reactos/dll/opengl/mesa/src/mesa/main/state.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  7.3
   4  *
   5  * Copyright (C) 1999-2008  Brian Paul   All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the "Software"),
   9  * to deal in the Software without restriction, including without limitation
  10  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  11  * and/or sell copies of the Software, and to permit persons to whom the
  12  * Software is furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included
  15  * in all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  21  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  22  * CONNECTION WITH THE SOFTWARE OR THE USE OR 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 "context.h"
  37 #include "debug.h"
  38 #include "macros.h"
  39 #include "framebuffer.h"
  40 #include "light.h"
  41 #include "matrix.h"
  42 #include "pixel.h"
  43 #include "program/program.h"
  44 #include "program/prog_parameter.h"
  45 #include "shaderobj.h"
  46 #include "state.h"
  47 #include "stencil.h"
  48 #include "texobj.h"
  49 #include "texstate.h"
  50 #include "varray.h"
  51
  52
  53 static void
  54 update_separate_specular(struct gl_context *ctx)
  55 {
  56    if (_mesa_need_secondary_color(ctx))
  57       ctx->_TriangleCaps |= DD_SEPARATE_SPECULAR;
  58    else
  59       ctx->_TriangleCaps &= ~DD_SEPARATE_SPECULAR;
  60 }
  61
  62
  63 /**
  64  * Helper for update_arrays().
  65  * \return  min(current min, array->_MaxElement).
  66  */
  67 static GLuint
  68 update_min(GLuint min, struct gl_client_array *array)
  69 {
  70    _mesa_update_array_max_element(array);
  71    return MIN2(min, array->_MaxElement);
  72 }
  73
  74
  75 /**
  76  * Update ctx->Array._MaxElement (the max legal index into all enabled arrays).
  77  * Need to do this upon new array state or new buffer object state.
  78  */
  79 static void
  80 update_arrays( struct gl_context *ctx )
  81 {
  82    struct gl_array_object *arrayObj = ctx->Array.ArrayObj;
  83    GLuint i, min = ~0;
  84
  85    /* find min of _MaxElement values for all enabled arrays.
  86     * Note that the generic arrays always take precedence over
  87     * the legacy arrays.
  88     */
  89
  90    /* 0 */
  91    if (ctx->VertexProgram._Current
  92        && arrayObj->VertexAttrib[VERT_ATTRIB_GENERIC0].Enabled) {
  93       min = update_min(min, &arrayObj->VertexAttrib[VERT_ATTRIB_GENERIC0]);
  94    }
  95    else if (arrayObj->VertexAttrib[VERT_ATTRIB_POS].Enabled) {
  96       min = update_min(min, &arrayObj->VertexAttrib[VERT_ATTRIB_POS]);
  97    }
  98
  99    /* 1 */
 100    if (ctx->VertexProgram._Enabled
 101        && arrayObj->VertexAttrib[VERT_ATTRIB_GENERIC1].Enabled) {
 102       min = update_min(min, &arrayObj->VertexAttrib[VERT_ATTRIB_GENERIC1]);
 103    }
 104    /* no conventional vertex weight array */
 105
 106    /* 2 */
 107    if (ctx->VertexProgram._Enabled
 108        && arrayObj->VertexAttrib[VERT_ATTRIB_GENERIC2].Enabled) {
 109       min = update_min(min, &arrayObj->VertexAttrib[VERT_ATTRIB_GENERIC2]);
 110    }
 111    else if (arrayObj->VertexAttrib[VERT_ATTRIB_NORMAL].Enabled) {
