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[mesa.git] / src / mesa / swrast / s_tritemp.h
1 /*
2 * Mesa 3-D graphics library
3 * Version: 6.1
4 *
5 * Copyright (C) 1999-2004 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 * Triangle Rasterizer Template
27 *
28 * This file is #include'd to generate custom triangle rasterizers.
29 *
30 * The following macros may be defined to indicate what auxillary information
31 * must be interplated across the triangle:
32 * INTERP_Z - if defined, interpolate vertex Z values
33 * INTERP_W - if defined, interpolate vertex W values
34 * INTERP_FOG - if defined, interpolate fog values
35 * INTERP_RGB - if defined, interpolate RGB values
36 * INTERP_ALPHA - if defined, interpolate Alpha values (req's INTERP_RGB)
37 * INTERP_SPEC - if defined, interpolate specular RGB values
38 * INTERP_INDEX - if defined, interpolate color index values
39 * INTERP_INT_TEX - if defined, interpolate integer ST texcoords
40 * (fast, simple 2-D texture mapping)
41 * INTERP_TEX - if defined, interpolate set 0 float STRQ texcoords
42 * NOTE: OpenGL STRQ = Mesa STUV (R was taken for red)
43 * INTERP_MULTITEX - if defined, interpolate N units of STRQ texcoords
44 *
45 * When one can directly address pixels in the color buffer the following
46 * macros can be defined and used to compute pixel addresses during
47 * rasterization (see pRow):
48 * PIXEL_TYPE - the datatype of a pixel (GLubyte, GLushort, GLuint)
49 * BYTES_PER_ROW - number of bytes per row in the color buffer
50 * PIXEL_ADDRESS(X,Y) - returns the address of pixel at (X,Y) where
51 * Y==0 at bottom of screen and increases upward.
52 *
53 * Similarly, for direct depth buffer access, this type is used for depth
54 * buffer addressing:
55 * DEPTH_TYPE - either GLushort or GLuint
56 *
57 * Optionally, one may provide one-time setup code per triangle:
58 * SETUP_CODE - code which is to be executed once per triangle
59 * CLEANUP_CODE - code to execute at end of triangle
60 *
61 * The following macro MUST be defined:
62 * RENDER_SPAN(span) - code to write a span of pixels.
63 *
64 * This code was designed for the origin to be in the lower-left corner.
65 *
66 * Inspired by triangle rasterizer code written by Allen Akin. Thanks Allen!
67 *
68 *
69 * Some notes on rasterization accuracy:
70 *
71 * This code uses fixed point arithmetic (the GLfixed type) to iterate
72 * over the triangle edges and interpolate ancillary data (such as Z,
73 * color, secondary color, etc). The number of fractional bits in
74 * GLfixed and the value of SUB_PIXEL_BITS has a direct bearing on the
75 * accuracy of rasterization.
76 *
77 * If SUB_PIXEL_BITS=4 then we'll snap the vertices to the nearest
78 * 1/16 of a pixel. If we're walking up a long, nearly vertical edge
79 * (dx=1/16, dy=1024) we'll need 4 + 10 = 14 fractional bits in
80 * GLfixed to walk the edge without error. If the maximum viewport
81 * height is 4K pixels, then we'll need 4 + 12 = 16 fractional bits.
82 *
83 * Historically, Mesa has used 11 fractional bits in GLfixed, snaps
84 * vertices to 1/16 pixel and allowed a maximum viewport height of 2K
85 * pixels. 11 fractional bits is actually insufficient for accurately
86 * rasterizing some triangles. More recently, the maximum viewport
87 * height was increased to 4K pixels. Thus, Mesa should be using 16
88 * fractional bits in GLfixed. Unfortunately, there may be some issues
89 * with setting FIXED_FRAC_BITS=16, such as multiplication overflow.
90 * This will have to be examined in some detail...
91 *
92 * For now, if you find rasterization errors, particularly with tall,
93 * sliver triangles, try increasing FIXED_FRAC_BITS and/or decreasing
94 * SUB_PIXEL_BITS.
95 */
96
97 /*
98 * ColorTemp is used for intermediate color values.
99 */
100 #if CHAN_TYPE == GL_FLOAT
101 #define ColorTemp GLfloat
102 #else
103 #define ColorTemp GLint /* same as GLfixed */
104 #endif
105
106
107 /*
108 * Walk triangle edges with GLfixed or GLdouble
109 */
110 #if TRIANGLE_WALK_DOUBLE
111 #define GLinterp GLdouble
112 #define InterpToInt(X) ((GLint) (X))
113 #define INTERP_ONE 1.0
114 #else
115 #define GLinterp GLfixed
116 #define InterpToInt(X) FixedToInt(X)
117 #define INTERP_ONE FIXED_ONE
118 #endif
119
120
121 /*
122 * Either loop over all texture units, or just use unit zero.
123 */
124 #ifdef INTERP_MULTITEX
125 #define TEX_UNIT_LOOP(CODE) \
126 { \
127 GLuint u; \
128 for (u = 0; u < ctx->Const.MaxTextureUnits; u++) { \
129 if (ctx->Texture._EnabledCoordUnits & (1 << u)) { \
130 CODE \
131 } \
132 } \
133 }
134 #define INTERP_TEX
135 #elif defined(INTERP_TEX)
136 #define TEX_UNIT_LOOP(CODE) \
137 { \
138 const GLuint u = 0; \
139 CODE \
140 }
141 #endif
142
143
144 static void NAME(GLcontext *ctx, const SWvertex *v0,
145 const SWvertex *v1,
146 const SWvertex *v2 )
147 {
148 typedef struct {
149 const SWvertex *v0, *v1; /* Y(v0) < Y(v1) */
150 #if TRIANGLE_WALK_DOUBLE
151 GLdouble dx; /* X(v1) - X(v0) */
152 GLdouble dy; /* Y(v1) - Y(v0) */
153 GLdouble dxdy; /* dx/dy */
154 GLdouble adjy; /* adjust from v[0]->fy to fsy, scaled */
155 GLdouble fsx; /* first sample point x coord */
156 GLdouble fsy;
157 GLdouble fx0; /*X of lower endpoint */
158 #else
159 GLfloat dx; /* X(v1) - X(v0) */
160 GLfloat dy; /* Y(v1) - Y(v0) */
161 GLfloat dxdy; /* dx/dy */
162 GLfixed fdxdy; /* dx/dy in fixed-point */
163 GLfloat adjy; /* adjust from v[0]->fy to fsy, scaled */
164 GLfixed fsx; /* first sample point x coord */
165 GLfixed fsy;
166 GLfixed fx0; /* fixed pt X of lower endpoint */
167 #endif
168 GLint lines; /* number of lines to be sampled on this edge */
169 } EdgeT;
170
171 #ifdef INTERP_Z
172 const GLint depthBits = ctx->Visual.depthBits;
173 const GLint fixedToDepthShift = depthBits <= 16 ? FIXED_SHIFT : 0;
174 const GLfloat maxDepth = ctx->DepthMaxF;
175 #define FixedToDepth(F) ((F) >> fixedToDepthShift)
176 #endif
177 EdgeT eMaj, eTop, eBot;
178 GLfloat oneOverArea;
179 const SWvertex *vMin, *vMid, *vMax; /* Y(vMin)<=Y(vMid)<=Y(vMax) */
180 GLfloat bf = SWRAST_CONTEXT(ctx)->_BackfaceSign;
181 #if !TRIANGLE_WALK_DOUBLE
182 const GLint snapMask = ~((FIXED_ONE / (1 << SUB_PIXEL_BITS)) - 1); /* for x/y coord snapping */
183 #endif
184 GLinterp vMin_fx, vMin_fy, vMid_fx, vMid_fy, vMax_fx, vMax_fy;
185
186 struct sw_span span;
187
188 INIT_SPAN(span, GL_POLYGON, 0, 0, 0);
189
190 #ifdef INTERP_Z
191 (void) fixedToDepthShift;
192 #endif
193
194 /*
195 printf("%s()\n", __FUNCTION__);
196 printf(" %g, %g, %g\n", v0->win[0], v0->win[1], v0->win[2]);
197 printf(" %g, %g, %g\n", v1->win[0], v1->win[1], v1->win[2]);
198 printf(" %g, %g, %g\n", v2->win[0], v2->win[1], v2->win[2]);
199 */
200 /*
201 ASSERT(v0->win[2] >= 0.0);
202 ASSERT(v1->win[2] >= 0.0);
203 ASSERT(v2->win[2] >= 0.0);
204 */
205 /* Compute fixed point x,y coords w/ half-pixel offsets and snapping.
