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 GLcontext.
  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 "ffvertex_prog.h"
  40 #include "framebuffer.h"
  41 #include "light.h"
  42 #include "matrix.h"
  43 #if FEATURE_pixel_transfer
  44 #include "pixel.h"
  45 #endif
  46 #include "shader/program.h"
  47 #include "state.h"
  48 #include "stencil.h"
  49 #include "texenvprogram.h"
  50 #include "texobj.h"
  51 #include "texstate.h"
  52
  53
  54 static void
  55 update_separate_specular(GLcontext *ctx)
  56 {
  57    if (NEED_SECONDARY_COLOR(ctx))
  58       ctx->_TriangleCaps |= DD_SEPARATE_SPECULAR;
  59    else
  60       ctx->_TriangleCaps &= ~DD_SEPARATE_SPECULAR;
  61 }
  62
  63
  64 /**
  65  * Update state dependent on vertex arrays.
  66  */
  67 static void
  68 update_arrays( GLcontext *ctx )
  69 {
  70    GLuint i, min;
  71
  72    /* find min of _MaxElement values for all enabled arrays */
  73
  74    /* 0 */
  75    if (ctx->VertexProgram._Current
  76        && ctx->Array.ArrayObj->VertexAttrib[VERT_ATTRIB_POS].Enabled) {
  77       min = ctx->Array.ArrayObj->VertexAttrib[VERT_ATTRIB_POS]._MaxElement;
  78    }
  79    else if (ctx->Array.ArrayObj->Vertex.Enabled) {
  80       min = ctx->Array.ArrayObj->Vertex._MaxElement;
  81    }
  82    else {
  83       /* can't draw anything without vertex positions! */
  84       min = 0;
  85    }
  86
  87    /* 1 */
  88    if (ctx->VertexProgram._Enabled
  89        && ctx->Array.ArrayObj->VertexAttrib[VERT_ATTRIB_WEIGHT].Enabled) {
  90       min = MIN2(min, ctx->Array.ArrayObj->VertexAttrib[VERT_ATTRIB_WEIGHT]._MaxElement);
  91    }
  92    /* no conventional vertex weight array */
  93
  94    /* 2 */
  95    if (ctx->VertexProgram._Enabled
  96        && ctx->Array.ArrayObj->VertexAttrib[VERT_ATTRIB_NORMAL].Enabled) {
  97       min = MIN2(min, ctx->Array.ArrayObj->VertexAttrib[VERT_ATTRIB_NORMAL]._MaxElement);
  98    }
  99    else if (ctx->Array.ArrayObj->Normal.Enabled) {
 100       min = MIN2(min, ctx->Array.ArrayObj->Normal._MaxElement);
 101    }
 102
 103    /* 3 */
 104    if (ctx->VertexProgram._Enabled
 105        && ctx->Array.ArrayObj->VertexAttrib[VERT_ATTRIB_COLOR0].Enabled) {
 106       min = MIN2(min, ctx->Array.ArrayObj->VertexAttrib[VERT_ATTRIB_COLOR0]._MaxElement);
 107    }
 108    else if (ctx->Array.ArrayObj->Color.Enabled) {
 109       min = MIN2(min, ctx->Array.ArrayObj->Color._MaxElement);
 110    }
 111
 112    /* 4 */
 113    if (ctx->VertexProgram._Enabled
 114        && ctx->Array.ArrayObj->VertexAttrib[VERT_ATTRIB_COLOR1].Enabled) {
 115       min = MIN2(min, ctx->Array.ArrayObj->VertexAttrib[VERT_ATTRIB_COLOR1]._MaxElement);
 116    }
 117    else if (ctx->Array.ArrayObj->SecondaryColor.Enabled) {
 118       min = MIN2(min, ctx->Array.ArrayObj->SecondaryColor._MaxElement);
 119    }
 120
 121    /* 5 */
 122    if (ctx->VertexProgram._Enabled
 123        && ctx->Array.ArrayObj->VertexAttrib[VERT_ATTRIB_FOG].Enabled) {
 124       min = MIN2(min, ctx->Array.ArrayObj->VertexAttrib[VERT_ATTRIB_FOG]._MaxElement);
 125    }
 126    else if (ctx->Array.ArrayObj->FogCoord.Enabled) {
 127       min = MIN2(min, ctx->Array.ArrayObj->FogCoord._MaxElement);
 128    }
 129
 130    /* 6 */
