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put braces around RENDER_SPAN macro when called, not when defined. Fixes -pedantic...
[mesa.git] / src / mesa / swrast / s_tritemp.h
1 /*
2 * Mesa 3-D graphics library
3 * Version: 6.5
4 *
5 * Copyright (C) 1999-2006 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
145 /*
146 * Some code we unfortunately need to prevent negative interpolated colors.
147 */
148 #ifndef CLAMP_INTERPOLANT
149 #define CLAMP_INTERPOLANT(CHANNEL, CHANNELSTEP, LEN) \
150 do { \
151 GLfixed endVal = span.CHANNEL + (LEN) * span.CHANNELSTEP; \
152 if (endVal < 0) { \
153 span.CHANNEL -= endVal; \
154 } \
155 if (span.CHANNEL < 0) { \
156 span.CHANNEL = 0; \
157 } \
158 } while (0)
159 #endif
160
161
162 static void NAME(GLcontext *ctx, const SWvertex *v0,
163 const SWvertex *v1,
164 const SWvertex *v2 )
165 {
166 typedef struct {
167 const SWvertex *v0, *v1; /* Y(v0) < Y(v1) */
168 #if TRIANGLE_WALK_DOUBLE
169 GLdouble dx; /* X(v1) - X(v0) */
170 GLdouble dy; /* Y(v1) - Y(v0) */
171 GLdouble dxdy; /* dx/dy */
172 GLdouble adjy; /* adjust from v[0]->fy to fsy, scaled */
173 GLdouble fsx; /* first sample point x coord */
174 GLdouble fsy;
175 GLdouble fx0; /*X of lower endpoint */
176 #else
177 GLfloat dx; /* X(v1) - X(v0) */
178 GLfloat dy; /* Y(v1) - Y(v0) */
179 GLfloat dxdy; /* dx/dy */
180 GLfixed fdxdy; /* dx/dy in fixed-point */
181 GLfloat adjy; /* adjust from v[0]->fy to fsy, scaled */
182 GLfixed fsx; /* first sample point x coord */
183 GLfixed fsy;
184 GLfixed fx0; /* fixed pt X of lower endpoint */
185 #endif
186 GLint lines; /* number of lines to be sampled on this edge */
187 } EdgeT;
188
189 #ifdef INTERP_Z
190 const GLint depthBits = ctx->DrawBuffer->Visual.depthBits;
191 const GLint fixedToDepthShift = depthBits <= 16 ? FIXED_SHIFT : 0;
192 const GLfloat maxDepth = ctx->DrawBuffer->_DepthMaxF;
193 #define FixedToDepth(F) ((F) >> fixedToDepthShift)
194 #endif
195 EdgeT eMaj, eTop, eBot;
196 GLfloat oneOverArea;
197 const SWvertex *vMin, *vMid, *vMax; /* Y(vMin)<=Y(vMid)<=Y(vMax) */
198 GLfloat bf = SWRAST_CONTEXT(ctx)->_BackfaceSign;
199 #if !TRIANGLE_WALK_DOUBLE
200 const GLint snapMask = ~((FIXED_ONE / (1 << SUB_PIXEL_BITS)) - 1); /* for x/y coord snapping */
201 #endif
202 GLinterp vMin_fx, vMin_fy, vMid_fx, vMid_fy, vMax_fx, vMax_fy;
203
204 struct sw_span span;
205
206 INIT_SPAN(span, GL_POLYGON, 0, 0, 0);
207
208 #ifdef INTERP_Z
209 (void) fixedToDepthShift;
210 #endif
211
212 /*
213 printf("%s()\n", __FUNCTION__);
214 printf(" %g, %g, %g\n", v0->win[0], v0->win[1], v0->win[2]);
215 printf(" %g, %g, %g\n", v1->win[0], v1->win[1], v1->win[2]);
216 printf(" %g, %g, %g\n", v2->win[0], v2->win[1], v2->win[2]);
217 */
218 /*
219 ASSERT(v0->win[2] >= 0.0);
220 ASSERT(v1->win[2] >= 0.0);
221 ASSERT(v2->win[2] >= 0.0);
222 */
223 /* Compute fixed point x,y coords w/ half-pixel offsets and snapping.
