summaryrefslogtreecommitdiff
path: root/src/mesa/swrast/s_tritemp.h
blob: c609210c0ec9f7bc0ee33edce200dddd901ff872 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
/*
 * Mesa 3-D graphics library
 * Version:  7.0
 *
 * Copyright (C) 1999-2007  Brian Paul   All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

/*
 * Triangle Rasterizer Template
 *
 * This file is #include'd to generate custom triangle rasterizers.
 *
 * The following macros may be defined to indicate what auxillary information
 * must be interpolated across the triangle:
 *    INTERP_Z        - if defined, interpolate integer Z values
 *    INTERP_RGB      - if defined, interpolate integer RGB values
 *    INTERP_ALPHA    - if defined, interpolate integer Alpha values
 *    INTERP_INDEX    - if defined, interpolate color index values
 *    INTERP_INT_TEX  - if defined, interpolate integer ST texcoords
 *                         (fast, simple 2-D texture mapping, without
 *                         perspective correction)
 *    INTERP_ATTRIBS  - if defined, interpolate arbitrary attribs (texcoords,
 *                         varying vars, etc)  This also causes W to be
 *                         computed for perspective correction).
 *
 * When one can directly address pixels in the color buffer the following
 * macros can be defined and used to compute pixel addresses during
 * rasterization (see pRow):
 *    PIXEL_TYPE          - the datatype of a pixel (GLubyte, GLushort, GLuint)
 *    BYTES_PER_ROW       - number of bytes per row in the color buffer
 *    PIXEL_ADDRESS(X,Y)  - returns the address of pixel at (X,Y) where
 *                          Y==0 at bottom of screen and increases upward.
 *
 * Similarly, for direct depth buffer access, this type is used for depth
 * buffer addressing (see zRow):
 *    DEPTH_TYPE          - either GLushort or GLuint
 *
 * Optionally, one may provide one-time setup code per triangle:
 *    SETUP_CODE    - code which is to be executed once per triangle
 *
 * The following macro MUST be defined:
 *    RENDER_SPAN(span) - code to write a span of pixels.
 *
 * This code was designed for the origin to be in the lower-left corner.
 *
 * Inspired by triangle rasterizer code written by Allen Akin.  Thanks Allen!
 *
 *
 * Some notes on rasterization accuracy:
 *
 * This code uses fixed point arithmetic (the GLfixed type) to iterate
 * over the triangle edges and interpolate ancillary data (such as Z,
 * color, secondary color, etc).  The number of fractional bits in
 * GLfixed and the value of SUB_PIXEL_BITS has a direct bearing on the
 * accuracy of rasterization.
 *
 * If SUB_PIXEL_BITS=4 then we'll snap the vertices to the nearest
 * 1/16 of a pixel.  If we're walking up a long, nearly vertical edge
 * (dx=1/16, dy=1024) we'll need 4 + 10 = 14 fractional bits in
 * GLfixed to walk the edge without error.  If the maximum viewport
 * height is 4K pixels, then we'll need 4 + 12 = 16 fractional bits.
 *
 * Historically, Mesa has used 11 fractional bits in GLfixed, snaps
 * vertices to 1/16 pixel and allowed a maximum viewport height of 2K
 * pixels.  11 fractional bits is actually insufficient for accurately
 * rasterizing some triangles.  More recently, the maximum viewport
 * height was increased to 4K pixels.  Thus, Mesa should be using 16
 * fractional bits in GLfixed.  Unfortunately, there may be some issues
 * with setting FIXED_FRAC_BITS=16, such as multiplication overflow.
 * This will have to be examined in some detail...
 *
 * For now, if you find rasterization errors, particularly with tall,
 * sliver triangles, try increasing FIXED_FRAC_BITS and/or decreasing
 * SUB_PIXEL_BITS.
 */


/*
 * Some code we unfortunately need to prevent negative interpolated colors.
 */
#ifndef CLAMP_INTERPOLANT
#define CLAMP_INTERPOLANT(CHANNEL, CHANNELSTEP, LEN)		\
do {								\
   GLfixed endVal = span.CHANNEL + (LEN) * span.CHANNELSTEP;	\
   if (endVal < 0) {						\
      span.CHANNEL -= endVal;					\
   }								\
   if (span.CHANNEL < 0) {					\
      span.CHANNEL = 0;						\
   }								\
} while (0)
#endif


static void NAME(GLcontext *ctx, const SWvertex *v0,
                                 const SWvertex *v1,
                                 const SWvertex *v2 )
{
   typedef struct {
      const SWvertex *v0, *v1;   /* Y(v0) < Y(v1) */
      GLfloat dx;	/* X(v1) - X(v0) */
      GLfloat dy;	/* Y(v1) - Y(v0) */
      GLfloat dxdy;	/* dx/dy */
      GLfixed fdxdy;	/* dx/dy in fixed-point */
      GLfloat adjy;	/* adjust from v[0]->fy to fsy, scaled */
      GLfixed fsx;	/* first sample point x coord */
      GLfixed fsy;
      GLfixed fx0;	/* fixed pt X of lower endpoint */
      GLint lines;	/* number of lines to be sampled on this edge */
   } EdgeT;

   const SWcontext *swrast = SWRAST_CONTEXT(ctx);
#ifdef INTERP_Z
   const GLint depthBits = ctx->DrawBuffer->Visual.depthBits;
   const GLint fixedToDepthShift = depthBits <= 16 ? FIXED_SHIFT : 0;
   const GLfloat maxDepth = ctx->DrawBuffer->_DepthMaxF;
#define FixedToDepth(F)  ((F) >> fixedToDepthShift)
#endif
   EdgeT eMaj, eTop, eBot;
   GLfloat oneOverArea;
   const SWvertex *vMin, *vMid, *vMax;  /* Y(vMin)<=Y(vMid)<=Y(vMax) */
   GLfloat bf = SWRAST_CONTEXT(ctx)->_BackfaceCullSign;
   const GLint snapMask = ~((FIXED_ONE / (1 << SUB_PIXEL_BITS)) - 1); /* for x/y coord snapping */
   GLfixed vMin_fx, vMin_fy, vMid_fx, vMid_fy, vMax_fx, vMax_fy;