 131    if (ctx->VertexProgram._Enabled
 132        && ctx->Array.ArrayObj->VertexAttrib[VERT_ATTRIB_COLOR_INDEX].Enabled) {
 133       min = MIN2(min, ctx->Array.ArrayObj->VertexAttrib[VERT_ATTRIB_COLOR_INDEX]._MaxElement);
 134    }
 135    else if (ctx->Array.ArrayObj->Index.Enabled) {
 136       min = MIN2(min, ctx->Array.ArrayObj->Index._MaxElement);
 137    }
 138
 139
 140    /* 7 */
 141    if (ctx->VertexProgram._Enabled
 142        && ctx->Array.ArrayObj->VertexAttrib[VERT_ATTRIB_EDGEFLAG].Enabled) {
 143       min = MIN2(min, ctx->Array.ArrayObj->VertexAttrib[VERT_ATTRIB_EDGEFLAG]._MaxElement);
 144    }
 145
 146    /* 8..15 */
 147    for (i = VERT_ATTRIB_TEX0; i <= VERT_ATTRIB_TEX7; i++) {
 148       if (ctx->VertexProgram._Enabled
 149           && ctx->Array.ArrayObj->VertexAttrib[i].Enabled) {
 150          min = MIN2(min, ctx->Array.ArrayObj->VertexAttrib[i]._MaxElement);
 151       }
 152       else if (i - VERT_ATTRIB_TEX0 < ctx->Const.MaxTextureCoordUnits
 153                && ctx->Array.ArrayObj->TexCoord[i - VERT_ATTRIB_TEX0].Enabled) {
 154          min = MIN2(min, ctx->Array.ArrayObj->TexCoord[i - VERT_ATTRIB_TEX0]._MaxElement);
 155       }
 156    }
 157
 158    /* 16..31 */
 159    if (ctx->VertexProgram._Current) {
 160       for (i = VERT_ATTRIB_GENERIC0; i < VERT_ATTRIB_MAX; i++) {
 161          if (ctx->Array.ArrayObj->VertexAttrib[i].Enabled) {
 162             min = MIN2(min, ctx->Array.ArrayObj->VertexAttrib[i]._MaxElement);
 163          }
 164       }
 165    }
 166
 167    if (ctx->Array.ArrayObj->EdgeFlag.Enabled) {
 168       min = MIN2(min, ctx->Array.ArrayObj->EdgeFlag._MaxElement);
 169    }
 170
 171    /* _MaxElement is one past the last legal array element */
 172    ctx->Array._MaxElement = min;
 173 }
 174
 175
 176 static void
 177 update_program(GLcontext *ctx)
 178 {
 179    const struct gl_shader_program *shProg = ctx->Shader.CurrentProgram;
 180    const struct gl_vertex_program *prevVP = ctx->VertexProgram._Current;
 181    const struct gl_fragment_program *prevFP = ctx->FragmentProgram._Current;
 182
 183    /* These _Enabled flags indicate if the program is enabled AND valid. */
 184    ctx->VertexProgram._Enabled = ctx->VertexProgram.Enabled
 185       && ctx->VertexProgram.Current->Base.Instructions;
 186    ctx->FragmentProgram._Enabled = ctx->FragmentProgram.Enabled
 187       && ctx->FragmentProgram.Current->Base.Instructions;
 188    ctx->ATIFragmentShader._Enabled = ctx->ATIFragmentShader.Enabled
 189       && ctx->ATIFragmentShader.Current->Instructions[0];
 190
 191    /*
 192     * Set the ctx->VertexProgram._Current and ctx->FragmentProgram._Current
 193     * pointers to the programs that should be enabled/used.  These will only
 194     * be NULL if we need to use the fixed-function code.
 195     *
 196     * These programs may come from several sources.  The priority is as
 197     * follows:
 198     *   1. OpenGL 2.0/ARB vertex/fragment shaders
 199     *   2. ARB/NV vertex/fragment programs
 200     *   3. Programs derived from fixed-function state.
 201     *
 202     * Note: it's possible for a vertex shader to get used with a fragment
 203     * program (and vice versa) here, but in practice that shouldn't ever
 204     * come up, or matter.