224 * And find the order of the 3 vertices along the Y axis.
225 */
226 {
227 #if TRIANGLE_WALK_DOUBLE
228 const GLdouble fy0 = v0->win[1] - 0.5;
229 const GLdouble fy1 = v1->win[1] - 0.5;
230 const GLdouble fy2 = v2->win[1] - 0.5;
231 #else
232 const GLfixed fy0 = FloatToFixed(v0->win[1] - 0.5F) & snapMask;
233 const GLfixed fy1 = FloatToFixed(v1->win[1] - 0.5F) & snapMask;
234 const GLfixed fy2 = FloatToFixed(v2->win[1] - 0.5F) & snapMask;
235 #endif
236 if (fy0 <= fy1) {
237 if (fy1 <= fy2) {
238 /* y0 <= y1 <= y2 */
239 vMin = v0; vMid = v1; vMax = v2;
240 vMin_fy = fy0; vMid_fy = fy1; vMax_fy = fy2;
241 }
242 else if (fy2 <= fy0) {
243 /* y2 <= y0 <= y1 */
244 vMin = v2; vMid = v0; vMax = v1;
245 vMin_fy = fy2; vMid_fy = fy0; vMax_fy = fy1;
246 }
247 else {
248 /* y0 <= y2 <= y1 */
249 vMin = v0; vMid = v2; vMax = v1;
250 vMin_fy = fy0; vMid_fy = fy2; vMax_fy = fy1;
251 bf = -bf;
252 }
253 }
254 else {
255 if (fy0 <= fy2) {
256 /* y1 <= y0 <= y2 */
257 vMin = v1; vMid = v0; vMax = v2;
258 vMin_fy = fy1; vMid_fy = fy0; vMax_fy = fy2;
259 bf = -bf;
260 }
261 else if (fy2 <= fy1) {
262 /* y2 <= y1 <= y0 */
263 vMin = v2; vMid = v1; vMax = v0;
264 vMin_fy = fy2; vMid_fy = fy1; vMax_fy = fy0;
265 bf = -bf;
266 }
267 else {
268 /* y1 <= y2 <= y0 */
269 vMin = v1; vMid = v2; vMax = v0;
270 vMin_fy = fy1; vMid_fy = fy2; vMax_fy = fy0;
271 }
272 }
273
274 /* fixed point X coords */
275 #if TRIANGLE_WALK_DOUBLE
276 vMin_fx = vMin->win[0] + 0.5;
277 vMid_fx = vMid->win[0] + 0.5;
278 vMax_fx = vMax->win[0] + 0.5;
279 #else
280 vMin_fx = FloatToFixed(vMin->win[0] + 0.5F) & snapMask;
281 vMid_fx = FloatToFixed(vMid->win[0] + 0.5F) & snapMask;
282 vMax_fx = FloatToFixed(vMax->win[0] + 0.5F) & snapMask;
283 #endif
284 }
285
286 /* vertex/edge relationship */
287 eMaj.v0 = vMin; eMaj.v1 = vMax; /*TODO: .v1's not needed */
288 eTop.v0 = vMid; eTop.v1 = vMax;
289 eBot.v0 = vMin; eBot.v1 = vMid;
290
291 /* compute deltas for each edge: vertex[upper] - vertex[lower] */
292 #if TRIANGLE_WALK_DOUBLE
293 eMaj.dx = vMax_fx - vMin_fx;
294 eMaj.dy = vMax_fy - vMin_fy;
295 eTop.dx = vMax_fx - vMid_fx;
296 eTop.dy = vMax_fy - vMid_fy;
297 eBot.dx = vMid_fx - vMin_fx;
298 eBot.dy = vMid_fy - vMin_fy;
299 #else
300 eMaj.dx = FixedToFloat(vMax_fx - vMin_fx);
301 eMaj.dy = FixedToFloat(vMax_fy - vMin_fy);
302 eTop.dx = FixedToFloat(vMax_fx - vMid_fx);
303 eTop.dy = FixedToFloat(vMax_fy - vMid_fy);
304 eBot.dx = FixedToFloat(vMid_fx - vMin_fx);
305 eBot.dy = FixedToFloat(vMid_fy - vMin_fy);
306 #endif
307
308 /* compute area, oneOverArea and perform backface culling */
309 {
310 #if TRIANGLE_WALK_DOUBLE
311 const GLdouble area = eMaj.dx * eBot.dy - eBot.dx * eMaj.dy;
