived from fixed-function state.
 129     *
 130     * Note: it's possible for a vertex shader to get used with a fragment
 131     * program (and vice versa) here, but in practice that shouldn't ever
 132     * come up, or matter.
 133     */
 134
 135    if (fsProg && fsProg->LinkStatus
 136        && fsProg->_LinkedShaders[MESA_SHADER_FRAGMENT]) {
 137       /* Use GLSL fragment shader */
 138       _mesa_reference_shader_program(ctx,
 139                                      &ctx->_Shader->_CurrentFragmentProgram,
 140                                      fsProg);
 141       _mesa_reference_fragprog(ctx, &ctx->FragmentProgram._Current,
 142                                gl_fragment_program(fsProg->_LinkedShaders[MESA_SHADER_FRAGMENT]->Program));
 143       _mesa_reference_fragprog(ctx, &ctx->FragmentProgram._TexEnvProgram,
 144                                NULL);
 145    }
 146    else if (ctx->FragmentProgram._Enabled) {
 147       /* Use user-defined fragment program */
 148       _mesa_reference_shader_program(ctx,
 149                                      &ctx->_Shader->_CurrentFragmentProgram,
 150                                      NULL);
 151       _mesa_reference_fragprog(ctx, &ctx->FragmentProgram._Current,
 152                                ctx->FragmentProgram.Current);
 153       _mesa_reference_fragprog(ctx, &ctx->FragmentProgram._TexEnvProgram,
 154                                NULL);
 155    }
 156    else if (ctx->ATIFragmentShader._Enabled &&
 157             ctx->ATIFragmentShader.Current->Program) {
 158        /* Use the enabled ATI fragment shader's associated program */
 159       _mesa_reference_shader_program(ctx,
 160                                      &ctx->_Shader->_CurrentFragmentProgram,
 161                                      NULL);
 162       _mesa_reference_fragprog(ctx, &ctx->FragmentProgram._Current,
 163                                gl_fragment_program(ctx->ATIFragmentShader.Current->Program));
 164       _mesa_reference_fragprog(ctx, &ctx->FragmentProgram._TexEnvProgram,
 165                                NULL);
 166    }
 167    else if (ctx->FragmentProgram._MaintainTexEnvProgram) {
 168       /* Use fragment program generated from fixed-function state */
 169       struct gl_shader_program *f = _mesa_get_fixed_func_fragment_program(ctx);
 170
 171       _mesa_reference_shader_program(ctx,
 172                                      &ctx->_Shader->_CurrentFragmentProgram,
 173                                      f);
 174       _mesa_reference_fragprog(ctx, &ctx->FragmentProgram._Current,
 175                                gl_fragment_program(f->_LinkedShaders[MESA_SHADER_FRAGMENT]->Program));
 176       _mesa_reference_fragprog(ctx, &ctx->FragmentProgram._TexEnvProgram,
 177                                gl_fragment_program(f->_LinkedShaders[MESA_SHADER_FRAGMENT]->Program));
 178    }
 179    else {
 180       /* No fragment program */
 181       _mesa_reference_fragprog(ctx, &ctx->FragmentProgram._Current, NULL);
 182       _mesa_reference_fragprog(ctx, &ctx->FragmentProgram._TexEnvProgram,
 183                                NULL);
 184    }
 185
 186    if (gsProg && gsProg->LinkStatus
 187        && gsProg->_LinkedShaders[MESA_SHADER_GEOMETRY]) {
 188       /* Use GLSL geometry shader */
 189       _mesa_reference_program(ctx, &ctx->GeometryProgram._Current,
 190                               gsProg->_LinkedShaders[MESA_SHADER_GEOMETRY]->Program);
 191    } else {
 192       /* No geometry program */
 193       _mesa_reference_program(ctx, &ctx->GeometryProgram._Current, NULL);
 194    }
 195
 196    if (tesProg && tesProg->LinkStatus
 197        && tesProg->_LinkedShaders[MESA_SHADER_TESS_EVAL]) {
 198       /* Use GLSL tessellation evaluation shader */
 199       _mesa_reference_program(ctx, &ctx->TessEvalProgram._Current,
 200          tesProg->_LinkedShaders[MESA_SHADER_TESS_EVAL]->Program);
 201    }
 202    else {
 203       /* No tessellation evaluation program */
 204       _mesa_reference_program(ctx, &ctx->TessEvalProgram._Current, NULL);
 205    }
 206
 207    if (tcsProg && tcsProg->LinkStatus
 208        && tcsProg->_LinkedShaders[MESA_SHADER_TESS_CTRL]) {
 209       /* Use GLSL tessellation control shader */
 210       _mesa_reference_program(ctx, &ctx->TessCtrlProgram._Current,
 211           tcsProg->_LinkedShaders[MESA_SHADER_TESS_CTRL]->Program);
 212    }
 213    else {
 214       /* No tessellation control program */
 215       _mesa_reference_program(ctx, &ctx->TessCtrlProgram._Current, NULL);
 216    }
 217
 218    /* Examine vertex program after fragment program as
 219     * _mesa_get_fixed_func_vertex_program() needs to know active
 220     * fragprog inputs.