 205     */
 206
 207    _mesa_reference_fragprog(ctx, &ctx->FragmentProgram._Current, NULL);
 208
 209    if (shProg && shProg->LinkStatus && shProg->FragmentProgram) {
 210       /* Use shader programs */
 211       _mesa_reference_fragprog(ctx, &ctx->FragmentProgram._Current,
 212                                shProg->FragmentProgram);
 213    }
 214    else if (ctx->FragmentProgram._Enabled) {
 215       /* use user-defined vertex program */
 216       _mesa_reference_fragprog(ctx, &ctx->FragmentProgram._Current,
 217                                ctx->FragmentProgram.Current);
 218    }
 219    else if (ctx->FragmentProgram._MaintainTexEnvProgram) {
 220       /* Use fragment program generated from fixed-function state.
 221        */
 222       _mesa_reference_fragprog(ctx, &ctx->FragmentProgram._Current,
 223                                _mesa_get_fixed_func_fragment_program(ctx));
 224       _mesa_reference_fragprog(ctx, &ctx->FragmentProgram._TexEnvProgram,
 225                                ctx->FragmentProgram._Current);
 226    }
 227    else {
 228       /* no fragment program */
 229       _mesa_reference_fragprog(ctx, &ctx->FragmentProgram._Current, NULL);
 230    }
 231
 232    /* Examine vertex program after fragment program as
 233     * _mesa_get_fixed_func_vertex_program() needs to know active
 234     * fragprog inputs.
 235     */
 236    if (shProg && shProg->LinkStatus && shProg->VertexProgram) {
 237       /* Use shader programs */
 238       _mesa_reference_vertprog(ctx, &ctx->VertexProgram._Current,
 239                             shProg->VertexProgram);
 240    }
 241    else if (ctx->VertexProgram._Enabled) {
 242       /* use user-defined vertex program */
 243       _mesa_reference_vertprog(ctx, &ctx->VertexProgram._Current,
 244                                ctx->VertexProgram.Current);
 245    }
 246    else if (ctx->VertexProgram._MaintainTnlProgram) {
 247       /* Use vertex program generated from fixed-function state.
 248        */
 249       _mesa_reference_vertprog(ctx, &ctx->VertexProgram._Current,
 250                                _mesa_get_fixed_func_vertex_program(ctx));
 251       _mesa_reference_vertprog(ctx, &ctx->VertexProgram._TnlProgram,
 252                                ctx->VertexProgram._Current);
 253    }
 254    else {
 255       /* no vertex program */
 256       _mesa_reference_vertprog(ctx, &ctx->VertexProgram._Current, NULL);
 257    }
 258
 259    /* XXX: get rid of _Active flag.
 260     */
 261 #if 1
 262    ctx->FragmentProgram._Active = ctx->FragmentProgram._Enabled;
 263    if (ctx->FragmentProgram._MaintainTexEnvProgram &&
 264        !ctx->FragmentProgram._Enabled) {
 265       if (ctx->FragmentProgram._UseTexEnvProgram)
 266          ctx->FragmentProgram._Active = GL_TRUE;
 267    }
 268 #endif
 269
 270    /* Let the driver know what's happening:
 271     */
 272    if (ctx->FragmentProgram._Current != prevFP && ctx->Driver.BindProgram) {
 273       ctx->Driver.BindProgram(ctx, GL_FRAGMENT_PROGRAM_ARB,
 274                               (struct gl_program *) ctx->FragmentProgram._Current);
 275    }
 276
 277    if (ctx->VertexProgram._Current != prevVP && ctx->Driver.BindProgram) {
 278       ctx->Driver.BindProgram(ctx, GL_VERTEX_PROGRAM_ARB,
 279                               (struct gl_program *) ctx->VertexProgram._Current);
 280    }
 281 }
 282
 283
 284 static void
 285 update_viewport_matrix(GLcontext *ctx)
 286 {
 287    const GLfloat depthMax = ctx->DrawBuffer->_DepthMaxF;
 288
 289    ASSERT(depthMax > 0);
 290
 291    /* Compute scale and bias values. This is really driver-specific
 292     * and should be maintained elsewhere if at all.
 293     * NOTE: RasterPos uses this.
 294     */
 295    _math_matrix_viewport(&ctx->Viewport._WindowMap,
 296                          ctx->Viewport.X, ctx->Viewport.Y,
 297                          ctx->Viewport.Width, ctx->Viewport.Height,
 298                          ctx->Viewport.Near, ctx->Viewport.Far,
 299                          depthMax);
 300 }
 301
 302
 303 /**
 304  * Update derived multisample state.