206 * And find the order of the 3 vertices along the Y axis.
207 */
208 {
209 #if TRIANGLE_WALK_DOUBLE
210 const GLdouble fy0 = v0->win[1] - 0.5;
211 const GLdouble fy1 = v1->win[1] - 0.5;
212 const GLdouble fy2 = v2->win[1] - 0.5;
213 #else
214 const GLfixed fy0 = FloatToFixed(v0->win[1] - 0.5F) & snapMask;
215 const GLfixed fy1 = FloatToFixed(v1->win[1] - 0.5F) & snapMask;
216 const GLfixed fy2 = FloatToFixed(v2->win[1] - 0.5F) & snapMask;
217 #endif
218 if (fy0 <= fy1) {
219 if (fy1 <= fy2) {
220 /* y0 <= y1 <= y2 */
221 vMin = v0; vMid = v1; vMax = v2;
222 vMin_fy = fy0; vMid_fy = fy1; vMax_fy = fy2;
223 }
224 else if (fy2 <= fy0) {
225 /* y2 <= y0 <= y1 */
226 vMin = v2; vMid = v0; vMax = v1;
227 vMin_fy = fy2; vMid_fy = fy0; vMax_fy = fy1;
228 }
229 else {
230 /* y0 <= y2 <= y1 */
231 vMin = v0; vMid = v2; vMax = v1;
232 vMin_fy = fy0; vMid_fy = fy2; vMax_fy = fy1;
233 bf = -bf;
234 }
235 }
236 else {
237 if (fy0 <= fy2) {
238 /* y1 <= y0 <= y2 */
239 vMin = v1; vMid = v0; vMax = v2;
240 vMin_fy = fy1; vMid_fy = fy0; vMax_fy = fy2;
241 bf = -bf;
242 }
243 else if (fy2 <= fy1) {
244 /* y2 <= y1 <= y0 */
245 vMin = v2; vMid = v1; vMax = v0;
246 vMin_fy = fy2; vMid_fy = fy1; vMax_fy = fy0;
247 bf = -bf;
248 }
249 else {
250 /* y1 <= y2 <= y0 */
251 vMin = v1; vMid = v2; vMax = v0;
252 vMin_fy = fy1; vMid_fy = fy2; vMax_fy = fy0;
253 }
254 }
255
256 /* fixed point X coords */
257 #if TRIANGLE_WALK_DOUBLE
258 vMin_fx = vMin->win[0] + 0.5;
259 vMid_fx = vMid->win[0] + 0.5;
260 vMax_fx = vMax->win[0] + 0.5;
261 #else
262 vMin_fx = FloatToFixed(vMin->win[0] + 0.5F) & snapMask;
263 vMid_fx = FloatToFixed(vMid->win[0] + 0.5F) & snapMask;
264 vMax_fx = FloatToFixed(vMax->win[0] + 0.5F) & snapMask;
265 #endif
266 }
267
268 /* vertex/edge relationship */
269 eMaj.v0 = vMin; eMaj.v1 = vMax; /*TODO: .v1's not needed */
270 eTop.v0 = vMid; eTop.v1 = vMax;
271 eBot.v0 = vMin; eBot.v1 = vMid;
272
273 /* compute deltas for each edge: vertex[upper] - vertex[lower] */
274 #if TRIANGLE_WALK_DOUBLE
275 eMaj.dx = vMax_fx - vMin_fx;
276 eMaj.dy = vMax_fy - vMin_fy;
277 eTop.dx = vMax_fx - vMid_fx;
278 eTop.dy = vMax_fy - vMid_fy;
279 eBot.dx = vMid_fx - vMin_fx;
280 eBot.dy = vMid_fy - vMin_fy;
281 #else
282 eMaj.dx = FixedToFloat(vMax_fx - vMin_fx);
283 eMaj.dy = FixedToFloat(vMax_fy - vMin_fy);
284 eTop.dx = FixedToFloat(vMax_fx - vMid_fx);
285 eTop.dy = FixedToFloat(vMax_fy - vMid_fy);
286 eBot.dx = FixedToFloat(vMid_fx - vMin_fx);
287 eBot.dy = FixedToFloat(vMid_fy - vMin_fy);
288 #endif
289
290 /* compute area, oneOverArea and perform backface culling */
291 {
292 #if TRIANGLE_WALK_DOUBLE
293 const GLdouble area = eMaj.dx * eBot.dy - eBot.dx * eMaj.dy;
294 #else
295 const GLfloat area = eMaj.dx * eBot.dy - eBot.dx * eMaj.dy;
296 #endif
297 /* Do backface culling */
298 if (area * bf < 0.0)
299 return;
300
301 if (IS_INF_OR_NAN(area) || area == 0.0F)
302 return;
303
304 oneOverArea = 1.0F / area;
305 }
306
307 span.facing = ctx->_Facing; /* for 2-sided stencil test */
308
309 /* Edge setup. For a triangle strip these could be reused... */
310 {
311 #if TRIANGLE_WALK_DOUBLE
312 eMaj.fsy = CEILF(vMin_fy);
313 eMaj.lines = (GLint) CEILF(vMax_fy - eMaj.fsy);
314 #else
315 eMaj.fsy = FixedCeil(vMin_fy);
316 eMaj.lines = FixedToInt(FixedCeil(vMax_fy - eMaj.fsy));
317 #endif
318 if (eMaj.lines > 0) {
319 eMaj.dxdy = eMaj.dx / eMaj.dy;
320 #if TRIANGLE_WALK_DOUBLE
321 eMaj.adjy = (eMaj.fsy - vMin_fy) * FIXED_SCALE; /* SCALED! */
322 eMaj.fx0 = vMin_fx;
323 eMaj.fsx = eMaj.fx0 + (eMaj.adjy * eMaj.dxdy) / (GLdouble) FIXED_SCALE;
324 #else
325 eMaj.fdxdy = SignedFloatToFixed(eMaj.dxdy);
326 eMaj.adjy = (GLfloat) (eMaj.fsy - vMin_fy); /* SCALED! */
327 eMaj.fx0 = vMin_fx;
328 eMaj.fsx = eMaj.fx0 + (GLfixed) (eMaj.adjy * eMaj.dxdy);
329 #endif
330 }
331 else {
332 return; /*CULLED*/
333 }
334
335 #if TRIANGLE_WALK_DOUBLE
336 eTop.fsy = CEILF(vMid_fy);
337 eTop.lines = (GLint) CEILF(vMax_fy - eTop.fsy);
338 #else
339 eTop.fsy = FixedCeil(vMid_fy);
340 eTop.lines = FixedToInt(FixedCeil(vMax_fy - eTop.fsy));
341 #endif
342 if (eTop.lines > 0) {
343 eTop.dxdy = eTop.dx / eTop.dy;
344 #if TRIANGLE_WALK_DOUBLE
345 eTop.adjy = (eTop.fsy - vMid_fy) * FIXED_SCALE; /* SCALED! */
346 eTop.fx0 = vMid_fx;
347 eTop.fsx = eTop.fx0 + (eTop.adjy * eTop.dxdy) / (GLdouble) FIXED_SCALE;
348 #else
349 eTop.fdxdy = SignedFloatToFixed(eTop.dxdy);
350 eTop.adjy = (GLfloat) (eTop.fsy - vMid_fy); /* SCALED! */
351 eTop.fx0 = vMid_fx;
352 eTop.fsx = eTop.fx0 + (GLfixed) (eTop.adjy * eTop.dxdy);
353 #endif
354 }
355
356 #if TRIANGLE_WALK_DOUBLE
357 eBot.fsy = CEILF(vMin_fy);
358 eBot.lines = (GLint) CEILF(vMid_fy - eBot.fsy);
359 #else
360 eBot.fsy = FixedCeil(vMin_fy);
361 eBot.lines = FixedToInt(FixedCeil(vMid_fy - eBot.fsy));
362 #endif
363 if (eBot.lines > 0) {
364 eBot.dxdy = eBot.dx / eBot.dy;
365 #if TRIANGLE_WALK_DOUBLE
366 eBot.adjy = (eBot.fsy - vMin_fy) * FIXED_SCALE; /* SCALED! */
367 eBot.fx0 = vMin_fx;
368 eBot.fsx = eBot.fx0 + (eBot.adjy * eBot.dxdy) / (GLdouble) FIXED_SCALE;
369 #else
370 eBot.fdxdy = SignedFloatToFixed(eBot.dxdy);
371 eBot.adjy = (GLfloat) (eBot.fsy - vMin_fy); /* SCALED! */
372 eBot.fx0 = vMin_fx;
373 eBot.fsx = eBot.fx0 + (GLfixed) (eBot.adjy * eBot.dxdy);
374 #endif
375 }
376 }
377
378 /*
379 * Conceptually, we view a triangle as two subtriangles
380 * separated by a perfectly horizontal line. The edge that is
381 * intersected by this line is one with maximal absolute dy; we
382 * call it a ``major'' edge. The other two edges are the
383 * ``top'' edge (for the upper subtriangle) and the ``bottom''
384 * edge (for the lower subtriangle). If either of these two
385 * edges is horizontal or very close to horizontal, the
386 * corresponding subtriangle might cover zero sample points;
387 * we take care to handle such cases, for performance as well
388 * as correctness.