 221     */
 222    if (vsProg && vsProg->LinkStatus
 223        && vsProg->_LinkedShaders[MESA_SHADER_VERTEX]) {
 224       /* Use GLSL vertex shader */
 225       _mesa_reference_vertprog(ctx, &ctx->VertexProgram._Current,
 226                                gl_vertex_program(vsProg->_LinkedShaders[MESA_SHADER_VERTEX]->Program));
 227    }
 228    else if (ctx->VertexProgram._Enabled) {
 229       /* Use user-defined vertex program */
 230       _mesa_reference_vertprog(ctx, &ctx->VertexProgram._Current,
 231                                ctx->VertexProgram.Current);
 232    }
 233    else if (ctx->VertexProgram._MaintainTnlProgram) {
 234       /* Use vertex program generated from fixed-function state */
 235       _mesa_reference_vertprog(ctx, &ctx->VertexProgram._Current,
 236                                _mesa_get_fixed_func_vertex_program(ctx));
 237       _mesa_reference_vertprog(ctx, &ctx->VertexProgram._TnlProgram,
 238                                ctx->VertexProgram._Current);
 239    }
 240    else {
 241       /* no vertex program */
 242       _mesa_reference_vertprog(ctx, &ctx->VertexProgram._Current, NULL);
 243    }
 244
 245    if (csProg && csProg->LinkStatus
 246        && csProg->_LinkedShaders[MESA_SHADER_COMPUTE]) {
 247       /* Use GLSL compute shader */
 248       _mesa_reference_compprog(ctx, &ctx->ComputeProgram._Current,
 249                                gl_compute_program(csProg->_LinkedShaders[MESA_SHADER_COMPUTE]->Program));
 250    } else {
 251       /* no compute program */
 252       _mesa_reference_compprog(ctx, &ctx->ComputeProgram._Current, NULL);
 253    }
 254
 255    /* Let the driver know what's happening:
 256     */
 257    if (ctx->FragmentProgram._Current != prevFP) {
 258       new_state |= _NEW_PROGRAM;
 259       if (ctx->Driver.BindProgram) {
 260          ctx->Driver.BindProgram(ctx, GL_FRAGMENT_PROGRAM_ARB,
 261                           (struct gl_program *) ctx->FragmentProgram._Current);
 262       }
 263    }
 264
 265    if (ctx->GeometryProgram._Current != prevGP) {
 266       new_state |= _NEW_PROGRAM;
 267       if (ctx->Driver.BindProgram) {
 268          ctx->Driver.BindProgram(ctx, GL_GEOMETRY_PROGRAM_NV,
 269                                  ctx->GeometryProgram._Current);
 270       }
 271    }
 272
 273    if (ctx->TessEvalProgram._Current != prevTEP) {
 274       new_state |= _NEW_PROGRAM;
 275       if (ctx->Driver.BindProgram) {
 276          ctx->Driver.BindProgram(ctx, GL_TESS_EVALUATION_PROGRAM_NV,
 277                                  ctx->TessEvalProgram._Current);
 278       }
 279    }
 280
 281    if (ctx->TessCtrlProgram._Current != prevTCP) {
 282       new_state |= _NEW_PROGRAM;
 283       if (ctx->Driver.BindProgram) {
 284          ctx->Driver.BindProgram(ctx, GL_TESS_CONTROL_PROGRAM_NV,
 285                                  ctx->TessCtrlProgram._Current);