 305  */
 306 static void
 307 update_multisample(GLcontext *ctx)
 308 {
 309    ctx->Multisample._Enabled = GL_FALSE;
 310    if (ctx->Multisample.Enabled &&
 311        ctx->DrawBuffer &&
 312        ctx->DrawBuffer->Visual.sampleBuffers)
 313       ctx->Multisample._Enabled = GL_TRUE;
 314 }
 315
 316
 317 /**
 318  * Update derived color/blend/logicop state.
 319  */
 320 static void
 321 update_color(GLcontext *ctx)
 322 {
 323    /* This is needed to support 1.1's RGB logic ops AND
 324     * 1.0's blending logicops.
 325     */
 326    ctx->Color._LogicOpEnabled = RGBA_LOGICOP_ENABLED(ctx);
 327 }
 328
 329
 330 /*
 331  * Check polygon state and set DD_TRI_CULL_FRONT_BACK and/or DD_TRI_OFFSET
 332  * in ctx->_TriangleCaps if needed.
 333  */
 334 static void
 335 update_polygon(GLcontext *ctx)
 336 {
 337    ctx->_TriangleCaps &= ~(DD_TRI_CULL_FRONT_BACK | DD_TRI_OFFSET);
 338
 339    if (ctx->Polygon.CullFlag && ctx->Polygon.CullFaceMode == GL_FRONT_AND_BACK)
 340       ctx->_TriangleCaps |= DD_TRI_CULL_FRONT_BACK;
 341
 342    if (   ctx->Polygon.OffsetPoint
 343        || ctx->Polygon.OffsetLine
 344        || ctx->Polygon.OffsetFill)
 345       ctx->_TriangleCaps |= DD_TRI_OFFSET;
 346 }
 347
 348
 349 /**
 350  * Update the ctx->_TriangleCaps bitfield.
 351  * XXX that bitfield should really go away someday!
 352  * This function must be called after other update_*() functions since
 353  * there are dependencies on some other derived values.
 354  */
 355 #if 0
 356 static void
 357 update_tricaps(GLcontext *ctx, GLbitfield new_state)
 358 {
 359    ctx->_TriangleCaps = 0;
 360
 361    /*
 362     * Points
 363     */
 364    if (1/*new_state & _NEW_POINT*/) {
 365       if (ctx->Point.SmoothFlag)
 366          ctx->_TriangleCaps |= DD_POINT_SMOOTH;
 367       if (ctx->Point.Size != 1.0F)
 368          ctx->_TriangleCaps |= DD_POINT_SIZE;
 369       if (ctx->Point._Attenuated)
 370          ctx->_TriangleCaps |= DD_POINT_ATTEN;
 371    }
 372
 373    /*
 374     * Lines
 375     */
 376    if (1/*new_state & _NEW_LINE*/) {
 377       if (ctx->Line.SmoothFlag)
 378          ctx->_TriangleCaps |= DD_LINE_SMOOTH;
 379       if (ctx->Line.StippleFlag)
 380          ctx->_TriangleCaps |= DD_LINE_STIPPLE;
 381       if (ctx->Line.Width != 1.0)
 382          ctx->_TriangleCaps |= DD_LINE_WIDTH;
 383    }
 384
 385    /*
 386     * Polygons
 387     */
 388    if (1/*new_state & _NEW_POLYGON*/) {
 389       if (ctx->Polygon.SmoothFlag)
 390          ctx->_TriangleCaps |= DD_TRI_SMOOTH;
 391       if (ctx->Polygon.StippleFlag)
 392          ctx->_TriangleCaps |= DD_TRI_STIPPLE;
 393       if (ctx->Polygon.FrontMode != GL_FILL
 394           || ctx->Polygon.BackMode != GL_FILL)
 395          ctx->_TriangleCaps |= DD_TRI_UNFILLED;
 396       if (ctx->Polygon.CullFlag
 397           && ctx->Polygon.CullFaceMode == GL_FRONT_AND_BACK)
 398          ctx->_TriangleCaps |= DD_TRI_CULL_FRONT_BACK;
 399       if (ctx->Polygon.OffsetPoint ||
 400           ctx->Polygon.OffsetLine ||
 401           ctx->Polygon.OffsetFill)
 402          ctx->_TriangleCaps |= DD_TRI_OFFSET;
 403    }
 404
 405    /*
 406     * Lighting and shading
 407     */
 408    if (ctx->Light.Enabled && ctx->Light.Model.TwoSide)
 409       ctx->_TriangleCaps |= DD_TRI_LIGHT_TWOSIDE;
 410    if (ctx->Light.ShadeModel == GL_FLAT)
 411       ctx->_TriangleCaps |= DD_FLATSHADE;
 412    if (NEED_SECONDARY_COLOR(ctx))
 413       ctx->_TriangleCaps |= DD_SEPARATE_SPECULAR;
 414
 415    /*
 416     * Stencil
 417     */
 418    if (ctx->Stencil._TestTwoSide)
 419       ctx->_TriangleCaps |= DD_TRI_TWOSTENCIL;
 420 }
 421 #endif
 422
 423
 424 /**
 425  * Compute derived GL state.