389 *
390 * By stepping rasterization parameters along the major edge,
391 * we can avoid recomputing them at the discontinuity where
392 * the top and bottom edges meet. However, this forces us to
393 * be able to scan both left-to-right and right-to-left.
394 * Also, we must determine whether the major edge is at the
395 * left or right side of the triangle. We do this by
396 * computing the magnitude of the cross-product of the major
397 * and top edges. Since this magnitude depends on the sine of
398 * the angle between the two edges, its sign tells us whether
399 * we turn to the left or to the right when travelling along
400 * the major edge to the top edge, and from this we infer
401 * whether the major edge is on the left or the right.
402 *
403 * Serendipitously, this cross-product magnitude is also a
404 * value we need to compute the iteration parameter
405 * derivatives for the triangle, and it can be used to perform
406 * backface culling because its sign tells us whether the
407 * triangle is clockwise or counterclockwise. In this code we
408 * refer to it as ``area'' because it's also proportional to
409 * the pixel area of the triangle.
410 */
411
412 {
413 GLint scan_from_left_to_right; /* true if scanning left-to-right */
414 #ifdef INTERP_INDEX
415 GLfloat didx, didy;
416 #endif
417
418 /*
419 * Execute user-supplied setup code
420 */
421 #ifdef SETUP_CODE
422 SETUP_CODE
423 #endif
424
425 scan_from_left_to_right = (oneOverArea < 0.0F);
426
427
428 /* compute d?/dx and d?/dy derivatives */
429 #ifdef INTERP_Z
430 span.interpMask |= SPAN_Z;
431 {
432 GLfloat eMaj_dz = vMax->win[2] - vMin->win[2];
433 GLfloat eBot_dz = vMid->win[2] - vMin->win[2];
434 span.dzdx = oneOverArea * (eMaj_dz * eBot.dy - eMaj.dy * eBot_dz);
435 if (span.dzdx > maxDepth || span.dzdx < -maxDepth) {
436 /* probably a sliver triangle */
437 span.dzdx = 0.0;
438 span.dzdy = 0.0;
439 }
440 else {
441 span.dzdy = oneOverArea * (eMaj.dx * eBot_dz - eMaj_dz * eBot.dx);
442 }
443 if (depthBits <= 16)
444 span.zStep = SignedFloatToFixed(span.dzdx);
445 else
446 span.zStep = (GLint) span.dzdx;
447 }
448 #endif
449 #ifdef INTERP_W
450 span.interpMask |= SPAN_W;
451 {
452 const GLfloat eMaj_dw = vMax->win[3] - vMin->win[3];
453 const GLfloat eBot_dw = vMid->win[3] - vMin->win[3];
454 span.dwdx = oneOverArea * (eMaj_dw * eBot.dy - eMaj.dy * eBot_dw);
455 span.dwdy = oneOverArea * (eMaj.dx * eBot_dw - eMaj_dw * eBot.dx);
456 }
457 #endif
458 #ifdef INTERP_FOG
459 span.interpMask |= SPAN_FOG;
460 {
461 # ifdef INTERP_W
462 const GLfloat wMax = vMax->win[3], wMin = vMin->win[3], wMid = vMid->win[3];
463 const GLfloat eMaj_dfog = vMax->fog * wMax - vMin->fog * wMin;
464 const GLfloat eBot_dfog = vMid->fog * wMid - vMin->fog * wMin;
465 # else
466 const GLfloat eMaj_dfog = vMax->fog - vMin->fog;
467 const GLfloat eBot_dfog = vMid->fog - vMin->fog;
468 # endif
469 span.dfogdx = oneOverArea * (eMaj_dfog * eBot.dy - eMaj.dy * eBot_dfog);
470 span.dfogdy = oneOverArea * (eMaj.dx * eBot_dfog - eMaj_dfog * eBot.dx);
471 span.fogStep = span.dfogdx;
472 }
473 #endif
474 #ifdef INTERP_RGB
475 span.interpMask |= SPAN_RGBA;
476 if (ctx->Light.ShadeModel == GL_SMOOTH) {
477 GLfloat eMaj_dr = (GLfloat) ((ColorTemp) vMax->color[RCOMP] - (ColorTemp) vMin->color[RCOMP]);
478 GLfloat eBot_dr = (GLfloat) ((ColorTemp) vMid->color[RCOMP] - (ColorTemp) vMin->color[RCOMP]);
479 GLfloat eMaj_dg = (GLfloat) ((ColorTemp) vMax->color[GCOMP] - (ColorTemp) vMin->color[GCOMP]);
480 GLfloat eBot_dg = (GLfloat) ((ColorTemp) vMid->color[GCOMP] - (ColorTemp) vMin->color[GCOMP]);
481 GLfloat eMaj_db = (GLfloat) ((ColorTemp) vMax->color[BCOMP] - (ColorTemp) vMin->color[BCOMP]);
482 GLfloat eBot_db = (GLfloat) ((ColorTemp) vMid->color[BCOMP] - (ColorTemp) vMin->color[BCOMP]);
483 # ifdef INTERP_ALPHA
484 GLfloat eMaj_da = (GLfloat) ((ColorTemp) vMax->color[ACOMP] - (ColorTemp) vMin->color[ACOMP]);
485 GLfloat eBot_da = (GLfloat) ((ColorTemp) vMid->color[ACOMP] - (ColorTemp) vMin->color[ACOMP]);
486 # endif
487 span.drdx = oneOverArea * (eMaj_dr * eBot.dy - eMaj.dy * eBot_dr);
488 span.drdy = oneOverArea * (eMaj.dx * eBot_dr - eMaj_dr * eBot.dx);
489 span.dgdx = oneOverArea * (eMaj_dg * eBot.dy - eMaj.dy * eBot_dg);
490 span.dgdy = oneOverArea * (eMaj.dx * eBot_dg - eMaj_dg * eBot.dx);
491 span.dbdx = oneOverArea * (eMaj_db * eBot.dy - eMaj.dy * eBot_db);
492 span.dbdy = oneOverArea * (eMaj.dx * eBot_db - eMaj_db * eBot.dx);
493 # if CHAN_TYPE == GL_FLOAT
494 span.redStep = span.drdx;
495 span.greenStep = span.dgdx;
496 span.blueStep = span.dbdx;
497 # else
498 span.redStep = SignedFloatToFixed(span.drdx);
499 span.greenStep = SignedFloatToFixed(span.dgdx);
500 span.blueStep = SignedFloatToFixed(span.dbdx);
501 # endif /* GL_FLOAT */
502 # ifdef INTERP_ALPHA
503 span.dadx = oneOverArea * (eMaj_da * eBot.dy - eMaj.dy * eBot_da);
504 span.dady = oneOverArea * (eMaj.dx * eBot_da - eMaj_da * eBot.dx);
505 # if CHAN_TYPE == GL_FLOAT
506 span.alphaStep = span.dadx;
507 # else
508 span.alphaStep = SignedFloatToFixed(span.dadx);
509 # endif /* GL_FLOAT */
510 # endif /* INTERP_ALPHA */
511 }
512 else {
513 ASSERT (ctx->Light.ShadeModel == GL_FLAT);
514 span.interpMask |= SPAN_FLAT;
515 span.drdx = span.drdy = 0.0F;
516 span.dgdx = span.dgdy = 0.0F;
517 span.dbdx = span.dbdy = 0.0F;
518 # if CHAN_TYPE == GL_FLOAT
519 span.redStep = 0.0F;