 112       min = update_min(min, &arrayObj->VertexAttrib[VERT_ATTRIB_NORMAL]);
 113    }
 114
 115    /* 3 */
 116    if (ctx->VertexProgram._Enabled
 117        && arrayObj->VertexAttrib[VERT_ATTRIB_GENERIC3].Enabled) {
 118       min = update_min(min, &arrayObj->VertexAttrib[VERT_ATTRIB_GENERIC3]);
 119    }
 120    else if (arrayObj->VertexAttrib[VERT_ATTRIB_COLOR0].Enabled) {
 121       min = update_min(min, &arrayObj->VertexAttrib[VERT_ATTRIB_COLOR0]);
 122    }
 123
 124    /* 4 */
 125    if (ctx->VertexProgram._Enabled
 126        && arrayObj->VertexAttrib[VERT_ATTRIB_GENERIC4].Enabled) {
 127       min = update_min(min, &arrayObj->VertexAttrib[VERT_ATTRIB_GENERIC4]);
 128    }
 129    else if (arrayObj->VertexAttrib[VERT_ATTRIB_COLOR1].Enabled) {
 130       min = update_min(min, &arrayObj->VertexAttrib[VERT_ATTRIB_COLOR1]);
 131    }
 132
 133    /* 5 */
 134    if (ctx->VertexProgram._Enabled
 135        && arrayObj->VertexAttrib[VERT_ATTRIB_GENERIC5].Enabled) {
 136       min = update_min(min, &arrayObj->VertexAttrib[VERT_ATTRIB_GENERIC5]);
 137    }
 138    else if (arrayObj->VertexAttrib[VERT_ATTRIB_FOG].Enabled) {
 139       min = update_min(min, &arrayObj->VertexAttrib[VERT_ATTRIB_FOG]);
 140    }
 141
 142    /* 6 */
 143    if (ctx->VertexProgram._Enabled
 144        && arrayObj->VertexAttrib[VERT_ATTRIB_GENERIC6].Enabled) {
 145       min = update_min(min, &arrayObj->VertexAttrib[VERT_ATTRIB_GENERIC6]);
 146    }
 147    else if (arrayObj->VertexAttrib[VERT_ATTRIB_COLOR_INDEX].Enabled) {
 148       min = update_min(min, &arrayObj->VertexAttrib[VERT_ATTRIB_COLOR_INDEX]);
 149    }
 150
 151    /* 7 */
 152    if (ctx->VertexProgram._Enabled
 153        && arrayObj->VertexAttrib[VERT_ATTRIB_GENERIC7].Enabled) {
 154       min = update_min(min, &arrayObj->VertexAttrib[VERT_ATTRIB_GENERIC7]);
 155    }
 156
 157    /* 8..15 */
 158    for (i = 0; i < VERT_ATTRIB_TEX_MAX; i++) {
 159       if (ctx->VertexProgram._Enabled
 160           && arrayObj->VertexAttrib[VERT_ATTRIB_GENERIC8 + i].Enabled) {
 161          min = update_min(min, &arrayObj->VertexAttrib[VERT_ATTRIB_GENERIC8 + i]);
 162       }
 163       else if (i < ctx->Const.MaxTextureCoordUnits
 164                && arrayObj->VertexAttrib[VERT_ATTRIB_TEX(i)].Enabled) {
 165          min = update_min(min, &arrayObj->VertexAttrib[VERT_ATTRIB_TEX(i)]);
 166       }
 167    }
 168
 169    /* 16..31 */
 170    if (ctx->VertexProgram._Current) {
 171       for (i = 0; i < VERT_ATTRIB_GENERIC_MAX; i++) {
 172          if (arrayObj->VertexAttrib[VERT_ATTRIB_GENERIC(i)].Enabled) {
 173             min = update_min(min, &arrayObj->VertexAttrib[VERT_ATTRIB_GENERIC(i)]);
 174          }
 175       }
 176    }
 177
 178    if (arrayObj->VertexAttrib[VERT_ATTRIB_EDGEFLAG].Enabled) {
 179       min = update_min(min, &arrayObj->VertexAttrib[VERT_ATTRIB_EDGEFLAG]);
 180    }
 181
 182    /* _MaxElement is one past the last legal array element */
 183    arrayObj->_MaxElement = min;
 184 }
 185
 186
 187 /**
 188  * Update the following fields:
 189  *   ctx->VertexProgram._Enabled
 190  *   ctx->FragmentProgram._Enabled
 191  *   ctx->ATIFragmentShader._Enabled
 192  * This needs to be done before texture state validation.