 426  * If __GLcontextRec::NewState is non-zero then this function \b must
 427  * be called before rendering anything.
 428  *
 429  * Calls dd_function_table::UpdateState to perform any internal state
 430  * management necessary.
 431  *
 432  * \sa _mesa_update_modelview_project(), _mesa_update_texture(),
 433  * _mesa_update_buffer_bounds(),
 434  * _mesa_update_lighting() and _mesa_update_tnl_spaces().
 435  */
 436 void
 437 _mesa_update_state_locked( GLcontext *ctx )
 438 {
 439    GLbitfield new_state = ctx->NewState;
 440    GLbitfield prog_flags = _NEW_PROGRAM;
 441
 442    if (new_state == _NEW_CURRENT_ATTRIB)
 443       goto out;
 444
 445    if (MESA_VERBOSE & VERBOSE_STATE)
 446       _mesa_print_state("_mesa_update_state", new_state);
 447
 448    if (new_state & (_NEW_MODELVIEW|_NEW_PROJECTION))
 449       _mesa_update_modelview_project( ctx, new_state );
 450
 451    if (new_state & (_NEW_PROGRAM|_NEW_TEXTURE|_NEW_TEXTURE_MATRIX))
 452       _mesa_update_texture( ctx, new_state );
 453
 454    if (new_state & _NEW_BUFFERS)
 455       _mesa_update_framebuffer(ctx);
 456
 457    if (new_state & (_NEW_SCISSOR | _NEW_BUFFERS | _NEW_VIEWPORT))
 458       _mesa_update_draw_buffer_bounds( ctx );
 459
 460    if (new_state & _NEW_POLYGON)
 461       update_polygon( ctx );
 462
 463    if (new_state & _NEW_LIGHT)
 464       _mesa_update_lighting( ctx );
 465
 466    if (new_state & _NEW_STENCIL)
 467       _mesa_update_stencil( ctx );
 468
 469 #if FEATURE_pixel_transfer
 470    if (new_state & _IMAGE_NEW_TRANSFER_STATE)
 471       _mesa_update_pixel( ctx, new_state );
 472 #endif
 473
 474    if (new_state & _DD_NEW_SEPARATE_SPECULAR)
 475       update_separate_specular( ctx );
 476
 477    if (new_state & (_NEW_ARRAY | _NEW_PROGRAM))
 478       update_arrays( ctx );
 479
 480    if (new_state & (_NEW_BUFFERS | _NEW_VIEWPORT))
 481       update_viewport_matrix(ctx);
 482
 483    if (new_state & _NEW_MULTISAMPLE)
 484       update_multisample( ctx );
 485
 486    if (new_state & _NEW_COLOR)
 487       update_color( ctx );
 488
 489 #if 0
 490    if (new_state & (_NEW_POINT | _NEW_LINE | _NEW_POLYGON | _NEW_LIGHT
 491                     | _NEW_STENCIL | _DD_NEW_SEPARATE_SPECULAR))
 492       update_tricaps( ctx, new_state );
 493 #endif
 494
 495    /* ctx->_NeedEyeCoords is now up to date.
 496     *
 497     * If the truth value of this variable has changed, update for the
 498     * new lighting space and recompute the positions of lights and the
 499     * normal transform.