 286       }
 287    }
 288
 289    if (ctx->VertexProgram._Current != prevVP) {
 290       new_state |= _NEW_PROGRAM;
 291       if (ctx->Driver.BindProgram) {
 292          ctx->Driver.BindProgram(ctx, GL_VERTEX_PROGRAM_ARB,
 293                             (struct gl_program *) ctx->VertexProgram._Current);
 294       }
 295    }
 296
 297    if (ctx->ComputeProgram._Current != prevCP) {
 298       new_state |= _NEW_PROGRAM;
 299       if (ctx->Driver.BindProgram) {
 300          ctx->Driver.BindProgram(ctx, GL_COMPUTE_PROGRAM_NV,
 301                                  (struct gl_program *) ctx->ComputeProgram._Current);
 302       }
 303    }
 304
 305    return new_state;
 306 }
 307
 308
 309 /**
 310  * Examine shader constants and return either _NEW_PROGRAM_CONSTANTS or 0.
 311  */
 312 static GLbitfield
 313 update_program_constants(struct gl_context *ctx)
 314 {
 315    GLbitfield new_state = 0x0;
 316
 317    if (ctx->FragmentProgram._Current) {
 318       const struct gl_program_parameter_list *params =
 319          ctx->FragmentProgram._Current->Base.Parameters;
 320       if (params && params->StateFlags & ctx->NewState) {
 321          new_state |= _NEW_PROGRAM_CONSTANTS;
 322       }
 323    }
 324
 325    /* Don't handle tessellation and geometry shaders here. They don't use
 326     * any state constants.
 327     */
 328
 329    if (ctx->VertexProgram._Current) {
 330       const struct gl_program_parameter_list *params =
 331          ctx->VertexProgram._Current->Base.Parameters;
 332       if (params && params->StateFlags & ctx->NewState) {
 333          new_state |= _NEW_PROGRAM_CONSTANTS;
 334       }
 335    }
 336
 337    return new_state;
 338 }
 339
 340
 341
 342
 343 /**
 344  * Update the ctx->Polygon._FrontBit flag.
 345  */
 346 static void
 347 update_frontbit(struct gl_context *ctx)
 348 {
 349    if (ctx->Transform.ClipOrigin == GL_LOWER_LEFT)
 350       ctx->Polygon._FrontBit = (ctx->Polygon.FrontFace == GL_CW);
 351    else
 352       ctx->Polygon._FrontBit = (ctx->Polygon.FrontFace == GL_CCW);
 353 }
 354
 355
 356 /**
 357  * Update the ctx->VertexProgram._TwoSideEnabled flag.
 358  */
 359 static void
 360 update_twoside(struct gl_context *ctx)
 361 {
 362    if (ctx->_Shader->CurrentProgram[MESA_SHADER_VERTEX] ||
 363        ctx->VertexProgram._Enabled) {
 364       ctx->VertexProgram._TwoSideEnabled = ctx->VertexProgram.TwoSideEnabled;
 365    } else {
 366       ctx->VertexProgram._TwoSideEnabled = (ctx->Light.Enabled &&
 367                                             ctx->Light.Model.TwoSide);
 368    }
 369 }
 370
 371
 372 /**
 373  * Compute derived GL state.
 374  * If __struct gl_contextRec::NewState is non-zero then this function \b must
 375  * be called before rendering anything.
 376  *
 377  * Calls dd_function_table::UpdateState to perform any internal state
 378  * management necessary.
