src/mesa/swrast/s_context.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  6.5
   4  *
   5  * Copyright (C) 1999-2005  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  * Authors:
  25  *    Keith Whitwell <keith@tungstengraphics.com>
  26  *    Brian Paul
  27  */
  28
  29 #include "imports.h"
  30 #include "bufferobj.h"
  31 #include "context.h"
  32 #include "colormac.h"
  33 #include "mtypes.h"
  34 #include "program.h"
  35 #include "texobj.h"
  36 #include "nvfragprog.h"
  37
  38 #include "swrast.h"
  39 #include "s_blend.h"
  40 #include "s_context.h"
  41 #include "s_lines.h"
  42 #include "s_points.h"
  43 #include "s_span.h"
  44 #include "s_triangle.h"
  45 #include "s_texfilter.h"
  46
  47
  48 /**
  49  * Recompute the value of swrast->_RasterMask, etc. according to
  50  * the current context.  The _RasterMask field can be easily tested by
  51  * drivers to determine certain basic GL state (does the primitive need
  52  * stenciling, logic-op, fog, etc?).
  53  */
  54 static void
  55 _swrast_update_rasterflags( GLcontext *ctx )
  56 {
  57    SWcontext *swrast = SWRAST_CONTEXT(ctx);
  58    GLbitfield rasterMask = 0;
  59
  60    if (ctx->Color.AlphaEnabled)           rasterMask |= ALPHATEST_BIT;
  61    if (ctx->Color.BlendEnabled)           rasterMask |= BLEND_BIT;
  62    if (ctx->Depth.Test)                   rasterMask |= DEPTH_BIT;
  63    if (swrast->_FogEnabled)               rasterMask |= FOG_BIT;
  64    if (ctx->Scissor.Enabled)              rasterMask |= CLIP_BIT;
  65    if (ctx->Stencil.Enabled)              rasterMask |= STENCIL_BIT;
  66    if (ctx->Visual.rgbMode) {
  67       const GLuint colorMask = *((GLuint *) &ctx->Color.ColorMask);
  68       if (colorMask != 0xffffffff)        rasterMask |= MASKING_BIT;
  69       if (ctx->Color._LogicOpEnabled)     rasterMask |= LOGIC_OP_BIT;
  70       if (ctx->Texture._EnabledUnits)     rasterMask |= TEXTURE_BIT;
  71    }
  72    else {
  73       if (ctx->Color.IndexMask != 0xffffffff) rasterMask |= MASKING_BIT;
  74       if (ctx->Color.IndexLogicOpEnabled)     rasterMask |= LOGIC_OP_BIT;
  75    }
  76
  77    if (   ctx->Viewport.X < 0
  78        || ctx->Viewport.X + ctx->Viewport.Width > (GLint) ctx->DrawBuffer->Width
  79        || ctx->Viewport.Y < 0
  80        || ctx->Viewport.Y + ctx->Viewport.Height > (GLint) ctx->DrawBuffer->Height) {
  81       rasterMask |= CLIP_BIT;
  82    }
  83
  84    if (ctx->Query.CurrentOcclusionObject)
  85       rasterMask |= OCCLUSION_BIT;
  86
  87
  88    /* If we're not drawing to exactly one color buffer set the
  89     * MULTI_DRAW_BIT flag.  Also set it if we're drawing to no
  90     * buffers or the RGBA or CI mask disables all writes.
  91     */
  92    if (ctx->DrawBuffer->_NumColorDrawBuffers[0] != 1) {
  93       /* more than one color buffer designated for writing (or zero buffers) */
  94       rasterMask |= MULTI_DRAW_BIT;
  95    }
  96    else if (ctx->Visual.rgbMode && *((GLuint *) ctx->Color.ColorMask) == 0) {
  97       rasterMask |= MULTI_DRAW_BIT; /* all RGBA channels disabled */
  98    }
  99    else if (!ctx->Visual.rgbMode && ctx->Color.IndexMask==0) {
 100       rasterMask |= MULTI_DRAW_BIT; /* all color index bits disabled */
 101    }
 102
 103    if (ctx->FragmentProgram._Active) {
 104       rasterMask |= FRAGPROG_BIT;
 105    }
 106
 107    if (ctx->ATIFragmentShader._Enabled) {
 108       rasterMask |= ATIFRAGSHADER_BIT;
 109    }
 110
 111    SWRAST_CONTEXT(ctx)->_RasterMask = rasterMask;
 112 }
 113
 114
 115 /**
 116  * Examine polycon culls tate to compute the _BackfaceSign field.