   SWspan span;

   (void) swrast;

   INIT_SPAN(span, GL_POLYGON);
   span.y = 0; /* silence warnings */

#ifdef INTERP_Z
   (void) fixedToDepthShift;
#endif

   /*
   printf("%s()\n", __FUNCTION__);
   printf("  %g, %g, %g\n",
          v0->attrib[FRAG_ATTRIB_WPOS][0],
          v0->attrib[FRAG_ATTRIB_WPOS][1],
          v0->attrib[FRAG_ATTRIB_WPOS][2]);
   printf("  %g, %g, %g\n",
          v1->attrib[FRAG_ATTRIB_WPOS][0],
          v1->attrib[FRAG_ATTRIB_WPOS][1],
          v1->attrib[FRAG_ATTRIB_WPOS][2]);
   printf("  %g, %g, %g\n",
          v2->attrib[FRAG_ATTRIB_WPOS][0],
          v2->attrib[FRAG_ATTRIB_WPOS][1],
          v2->attrib[FRAG_ATTRIB_WPOS][2]);
   */

   /* Compute fixed point x,y coords w/ half-pixel offsets and snapping.
    * And find the order of the 3 vertices along the Y axis.
    */
   {
      const GLfixed fy0 = FloatToFixed(v0->attrib[FRAG_ATTRIB_WPOS][1] - 0.5F) & snapMask;
      const GLfixed fy1 = FloatToFixed(v1->attrib[FRAG_ATTRIB_WPOS][1] - 0.5F) & snapMask;
      const GLfixed fy2 = FloatToFixed(v2->attrib[FRAG_ATTRIB_WPOS][1] - 0.5F) & snapMask;
      if (fy0 <= fy1) {
         if (fy1 <= fy2) {
            /* y0 <= y1 <= y2 */
            vMin = v0;   vMid = v1;   vMax = v2;
            vMin_fy = fy0;  vMid_fy = fy1;  vMax_fy = fy2;
         }
         else if (fy2 <= fy0) {
            /* y2 <= y0 <= y1 */
            vMin = v2;   vMid = v0;   vMax = v1;
            vMin_fy = fy2;  vMid_fy = fy0;  vMax_fy = fy1;
         }
         else {
            /* y0 <= y2 <= y1 */
            vMin = v0;   vMid = v2;   vMax = v1;
            vMin_fy = fy0;  vMid_fy = fy2;  vMax_fy = fy1;
            bf = -bf;
         }
      }
      else {
         if (fy0 <= fy2) {
            /* y1 <= y0 <= y2 */
            vMin = v1;   vMid = v0;   vMax = v2;
            vMin_fy = fy1;  vMid_fy = fy0;  vMax_fy = fy2;
            bf = -bf;
         }
         else if (fy2 <= fy1) {
            /* y2 <= y1 <= y0 */
            vMin = v2;   vMid = v1;   vMax = v0;
            vMin_fy = fy2;  vMid_fy = fy1;  vMax_fy = fy0;
            bf = -bf;
         }
         else {
            /* y1 <= y2 <= y0 */
            vMin = v1;   vMid = v2;   vMax = v0;
            vMin_fy = fy1;  vMid_fy = fy2;  vMax_fy = fy0;
         }
      }

      /* fixed point X coords */
      vMin_fx = FloatToFixed(vMin->attrib[FRAG_ATTRIB_WPOS][0] + 0.5F) & snapMask;
      vMid_fx = FloatToFixed(vMid->attrib[FRAG_ATTRIB_WPOS][0] + 0.5F) & snapMask;
      vMax_fx = FloatToFixed(vMax->attrib[FRAG_ATTRIB_WPOS][0] + 0.5F) & snapMask;
   }

   /* vertex/edge relationship */
   eMaj.v0 = vMin;   eMaj.v1 = vMax;   /*TODO: .v1's not needed */
   eTop.v0 = vMid;   eTop.v1 = vMax;
   eBot.v0 = vMin;   eBot.v1 = vMid;

   /* compute deltas for each edge:  vertex[upper] - vertex[lower] */
   eMaj.dx = FixedToFloat(vMax_fx - vMin_fx);
   eMaj.dy = FixedToFloat(vMax_fy - vMin_fy);
   eTop.dx = FixedToFloat(vMax_fx - vMid_fx);
   eTop.dy = FixedToFloat(vMax_fy - vMid_fy);
   eBot.dx = FixedToFloat(vMid_fx - vMin_fx);
   eBot.dy = FixedToFloat(vMid_fy - vMin_fy);

   /* compute area, oneOverArea and perform backface culling */
   {
      const GLfloat area = eMaj.dx * eBot.dy - eBot.dx * eMaj.dy;
      /* Do backface culling */

      if (area * bf < 0.0)
         return;

      if (IS_INF_OR_NAN(area) || area == 0.0F)
         return;

      oneOverArea = 1.0F / area;

      /* 0 = front, 1 = back */
      span.facing = oneOverArea * swrast->_BackfaceSign > 0.0F;
   }