520 span.greenStep = 0.0F;
521 span.blueStep = 0.0F;
522 # else
523 span.redStep = 0;
524 span.greenStep = 0;
525 span.blueStep = 0;
526 # endif /* GL_FLOAT */
527 # ifdef INTERP_ALPHA
528 span.dadx = span.dady = 0.0F;
529 # if CHAN_TYPE == GL_FLOAT
530 span.alphaStep = 0.0F;
531 # else
532 span.alphaStep = 0;
533 # endif /* GL_FLOAT */
534 # endif
535 }
536 #endif /* INTERP_RGB */
537 #ifdef INTERP_SPEC
538 span.interpMask |= SPAN_SPEC;
539 if (ctx->Light.ShadeModel == GL_SMOOTH) {
540 GLfloat eMaj_dsr = (GLfloat) ((ColorTemp) vMax->specular[RCOMP] - (ColorTemp) vMin->specular[RCOMP]);
541 GLfloat eBot_dsr = (GLfloat) ((ColorTemp) vMid->specular[RCOMP] - (ColorTemp) vMin->specular[RCOMP]);
542 GLfloat eMaj_dsg = (GLfloat) ((ColorTemp) vMax->specular[GCOMP] - (ColorTemp) vMin->specular[GCOMP]);
543 GLfloat eBot_dsg = (GLfloat) ((ColorTemp) vMid->specular[GCOMP] - (ColorTemp) vMin->specular[GCOMP]);
544 GLfloat eMaj_dsb = (GLfloat) ((ColorTemp) vMax->specular[BCOMP] - (ColorTemp) vMin->specular[BCOMP]);
545 GLfloat eBot_dsb = (GLfloat) ((ColorTemp) vMid->specular[BCOMP] - (ColorTemp) vMin->specular[BCOMP]);
546 span.dsrdx = oneOverArea * (eMaj_dsr * eBot.dy - eMaj.dy * eBot_dsr);
547 span.dsrdy = oneOverArea * (eMaj.dx * eBot_dsr - eMaj_dsr * eBot.dx);
548 span.dsgdx = oneOverArea * (eMaj_dsg * eBot.dy - eMaj.dy * eBot_dsg);
549 span.dsgdy = oneOverArea * (eMaj.dx * eBot_dsg - eMaj_dsg * eBot.dx);
550 span.dsbdx = oneOverArea * (eMaj_dsb * eBot.dy - eMaj.dy * eBot_dsb);
551 span.dsbdy = oneOverArea * (eMaj.dx * eBot_dsb - eMaj_dsb * eBot.dx);
552 # if CHAN_TYPE == GL_FLOAT
553 span.specRedStep = span.dsrdx;
554 span.specGreenStep = span.dsgdx;
555 span.specBlueStep = span.dsbdx;
556 # else
557 span.specRedStep = SignedFloatToFixed(span.dsrdx);
558 span.specGreenStep = SignedFloatToFixed(span.dsgdx);
559 span.specBlueStep = SignedFloatToFixed(span.dsbdx);
560 # endif
561 }
562 else {
563 span.dsrdx = span.dsrdy = 0.0F;
564 span.dsgdx = span.dsgdy = 0.0F;
565 span.dsbdx = span.dsbdy = 0.0F;
566 # if CHAN_TYPE == GL_FLOAT
567 span.specRedStep = 0.0F;
568 span.specGreenStep = 0.0F;
569 span.specBlueStep = 0.0F;
570 # else
571 span.specRedStep = 0;
572 span.specGreenStep = 0;
573 span.specBlueStep = 0;
574 # endif
575 }
576 #endif /* INTERP_SPEC */
577 #ifdef INTERP_INDEX
578 span.interpMask |= SPAN_INDEX;
579 if (ctx->Light.ShadeModel == GL_SMOOTH) {
580 GLfloat eMaj_di = vMax->index - vMin->index;
581 GLfloat eBot_di = vMid->index - vMin->index;
582 didx = oneOverArea * (eMaj_di * eBot.dy - eMaj.dy * eBot_di);
583 didy = oneOverArea * (eMaj.dx * eBot_di - eMaj_di * eBot.dx);
584 span.indexStep = SignedFloatToFixed(didx);
585 }
586 else {
587 span.interpMask |= SPAN_FLAT;
588 didx = didy = 0.0F;
589 span.indexStep = 0;
590 }
591 #endif
592 #ifdef INTERP_INT_TEX
593 span.interpMask |= SPAN_INT_TEXTURE;
594 {
595 GLfloat eMaj_ds = (vMax->texcoord[0][0] - vMin->texcoord[0][0]) * S_SCALE;
596 GLfloat eBot_ds = (vMid->texcoord[0][0] - vMin->texcoord[0][0]) * S_SCALE;
597 GLfloat eMaj_dt = (vMax->texcoord[0][1] - vMin->texcoord[0][1]) * T_SCALE;
598 GLfloat eBot_dt = (vMid->texcoord[0][1] - vMin->texcoord[0][1]) * T_SCALE;
599 span.texStepX[0][0] = oneOverArea * (eMaj_ds * eBot.dy - eMaj.dy * eBot_ds);
600 span.texStepY[0][0] = oneOverArea * (eMaj.dx * eBot_ds - eMaj_ds * eBot.dx);
601 span.texStepX[0][1] = oneOverArea * (eMaj_dt * eBot.dy - eMaj.dy * eBot_dt);
602 span.texStepY[0][1] = oneOverArea * (eMaj.dx * eBot_dt - eMaj_dt * eBot.dx);
603 span.intTexStep[0] = SignedFloatToFixed(span.texStepX[0][0]);
604 span.intTexStep[1] = SignedFloatToFixed(span.texStepX[0][1]);
605 }
606 #endif
607 #ifdef INTERP_TEX
608 span.interpMask |= SPAN_TEXTURE;
609 {
610 /* win[3] is 1/W */
611 const GLfloat wMax = vMax->win[3], wMin = vMin->win[3], wMid = vMid->win[3];
612 TEX_UNIT_LOOP(
613 GLfloat eMaj_ds = vMax->texcoord[u][0] * wMax - vMin->texcoord[u][0] * wMin;
614 GLfloat eBot_ds = vMid->texcoord[u][0] * wMid - vMin->texcoord[u][0] * wMin;
615 GLfloat eMaj_dt = vMax->texcoord[u][1] * wMax - vMin->texcoord[u][1] * wMin;
616 GLfloat eBot_dt = vMid->texcoord[u][1] * wMid - vMin->texcoord[u][1] * wMin;
617 GLfloat eMaj_du = vMax->texcoord[u][2] * wMax - vMin->texcoord[u][2] * wMin;
618 GLfloat eBot_du = vMid->texcoord[u][2] * wMid - vMin->texcoord[u][2] * wMin;
619 GLfloat eMaj_dv = vMax->texcoord[u][3] * wMax - vMin->texcoord[u][3] * wMin;
620 GLfloat eBot_dv = vMid->texcoord[u][3] * wMid - vMin->texcoord[u][3] * wMin;
621 span.texStepX[u][0] = oneOverArea * (eMaj_ds * eBot.dy - eMaj.dy * eBot_ds);
622 span.texStepY[u][0] = oneOverArea * (eMaj.dx * eBot_ds - eMaj_ds * eBot.dx);
623 span.texStepX[u][1] = oneOverArea * (eMaj_dt * eBot.dy - eMaj.dy * eBot_dt);
624 span.texStepY[u][1] = oneOverArea * (eMaj.dx * eBot_dt - eMaj_dt * eBot.dx);
625 span.texStepX[u][2] = oneOverArea * (eMaj_du * eBot.dy - eMaj.dy * eBot_du);
626 span.texStepY[u][2] = oneOverArea * (eMaj.dx * eBot_du - eMaj_du * eBot.dx);
627 span.texStepX[u][3] = oneOverArea * (eMaj_dv * eBot.dy - eMaj.dy * eBot_dv);
628 span.texStepY[u][3] = oneOverArea * (eMaj.dx * eBot_dv - eMaj_dv * eBot.dx);
629 )
630 }
631 #endif
632
633 /*
634 * We always sample at pixel centers. However, we avoid
635 * explicit half-pixel offsets in this code by incorporating
636 * the proper offset in each of x and y during the
637 * transformation to window coordinates.