 379  *
 380  * \sa _mesa_update_modelview_project(), _mesa_update_texture(),
 381  * _mesa_update_buffer_bounds(),
 382  * _mesa_update_lighting() and _mesa_update_tnl_spaces().
 383  */
 384 void
 385 _mesa_update_state_locked( struct gl_context *ctx )
 386 {
 387    GLbitfield new_state = ctx->NewState;
 388    GLbitfield prog_flags = _NEW_PROGRAM;
 389    GLbitfield new_prog_state = 0x0;
 390    const GLbitfield computed_states = ~(_NEW_CURRENT_ATTRIB | _NEW_LINE);
 391
 392    /* we can skip a bunch of state validation checks if the dirty
 393     * state matches one or more bits in 'computed_states'.
 394     */
 395    if ((new_state & computed_states) == 0)
 396       goto out;
 397
 398    if (MESA_VERBOSE & VERBOSE_STATE)
 399       _mesa_print_state("_mesa_update_state", new_state);
 400
 401    /* Determine which state flags effect vertex/fragment program state */
 402    if (ctx->FragmentProgram._MaintainTexEnvProgram) {
 403       prog_flags |= (_NEW_BUFFERS | _NEW_TEXTURE | _NEW_FOG |
 404                      _NEW_VARYING_VP_INPUTS | _NEW_LIGHT | _NEW_POINT |
 405                      _NEW_RENDERMODE | _NEW_PROGRAM | _NEW_FRAG_CLAMP |
 406                      _NEW_COLOR);
 407    }
 408    if (ctx->VertexProgram._MaintainTnlProgram) {
 409       prog_flags |= (_NEW_VARYING_VP_INPUTS | _NEW_TEXTURE |
 410                      _NEW_TEXTURE_MATRIX | _NEW_TRANSFORM | _NEW_POINT |
 411                      _NEW_FOG | _NEW_LIGHT |
 412                      _MESA_NEW_NEED_EYE_COORDS);
 413    }
 414
 415    /*
 416     * Now update derived state info
 417     */
 418
 419    if (new_state & prog_flags)
 420       update_program_enables( ctx );
 421
 422    if (new_state & (_NEW_MODELVIEW|_NEW_PROJECTION))
 423       _mesa_update_modelview_project( ctx, new_state );
 424
 425    if (new_state & (_NEW_PROGRAM|_NEW_TEXTURE|_NEW_TEXTURE_MATRIX))
 426       _mesa_update_texture( ctx, new_state );
 427
 428    if (new_state & _NEW_POLYGON)
 429       update_frontbit( ctx );
 430
 431    if (new_state & _NEW_BUFFERS)
 432       _mesa_update_framebuffer(ctx, ctx->ReadBuffer, ctx->DrawBuffer);
 433
 434    if (new_state & (_NEW_SCISSOR | _NEW_BUFFERS | _NEW_VIEWPORT))
 435       _mesa_update_draw_buffer_bounds(ctx, ctx->DrawBuffer);
 436
 437    if (new_state & _NEW_LIGHT)
 438       _mesa_update_lighting( ctx );
 439
 440    if (new_state & (_NEW_LIGHT | _NEW_PROGRAM))
 441       update_twoside( ctx );
 442
 443    if (new_state & (_NEW_STENCIL | _NEW_BUFFERS))
 444       _mesa_update_stencil( ctx );
 445
 446    if (new_state & _NEW_PIXEL)
 447       _mesa_update_pixel( ctx, new_state );
 448
 449    /* ctx->_NeedEyeCoords is now up to date.
 450     *
 451     * If the truth value of this variable has changed, update for the
 452     * new lighting space and recompute the positions of lights and the
 453     * normal transform.
 454     *
 455     * If the lighting space hasn't changed, may still need to recompute
 456     * light positions & normal transforms for other reasons.
 457     */
 458    if (new_state & _MESA_NEW_NEED_EYE_COORDS)
 459       _mesa_update_tnl_spaces( ctx, new_state );
 460
 461    if (new_state & prog_flags) {
 462       /* When we generate programs from fixed-function vertex/fragment state
 463        * this call may generate/bind a new program.  If so, we need to
 464        * propogate the _NEW_PROGRAM flag to the driver.