 117  * _BackfaceSign will be 0 if no culling, -1 if culling back-faces,
 118  * and 1 if culling front-faces.  The Polygon FrontFace state also
 119  * factors in.
 120  */
 121 static void
 122 _swrast_update_polygon( GLcontext *ctx )
 123 {
 124    GLfloat backface_sign = 1;
 125
 126    if (ctx->Polygon.CullFlag) {
 127       backface_sign = 1;
 128       switch(ctx->Polygon.CullFaceMode) {
 129       case GL_BACK:
 130          if(ctx->Polygon.FrontFace==GL_CCW)
 131             backface_sign = -1;
 132          break;
 133       case GL_FRONT:
 134          if(ctx->Polygon.FrontFace!=GL_CCW)
 135             backface_sign = -1;
 136          break;
 137       default:
 138       case GL_FRONT_AND_BACK:
 139          backface_sign = 0;
 140          break;
 141       }
 142    }
 143    else {
 144       backface_sign = 0;
 145    }
 146
 147    SWRAST_CONTEXT(ctx)->_BackfaceSign = backface_sign;
 148 }
 149
 150
 151 /**
 152  * Update the _PreferPixelFog field to indicate if we need to compute
 153  * fog factors per-fragment.
 154  */
 155 static void
 156 _swrast_update_fog_hint( GLcontext *ctx )
 157 {
 158    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 159    swrast->_PreferPixelFog = (!swrast->AllowVertexFog ||
 160                               ctx->FragmentProgram._Enabled || /* not _Active! */
 161                               (ctx->Hint.Fog == GL_NICEST &&
 162                                swrast->AllowPixelFog));
 163 }
 164
 165
 166
 167 /**
 168  * Update the swrast->_AnyTextureCombine flag.
 169  */
 170 static void
 171 _swrast_update_texture_env( GLcontext *ctx )
 172 {
 173    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 174    GLuint i;
 175    swrast->_AnyTextureCombine = GL_FALSE;
 176    for (i = 0; i < ctx->Const.MaxTextureUnits; i++) {
 177       if (ctx->Texture.Unit[i].EnvMode == GL_COMBINE_EXT ||
 178           ctx->Texture.Unit[i].EnvMode == GL_COMBINE4_NV) {
 179          swrast->_AnyTextureCombine = GL_TRUE;
 180          return;
 181       }
 182    }
 183 }
 184
 185
 186 /**
 187  * Update swrast->_FogColor and swrast->_FogEnable values.
 188  */
 189 static void
 190 _swrast_update_fog_state( GLcontext *ctx )
 191 {
 192    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 193
 194    /* convert fog color to GLchan values */
 195    CLAMPED_FLOAT_TO_CHAN(swrast->_FogColor[RCOMP], ctx->Fog.Color[RCOMP]);
 196    CLAMPED_FLOAT_TO_CHAN(swrast->_FogColor[GCOMP], ctx->Fog.Color[GCOMP]);
 197    CLAMPED_FLOAT_TO_CHAN(swrast->_FogColor[BCOMP], ctx->Fog.Color[BCOMP]);
 198
 199    /* determine if fog is needed, and if so, which fog mode */
 200    swrast->_FogEnabled = GL_FALSE;
 201    if (ctx->FragmentProgram._Active) {
 202       if (ctx->FragmentProgram._Current->Base.Target==GL_FRAGMENT_PROGRAM_ARB) {
 203          const struct fragment_program *p
 204             = (struct fragment_program *) ctx->FragmentProgram._Current;
 205          if (p->FogOption != GL_NONE) {
 206             swrast->_FogEnabled = GL_TRUE;
 207             swrast->_FogMode = p->FogOption;
 208          }
 209       }
 210    }
 211    else if (ctx->Fog.Enabled) {
 212       swrast->_FogEnabled = GL_TRUE;
 213       swrast->_FogMode = ctx->Fog.Mode;
 214    }
 215 }
 216
 217
 218 /**
 219  * Update state for running fragment programs.  Basically, load the
 220  * program parameters with current state values.