   /* Edge setup.  For a triangle strip these could be reused... */
   {
      eMaj.fsy = FixedCeil(vMin_fy);
      eMaj.lines = FixedToInt(FixedCeil(vMax_fy - eMaj.fsy));
      if (eMaj.lines > 0) {
         eMaj.dxdy = eMaj.dx / eMaj.dy;
         eMaj.fdxdy = SignedFloatToFixed(eMaj.dxdy);
         eMaj.adjy = (GLfloat) (eMaj.fsy - vMin_fy);  /* SCALED! */
         eMaj.fx0 = vMin_fx;
         eMaj.fsx = eMaj.fx0 + (GLfixed) (eMaj.adjy * eMaj.dxdy);
      }
      else {
         return;  /*CULLED*/
      }

      eTop.fsy = FixedCeil(vMid_fy);
      eTop.lines = FixedToInt(FixedCeil(vMax_fy - eTop.fsy));
      if (eTop.lines > 0) {
         eTop.dxdy = eTop.dx / eTop.dy;
         eTop.fdxdy = SignedFloatToFixed(eTop.dxdy);
         eTop.adjy = (GLfloat) (eTop.fsy - vMid_fy); /* SCALED! */
         eTop.fx0 = vMid_fx;
         eTop.fsx = eTop.fx0 + (GLfixed) (eTop.adjy * eTop.dxdy);
      }

      eBot.fsy = FixedCeil(vMin_fy);
      eBot.lines = FixedToInt(FixedCeil(vMid_fy - eBot.fsy));
      if (eBot.lines > 0) {
         eBot.dxdy = eBot.dx / eBot.dy;
         eBot.fdxdy = SignedFloatToFixed(eBot.dxdy);
         eBot.adjy = (GLfloat) (eBot.fsy - vMin_fy);  /* SCALED! */
         eBot.fx0 = vMin_fx;
         eBot.fsx = eBot.fx0 + (GLfixed) (eBot.adjy * eBot.dxdy);
      }
   }

   /*
    * Conceptually, we view a triangle as two subtriangles
    * separated by a perfectly horizontal line.  The edge that is
    * intersected by this line is one with maximal absolute dy; we
    * call it a ``major'' edge.  The other two edges are the
    * ``top'' edge (for the upper subtriangle) and the ``bottom''
    * edge (for the lower subtriangle).  If either of these two
    * edges is horizontal or very close to horizontal, the
    * corresponding subtriangle might cover zero sample points;
    * we take care to handle such cases, for performance as well
    * as correctness.
    *
    * By stepping rasterization parameters along the major edge,
    * we can avoid recomputing them at the discontinuity where
    * the top and bottom edges meet.  However, this forces us to
    * be able to scan both left-to-right and right-to-left.
    * Also, we must determine whether the major edge is at the
    * left or right side of the triangle.  We do this by
    * computing the magnitude of the cross-product of the major
    * and top edges.  Since this magnitude depends on the sine of
    * the angle between the two edges, its sign tells us whether
    * we turn to the left or to the right when travelling along
    * the major edge to the top edge, and from this we infer
    * whether the major edge is on the left or the right.
    *
    * Serendipitously, this cross-product magnitude is also a
    * value we need to compute the iteration parameter
    * derivatives for the triangle, and it can be used to perform
    * backface culling because its sign tells us whether the
    * triangle is clockwise or counterclockwise.  In this code we
    * refer to it as ``area'' because it's also proportional to
    * the pixel area of the triangle.
    */

   {
      GLint scan_from_left_to_right;  /* true if scanning left-to-right */
#ifdef INTERP_INDEX
      GLfloat didx, didy;
#endif

      /*
       * Execute user-supplied setup code
       */
#ifdef SETUP_CODE
      SETUP_CODE
#endif

      scan_from_left_to_right = (oneOverArea < 0.0F);