 465        */
 466       new_prog_state |= update_program( ctx );
 467    }
 468
 469    if (new_state & _NEW_ARRAY)
 470       _mesa_update_vao_client_arrays(ctx, ctx->Array.VAO);
 471
 472  out:
 473    new_prog_state |= update_program_constants(ctx);
 474
 475    /*
 476     * Give the driver a chance to act upon the new_state flags.
 477     * The driver might plug in different span functions, for example.
 478     * Also, this is where the driver can invalidate the state of any
 479     * active modules (such as swrast_setup, swrast, tnl, etc).
 480     *
 481     * Set ctx->NewState to zero to avoid recursion if
 482     * Driver.UpdateState() has to call FLUSH_VERTICES().  (fixed?)
 483     */
 484    new_state = ctx->NewState | new_prog_state;
 485    ctx->NewState = 0;
 486    ctx->Driver.UpdateState(ctx, new_state);
 487    ctx->Array.VAO->NewArrays = 0x0;
 488 }
 489
 490
 491 /* This is the usual entrypoint for state updates:
 492  */
 493 void
 494 _mesa_update_state( struct gl_context *ctx )
 495 {
 496    _mesa_lock_context_textures(ctx);
 497    _mesa_update_state_locked(ctx);
 498    _mesa_unlock_context_textures(ctx);
 499 }
 500
 501
 502
 503
 504 /**
 505  * Want to figure out which fragment program inputs are actually
 506  * constant/current values from ctx->Current.  These should be
 507  * referenced as a tracked state variable rather than a fragment
 508  * program input, to save the overhead of putting a constant value in
 509  * every submitted vertex, transferring it to hardware, interpolating
 510  * it across the triangle, etc...
 511  *
 512  * When there is a VP bound, just use vp->outputs.  But when we're
 513  * generating vp from fixed function state, basically want to
 514  * calculate:
 515  *
 516  * vp_out_2_fp_in( vp_in_2_vp_out( varying_inputs ) |
 517  *                 potential_vp_outputs )
 518  *
 519  * Where potential_vp_outputs is calculated by looking at enabled
 520  * texgen, etc.
 521  *
 522  * The generated fragment program should then only declare inputs that
 523  * may vary or otherwise differ from the ctx->Current values.
 524  * Otherwise, the fp should track them as state values instead.
 525  */
 526 void
 527 _mesa_set_varying_vp_inputs( struct gl_context *ctx,
 528                              GLbitfield64 varying_inputs )
 529 {
 530    if (ctx->varying_vp_inputs != varying_inputs) {
 531       ctx->varying_vp_inputs = varying_inputs;
 532
 533       /* Only the fixed-func generated programs need to use the flag
 534        * and the fixed-func fragment program uses it only if there is also
 535        * a fixed-func vertex program, so this only depends on the latter.
 536        *
 537        * It's okay to check the VP pointer here, because this is called after
 538        * _mesa_update_state in the vbo module. */
 539       if (ctx->VertexProgram._TnlProgram ||
 540           ctx->FragmentProgram._TexEnvProgram) {
 541          ctx->NewState |= _NEW_VARYING_VP_INPUTS;
 542       }
 543       /*printf("%s %x\n", __func__, varying_inputs);*/
 544    }
 545 }
 546
 547
 548 /**
 549  * Used by drivers to tell core Mesa that the driver is going to
 550  * install/ use its own vertex program.  In particular, this will
 551  * prevent generated fragment programs from using state vars instead
 552  * of ordinary varyings/inputs.
 553  */
 554 void
 555 _mesa_set_vp_override(struct gl_context *ctx, GLboolean flag)
 556 {
 557    if (ctx->VertexProgram._Overriden != flag) {
 558       ctx->VertexProgram._Overriden = flag;
 559
 560       /* Set one of the bits which will trigger fragment program
 561        * regeneration:
 562        */
 563       ctx->NewState |= _NEW_PROGRAM;
 564    }
 565 }