 221  */
 222 static void
 223 _swrast_update_fragment_program( GLcontext *ctx )
 224 {
 225    if (ctx->FragmentProgram._Active) {
 226       struct fragment_program *program = ctx->FragmentProgram._Current;
 227       _mesa_load_state_parameters(ctx, program->Parameters);
 228    }
 229 }
 230
 231
 232
 233 #define _SWRAST_NEW_DERIVED (_SWRAST_NEW_RASTERMASK |   \
 234                              _NEW_TEXTURE |             \
 235                              _NEW_HINT |                \
 236                              _NEW_POLYGON )
 237
 238 /* State referenced by _swrast_choose_triangle, _swrast_choose_line.
 239  */
 240 #define _SWRAST_NEW_TRIANGLE (_SWRAST_NEW_DERIVED |             \
 241                               _NEW_RENDERMODE|                  \
 242                               _NEW_POLYGON|                     \
 243                               _NEW_DEPTH|                       \
 244                               _NEW_STENCIL|                     \
 245                               _NEW_COLOR|                       \
 246                               _NEW_TEXTURE|                     \
 247                               _SWRAST_NEW_RASTERMASK|           \
 248                               _NEW_LIGHT|                       \
 249                               _NEW_FOG |                        \
 250                               _DD_NEW_SEPARATE_SPECULAR)
 251
 252 #define _SWRAST_NEW_LINE (_SWRAST_NEW_DERIVED |         \
 253                           _NEW_RENDERMODE|              \
 254                           _NEW_LINE|                    \
 255                           _NEW_TEXTURE|                 \
 256                           _NEW_LIGHT|                   \
 257                           _NEW_FOG|                     \
 258                           _NEW_DEPTH |                  \
 259                           _DD_NEW_SEPARATE_SPECULAR)
 260
 261 #define _SWRAST_NEW_POINT (_SWRAST_NEW_DERIVED |        \
 262                            _NEW_RENDERMODE |            \
 263                            _NEW_POINT |                 \
 264                            _NEW_TEXTURE |               \
 265                            _NEW_LIGHT |                 \
 266                            _NEW_FOG |                   \
 267                            _DD_NEW_SEPARATE_SPECULAR)
 268
 269 #define _SWRAST_NEW_TEXTURE_SAMPLE_FUNC _NEW_TEXTURE
 270
 271 #define _SWRAST_NEW_TEXTURE_ENV_MODE _NEW_TEXTURE
 272
 273 #define _SWRAST_NEW_BLEND_FUNC _NEW_COLOR
 274
 275
 276
 277 /**
 278  * Stub for swrast->Triangle to select a true triangle function
 279  * after a state change.
 280  */
 281 static void
 282 _swrast_validate_triangle( GLcontext *ctx,
 283                            const SWvertex *v0,
 284                            const SWvertex *v1,
 285                            const SWvertex *v2 )
 286 {
 287    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 288
 289    _swrast_validate_derived( ctx );
 290    swrast->choose_triangle( ctx );
 291
 292    if (ctx->Texture._EnabledUnits == 0
 293        && NEED_SECONDARY_COLOR(ctx)
 294        && !ctx->FragmentProgram._Active) {
 295       /* separate specular color, but no texture */
 296       swrast->SpecTriangle = swrast->Triangle;
 297       swrast->Triangle = _swrast_add_spec_terms_triangle;
 298    }
 299
 300    swrast->Triangle( ctx, v0, v1, v2 );
 301 }
 302
 303 /**
 304  * Called via swrast->Line.  Examine current GL state and choose a software
 305  * line routine.  Then call it.