 193  */
 194 static void
 195 update_program_enables(struct gl_context *ctx)
 196 {
 197    /* These _Enabled flags indicate if the user-defined ARB/NV vertex/fragment
 198     * program is enabled AND valid.  Similarly for ATI fragment shaders.
 199     * GLSL shaders not relevant here.
 200     */
 201    ctx->VertexProgram._Enabled = ctx->VertexProgram.Enabled
 202       && ctx->VertexProgram.Current->Base.Instructions;
 203    ctx->FragmentProgram._Enabled = ctx->FragmentProgram.Enabled
 204       && ctx->FragmentProgram.Current->Base.Instructions;
 205 }
 206
 207
 208 /**
 209  * Update the ctx->Vertex/Geometry/FragmentProgram._Current pointers to point
 210  * to the current/active programs.  Then call ctx->Driver.BindProgram() to
 211  * tell the driver which programs to use.
 212  *
 213  * Programs may come from 3 sources: GLSL shaders, ARB/NV_vertex/fragment
 214  * programs or programs derived from fixed-function state.
 215  *
 216  * This function needs to be called after texture state validation in case
 217  * we're generating a fragment program from fixed-function texture state.
 218  *
 219  * \return bitfield which will indicate _NEW_PROGRAM state if a new vertex
 220  * or fragment program is being used.
 221  */
 222 static GLbitfield
 223 update_program(struct gl_context *ctx)
 224 {
 225    const struct gl_shader_program *vsProg = ctx->Shader.CurrentVertexProgram;
 226    struct gl_shader_program *fsProg = ctx->Shader.CurrentFragmentProgram;
 227    const struct gl_vertex_program *prevVP = ctx->VertexProgram._Current;
 228    const struct gl_fragment_program *prevFP = ctx->FragmentProgram._Current;
 229    GLbitfield new_state = 0x0;
 230
 231    /*
 232     * Set the ctx->VertexProgram._Current and ctx->FragmentProgram._Current
 233     * pointers to the programs that should be used for rendering.  If either
 234     * is NULL, use fixed-function code paths.
 235     *
 236     * These programs may come from several sources.  The priority is as
 237     * follows:
 238     *   1. OpenGL 2.0/ARB vertex/fragment shaders
 239     *   2. ARB/NV vertex/fragment programs
 240     *   3. Programs derived from fixed-function state.
 241     *
 242     * Note: it's possible for a vertex shader to get used with a fragment
 243     * program (and vice versa) here, but in practice that shouldn't ever
 244     * come up, or matter.
 245     */
 246
 247    if (fsProg && fsProg->LinkStatus
 248        && fsProg->_LinkedShaders[MESA_SHADER_FRAGMENT]) {
 249       /* Use GLSL fragment shader */
 250       _mesa_reference_shader_program(ctx,
 251                                      &ctx->Shader._CurrentFragmentProgram,
 252                                      fsProg);
 253       _mesa_reference_fragprog(ctx, &ctx->FragmentProgram._Current,
 254                                (struct gl_fragment_program *)
 255                                fsProg->_LinkedShaders[MESA_SHADER_FRAGMENT]->Program);
 256    }
 257    else if (ctx->FragmentProgram._Enabled) {
 258       /* Use user-defined fragment program */
 259       _mesa_reference_shader_program(ctx,
 260                                      &ctx->Shader._CurrentFragmentProgram,
 261                                      NULL);
 262       _mesa_reference_fragprog(ctx, &ctx->FragmentProgram._Current,
 263                                ctx->FragmentProgram.Current);
 264    }
 265    else {
 266       /* No fragment program */
 267       _mesa_reference_fragprog(ctx, &ctx->FragmentProgram._Current, NULL);
 268    }
 269
 270    /* Examine vertex program after fragment program as
 271     * _mesa_get_fixed_func_vertex_program() needs to know active
 272     * fragprog inputs.