      /* compute d?/dx and d?/dy derivatives */
#ifdef INTERP_Z
      span.interpMask |= SPAN_Z;
      {
         GLfloat eMaj_dz = vMax->attrib[FRAG_ATTRIB_WPOS][2] - vMin->attrib[FRAG_ATTRIB_WPOS][2];
         GLfloat eBot_dz = vMid->attrib[FRAG_ATTRIB_WPOS][2] - vMin->attrib[FRAG_ATTRIB_WPOS][2];
         span.attrStepX[FRAG_ATTRIB_WPOS][2] = oneOverArea * (eMaj_dz * eBot.dy - eMaj.dy * eBot_dz);
         if (span.attrStepX[FRAG_ATTRIB_WPOS][2] > maxDepth ||
             span.attrStepX[FRAG_ATTRIB_WPOS][2] < -maxDepth) {
            /* probably a sliver triangle */
            span.attrStepX[FRAG_ATTRIB_WPOS][2] = 0.0;
            span.attrStepY[FRAG_ATTRIB_WPOS][2] = 0.0;
         }
         else {
            span.attrStepY[FRAG_ATTRIB_WPOS][2] = oneOverArea * (eMaj.dx * eBot_dz - eMaj_dz * eBot.dx);
         }
         if (depthBits <= 16)
            span.zStep = SignedFloatToFixed(span.attrStepX[FRAG_ATTRIB_WPOS][2]);
         else
            span.zStep = (GLint) span.attrStepX[FRAG_ATTRIB_WPOS][2];
      }
#endif
#ifdef INTERP_RGB
      span.interpMask |= SPAN_RGBA;
      if (ctx->Light.ShadeModel == GL_SMOOTH) {
         GLfloat eMaj_dr = (GLfloat) (vMax->color[RCOMP] - vMin->color[RCOMP]);
         GLfloat eBot_dr = (GLfloat) (vMid->color[RCOMP] - vMin->color[RCOMP]);
         GLfloat eMaj_dg = (GLfloat) (vMax->color[GCOMP] - vMin->color[GCOMP]);
         GLfloat eBot_dg = (GLfloat) (vMid->color[GCOMP] - vMin->color[GCOMP]);
         GLfloat eMaj_db = (GLfloat) (vMax->color[BCOMP] - vMin->color[BCOMP]);
         GLfloat eBot_db = (GLfloat) (vMid->color[BCOMP] - vMin->color[BCOMP]);
#  ifdef INTERP_ALPHA
         GLfloat eMaj_da = (GLfloat) (vMax->color[ACOMP] - vMin->color[ACOMP]);
         GLfloat eBot_da = (GLfloat) (vMid->color[ACOMP] - vMin->color[ACOMP]);
#  endif
         span.attrStepX[FRAG_ATTRIB_COL0][0] = oneOverArea * (eMaj_dr * eBot.dy - eMaj.dy * eBot_dr);
         span.attrStepY[FRAG_ATTRIB_COL0][0] = oneOverArea * (eMaj.dx * eBot_dr - eMaj_dr * eBot.dx);
         span.attrStepX[FRAG_ATTRIB_COL0][1] = oneOverArea * (eMaj_dg * eBot.dy - eMaj.dy * eBot_dg);
         span.attrStepY[FRAG_ATTRIB_COL0][1] = oneOverArea * (eMaj.dx * eBot_dg - eMaj_dg * eBot.dx);
         span.attrStepX[FRAG_ATTRIB_COL0][2] = oneOverArea * (eMaj_db * eBot.dy - eMaj.dy * eBot_db);
         span.attrStepY[FRAG_ATTRIB_COL0][2] = oneOverArea * (eMaj.dx * eBot_db - eMaj_db * eBot.dx);
         span.redStep   = SignedFloatToFixed(span.attrStepX[FRAG_ATTRIB_COL0][0]);
         span.greenStep = SignedFloatToFixed(span.attrStepX[FRAG_ATTRIB_COL0][1]);
         span.blueStep  = SignedFloatToFixed(span.attrStepX[FRAG_ATTRIB_COL0][2]);
#  ifdef INTERP_ALPHA
         span.attrStepX[FRAG_ATTRIB_COL0][3] = oneOverArea * (eMaj_da * eBot.dy - eMaj.dy * eBot_da);
         span.attrStepY[FRAG_ATTRIB_COL0][3] = oneOverArea * (eMaj.dx * eBot_da - eMaj_da * eBot.dx);
         span.alphaStep = SignedFloatToFixed(span.attrStepX[FRAG_ATTRIB_COL0][3]);
#  endif /* INTERP_ALPHA */
      }
      else {
         ASSERT(ctx->Light.ShadeModel == GL_FLAT);
         span.interpMask |= SPAN_FLAT;
         span.attrStepX[FRAG_ATTRIB_COL0][0] = span.attrStepY[FRAG_ATTRIB_COL0][0] = 0.0F;
         span.attrStepX[FRAG_ATTRIB_COL0][1] = span.attrStepY[FRAG_ATTRIB_COL0][1] = 0.0F;
         span.attrStepX[FRAG_ATTRIB_COL0][2] = span.attrStepY[FRAG_ATTRIB_COL0][2] = 0.0F;
	 span.redStep   = 0;
	 span.greenStep = 0;
	 span.blueStep  = 0;
#  ifdef INTERP_ALPHA
         span.attrStepX[FRAG_ATTRIB_COL0][3] = span.attrStepY[FRAG_ATTRIB_COL0][3] = 0.0F;
	 span.alphaStep = 0;
#  endif
      }
#endif /* INTERP_RGB */
#ifdef INTERP_INDEX
      span.interpMask |= SPAN_INDEX;
      if (ctx->Light.ShadeModel == GL_SMOOTH) {
         GLfloat eMaj_di = vMax->attrib[FRAG_ATTRIB_CI][0] - vMin->attrib[FRAG_ATTRIB_CI][0];
         GLfloat eBot_di = vMid->attrib[FRAG_ATTRIB_CI][0] - vMin->attrib[FRAG_ATTRIB_CI][0];
         didx = oneOverArea * (eMaj_di * eBot.dy - eMaj.dy * eBot_di);
         didy = oneOverArea * (eMaj.dx * eBot_di - eMaj_di * eBot.dx);
         span.indexStep = SignedFloatToFixed(didx);
      }
      else {
         span.interpMask |= SPAN_FLAT;
         didx = didy = 0.0F;
         span.indexStep = 0;
      }
#endif
#ifdef INTERP_INT_TEX
      {
         GLfloat eMaj_ds = (vMax->attrib[FRAG_ATTRIB_TEX0][0] - vMin->attrib[FRAG_ATTRIB_TEX0][0]) * S_SCALE;
         GLfloat eBot_ds = (vMid->attrib[FRAG_ATTRIB_TEX0][0] - vMin->attrib[FRAG_ATTRIB_TEX0][0]) * S_SCALE;
         GLfloat eMaj_dt = (vMax->attrib[FRAG_ATTRIB_TEX0][1] - vMin->attrib[FRAG_ATTRIB_TEX0][1]) * T_SCALE;
         GLfloat eBot_dt = (vMid->attrib[FRAG_ATTRIB_TEX0][1] - vMin->attrib[FRAG_ATTRIB_TEX0][1]) * T_SCALE;
         span.attrStepX[FRAG_ATTRIB_TEX0][0] = oneOverArea * (eMaj_ds * eBot.dy - eMaj.dy * eBot_ds);
         span.attrStepY[FRAG_ATTRIB_TEX0][0] = oneOverArea * (eMaj.dx * eBot_ds - eMaj_ds * eBot.dx);
         span.attrStepX[FRAG_ATTRIB_TEX0][1] = oneOverArea * (eMaj_dt * eBot.dy - eMaj.dy * eBot_dt);
         span.attrStepY[FRAG_ATTRIB_TEX0][1] = oneOverArea * (eMaj.dx * eBot_dt - eMaj_dt * eBot.dx);
         span.intTexStep[0] = SignedFloatToFixed(span.attrStepX[FRAG_ATTRIB_TEX0][0]);
         span.intTexStep[1] = SignedFloatToFixed(span.attrStepX[FRAG_ATTRIB_TEX0][1]);
      }
#endif
#ifdef INTERP_ATTRIBS
      {
         /* attrib[FRAG_ATTRIB_WPOS][3] is 1/W */
         const GLfloat wMax = vMax->attrib[FRAG_ATTRIB_WPOS][3];
         const GLfloat wMin = vMin->attrib[FRAG_ATTRIB_WPOS][3];
         const GLfloat wMid = vMid->attrib[FRAG_ATTRIB_WPOS][3];
         {
            const GLfloat eMaj_dw = wMax - wMin;
            const GLfloat eBot_dw = wMid - wMin;
            span.attrStepX[FRAG_ATTRIB_WPOS][3] = oneOverArea * (eMaj_dw * eBot.dy - eMaj.dy * eBot_dw);
            span.attrStepY[FRAG_ATTRIB_WPOS][3] = oneOverArea * (eMaj.dx * eBot_dw - eMaj_dw * eBot.dx);
         }
         ATTRIB_LOOP_BEGIN
            if (swrast->_InterpMode[attr] == GL_FLAT) {
               ASSIGN_4V(span.attrStepX[attr], 0.0, 0.0, 0.0, 0.0);
               ASSIGN_4V(span.attrStepY[attr], 0.0, 0.0, 0.0, 0.0);
            }
            else {
               GLuint c;
               for (c = 0; c < 4; c++) {
                  GLfloat eMaj_da = vMax->attrib[attr][c] * wMax - vMin->attrib[attr][c] * wMin;
                  GLfloat eBot_da = vMid->attrib[attr][c] * wMid - vMin->attrib[attr][c] * wMin;
                  span.attrStepX[attr][c] = oneOverArea * (eMaj_da * eBot.dy - eMaj.dy * eBot_da);
                  span.attrStepY[attr][c] = oneOverArea * (eMaj.dx * eBot_da - eMaj_da * eBot.dx);
               }
            }
         ATTRIB_LOOP_END
      }
#endif