312 #else
313 const GLfloat area = eMaj.dx * eBot.dy - eBot.dx * eMaj.dy;
314 #endif
315 /* Do backface culling */
316 if (area * bf < 0.0)
317 return;
318
319 if (IS_INF_OR_NAN(area) || area == 0.0F)
320 return;
321
322 oneOverArea = 1.0F / area;
323 }
324
325
326 span.facing = ctx->_Facing; /* for 2-sided stencil test */
327
328 /* Edge setup. For a triangle strip these could be reused... */
329 {
330 #if TRIANGLE_WALK_DOUBLE
331 eMaj.fsy = CEILF(vMin_fy);
332 eMaj.lines = (GLint) CEILF(vMax_fy - eMaj.fsy);
333 #else
334 eMaj.fsy = FixedCeil(vMin_fy);
335 eMaj.lines = FixedToInt(FixedCeil(vMax_fy - eMaj.fsy));
336 #endif
337 if (eMaj.lines > 0) {
338 eMaj.dxdy = eMaj.dx / eMaj.dy;
339 #if TRIANGLE_WALK_DOUBLE
340 eMaj.adjy = (eMaj.fsy - vMin_fy) * FIXED_SCALE; /* SCALED! */
341 eMaj.fx0 = vMin_fx;
342 eMaj.fsx = eMaj.fx0 + (eMaj.adjy * eMaj.dxdy) / (GLdouble) FIXED_SCALE;
343 #else
344 eMaj.fdxdy = SignedFloatToFixed(eMaj.dxdy);
345 eMaj.adjy = (GLfloat) (eMaj.fsy - vMin_fy); /* SCALED! */
346 eMaj.fx0 = vMin_fx;
347 eMaj.fsx = eMaj.fx0 + (GLfixed) (eMaj.adjy * eMaj.dxdy);
348 #endif
349 }
350 else {
351 return; /*CULLED*/
352 }
353
354 #if TRIANGLE_WALK_DOUBLE
355 eTop.fsy = CEILF(vMid_fy);
356 eTop.lines = (GLint) CEILF(vMax_fy - eTop.fsy);
357 #else
358 eTop.fsy = FixedCeil(vMid_fy);
359 eTop.lines = FixedToInt(FixedCeil(vMax_fy - eTop.fsy));
360 #endif
361 if (eTop.lines > 0) {
362 eTop.dxdy = eTop.dx / eTop.dy;
363 #if TRIANGLE_WALK_DOUBLE
364 eTop.adjy = (eTop.fsy - vMid_fy) * FIXED_SCALE; /* SCALED! */
365 eTop.fx0 = vMid_fx;
366 eTop.fsx = eTop.fx0 + (eTop.adjy * eTop.dxdy) / (GLdouble) FIXED_SCALE;
367 #else
368 eTop.fdxdy = SignedFloatToFixed(eTop.dxdy);
369 eTop.adjy = (GLfloat) (eTop.fsy - vMid_fy); /* SCALED! */
370 eTop.fx0 = vMid_fx;
371 eTop.fsx = eTop.fx0 + (GLfixed) (eTop.adjy * eTop.dxdy);
372 #endif
373 }
374
375 #if TRIANGLE_WALK_DOUBLE
376 eBot.fsy = CEILF(vMin_fy);
377 eBot.lines = (GLint) CEILF(vMid_fy - eBot.fsy);
378 #else
379 eBot.fsy = FixedCeil(vMin_fy);
380 eBot.lines = FixedToInt(FixedCeil(vMid_fy - eBot.fsy));
381 #endif
382 if (eBot.lines > 0) {
383 eBot.dxdy = eBot.dx / eBot.dy;
384 #if TRIANGLE_WALK_DOUBLE
385 eBot.adjy = (eBot.fsy - vMin_fy) * FIXED_SCALE; /* SCALED! */
386 eBot.fx0 = vMin_fx;
387 eBot.fsx = eBot.fx0 + (eBot.adjy * eBot.dxdy) / (GLdouble) FIXED_SCALE;
388 #else
389 eBot.fdxdy = SignedFloatToFixed(eBot.dxdy);
390 eBot.adjy = (GLfloat) (eBot.fsy - vMin_fy); /* SCALED! */
391 eBot.fx0 = vMin_fx;
392 eBot.fsx = eBot.fx0 + (GLfixed) (eBot.adjy * eBot.dxdy);
393 #endif
394 }
395 }
396
397 /*
398 * Conceptually, we view a triangle as two subtriangles
399 * separated by a perfectly horizontal line. The edge that is