 306  */
 307 static void
 308 _swrast_validate_line( GLcontext *ctx, const SWvertex *v0, const SWvertex *v1 )
 309 {
 310    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 311
 312    _swrast_validate_derived( ctx );
 313    swrast->choose_line( ctx );
 314
 315    if (ctx->Texture._EnabledUnits == 0
 316        && NEED_SECONDARY_COLOR(ctx)
 317        && !ctx->FragmentProgram._Active) {
 318       swrast->SpecLine = swrast->Line;
 319       swrast->Line = _swrast_add_spec_terms_line;
 320    }
 321
 322
 323    swrast->Line( ctx, v0, v1 );
 324 }
 325
 326 /**
 327  * Called via swrast->Point.  Examine current GL state and choose a software
 328  * point routine.  Then call it.
 329  */
 330 static void
 331 _swrast_validate_point( GLcontext *ctx, const SWvertex *v0 )
 332 {
 333    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 334
 335    _swrast_validate_derived( ctx );
 336    swrast->choose_point( ctx );
 337
 338    if (ctx->Texture._EnabledUnits == 0
 339        && NEED_SECONDARY_COLOR(ctx)
 340        && !ctx->FragmentProgram._Active) {
 341       swrast->SpecPoint = swrast->Point;
 342       swrast->Point = _swrast_add_spec_terms_point;
 343    }
 344
 345    swrast->Point( ctx, v0 );
 346 }
 347
 348
 349 /**
 350  * Called via swrast->BlendFunc.  Examine GL state to choose a blending
 351  * function, then call it.
 352  */
 353 static void _ASMAPI
 354 _swrast_validate_blend_func( GLcontext *ctx, GLuint n,
 355                              const GLubyte mask[],
 356                              GLchan src[][4],
 357                              CONST GLchan dst[][4] )
 358 {
 359    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 360
 361    _swrast_validate_derived( ctx );
 362    _swrast_choose_blend_func( ctx );
 363
 364    swrast->BlendFunc( ctx, n, mask, src, dst );
 365 }
 366
 367
 368 static void
 369 _swrast_sleep( GLcontext *ctx, GLbitfield new_state )
 370 {
 371    (void) ctx; (void) new_state;
 372 }
 373
 374
 375 static void
 376 _swrast_invalidate_state( GLcontext *ctx, GLbitfield new_state )
 377 {
 378    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 379    GLuint i;
 380
 381    swrast->NewState |= new_state;
 382
 383    /* After 10 statechanges without any swrast functions being called,
 384     * put the module to sleep.
 385     */
 386    if (++swrast->StateChanges > 10) {
 387       swrast->InvalidateState = _swrast_sleep;
 388       swrast->NewState = ~0;
 389       new_state = ~0;
 390    }
 391
 392    if (new_state & swrast->invalidate_triangle)
 393       swrast->Triangle = _swrast_validate_triangle;
 394
 395    if (new_state & swrast->invalidate_line)
 396       swrast->Line = _swrast_validate_line;
 397
 398    if (new_state & swrast->invalidate_point)
 399       swrast->Point = _swrast_validate_point;
 400
 401    if (new_state & _SWRAST_NEW_BLEND_FUNC)
 402       swrast->BlendFunc = _swrast_validate_blend_func;
 403
 404    if (new_state & _SWRAST_NEW_TEXTURE_SAMPLE_FUNC)
 405       for (i = 0 ; i < ctx->Const.MaxTextureUnits ; i++)
 406          swrast->TextureSample[i] = NULL;
 407 }
 408
 409
 410 static void
 411 _swrast_update_texture_samplers(GLcontext *ctx)
 412 {
 413    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 414    GLuint u;