638 *
639 * We also apply the usual rasterization rules to prevent
640 * cracks and overlaps. A pixel is considered inside a
641 * subtriangle if it meets all of four conditions: it is on or
642 * to the right of the left edge, strictly to the left of the
643 * right edge, on or below the top edge, and strictly above
644 * the bottom edge. (Some edges may be degenerate.)
645 *
646 * The following discussion assumes left-to-right scanning
647 * (that is, the major edge is on the left); the right-to-left
648 * case is a straightforward variation.
649 *
650 * We start by finding the half-integral y coordinate that is
651 * at or below the top of the triangle. This gives us the
652 * first scan line that could possibly contain pixels that are
653 * inside the triangle.
654 *
655 * Next we creep down the major edge until we reach that y,
656 * and compute the corresponding x coordinate on the edge.
657 * Then we find the half-integral x that lies on or just
658 * inside the edge. This is the first pixel that might lie in
659 * the interior of the triangle. (We won't know for sure
660 * until we check the other edges.)
661 *
662 * As we rasterize the triangle, we'll step down the major
663 * edge. For each step in y, we'll move an integer number
664 * of steps in x. There are two possible x step sizes, which
665 * we'll call the ``inner'' step (guaranteed to land on the
666 * edge or inside it) and the ``outer'' step (guaranteed to
667 * land on the edge or outside it). The inner and outer steps
668 * differ by one. During rasterization we maintain an error
669 * term that indicates our distance from the true edge, and
670 * select either the inner step or the outer step, whichever
671 * gets us to the first pixel that falls inside the triangle.
672 *
673 * All parameters (z, red, etc.) as well as the buffer
674 * addresses for color and z have inner and outer step values,
675 * so that we can increment them appropriately. This method
676 * eliminates the need to adjust parameters by creeping a
677 * sub-pixel amount into the triangle at each scanline.
678 */
679
680 {
681 GLint subTriangle;
682 GLinterp fxLeftEdge = 0, fxRightEdge = 0;
683 GLinterp fdxLeftEdge = 0, fdxRightEdge = 0;
684 GLinterp fError = 0, fdError = 0;
685 #ifdef PIXEL_ADDRESS
686 PIXEL_TYPE *pRow = NULL;
687 GLint dPRowOuter = 0, dPRowInner; /* offset in bytes */
688 #endif
689 #ifdef INTERP_Z
690 # ifdef DEPTH_TYPE
691 DEPTH_TYPE *zRow = NULL;
692 GLint dZRowOuter = 0, dZRowInner; /* offset in bytes */
693 # endif
694 GLfixed zLeft = 0, fdzOuter = 0, fdzInner;
695 #endif
696 #ifdef INTERP_W
697 GLfloat wLeft = 0, dwOuter = 0, dwInner;
698 #endif
699 #ifdef INTERP_FOG
700 GLfloat fogLeft = 0, dfogOuter = 0, dfogInner;
701 #endif
702 #ifdef INTERP_RGB
703 ColorTemp rLeft = 0, fdrOuter = 0, fdrInner;
704 ColorTemp gLeft = 0, fdgOuter = 0, fdgInner;
705 ColorTemp bLeft = 0, fdbOuter = 0, fdbInner;
706 #endif
707 #ifdef INTERP_ALPHA
708 ColorTemp aLeft = 0, fdaOuter = 0, fdaInner;
709 #endif
710 #ifdef INTERP_SPEC
711 ColorTemp srLeft=0, dsrOuter=0, dsrInner;
712 ColorTemp sgLeft=0, dsgOuter=0, dsgInner;
713 ColorTemp sbLeft=0, dsbOuter=0, dsbInner;
714 #endif
715 #ifdef INTERP_INDEX
716 GLfixed iLeft=0, diOuter=0, diInner;
717 #endif
718 #ifdef INTERP_INT_TEX
719 GLfixed sLeft=0, dsOuter=0, dsInner;
720 GLfixed tLeft=0, dtOuter=0, dtInner;
721 #endif
722 #ifdef INTERP_TEX
723 GLfloat sLeft[MAX_TEXTURE_COORD_UNITS];
724 GLfloat tLeft[MAX_TEXTURE_COORD_UNITS];
725 GLfloat uLeft[MAX_TEXTURE_COORD_UNITS];
726 GLfloat vLeft[MAX_TEXTURE_COORD_UNITS];
727 GLfloat dsOuter[MAX_TEXTURE_COORD_UNITS], dsInner[MAX_TEXTURE_COORD_UNITS];
728 GLfloat dtOuter[MAX_TEXTURE_COORD_UNITS], dtInner[MAX_TEXTURE_COORD_UNITS];
729 GLfloat duOuter[MAX_TEXTURE_COORD_UNITS], duInner[MAX_TEXTURE_COORD_UNITS];
730 GLfloat dvOuter[MAX_TEXTURE_COORD_UNITS], dvInner[MAX_TEXTURE_COORD_UNITS];
731 #endif
732
733 for (subTriangle=0; subTriangle<=1; subTriangle++) {
734 EdgeT *eLeft, *eRight;
735 int setupLeft, setupRight;
736 int lines;
737
738 if (subTriangle==0) {
739 /* bottom half */
740 if (scan_from_left_to_right) {
741 eLeft = &eMaj;
742 eRight = &eBot;
743 lines = eRight->lines;
744 setupLeft = 1;
745 setupRight = 1;
746 }
747 else {
748 eLeft = &eBot;
749 eRight = &eMaj;
750 lines = eLeft->lines;
751 setupLeft = 1;
752 setupRight = 1;
753 }
754 }
755 else {
756 /* top half */
757 if (scan_from_left_to_right) {
758 eLeft = &eMaj;
759 eRight = &eTop;
760 lines = eRight->lines;
761 setupLeft = 0;
762 setupRight = 1;
763 }
764 else {
765 eLeft = &eTop;
766 eRight = &eMaj;
767 lines = eLeft->lines;
768 setupLeft = 1;
769 setupRight = 0;
770 }
771 if (lines == 0)
772 return;
773 }
774
775 if (setupLeft && eLeft->lines > 0) {
776 const SWvertex *vLower = eLeft->v0;
777 #if TRIANGLE_WALK_DOUBLE
778 const GLdouble fsy = eLeft->fsy;
779 const GLdouble fsx = eLeft->fsx;
780 const GLdouble fx = CEILF(fsx);
781 const GLdouble adjx = (fx - eLeft->fx0) * FIXED_SCALE; /* SCALED! */
782 #else
783 const GLfixed fsy = eLeft->fsy;
784 const GLfixed fsx = eLeft->fsx; /* no fractional part */
785 const GLfixed fx = FixedCeil(fsx); /* no fractional part */
786 const GLfixed adjx = (GLinterp) (fx - eLeft->fx0); /* SCALED! */
787 #endif
788 const GLinterp adjy = (GLinterp) eLeft->adjy; /* SCALED! */
789 GLint idxOuter;
790 #if TRIANGLE_WALK_DOUBLE
791 GLdouble dxOuter;
792
793 fError = fx - fsx - 1.0;
794 fxLeftEdge = fsx;
795 fdxLeftEdge = eLeft->dxdy;
796 dxOuter = FLOORF(fdxLeftEdge);
797 fdError = dxOuter - fdxLeftEdge + 1.0;
798 idxOuter = (GLint) dxOuter;
799 span.y = (GLint) fsy;
800 #else
801 GLfloat dxOuter;
802 GLfixed fdxOuter;
803
804 fError = fx - fsx - FIXED_ONE;
805 fxLeftEdge = fsx - FIXED_EPSILON;
806 fdxLeftEdge = eLeft->fdxdy;
807 fdxOuter = FixedFloor(fdxLeftEdge - FIXED_EPSILON);
808 fdError = fdxOuter - fdxLeftEdge + FIXED_ONE;
809 idxOuter = FixedToInt(fdxOuter);
810 dxOuter = (GLfloat) idxOuter;
811 span.y = FixedToInt(fsy);
812 #endif
813
814 /* silence warnings on some compilers */
815 (void) dxOuter;
816 (void) adjx;
817 (void) adjy;
818 (void) vLower;
819
820 #ifdef PIXEL_ADDRESS
821 {
822 pRow = (PIXEL_TYPE *) PIXEL_ADDRESS(InterpToInt(fxLeftEdge), span.y);
823 dPRowOuter = -((int)BYTES_PER_ROW) + idxOuter * sizeof(PIXEL_TYPE);
824 /* negative because Y=0 at bottom and increases upward */
825 }
826 #endif
827 /*
828 * Now we need the set of parameter (z, color, etc.) values at
829 * the point (fx, fsy). This gives us properly-sampled parameter
830 * values that we can step from pixel to pixel. Furthermore,
831 * although we might have intermediate results that overflow
832 * the normal parameter range when we step temporarily outside
833 * the triangle, we shouldn't overflow or underflow for any
834 * pixel that's actually inside the triangle.