      /*
       * We always sample at pixel centers.  However, we avoid
       * explicit half-pixel offsets in this code by incorporating
       * the proper offset in each of x and y during the
       * transformation to window coordinates.
       *
       * We also apply the usual rasterization rules to prevent
       * cracks and overlaps.  A pixel is considered inside a
       * subtriangle if it meets all of four conditions: it is on or
       * to the right of the left edge, strictly to the left of the
       * right edge, on or below the top edge, and strictly above
       * the bottom edge.  (Some edges may be degenerate.)
       *
       * The following discussion assumes left-to-right scanning
       * (that is, the major edge is on the left); the right-to-left
       * case is a straightforward variation.
       *
       * We start by finding the half-integral y coordinate that is
       * at or below the top of the triangle.  This gives us the
       * first scan line that could possibly contain pixels that are
       * inside the triangle.
       *
       * Next we creep down the major edge until we reach that y,
       * and compute the corresponding x coordinate on the edge.
       * Then we find the half-integral x that lies on or just
       * inside the edge.  This is the first pixel that might lie in
       * the interior of the triangle.  (We won't know for sure
       * until we check the other edges.)
       *
       * As we rasterize the triangle, we'll step down the major
       * edge.  For each step in y, we'll move an integer number
       * of steps in x.  There are two possible x step sizes, which
       * we'll call the ``inner'' step (guaranteed to land on the
       * edge or inside it) and the ``outer'' step (guaranteed to
       * land on the edge or outside it).  The inner and outer steps
       * differ by one.  During rasterization we maintain an error
       * term that indicates our distance from the true edge, and
       * select either the inner step or the outer step, whichever
       * gets us to the first pixel that falls inside the triangle.
       *
       * All parameters (z, red, etc.) as well as the buffer
       * addresses for color and z have inner and outer step values,
       * so that we can increment them appropriately.  This method
       * eliminates the need to adjust parameters by creeping a
       * sub-pixel amount into the triangle at each scanline.
       */

      {
         GLint subTriangle;
         GLfixed fxLeftEdge = 0, fxRightEdge = 0;
         GLfixed fdxLeftEdge = 0, fdxRightEdge = 0;
         GLfixed fError = 0, fdError = 0;
#ifdef PIXEL_ADDRESS
         PIXEL_TYPE *pRow = NULL;
         GLint dPRowOuter = 0, dPRowInner;  /* offset in bytes */
#endif
#ifdef INTERP_Z
#  ifdef DEPTH_TYPE
         struct gl_renderbuffer *zrb
            = ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer;
         DEPTH_TYPE *zRow = NULL;
         GLint dZRowOuter = 0, dZRowInner;  /* offset in bytes */
#  endif
         GLuint zLeft = 0;
         GLfixed fdzOuter = 0, fdzInner;
#endif
#ifdef INTERP_RGB
         GLint rLeft = 0, fdrOuter = 0, fdrInner;
         GLint gLeft = 0, fdgOuter = 0, fdgInner;
         GLint bLeft = 0, fdbOuter = 0, fdbInner;
#endif
#ifdef INTERP_ALPHA
         GLint aLeft = 0, fdaOuter = 0, fdaInner;
#endif
#ifdef INTERP_INDEX
         GLfixed iLeft=0, diOuter=0, diInner;
#endif
#ifdef INTERP_INT_TEX
         GLfixed sLeft=0, dsOuter=0, dsInner;
         GLfixed tLeft=0, dtOuter=0, dtInner;
#endif
#ifdef INTERP_ATTRIBS
         GLfloat wLeft = 0, dwOuter = 0, dwInner;
         GLfloat attrLeft[FRAG_ATTRIB_MAX][4];
         GLfloat daOuter[FRAG_ATTRIB_MAX][4], daInner[FRAG_ATTRIB_MAX][4];
#endif

         for (subTriangle=0; subTriangle<=1; subTriangle++) {
            EdgeT *eLeft, *eRight;
            int setupLeft, setupRight;
            int lines;