 273     */
 274    if (vsProg && vsProg->LinkStatus
 275        && vsProg->_LinkedShaders[MESA_SHADER_VERTEX]) {
 276       /* Use GLSL vertex shader */
 277       _mesa_reference_vertprog(ctx, &ctx->VertexProgram._Current,
 278                                (struct gl_vertex_program *)
 279                                vsProg->_LinkedShaders[MESA_SHADER_VERTEX]->Program);
 280    }
 281    else if (ctx->VertexProgram._Enabled) {
 282       /* Use user-defined vertex program */
 283       _mesa_reference_vertprog(ctx, &ctx->VertexProgram._Current,
 284                                ctx->VertexProgram.Current);
 285    }
 286    else {
 287       /* no vertex program */
 288       _mesa_reference_vertprog(ctx, &ctx->VertexProgram._Current, NULL);
 289    }
 290
 291    /* Let the driver know what's happening:
 292     */
 293    if (ctx->FragmentProgram._Current != prevFP) {
 294       new_state |= _NEW_PROGRAM;
 295       if (ctx->Driver.BindProgram) {
 296          ctx->Driver.BindProgram(ctx, GL_FRAGMENT_PROGRAM_ARB,
 297                           (struct gl_program *) ctx->FragmentProgram._Current);
 298       }
 299    }
 300
 301    if (ctx->VertexProgram._Current != prevVP) {
 302       new_state |= _NEW_PROGRAM;
 303       if (ctx->Driver.BindProgram) {
 304          ctx->Driver.BindProgram(ctx, GL_VERTEX_PROGRAM_ARB,
 305                             (struct gl_program *) ctx->VertexProgram._Current);
 306       }
 307    }
 308
 309    return new_state;
 310 }
 311
 312
 313 /**
 314  * Examine shader constants and return either _NEW_PROGRAM_CONSTANTS or 0.
 315  */
 316 static GLbitfield
 317 update_program_constants(struct gl_context *ctx)
 318 {
 319    GLbitfield new_state = 0x0;
 320
 321    if (ctx->FragmentProgram._Current) {
 322       const struct gl_program_parameter_list *params =
 323          ctx->FragmentProgram._Current->Base.Parameters;
 324       if (params && params->StateFlags & ctx->NewState) {
 325          new_state |= _NEW_PROGRAM_CONSTANTS;
 326       }
 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 static void
 344 update_viewport_matrix(struct gl_context *ctx)
 345 {
 346    const GLfloat depthMax = ctx->DrawBuffer->_DepthMaxF;
 347
 348    ASSERT(depthMax > 0);
 349
 350    /* Compute scale and bias values. This is really driver-specific
 351     * and should be maintained elsewhere if at all.
 352     * NOTE: RasterPos uses this.
 353     */
 354    _math_matrix_viewport(&ctx->Viewport._WindowMap,
 355                          ctx->Viewport.X, ctx->Viewport.Y,
 356                          ctx->Viewport.Width, ctx->Viewport.Height,
 357                          ctx->Viewport.Near, ctx->Viewport.Far,
 358                          depthMax);
 359 }
 360
 361
 362 /**
 363  * Update the ctx->VertexProgram._TwoSideEnabled flag.