 415
 416    for (u = 0; u < ctx->Const.MaxTextureImageUnits; u++) {
 417       const struct gl_texture_object *tObj = ctx->Texture.Unit[u]._Current;
 418       if (tObj)
 419          swrast->TextureSample[u] =
 420             _swrast_choose_texture_sample_func(ctx, tObj);
 421    }
 422 }
 423
 424
 425 void
 426 _swrast_validate_derived( GLcontext *ctx )
 427 {
 428    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 429
 430    if (swrast->NewState) {
 431       if (swrast->NewState & _SWRAST_NEW_RASTERMASK)
 432          _swrast_update_rasterflags( ctx );
 433
 434       if (swrast->NewState & _NEW_POLYGON)
 435          _swrast_update_polygon( ctx );
 436
 437       if (swrast->NewState & (_NEW_HINT | _NEW_PROGRAM))
 438          _swrast_update_fog_hint( ctx );
 439
 440       if (swrast->NewState & _SWRAST_NEW_TEXTURE_ENV_MODE)
 441          _swrast_update_texture_env( ctx );
 442
 443       if (swrast->NewState & (_NEW_FOG | _NEW_PROGRAM))
 444          _swrast_update_fog_state( ctx );
 445
 446       if (swrast->NewState & _NEW_PROGRAM)
 447          _swrast_update_fragment_program( ctx );
 448
 449       if (swrast->NewState & _NEW_TEXTURE)
 450          _swrast_update_texture_samplers( ctx );
 451
 452       swrast->NewState = 0;
 453       swrast->StateChanges = 0;
 454       swrast->InvalidateState = _swrast_invalidate_state;
 455    }
 456 }
 457
 458 #define SWRAST_DEBUG 0
 459
 460 /* Public entrypoints:  See also s_accum.c, s_bitmap.c, etc.
 461  */
 462 void
 463 _swrast_Quad( GLcontext *ctx,
 464               const SWvertex *v0, const SWvertex *v1,
 465               const SWvertex *v2, const SWvertex *v3 )
 466 {
 467    if (SWRAST_DEBUG) {
 468       _mesa_debug(ctx, "_swrast_Quad\n");
 469       _swrast_print_vertex( ctx, v0 );
 470       _swrast_print_vertex( ctx, v1 );
 471       _swrast_print_vertex( ctx, v2 );
 472       _swrast_print_vertex( ctx, v3 );
 473    }
 474    SWRAST_CONTEXT(ctx)->Triangle( ctx, v0, v1, v3 );
 475    SWRAST_CONTEXT(ctx)->Triangle( ctx, v1, v2, v3 );
 476 }
 477
 478 void
 479 _swrast_Triangle( GLcontext *ctx, const SWvertex *v0,
 480                   const SWvertex *v1, const SWvertex *v2 )
 481 {
 482    if (SWRAST_DEBUG) {
 483       _mesa_debug(ctx, "_swrast_Triangle\n");
 484       _swrast_print_vertex( ctx, v0 );
 485       _swrast_print_vertex( ctx, v1 );
 486       _swrast_print_vertex( ctx, v2 );
 487    }
 488    SWRAST_CONTEXT(ctx)->Triangle( ctx, v0, v1, v2 );
 489 }
 490
 491 void
 492 _swrast_Line( GLcontext *ctx, const SWvertex *v0, const SWvertex *v1 )
 493 {
 494    if (SWRAST_DEBUG) {
 495       _mesa_debug(ctx, "_swrast_Line\n");
 496       _swrast_print_vertex( ctx, v0 );
 497       _swrast_print_vertex( ctx, v1 );
 498    }
 499    SWRAST_CONTEXT(ctx)->Line( ctx, v0, v1 );
 500 }
 501
 502 void
 503 _swrast_Point( GLcontext *ctx, const SWvertex *v0 )
 504 {
 505    if (SWRAST_DEBUG) {
 506       _mesa_debug(ctx, "_swrast_Point\n");
 507       _swrast_print_vertex( ctx, v0 );
 508    }
 509    SWRAST_CONTEXT(ctx)->Point( ctx, v0 );
 510 }
 511
 512 void
 513 _swrast_InvalidateState( GLcontext *ctx, GLbitfield new_state )
 514 {
 515    if (SWRAST_DEBUG) {
 516       _mesa_debug(ctx, "_swrast_InvalidateState\n");