            if (subTriangle==0) {
               /* bottom half */
               if (scan_from_left_to_right) {
                  eLeft = &eMaj;
                  eRight = &eBot;
                  lines = eRight->lines;
                  setupLeft = 1;
                  setupRight = 1;
               }
               else {
                  eLeft = &eBot;
                  eRight = &eMaj;
                  lines = eLeft->lines;
                  setupLeft = 1;
                  setupRight = 1;
               }
            }
            else {
               /* top half */
               if (scan_from_left_to_right) {
                  eLeft = &eMaj;
                  eRight = &eTop;
                  lines = eRight->lines;
                  setupLeft = 0;
                  setupRight = 1;
               }
               else {
                  eLeft = &eTop;
                  eRight = &eMaj;
                  lines = eLeft->lines;
                  setupLeft = 1;
                  setupRight = 0;
               }
               if (lines == 0)
                  return;
            }

            if (setupLeft && eLeft->lines > 0) {
               const SWvertex *vLower = eLeft->v0;
               const GLfixed fsy = eLeft->fsy;
               const GLfixed fsx = eLeft->fsx;  /* no fractional part */
               const GLfixed fx = FixedCeil(fsx);  /* no fractional part */
               const GLfixed adjx = (GLfixed) (fx - eLeft->fx0); /* SCALED! */
               const GLfixed adjy = (GLfixed) eLeft->adjy;      /* SCALED! */
               GLint idxOuter;
               GLfloat dxOuter;
               GLfixed fdxOuter;

               fError = fx - fsx - FIXED_ONE;
               fxLeftEdge = fsx - FIXED_EPSILON;
               fdxLeftEdge = eLeft->fdxdy;
               fdxOuter = FixedFloor(fdxLeftEdge - FIXED_EPSILON);
               fdError = fdxOuter - fdxLeftEdge + FIXED_ONE;
               idxOuter = FixedToInt(fdxOuter);
               dxOuter = (GLfloat) idxOuter;
               span.y = FixedToInt(fsy);

               /* silence warnings on some compilers */
               (void) dxOuter;
               (void) adjx;
               (void) adjy;
               (void) vLower;

#ifdef PIXEL_ADDRESS
               {
                  pRow = (PIXEL_TYPE *) PIXEL_ADDRESS(FixedToInt(fxLeftEdge), span.y);
                  dPRowOuter = -((int)BYTES_PER_ROW) + idxOuter * sizeof(PIXEL_TYPE);
                  /* negative because Y=0 at bottom and increases upward */
               }
#endif
               /*
                * Now we need the set of parameter (z, color, etc.) values at
                * the point (fx, fsy).  This gives us properly-sampled parameter
                * values that we can step from pixel to pixel.  Furthermore,
                * although we might have intermediate results that overflow
                * the normal parameter range when we step temporarily outside
                * the triangle, we shouldn't overflow or underflow for any
                * pixel that's actually inside the triangle.
                */

#ifdef INTERP_Z
               {
                  GLfloat z0 = vLower->attrib[FRAG_ATTRIB_WPOS][2];
                  if (depthBits <= 16) {
                     /* interpolate fixed-pt values */
                     GLfloat tmp = (z0 * FIXED_SCALE
                                    + span.attrStepX[FRAG_ATTRIB_WPOS][2] * adjx
                                    + span.attrStepY[FRAG_ATTRIB_WPOS][2] * adjy) + FIXED_HALF;
                     if (tmp < MAX_GLUINT / 2)
                        zLeft = (GLfixed) tmp;
                     else
                        zLeft = MAX_GLUINT / 2;
                     fdzOuter = SignedFloatToFixed(span.attrStepY[FRAG_ATTRIB_WPOS][2] +
                                                   dxOuter * span.attrStepX[FRAG_ATTRIB_WPOS][2]);
                  }
                  else {
                     /* interpolate depth values w/out scaling */
                     zLeft = (GLuint) (z0 + span.attrStepX[FRAG_ATTRIB_WPOS][2] * FixedToFloat(adjx)
                                          + span.attrStepY[FRAG_ATTRIB_WPOS][2] * FixedToFloat(adjy));
                     fdzOuter = (GLint) (span.attrStepY[FRAG_ATTRIB_WPOS][2] +
                                         dxOuter * span.attrStepX[FRAG_ATTRIB_WPOS][2]);
                  }
#  ifdef DEPTH_TYPE
                  zRow = (DEPTH_TYPE *)
                    zrb->GetPointer(ctx, zrb, FixedToInt(fxLeftEdge), span.y);
                  dZRowOuter = (ctx->DrawBuffer->Width + idxOuter) * sizeof(DEPTH_TYPE);
#  endif
               }
#endif
#ifdef INTERP_RGB
               if (ctx->Light.ShadeModel == GL_SMOOTH) {
                  rLeft = (GLint)(ChanToFixed(vLower->color[RCOMP])
                                  + span.attrStepX[FRAG_ATTRIB_COL0][0] * adjx
                                  + span.attrStepY[FRAG_ATTRIB_COL0][0] * adjy) + FIXED_HALF;
                  gLeft = (GLint)(ChanToFixed(vLower->color[GCOMP])
                                  + span.attrStepX[FRAG_ATTRIB_COL0][1] * adjx
                                  + span.attrStepY[FRAG_ATTRIB_COL0][1] * adjy) + FIXED_HALF;
                  bLeft = (GLint)(ChanToFixed(vLower->color[BCOMP])
                                  + span.attrStepX[FRAG_ATTRIB_COL0][2] * adjx
                                  + span.attrStepY[FRAG_ATTRIB_COL0][2] * adjy) + FIXED_HALF;
                  fdrOuter = SignedFloatToFixed(span.attrStepY[FRAG_ATTRIB_COL0][0]
                                                + dxOuter * span.attrStepX[FRAG_ATTRIB_COL0][0]);
                  fdgOuter = SignedFloatToFixed(span.attrStepY[FRAG_ATTRIB_COL0][1]
                                                + dxOuter * span.attrStepX[FRAG_ATTRIB_COL0][1]);
                  fdbOuter = SignedFloatToFixed(span.attrStepY[FRAG_ATTRIB_COL0][2]
                                                + dxOuter * span.attrStepX[FRAG_ATTRIB_COL0][2]);
#  ifdef INTERP_ALPHA
                  aLeft = (GLint)(ChanToFixed(vLower->color[ACOMP])
                                  + span.attrStepX[FRAG_ATTRIB_COL0][3] * adjx
                                  + span.attrStepY[FRAG_ATTRIB_COL0][3] * adjy) + FIXED_HALF;
                  fdaOuter = SignedFloatToFixed(span.attrStepY[FRAG_ATTRIB_COL0][3]
                                                + dxOuter * span.attrStepX[FRAG_ATTRIB_COL0][3]);
#  endif
               }
               else {
                  ASSERT(ctx->Light.ShadeModel == GL_FLAT);
                  rLeft = ChanToFixed(v2->color[RCOMP]);
                  gLeft = ChanToFixed(v2->color[GCOMP]);
                  bLeft = ChanToFixed(v2->color[BCOMP]);
                  fdrOuter = fdgOuter = fdbOuter = 0;
#  ifdef INTERP_ALPHA
                  aLeft = ChanToFixed(v2->color[ACOMP]);
                  fdaOuter = 0;
#  endif
               }
#endif /* INTERP_RGB */