 364  */
 365 static void
 366 update_twoside(struct gl_context *ctx)
 367 {
 368    if (ctx->Shader.CurrentVertexProgram ||
 369        ctx->VertexProgram._Enabled) {
 370       ctx->VertexProgram._TwoSideEnabled = ctx->VertexProgram.TwoSideEnabled;
 371    } else {
 372       ctx->VertexProgram._TwoSideEnabled = (ctx->Light.Enabled &&
 373                                             ctx->Light.Model.TwoSide);
 374    }
 375 }
 376
 377
 378 /*
 379  * Check polygon state and set DD_TRI_CULL_FRONT_BACK and/or DD_TRI_OFFSET
 380  * in ctx->_TriangleCaps if needed.
 381  */
 382 static void
 383 update_polygon(struct gl_context *ctx)
 384 {
 385    ctx->_TriangleCaps &= ~(DD_TRI_CULL_FRONT_BACK | DD_TRI_OFFSET);
 386
 387    if (ctx->Polygon.CullFlag && ctx->Polygon.CullFaceMode == GL_FRONT_AND_BACK)
 388       ctx->_TriangleCaps |= DD_TRI_CULL_FRONT_BACK;
 389
 390    if (   ctx->Polygon.OffsetPoint
 391        || ctx->Polygon.OffsetLine
 392        || ctx->Polygon.OffsetFill)
 393       ctx->_TriangleCaps |= DD_TRI_OFFSET;
 394 }
 395
 396
 397 /**
 398  * Update the ctx->_TriangleCaps bitfield.
 399  * XXX that bitfield should really go away someday!
 400  * This function must be called after other update_*() functions since
 401  * there are dependencies on some other derived values.
 402  */
 403 #if 0
 404 static void
 405 update_tricaps(struct gl_context *ctx, GLbitfield new_state)
 406 {
 407    ctx->_TriangleCaps = 0;
 408
 409    /*
 410     * Points
 411     */
 412    if (1/*new_state & _NEW_POINT*/) {
 413       if (ctx->Point.SmoothFlag)
 414          ctx->_TriangleCaps |= DD_POINT_SMOOTH;
 415       if (ctx->Point._Attenuated)
 416          ctx->_TriangleCaps |= DD_POINT_ATTEN;
 417    }
 418
 419    /*
 420     * Lines
 421     */
 422    if (1/*new_state & _NEW_LINE*/) {
 423       if (ctx->Line.SmoothFlag)
 424          ctx->_TriangleCaps |= DD_LINE_SMOOTH;
 425       if (ctx->Line.StippleFlag)
 426          ctx->_TriangleCaps |= DD_LINE_STIPPLE;
 427    }
 428
 429    /*
 430     * Polygons
 431     */
 432    if (1/*new_state & _NEW_POLYGON*/) {
 433       if (ctx->Polygon.SmoothFlag)
 434          ctx->_TriangleCaps |= DD_TRI_SMOOTH;
 435       if (ctx->Polygon.StippleFlag)
 436          ctx->_TriangleCaps |= DD_TRI_STIPPLE;
 437       if (ctx->Polygon.FrontMode != GL_FILL
 438           || ctx->Polygon.BackMode != GL_FILL)
 439          ctx->_TriangleCaps |= DD_TRI_UNFILLED;
 440       if (ctx->Polygon.CullFlag
 441           && ctx->Polygon.CullFaceMode == GL_FRONT_AND_BACK)
 442          ctx->_TriangleCaps |= DD_TRI_CULL_FRONT_BACK;
 443       if (ctx->Polygon.OffsetPoint ||
 444           ctx->Polygon.OffsetLine ||
 445           ctx->Polygon.OffsetFill)
 446          ctx->_TriangleCaps |= DD_TRI_OFFSET;
 447    }
 448
 449    /*
 450     * Lighting and shading
 451     */
 452    if (ctx->Light.Enabled && ctx->Light.Model.TwoSide)
 453       ctx->_TriangleCaps |= DD_TRI_LIGHT_TWOSIDE;
 454    if (ctx->Light.ShadeModel == GL_FLAT)
 455       ctx->_TriangleCaps |= DD_FLATSHADE;
 456    if (_mesa_need_secondary_color(ctx))
 457       ctx->_TriangleCaps |= DD_SEPARATE_SPECULAR;
 458
 459    /*
 460     * Stencil
 461     */
 462    if (ctx->Stencil._TestTwoSide)
 463       ctx->_TriangleCaps |= DD_TRI_TWOSTENCIL;
 464 }
 465 #endif
 466
 467
 468 /**
 469  * Compute derived GL state.