 517    }
 518    SWRAST_CONTEXT(ctx)->InvalidateState( ctx, new_state );
 519 }
 520
 521 void
 522 _swrast_ResetLineStipple( GLcontext *ctx )
 523 {
 524    if (SWRAST_DEBUG) {
 525       _mesa_debug(ctx, "_swrast_ResetLineStipple\n");
 526    }
 527    SWRAST_CONTEXT(ctx)->StippleCounter = 0;
 528 }
 529
 530 void
 531 _swrast_allow_vertex_fog( GLcontext *ctx, GLboolean value )
 532 {
 533    if (SWRAST_DEBUG) {
 534       _mesa_debug(ctx, "_swrast_allow_vertex_fog %d\n", value);
 535    }
 536    SWRAST_CONTEXT(ctx)->InvalidateState( ctx, _NEW_HINT );
 537    SWRAST_CONTEXT(ctx)->AllowVertexFog = value;
 538 }
 539
 540 void
 541 _swrast_allow_pixel_fog( GLcontext *ctx, GLboolean value )
 542 {
 543    if (SWRAST_DEBUG) {
 544       _mesa_debug(ctx, "_swrast_allow_pixel_fog %d\n", value);
 545    }
 546    SWRAST_CONTEXT(ctx)->InvalidateState( ctx, _NEW_HINT );
 547    SWRAST_CONTEXT(ctx)->AllowPixelFog = value;
 548 }
 549
 550
 551 GLboolean
 552 _swrast_CreateContext( GLcontext *ctx )
 553 {
 554    GLuint i;
 555    SWcontext *swrast = (SWcontext *)CALLOC(sizeof(SWcontext));
 556
 557    if (SWRAST_DEBUG) {
 558       _mesa_debug(ctx, "_swrast_CreateContext\n");
 559    }
 560
 561    if (!swrast)
 562       return GL_FALSE;
 563
 564    swrast->NewState = ~0;
 565
 566    swrast->choose_point = _swrast_choose_point;
 567    swrast->choose_line = _swrast_choose_line;
 568    swrast->choose_triangle = _swrast_choose_triangle;
 569
 570    swrast->invalidate_point = _SWRAST_NEW_POINT;
 571    swrast->invalidate_line = _SWRAST_NEW_LINE;
 572    swrast->invalidate_triangle = _SWRAST_NEW_TRIANGLE;
 573
 574    swrast->Point = _swrast_validate_point;
 575    swrast->Line = _swrast_validate_line;
 576    swrast->Triangle = _swrast_validate_triangle;
 577    swrast->InvalidateState = _swrast_sleep;
 578    swrast->BlendFunc = _swrast_validate_blend_func;
 579
 580    swrast->AllowVertexFog = GL_TRUE;
 581    swrast->AllowPixelFog = GL_TRUE;
 582
 583    /* Optimized Accum buffer */
 584    swrast->_IntegerAccumMode = GL_FALSE;
 585    swrast->_IntegerAccumScaler = 0.0;
 586
 587    for (i = 0; i < MAX_TEXTURE_IMAGE_UNITS; i++)
 588       swrast->TextureSample[i] = NULL;
 589
 590    swrast->SpanArrays = MALLOC_STRUCT(span_arrays);
 591    if (!swrast->SpanArrays) {
 592       FREE(swrast);
 593       return GL_FALSE;
 594    }
 595
 596    /* init point span buffer */
 597    swrast->PointSpan.primitive = GL_POINT;
 598    swrast->PointSpan.start = 0;
 599    swrast->PointSpan.end = 0;
 600    swrast->PointSpan.facing = 0;
 601    swrast->PointSpan.array = swrast->SpanArrays;
 602
 603    assert(ctx->Const.MaxTextureUnits > 0);
 604    assert(ctx->Const.MaxTextureUnits <= MAX_TEXTURE_UNITS);
 605
 606    swrast->TexelBuffer = (GLchan *) MALLOC(ctx->Const.MaxTextureUnits *
 607                                            MAX_WIDTH * 4 * sizeof(GLchan));
 608    if (!swrast->TexelBuffer) {
 609       FREE(swrast->SpanArrays);
 610       FREE(swrast);
 611       return GL_FALSE;
 612    }
 613
 614    ctx->swrast_context = swrast;
 615
 616    return GL_TRUE;
 617 }
 618
 619 void
 620 _swrast_DestroyContext( GLcontext *ctx )
 621 {
 622    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 623