#ifdef INTERP_INDEX
               if (ctx->Light.ShadeModel == GL_SMOOTH) {
                  iLeft = (GLfixed)(vLower->attrib[FRAG_ATTRIB_CI][0] * FIXED_SCALE
                                 + didx * adjx + didy * adjy) + FIXED_HALF;
                  diOuter = SignedFloatToFixed(didy + dxOuter * didx);
               }
               else {
                  ASSERT(ctx->Light.ShadeModel == GL_FLAT);
                  iLeft = FloatToFixed(v2->attrib[FRAG_ATTRIB_CI][0]);
                  diOuter = 0;
               }
#endif
#ifdef INTERP_INT_TEX
               {
                  GLfloat s0, t0;
                  s0 = vLower->attrib[FRAG_ATTRIB_TEX0][0] * S_SCALE;
                  sLeft = (GLfixed)(s0 * FIXED_SCALE + span.attrStepX[FRAG_ATTRIB_TEX0][0] * adjx
                                 + span.attrStepY[FRAG_ATTRIB_TEX0][0] * adjy) + FIXED_HALF;
                  dsOuter = SignedFloatToFixed(span.attrStepY[FRAG_ATTRIB_TEX0][0]
                                               + dxOuter * span.attrStepX[FRAG_ATTRIB_TEX0][0]);

                  t0 = vLower->attrib[FRAG_ATTRIB_TEX0][1] * T_SCALE;
                  tLeft = (GLfixed)(t0 * FIXED_SCALE + span.attrStepX[FRAG_ATTRIB_TEX0][1] * adjx
                                 + span.attrStepY[FRAG_ATTRIB_TEX0][1] * adjy) + FIXED_HALF;
                  dtOuter = SignedFloatToFixed(span.attrStepY[FRAG_ATTRIB_TEX0][1]
                                               + dxOuter * span.attrStepX[FRAG_ATTRIB_TEX0][1]);
               }
#endif
#ifdef INTERP_ATTRIBS
               {
                  const GLuint attr = FRAG_ATTRIB_WPOS;
                  wLeft = vLower->attrib[FRAG_ATTRIB_WPOS][3]
                        + (span.attrStepX[attr][3] * adjx
                           + span.attrStepY[attr][3] * adjy) * (1.0F/FIXED_SCALE);
                  dwOuter = span.attrStepY[attr][3] + dxOuter * span.attrStepX[attr][3];
               }
               ATTRIB_LOOP_BEGIN
                  const GLfloat invW = vLower->attrib[FRAG_ATTRIB_WPOS][3];
                  if (swrast->_InterpMode[attr] == GL_FLAT) {
                     GLuint c;
                     for (c = 0; c < 4; c++) {
                        attrLeft[attr][c] = v2->attrib[attr][c] * invW;
                        daOuter[attr][c] = 0.0;
                     }
                  }
                  else {
                     GLuint c;
                     for (c = 0; c < 4; c++) {
                        const GLfloat a = vLower->attrib[attr][c] * invW;
                        attrLeft[attr][c] = a + (  span.attrStepX[attr][c] * adjx
                                                 + span.attrStepY[attr][c] * adjy) * (1.0F/FIXED_SCALE);
                        daOuter[attr][c] = span.attrStepY[attr][c] + dxOuter * span.attrStepX[attr][c];
                     }
                  }
               ATTRIB_LOOP_END
#endif
            } /*if setupLeft*/


            if (setupRight && eRight->lines>0) {
               fxRightEdge = eRight->fsx - FIXED_EPSILON;
               fdxRightEdge = eRight->fdxdy;
            }

            if (lines==0) {
               continue;
            }


            /* Rasterize setup */
#ifdef PIXEL_ADDRESS
            dPRowInner = dPRowOuter + sizeof(PIXEL_TYPE);
#endif
#ifdef INTERP_Z
#  ifdef DEPTH_TYPE
            dZRowInner = dZRowOuter + sizeof(DEPTH_TYPE);
#  endif
            fdzInner = fdzOuter + span.zStep;
#endif
#ifdef INTERP_RGB
            fdrInner = fdrOuter + span.redStep;
            fdgInner = fdgOuter + span.greenStep;
            fdbInner = fdbOuter + span.blueStep;
#endif
#ifdef INTERP_ALPHA
            fdaInner = fdaOuter + span.alphaStep;
#endif
#ifdef INTERP_INDEX
            diInner = diOuter + span.indexStep;
#endif
#ifdef INTERP_INT_TEX
            dsInner = dsOuter + span.intTexStep[0];
            dtInner = dtOuter + span.intTexStep[1];
#endif
#ifdef INTERP_ATTRIBS
            dwInner = dwOuter + span.attrStepX[FRAG_ATTRIB_WPOS][3];
            ATTRIB_LOOP_BEGIN
               GLuint c;
               for (c = 0; c < 4; c++) {
                  daInner[attr][c] = daOuter[attr][c] + span.attrStepX[attr][c];
               }
            ATTRIB_LOOP_END
#endif

            while (lines > 0) {
               /* initialize the span interpolants to the leftmost value */
               /* ff = fixed-pt fragment */
               const GLint right = FixedToInt(fxRightEdge);
               span.x = FixedToInt(fxLeftEdge);
               if (right <= span.x)
                  span.end = 0;
               else
                  span.end = right - span.x;