 470  * If __struct gl_contextRec::NewState is non-zero then this function \b must
 471  * be called before rendering anything.
 472  *
 473  * Calls dd_function_table::UpdateState to perform any internal state
 474  * management necessary.
 475  *
 476  * \sa _mesa_update_modelview_project(), _mesa_update_texture(),
 477  * _mesa_update_buffer_bounds(),
 478  * _mesa_update_lighting() and _mesa_update_tnl_spaces().
 479  */
 480 void
 481 _mesa_update_state_locked( struct gl_context *ctx )
 482 {
 483    GLbitfield new_state = ctx->NewState;
 484    GLbitfield prog_flags = _NEW_PROGRAM;
 485    GLbitfield new_prog_state = 0x0;
 486
 487    if (new_state == _NEW_CURRENT_ATTRIB)
 488       goto out;
 489
 490    if (MESA_VERBOSE & VERBOSE_STATE)
 491       _mesa_print_state("_mesa_update_state", new_state);
 492
 493    /*
 494     * Now update derived state info
 495     */
 496
 497    if (new_state & prog_flags)
 498       update_program_enables( ctx );
 499
 500    if (new_state & (_NEW_MODELVIEW|_NEW_PROJECTION))
 501       _mesa_update_modelview_project( ctx, new_state );
 502
 503    if (new_state & (_NEW_PROGRAM|_NEW_TEXTURE|_NEW_TEXTURE_MATRIX))
 504       _mesa_update_texture( ctx, new_state );
 505
 506    if (new_state & _NEW_BUFFERS)
 507       _mesa_update_framebuffer(ctx);
 508
 509    if (new_state & (_NEW_SCISSOR | _NEW_BUFFERS | _NEW_VIEWPORT))
 510       _mesa_update_draw_buffer_bounds( ctx );
 511
 512    if (new_state & _NEW_POLYGON)
 513       update_polygon( ctx );
 514
 515    if (new_state & _NEW_LIGHT)
 516       _mesa_update_lighting( ctx );
 517
 518    if (new_state & (_NEW_LIGHT | _NEW_PROGRAM))
 519       update_twoside( ctx );
 520
 521    if (new_state & (_NEW_STENCIL | _NEW_BUFFERS))
 522       _mesa_update_stencil( ctx );
 523
 524    if (new_state & _NEW_PIXEL)
 525       _mesa_update_pixel( ctx, new_state );
 526
 527    if (new_state & _DD_NEW_SEPARATE_SPECULAR)
 528       update_separate_specular( ctx );
 529
 530    if (new_state & (_NEW_BUFFERS | _NEW_VIEWPORT))
 531       update_viewport_matrix(ctx);
 532
 533 #if 0
 534    if (new_state & (_NEW_POINT | _NEW_LINE | _NEW_POLYGON | _NEW_LIGHT
 535                     | _NEW_STENCIL | _DD_NEW_SEPARATE_SPECULAR))
 536       update_tricaps( ctx, new_state );
 537 #endif
 538
 539    /* ctx->_NeedEyeCoords is now up to date.
 540     *
 541     * If the truth value of this variable has changed, update for the
 542     * new lighting space and recompute the positions of lights and the
 543     * normal transform.
 544     *
 545     * If the lighting space hasn't changed, may still need to recompute
 546     * light positions & normal transforms for other reasons.