 500     *
 501     * If the lighting space hasn't changed, may still need to recompute
 502     * light positions & normal transforms for other reasons.
 503     */
 504    if (new_state & _MESA_NEW_NEED_EYE_COORDS)
 505       _mesa_update_tnl_spaces( ctx, new_state );
 506
 507    if (ctx->FragmentProgram._MaintainTexEnvProgram) {
 508       prog_flags |= (_NEW_ARRAY | _NEW_TEXTURE_MATRIX | _NEW_LIGHT |
 509                      _NEW_RENDERMODE |
 510                      _NEW_TEXTURE | _NEW_FOG | _DD_NEW_SEPARATE_SPECULAR);
 511    }
 512    if (ctx->VertexProgram._MaintainTnlProgram) {
 513       prog_flags |= (_NEW_ARRAY | _NEW_TEXTURE | _NEW_TEXTURE_MATRIX |
 514                      _NEW_RENDERMODE |
 515                      _NEW_TRANSFORM | _NEW_POINT |
 516                      _NEW_FOG | _NEW_LIGHT |
 517                      _MESA_NEW_NEED_EYE_COORDS);
 518    }
 519    if (new_state & prog_flags)
 520       update_program( ctx );
 521
 522
 523
 524    /*
 525     * Give the driver a chance to act upon the new_state flags.
 526     * The driver might plug in different span functions, for example.
 527     * Also, this is where the driver can invalidate the state of any
 528     * active modules (such as swrast_setup, swrast, tnl, etc).
 529     *
 530     * Set ctx->NewState to zero to avoid recursion if
 531     * Driver.UpdateState() has to call FLUSH_VERTICES().  (fixed?)
 532     */
 533  out:
 534    new_state = ctx->NewState;
 535    ctx->NewState = 0;
 536    ctx->Driver.UpdateState(ctx, new_state);
 537    ctx->Array.NewState = 0;
 538 }
 539
 540
 541 /* This is the usual entrypoint for state updates:
 542  */
 543 void
 544 _mesa_update_state( GLcontext *ctx )
 545 {
 546    _mesa_lock_context_textures(ctx);
 547    _mesa_update_state_locked(ctx);
 548    _mesa_unlock_context_textures(ctx);
 549 }
 550
 551
 552
 553
 554 /**
 555  * Want to figure out which fragment program inputs are actually
 556  * constant/current values from ctx->Current.  These should be
 557  * referenced as a tracked state variable rather than a fragment
 558  * program input, to save the overhead of putting a constant value in
 559  * every submitted vertex, transferring it to hardware, interpolating
 560  * it across the triangle, etc...
 561  *
 562  * When there is a VP bound, just use vp->outputs.  But when we're
 563  * generating vp from fixed function state, basically want to
 564  * calculate:
 565  *
 566  * vp_out_2_fp_in( vp_in_2_vp_out( varying_inputs ) |
 567  *                 potential_vp_outputs )
 568  *
 569  * Where potential_vp_outputs is calculated by looking at enabled
 570  * texgen, etc.
 571  *
 572  * The generated fragment program should then only declare inputs that
 573  * may vary or otherwise differ from the ctx->Current values.
 574  * Otherwise, the fp should track them as state values instead.
 575  */
 576 void
 577 _mesa_set_varying_vp_inputs( GLcontext *ctx,
 578                              GLbitfield varying_inputs )
 579 {
 580    if (ctx->varying_vp_inputs != varying_inputs) {
 581       ctx->varying_vp_inputs = varying_inputs;
 582       ctx->NewState |= _NEW_ARRAY;
 583       /*_mesa_printf("%s %x\n", __FUNCTION__, varying_inputs);*/
 584    }
 585 }
 586
 587
 588 /**
 589  * Used by drivers to tell core Mesa that the driver is going to
 590  * install/ use its own vertex program.  In particular, this will
 591  * prevent generated fragment programs from using state vars instead
 592  * of ordinary varyings/inputs.
 593  */
 594 void
 595 _mesa_set_vp_override(GLcontext *ctx, GLboolean flag)
 596 {
 597    if (ctx->VertexProgram._Overriden != flag) {
 598       ctx->VertexProgram._Overriden = flag;
 599
 600       /* Set one of the bits which will trigger fragment program
 601        * regeneration:
 602        */
 603       ctx->NewState |= _NEW_ARRAY;
 604    }
 605 }