835 */
836
837 #ifdef INTERP_Z
838 {
839 GLfloat z0 = vLower->win[2];
840 if (depthBits <= 16) {
841 /* interpolate fixed-pt values */
842 GLfloat tmp = (z0 * FIXED_SCALE + span.dzdx * adjx + span.dzdy * adjy) + FIXED_HALF;
843 if (tmp < MAX_GLUINT / 2)
844 zLeft = (GLfixed) tmp;
845 else
846 zLeft = MAX_GLUINT / 2;
847 fdzOuter = SignedFloatToFixed(span.dzdy + dxOuter * span.dzdx);
848 }
849 else {
850 /* interpolate depth values exactly */
851 zLeft = (GLint) (z0 + span.dzdx * FixedToFloat(adjx) + span.dzdy * FixedToFloat(adjy));
852 fdzOuter = (GLint) (span.dzdy + dxOuter * span.dzdx);
853 }
854 # ifdef DEPTH_TYPE
855 zRow = (DEPTH_TYPE *)
856 _swrast_zbuffer_address(ctx, InterpToInt(fxLeftEdge), span.y);
857 dZRowOuter = (ctx->DrawBuffer->Width + idxOuter) * sizeof(DEPTH_TYPE);
858 # endif
859 }
860 #endif
861 #ifdef INTERP_W
862 wLeft = vLower->win[3] + (span.dwdx * adjx + span.dwdy * adjy) * (1.0F/FIXED_SCALE);
863 dwOuter = span.dwdy + dxOuter * span.dwdx;
864 #endif
865 #ifdef INTERP_FOG
866 # ifdef INTERP_W
867 fogLeft = vLower->fog * vLower->win[3] + (span.dfogdx * adjx + span.dfogdy * adjy) * (1.0F/FIXED_SCALE);
868 # else
869 fogLeft = vLower->fog + (span.dfogdx * adjx + span.dfogdy * adjy) * (1.0F/FIXED_SCALE);
870 # endif
871 dfogOuter = span.dfogdy + dxOuter * span.dfogdx;
872 #endif
873 #ifdef INTERP_RGB
874 if (ctx->Light.ShadeModel == GL_SMOOTH) {
875 # if CHAN_TYPE == GL_FLOAT
876 rLeft = vLower->color[RCOMP] + (span.drdx * adjx + span.drdy * adjy) * (1.0F / FIXED_SCALE);
877 gLeft = vLower->color[GCOMP] + (span.dgdx * adjx + span.dgdy * adjy) * (1.0F / FIXED_SCALE);
878 bLeft = vLower->color[BCOMP] + (span.dbdx * adjx + span.dbdy * adjy) * (1.0F / FIXED_SCALE);
879 fdrOuter = span.drdy + dxOuter * span.drdx;
880 fdgOuter = span.dgdy + dxOuter * span.dgdx;
881 fdbOuter = span.dbdy + dxOuter * span.dbdx;
882 # else
883 rLeft = (GLint)(ChanToFixed(vLower->color[RCOMP]) + span.drdx * adjx + span.drdy * adjy) + FIXED_HALF;
884 gLeft = (GLint)(ChanToFixed(vLower->color[GCOMP]) + span.dgdx * adjx + span.dgdy * adjy) + FIXED_HALF;
885 bLeft = (GLint)(ChanToFixed(vLower->color[BCOMP]) + span.dbdx * adjx + span.dbdy * adjy) + FIXED_HALF;
886 fdrOuter = SignedFloatToFixed(span.drdy + dxOuter * span.drdx);
887 fdgOuter = SignedFloatToFixed(span.dgdy + dxOuter * span.dgdx);
888 fdbOuter = SignedFloatToFixed(span.dbdy + dxOuter * span.dbdx);
889 # endif
890 # ifdef INTERP_ALPHA
891 # if CHAN_TYPE == GL_FLOAT
892 aLeft = vLower->color[ACOMP] + (span.dadx * adjx + span.dady * adjy) * (1.0F / FIXED_SCALE);
893 fdaOuter = span.dady + dxOuter * span.dadx;
894 # else
895 aLeft = (GLint)(ChanToFixed(vLower->color[ACOMP]) + span.dadx * adjx + span.dady * adjy) + FIXED_HALF;
896 fdaOuter = SignedFloatToFixed(span.dady + dxOuter * span.dadx);
897 # endif
898 # endif
899 }
900 else {
901 ASSERT (ctx->Light.ShadeModel == GL_FLAT);
902 # if CHAN_TYPE == GL_FLOAT
903 rLeft = v2->color[RCOMP];
904 gLeft = v2->color[GCOMP];
905 bLeft = v2->color[BCOMP];
906 fdrOuter = fdgOuter = fdbOuter = 0.0F;
907 # else
908 rLeft = ChanToFixed(v2->color[RCOMP]);
909 gLeft = ChanToFixed(v2->color[GCOMP]);
910 bLeft = ChanToFixed(v2->color[BCOMP]);
911 fdrOuter = fdgOuter = fdbOuter = 0;
912 # endif
913 # ifdef INTERP_ALPHA
914 # if CHAN_TYPE == GL_FLOAT
915 aLeft = v2->color[ACOMP];
916 fdaOuter = 0.0F;
917 # else
918 aLeft = ChanToFixed(v2->color[ACOMP]);
919 fdaOuter = 0;
920 # endif
921 # endif
922 }
923 #endif
924
925 #ifdef INTERP_SPEC
926 if (ctx->Light.ShadeModel == GL_SMOOTH) {
927 # if CHAN_TYPE == GL_FLOAT
928 srLeft = vLower->specular[RCOMP] + (span.dsrdx * adjx + span.dsrdy * adjy) * (1.0F / FIXED_SCALE);
929 sgLeft = vLower->specular[GCOMP] + (span.dsgdx * adjx + span.dsgdy * adjy) * (1.0F / FIXED_SCALE);
930 sbLeft = vLower->specular[BCOMP] + (span.dsbdx * adjx + span.dsbdy * adjy) * (1.0F / FIXED_SCALE);
931 dsrOuter = span.dsrdy + dxOuter * span.dsrdx;
932 dsgOuter = span.dsgdy + dxOuter * span.dsgdx;
933 dsbOuter = span.dsbdy + dxOuter * span.dsbdx;
934 # else
935 srLeft = (GLfixed) (ChanToFixed(vLower->specular[RCOMP]) + span.dsrdx * adjx + span.dsrdy * adjy) + FIXED_HALF;
936 sgLeft = (GLfixed) (ChanToFixed(vLower->specular[GCOMP]) + span.dsgdx * adjx + span.dsgdy * adjy) + FIXED_HALF;
937 sbLeft = (GLfixed) (ChanToFixed(vLower->specular[BCOMP]) + span.dsbdx * adjx + span.dsbdy * adjy) + FIXED_HALF;
938 dsrOuter = SignedFloatToFixed(span.dsrdy + dxOuter * span.dsrdx);
939 dsgOuter = SignedFloatToFixed(span.dsgdy + dxOuter * span.dsgdx);
940 dsbOuter = SignedFloatToFixed(span.dsbdy + dxOuter * span.dsbdx);
941 # endif
942 }
943 else {
944 #if CHAN_TYPE == GL_FLOAT
945 srLeft = v2->specular[RCOMP];
946 sgLeft = v2->specular[GCOMP];
947 sbLeft = v2->specular[BCOMP];
948 dsrOuter = dsgOuter = dsbOuter = 0.0F;
949 # else
950 srLeft = ChanToFixed(v2->specular[RCOMP]);
951 sgLeft = ChanToFixed(v2->specular[GCOMP]);