 547     */
 548    if (new_state & _MESA_NEW_NEED_EYE_COORDS)
 549       _mesa_update_tnl_spaces( ctx, new_state );
 550
 551    if (new_state & prog_flags) {
 552       /* When we generate programs from fixed-function vertex/fragment state
 553        * this call may generate/bind a new program.  If so, we need to
 554        * propogate the _NEW_PROGRAM flag to the driver.
 555        */
 556       new_prog_state |= update_program( ctx );
 557    }
 558
 559    if (new_state & (_NEW_ARRAY | _NEW_PROGRAM | _NEW_BUFFER_OBJECT))
 560       update_arrays( ctx );
 561
 562  out:
 563    new_prog_state |= update_program_constants(ctx);
 564
 565    /*
 566     * Give the driver a chance to act upon the new_state flags.
 567     * The driver might plug in different span functions, for example.
 568     * Also, this is where the driver can invalidate the state of any
 569     * active modules (such as swrast_setup, swrast, tnl, etc).
 570     *
 571     * Set ctx->NewState to zero to avoid recursion if
 572     * Driver.UpdateState() has to call FLUSH_VERTICES().  (fixed?)
 573     */
 574    new_state = ctx->NewState | new_prog_state;
 575    ctx->NewState = 0;
 576    ctx->Driver.UpdateState(ctx, new_state);
 577    ctx->Array.NewState = 0;
 578    if (!ctx->Array.RebindArrays)
 579       ctx->Array.RebindArrays = (new_state & (_NEW_ARRAY | _NEW_PROGRAM)) != 0;
 580 }
 581
 582
 583 /* This is the usual entrypoint for state updates:
 584  */
 585 void
 586 _mesa_update_state( struct gl_context *ctx )
 587 {
 588    _mesa_lock_context_textures(ctx);
 589    _mesa_update_state_locked(ctx);
 590    _mesa_unlock_context_textures(ctx);
 591 }
 592
 593
 594
 595
 596 /**
 597  * Want to figure out which fragment program inputs are actually
 598  * constant/current values from ctx->Current.  These should be
 599  * referenced as a tracked state variable rather than a fragment
 600  * program input, to save the overhead of putting a constant value in
 601  * every submitted vertex, transferring it to hardware, interpolating
 602  * it across the triangle, etc...
 603  *
 604  * When there is a VP bound, just use vp->outputs.  But when we're
 605  * generating vp from fixed function state, basically want to
 606  * calculate:
 607  *
 608  * vp_out_2_fp_in( vp_in_2_vp_out( varying_inputs ) |
 609  *                 potential_vp_outputs )
 610  *
 611  * Where potential_vp_outputs is calculated by looking at enabled
 612  * texgen, etc.
 613  *
 614  * The generated fragment program should then only declare inputs that
 615  * may vary or otherwise differ from the ctx->Current values.
 616  * Otherwise, the fp should track them as state values instead.
 617  */
 618 void
 619 _mesa_set_varying_vp_inputs( struct gl_context *ctx,
 620                              GLbitfield64 varying_inputs )
 621 {
 622    if (ctx->varying_vp_inputs != varying_inputs) {
 623       ctx->varying_vp_inputs = varying_inputs;
 624       ctx->NewState |= _NEW_ARRAY;
 625       /*printf("%s %x\n", __FUNCTION__, varying_inputs);*/
 626    }
 627 }
 628
 629
 630 /**
 631  * Used by drivers to tell core Mesa that the driver is going to
 632  * install/ use its own vertex program.  In particular, this will
 633  * prevent generated fragment programs from using state vars instead
 634  * of ordinary varyings/inputs.
 635  */
 636 void
 637 _mesa_set_vp_override(struct gl_context *ctx, GLboolean flag)
 638 {
 639    if (ctx->VertexProgram._Overriden != flag) {
 640       ctx->VertexProgram._Overriden = flag;
 641
 642       /* Set one of the bits which will trigger fragment program
 643        * regeneration:
 644        */
 645       ctx->NewState |= _NEW_PROGRAM;
 646    }
 647 }