 624    if (SWRAST_DEBUG) {
 625       _mesa_debug(ctx, "_swrast_DestroyContext\n");
 626    }
 627
 628    FREE( swrast->SpanArrays );
 629    FREE( swrast->TexelBuffer );
 630    FREE( swrast );
 631
 632    ctx->swrast_context = 0;
 633 }
 634
 635
 636 struct swrast_device_driver *
 637 _swrast_GetDeviceDriverReference( GLcontext *ctx )
 638 {
 639    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 640    return &swrast->Driver;
 641 }
 642
 643 void
 644 _swrast_flush( GLcontext *ctx )
 645 {
 646    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 647    /* flush any pending fragments from rendering points */
 648    if (swrast->PointSpan.end > 0) {
 649       if (ctx->Visual.rgbMode) {
 650          _swrast_write_rgba_span(ctx, &(swrast->PointSpan));
 651       }
 652       else {
 653          _swrast_write_index_span(ctx, &(swrast->PointSpan));
 654       }
 655       swrast->PointSpan.end = 0;
 656    }
 657 }
 658
 659 void
 660 _swrast_render_primitive( GLcontext *ctx, GLenum prim )
 661 {
 662    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 663    if (swrast->Primitive == GL_POINTS && prim != GL_POINTS) {
 664       _swrast_flush(ctx);
 665    }
 666    swrast->Primitive = prim;
 667 }
 668
 669
 670 void
 671 _swrast_render_start( GLcontext *ctx )
 672 {
 673    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 674    if (swrast->Driver.SpanRenderStart)
 675       swrast->Driver.SpanRenderStart( ctx );
 676    swrast->PointSpan.end = 0;
 677 }
 678
 679 void
 680 _swrast_render_finish( GLcontext *ctx )
 681 {
 682    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 683    if (swrast->Driver.SpanRenderFinish)
 684       swrast->Driver.SpanRenderFinish( ctx );
 685
 686    _swrast_flush(ctx);
 687 }
 688
 689
 690 #define SWRAST_DEBUG_VERTICES 0
 691
 692 void
 693 _swrast_print_vertex( GLcontext *ctx, const SWvertex *v )
 694 {
 695    GLuint i;
 696
 697    if (SWRAST_DEBUG_VERTICES) {
 698       _mesa_debug(ctx, "win %f %f %f %f\n",
 699                   v->win[0], v->win[1], v->win[2], v->win[3]);
 700
 701       for (i = 0 ; i < ctx->Const.MaxTextureUnits ; i++)
 702          if (ctx->Texture.Unit[i]._ReallyEnabled)
 703             _mesa_debug(ctx, "texcoord[%d] %f %f %f %f\n", i,
 704                         v->texcoord[i][0], v->texcoord[i][1],
 705                         v->texcoord[i][2], v->texcoord[i][3]);
 706
 707 #if CHAN_TYPE == GL_FLOAT
 708       _mesa_debug(ctx, "color %f %f %f %f\n",
 709                   v->color[0], v->color[1], v->color[2], v->color[3]);
 710       _mesa_debug(ctx, "spec %f %f %f %f\n",
 711                   v->specular[0], v->specular[1],
 712                   v->specular[2], v->specular[3]);
 713 #else
 714       _mesa_debug(ctx, "color %d %d %d %d\n",
 715                   v->color[0], v->color[1], v->color[2], v->color[3]);
 716       _mesa_debug(ctx, "spec %d %d %d %d\n",
 717                   v->specular[0], v->specular[1],
 718                   v->specular[2], v->specular[3]);
 719 #endif
 720       _mesa_debug(ctx, "fog %f\n", v->fog);
 721       _mesa_debug(ctx, "index %d\n", v->index);
 722       _mesa_debug(ctx, "pointsize %f\n", v->pointSize);
 723       _mesa_debug(ctx, "\n");
 724    }
 725 }