#ifdef INTERP_Z
               span.z = zLeft;
#endif
#ifdef INTERP_RGB
               span.red = rLeft;
               span.green = gLeft;
               span.blue = bLeft;
#endif
#ifdef INTERP_ALPHA
               span.alpha = aLeft;
#endif
#ifdef INTERP_INDEX
               span.index = iLeft;
#endif
#ifdef INTERP_INT_TEX
               span.intTex[0] = sLeft;
               span.intTex[1] = tLeft;
#endif

#ifdef INTERP_ATTRIBS
               span.attrStart[FRAG_ATTRIB_WPOS][3] = wLeft;
               ATTRIB_LOOP_BEGIN
                  GLuint c;
                  for (c = 0; c < 4; c++) {
                     span.attrStart[attr][c] = attrLeft[attr][c];
                  }
               ATTRIB_LOOP_END
#endif

               /* This is where we actually generate fragments */
               /* XXX the test for span.y > 0 _shouldn't_ be needed but
                * it fixes a problem on 64-bit Opterons (bug 4842).
                */
               if (span.end > 0 && span.y >= 0) {
                  const GLint len = span.end - 1;
                  (void) len;
#ifdef INTERP_RGB
                  CLAMP_INTERPOLANT(red, redStep, len);
                  CLAMP_INTERPOLANT(green, greenStep, len);
                  CLAMP_INTERPOLANT(blue, blueStep, len);
#endif
#ifdef INTERP_ALPHA
                  CLAMP_INTERPOLANT(alpha, alphaStep, len);
#endif
#ifdef INTERP_INDEX
                  CLAMP_INTERPOLANT(index, indexStep, len);
#endif
                  {
                     RENDER_SPAN( span );
                  }
               }

               /*
                * Advance to the next scan line.  Compute the
                * new edge coordinates, and adjust the
                * pixel-center x coordinate so that it stays
                * on or inside the major edge.
                */
               span.y++;
               lines--;

               fxLeftEdge += fdxLeftEdge;
               fxRightEdge += fdxRightEdge;

               fError += fdError;
               if (fError >= 0) {
                  fError -= FIXED_ONE;

#ifdef PIXEL_ADDRESS
                  pRow = (PIXEL_TYPE *) ((GLubyte *) pRow + dPRowOuter);
#endif
#ifdef INTERP_Z
#  ifdef DEPTH_TYPE
                  zRow = (DEPTH_TYPE *) ((GLubyte *) zRow + dZRowOuter);
#  endif
                  zLeft += fdzOuter;
#endif
#ifdef INTERP_RGB
                  rLeft += fdrOuter;
                  gLeft += fdgOuter;
                  bLeft += fdbOuter;
#endif
#ifdef INTERP_ALPHA
                  aLeft += fdaOuter;
#endif
#ifdef INTERP_INDEX
                  iLeft += diOuter;
#endif
#ifdef INTERP_INT_TEX
                  sLeft += dsOuter;
                  tLeft += dtOuter;
#endif
#ifdef INTERP_ATTRIBS
                  wLeft += dwOuter;
                  ATTRIB_LOOP_BEGIN
                     GLuint c;
                     for (c = 0; c < 4; c++) {
                        attrLeft[attr][c] += daOuter[attr][c];
                     }
                  ATTRIB_LOOP_END
#endif
               }
               else {
#ifdef PIXEL_ADDRESS
                  pRow = (PIXEL_TYPE *) ((GLubyte *) pRow + dPRowInner);
#endif
#ifdef INTERP_Z
#  ifdef DEPTH_TYPE
                  zRow = (DEPTH_TYPE *) ((GLubyte *) zRow + dZRowInner);
#  endif
                  zLeft += fdzInner;
#endif
#ifdef INTERP_RGB
                  rLeft += fdrInner;
                  gLeft += fdgInner;
                  bLeft += fdbInner;
#endif
#ifdef INTERP_ALPHA
                  aLeft += fdaInner;
#endif
#ifdef INTERP_INDEX
                  iLeft += diInner;
#endif
#ifdef INTERP_INT_TEX
                  sLeft += dsInner;
                  tLeft += dtInner;
#endif
#ifdef INTERP_ATTRIBS
                  wLeft += dwInner;
                  ATTRIB_LOOP_BEGIN
                     GLuint c;
                     for (c = 0; c < 4; c++) {
                        attrLeft[attr][c] += daInner[attr][c];
                     }
                  ATTRIB_LOOP_END
#endif
               }
            } /*while lines>0*/

         } /* for subTriangle */

      }
   }
}

#undef SETUP_CODE
#undef RENDER_SPAN

#undef PIXEL_TYPE
#undef BYTES_PER_ROW
#undef PIXEL_ADDRESS
#undef DEPTH_TYPE

#undef INTERP_Z
#undef INTERP_RGB
#undef INTERP_ALPHA
#undef INTERP_INDEX
#undef INTERP_INT_TEX
#undef INTERP_ATTRIBS

#undef S_SCALE
#undef T_SCALE

#undef FixedToDepth

#undef NAME