952 sbLeft = ChanToFixed(v2->specular[BCOMP]);
953 dsrOuter = dsgOuter = dsbOuter = 0;
954 # endif
955 }
956 #endif
957
958 #ifdef INTERP_INDEX
959 if (ctx->Light.ShadeModel == GL_SMOOTH) {
960 iLeft = (GLfixed)(vLower->index * FIXED_SCALE
961 + didx * adjx + didy * adjy) + FIXED_HALF;
962 diOuter = SignedFloatToFixed(didy + dxOuter * didx);
963 }
964 else {
965 iLeft = FloatToFixed(v2->index);
966 diOuter = 0;
967 }
968 #endif
969 #ifdef INTERP_INT_TEX
970 {
971 GLfloat s0, t0;
972 s0 = vLower->texcoord[0][0] * S_SCALE;
973 sLeft = (GLfixed)(s0 * FIXED_SCALE + span.texStepX[0][0] * adjx
974 + span.texStepY[0][0] * adjy) + FIXED_HALF;
975 dsOuter = SignedFloatToFixed(span.texStepY[0][0] + dxOuter * span.texStepX[0][0]);
976
977 t0 = vLower->texcoord[0][1] * T_SCALE;
978 tLeft = (GLfixed)(t0 * FIXED_SCALE + span.texStepX[0][1] * adjx
979 + span.texStepY[0][1] * adjy) + FIXED_HALF;
980 dtOuter = SignedFloatToFixed(span.texStepY[0][1] + dxOuter * span.texStepX[0][1]);
981 }
982 #endif
983 #ifdef INTERP_TEX
984 TEX_UNIT_LOOP(
985 const GLfloat invW = vLower->win[3];
986 const GLfloat s0 = vLower->texcoord[u][0] * invW;
987 const GLfloat t0 = vLower->texcoord[u][1] * invW;
988 const GLfloat u0 = vLower->texcoord[u][2] * invW;
989 const GLfloat v0 = vLower->texcoord[u][3] * invW;
990 sLeft[u] = s0 + (span.texStepX[u][0] * adjx + span.texStepY[u][0] * adjy) * (1.0F/FIXED_SCALE);
991 tLeft[u] = t0 + (span.texStepX[u][1] * adjx + span.texStepY[u][1] * adjy) * (1.0F/FIXED_SCALE);
992 uLeft[u] = u0 + (span.texStepX[u][2] * adjx + span.texStepY[u][2] * adjy) * (1.0F/FIXED_SCALE);
993 vLeft[u] = v0 + (span.texStepX[u][3] * adjx + span.texStepY[u][3] * adjy) * (1.0F/FIXED_SCALE);
994 dsOuter[u] = span.texStepY[u][0] + dxOuter * span.texStepX[u][0];
995 dtOuter[u] = span.texStepY[u][1] + dxOuter * span.texStepX[u][1];
996 duOuter[u] = span.texStepY[u][2] + dxOuter * span.texStepX[u][2];
997 dvOuter[u] = span.texStepY[u][3] + dxOuter * span.texStepX[u][3];
998 )
999 #endif
1000 } /*if setupLeft*/
1001
1002
1003 if (setupRight && eRight->lines>0) {
1004 #if TRIANGLE_WALK_DOUBLE
1005 fxRightEdge = eRight->fsx;
1006 fdxRightEdge = eRight->dxdy;
1007 #else
1008 fxRightEdge = eRight->fsx - FIXED_EPSILON;
1009 fdxRightEdge = eRight->fdxdy;
1010 #endif
1011 }
1012
1013 if (lines==0) {
1014 continue;
1015 }
1016
1017
1018 /* Rasterize setup */
1019 #ifdef PIXEL_ADDRESS
1020 dPRowInner = dPRowOuter + sizeof(PIXEL_TYPE);
1021 #endif
1022 #ifdef INTERP_Z
1023 # ifdef DEPTH_TYPE
1024 dZRowInner = dZRowOuter + sizeof(DEPTH_TYPE);
1025 # endif
1026 fdzInner = fdzOuter + span.zStep;
1027 #endif
1028 #ifdef INTERP_W
1029 dwInner = dwOuter + span.dwdx;
1030 #endif
1031 #ifdef INTERP_FOG
1032 dfogInner = dfogOuter + span.dfogdx;
1033 #endif
1034 #ifdef INTERP_RGB
1035 fdrInner = fdrOuter + span.redStep;
1036 fdgInner = fdgOuter + span.greenStep;
1037 fdbInner = fdbOuter + span.blueStep;
1038 #endif
1039 #ifdef INTERP_ALPHA
1040 fdaInner = fdaOuter + span.alphaStep;
1041 #endif
1042 #ifdef INTERP_SPEC
1043 dsrInner = dsrOuter + span.specRedStep;
1044 dsgInner = dsgOuter + span.specGreenStep;
1045 dsbInner = dsbOuter + span.specBlueStep;
1046 #endif
1047 #ifdef INTERP_INDEX
1048 diInner = diOuter + span.indexStep;
1049 #endif
1050 #ifdef INTERP_INT_TEX
1051 dsInner = dsOuter + span.intTexStep[0];
1052 dtInner = dtOuter + span.intTexStep[1];
1053 #endif
1054 #ifdef INTERP_TEX
1055 TEX_UNIT_LOOP(
1056 dsInner[u] = dsOuter[u] + span.texStepX[u][0];
1057 dtInner[u] = dtOuter[u] + span.texStepX[u][1];
1058 duInner[u] = duOuter[u] + span.texStepX[u][2];
1059 dvInner[u] = dvOuter[u] + span.texStepX[u][3];
1060 )
1061 #endif
1062
1063 while (lines > 0) {
1064 /* initialize the span interpolants to the leftmost value */
1065 /* ff = fixed-pt fragment */
1066 const GLint right = InterpToInt(fxRightEdge);
1067 span.x = InterpToInt(fxLeftEdge);
1068
1069 if (right <= span.x)
1070 span.end = 0;
1071 else
1072 span.end = right - span.x;
1073
1074 #ifdef INTERP_Z
1075 span.z = zLeft;
1076 #endif
1077 #ifdef INTERP_W
1078 span.w = wLeft;
1079 #endif
1080 #ifdef INTERP_FOG
1081 span.fog = fogLeft;
1082 #endif
1083 #ifdef INTERP_RGB
1084 span.red = rLeft;
1085 span.green = gLeft;
1086 span.blue = bLeft;
1087 #endif
1088 #ifdef INTERP_ALPHA
1089 span.alpha = aLeft;
1090 #endif
1091 #ifdef INTERP_SPEC
1092 span.specRed = srLeft;
1093 span.specGreen = sgLeft;
1094 span.specBlue = sbLeft;
1095 #endif
1096 #ifdef INTERP_INDEX
1097 span.index = iLeft;
1098 #endif
1099 #ifdef INTERP_INT_TEX
1100 span.intTex[0] = sLeft;
1101 span.intTex[1] = tLeft;
1102 #endif
1103
1104 #ifdef INTERP_TEX
1105 TEX_UNIT_LOOP(
1106 span.tex[u][0] = sLeft[u];
1107 span.tex[u][1] = tLeft[u];
1108 span.tex[u][2] = uLeft[u];
1109 span.tex[u][3] = vLeft[u];
1110 )
1111 #endif
1112
1113 if (span.end > 1) {
1114 /* Under rare circumstances, we might have to fudge the
1115 * colors. XXX does this really happen anymore???
1116 */
1117 const GLint len = span.end - 1;
1118 (void) len;
1119 #ifdef INTERP_RGB
1120 {
1121 GLfixed ffrend = span.red + len * span.redStep;
1122 GLfixed ffgend = span.green + len * span.greenStep;
1123 GLfixed ffbend = span.blue + len * span.blueStep;
1124 if (ffrend < 0) {
1125 span.red -= ffrend;
1126 if (span.red < 0)
1127 span.red = 0;
1128 }
1129 if (ffgend < 0) {
1130 span.green -= ffgend;
1131 if (span.green < 0)
1132 span.green = 0;
1133 }
1134 if (ffbend < 0) {
1135 span.blue -= ffbend;
1136 if (span.blue < 0)
1137 span.blue = 0;
1138 }
1139 }
1140 #endif
1141 #ifdef INTERP_ALPHA
1142 {
1143 GLfixed ffaend = span.alpha + len * span.alphaStep;
1144 if (ffaend < 0) {
1145 span.alpha -= ffaend;
1146 if (span.alpha < 0)
1147 span.alpha = 0;
1148 }
1149 }
1150 #endif
1151 #ifdef INTERP_SPEC
1152 {
1153 GLfixed ffsrend = span.specRed + len * span.specRedStep;
1154 GLfixed ffsgend = span.specGreen + len * span.specGreenStep;
1155 GLfixed ffsbend = span.specBlue + len * span.specBlueStep;
1156 if (ffsrend < 0) {
1157 span.specRed -= ffsrend;
1158 if (span.specRed < 0)
1159 span.specRed = 0;
1160 }
1161 if (ffsgend < 0) {
1162 span.specGreen -= ffsgend;
1163 if (span.specGreen < 0)
1164 span.specGreen = 0;
1165 }
1166 if (ffsbend < 0) {
1167 span.specBlue -= ffsbend;
1168 if (span.specBlue < 0)
1169 span.specBlue = 0;
1170 }
1171 }
1172 #endif
1173 #ifdef INTERP_INDEX
1174 if (span.index < 0)
1175 span.index = 0;
1176 #endif
1177 } /* span.end > 1 */
1178
1179 /* This is where we actually generate fragments */
1180 if (span.end > 0) {
1181 RENDER_SPAN( span );
1182 }
1183
1184 /*
1185 * Advance to the next scan line. Compute the
1186 * new edge coordinates, and adjust the
1187 * pixel-center x coordinate so that it stays
1188 * on or inside the major edge.
1189 */
1190 span.y++;
1191 lines--;
1192
1193 fxLeftEdge += fdxLeftEdge;
1194 fxRightEdge += fdxRightEdge;
1195
1196 fError += fdError;
1197 if (fError >= 0) {
1198 fError -= INTERP_ONE;
1199
1200 #ifdef PIXEL_ADDRESS
1201 pRow = (PIXEL_TYPE *) ((GLubyte *) pRow + dPRowOuter);
1202 #endif
1203 #ifdef INTERP_Z
1204 # ifdef DEPTH_TYPE
1205 zRow = (DEPTH_TYPE *) ((GLubyte *) zRow + dZRowOuter);
1206 # endif
1207 zLeft += fdzOuter;
1208 #endif
1209 #ifdef INTERP_W
1210 wLeft += dwOuter;
1211 #endif
1212 #ifdef INTERP_FOG
1213 fogLeft += dfogOuter;
1214 #endif
1215 #ifdef INTERP_RGB
1216 rLeft += fdrOuter;
1217 gLeft += fdgOuter;
1218 bLeft += fdbOuter;
1219 #endif
1220 #ifdef INTERP_ALPHA
1221 aLeft += fdaOuter;
1222 #endif
1223 #ifdef INTERP_SPEC
1224 srLeft += dsrOuter;
1225 sgLeft += dsgOuter;
1226 sbLeft += dsbOuter;
1227 #endif
1228 #ifdef INTERP_INDEX
1229 iLeft += diOuter;
1230 #endif
1231 #ifdef INTERP_INT_TEX
1232 sLeft += dsOuter;
1233 tLeft += dtOuter;
1234 #endif
1235 #ifdef INTERP_TEX
1236 TEX_UNIT_LOOP(
1237 sLeft[u] += dsOuter[u];
1238 tLeft[u] += dtOuter[u];
1239 uLeft[u] += duOuter[u];
1240 vLeft[u] += dvOuter[u];
1241 )
1242 #endif
1243 }
1244 else {
1245 #ifdef PIXEL_ADDRESS
1246 pRow = (PIXEL_TYPE *) ((GLubyte *) pRow + dPRowInner);
1247 #endif
1248 #ifdef INTERP_Z
1249 # ifdef DEPTH_TYPE
1250 zRow = (DEPTH_TYPE *) ((GLubyte *) zRow + dZRowInner);
1251 # endif
1252 zLeft += fdzInner;
1253 #endif
1254 #ifdef INTERP_W
1255 wLeft += dwInner;
1256 #endif
1257 #ifdef INTERP_FOG
1258 fogLeft += dfogInner;
1259 #endif
1260 #ifdef INTERP_RGB
1261 rLeft += fdrInner;
1262 gLeft += fdgInner;
1263 bLeft += fdbInner;
1264 #endif
1265 #ifdef INTERP_ALPHA
1266 aLeft += fdaInner;
1267 #endif
1268 #ifdef INTERP_SPEC
1269 srLeft += dsrInner;
1270 sgLeft += dsgInner;
1271 sbLeft += dsbInner;
1272 #endif
1273 #ifdef INTERP_INDEX
1274 iLeft += diInner;
1275 #endif
1276 #ifdef INTERP_INT_TEX
1277 sLeft += dsInner;
1278 tLeft += dtInner;
1279 #endif
1280 #ifdef INTERP_TEX
1281 TEX_UNIT_LOOP(
1282 sLeft[u] += dsInner[u];
1283 tLeft[u] += dtInner[u];
1284 uLeft[u] += duInner[u];
1285 vLeft[u] += dvInner[u];
1286 )
1287 #endif
1288 }
1289 } /*while lines>0*/
1290
1291 } /* for subTriangle */
1292
1293 }
1294 #ifdef CLEANUP_CODE
1295 CLEANUP_CODE
1296 #endif
1297 }
1298 }
1299
1300 #undef SETUP_CODE
1301 #undef CLEANUP_CODE
1302 #undef RENDER_SPAN
1303
1304 #undef PIXEL_TYPE
1305 #undef BYTES_PER_ROW
1306 #undef PIXEL_ADDRESS
1307
1308 #undef INTERP_Z
1309 #undef INTERP_W
1310 #undef INTERP_FOG
1311 #undef INTERP_RGB
1312 #undef INTERP_ALPHA
1313 #undef INTERP_SPEC
1314 #undef INTERP_INDEX
1315 #undef INTERP_INT_TEX
1316 #undef INTERP_TEX
1317 #undef INTERP_MULTITEX
1318 #undef TEX_UNIT_LOOP
1319
1320 #undef S_SCALE
1321 #undef T_SCALE
1322
1323 #undef FixedToDepth
1324 #undef ColorTemp
1325 #undef GLinterp
1326 #undef InterpToInt
1327 #undef INTERP_ONE
1328
1329 #undef NAME