400 * intersected by this line is one with maximal absolute dy; we
401 * call it a ``major'' edge. The other two edges are the
402 * ``top'' edge (for the upper subtriangle) and the ``bottom''
403 * edge (for the lower subtriangle). If either of these two
404 * edges is horizontal or very close to horizontal, the
405 * corresponding subtriangle might cover zero sample points;
406 * we take care to handle such cases, for performance as well
407 * as correctness.
408 *
409 * By stepping rasterization parameters along the major edge,
410 * we can avoid recomputing them at the discontinuity where
411 * the top and bottom edges meet. However, this forces us to
412 * be able to scan both left-to-right and right-to-left.
413 * Also, we must determine whether the major edge is at the
414 * left or right side of the triangle. We do this by
415 * computing the magnitude of the cross-product of the major
416 * and top edges. Since this magnitude depends on the sine of
417 * the angle between the two edges, its sign tells us whether
418 * we turn to the left or to the right when travelling along
419 * the major edge to the top edge, and from this we infer
420 * whether the major edge is on the left or the right.
421 *
422 * Serendipitously, this cross-product magnitude is also a
423 * value we need to compute the iteration parameter
424 * derivatives for the triangle, and it can be used to perform
425 * backface culling because its sign tells us whether the
426 * triangle is clockwise or counterclockwise. In this code we
427 * refer to it as ``area'' because it's also proportional to
428 * the pixel area of the triangle.
429 */
430
431 {
432 GLint scan_from_left_to_right; /* true if scanning left-to-right */
433 #ifdef INTERP_INDEX
434 GLfloat didx, didy;
435 #endif
436
437 /*
438 * Execute user-supplied setup code
439 */
440 #ifdef SETUP_CODE
441 SETUP_CODE
442 #endif
443
444 scan_from_left_to_right = (oneOverArea < 0.0F);
445
446
447 /* compute d?/dx and d?/dy derivatives */
448 #ifdef INTERP_Z
449 span.interpMask |= SPAN_Z;
450 {
451 GLfloat eMaj_dz = vMax->win[2] - vMin->win[2];
452 GLfloat eBot_dz = vMid->win[2] - vMin->win[2];
453 span.dzdx = oneOverArea * (eMaj_dz * eBot.dy - eMaj.dy * eBot_dz);
454 if (span.dzdx > maxDepth || span.dzdx < -maxDepth) {
455 /* probably a sliver triangle */
456 span.dzdx = 0.0;
457 span.dzdy = 0.0;
458 }
459 else {
460 span.dzdy = oneOverArea * (eMaj.dx * eBot_dz - eMaj_dz * eBot.dx);
461 }
462 if (depthBits <= 16)
463 span.zStep = SignedFloatToFixed(span.dzdx);
464 else
465 span.zStep = (GLint) span.dzdx;
466 }
467 #endif
468 #ifdef INTERP_W
469 span.interpMask |= SPAN_W;
470 {
471 const GLfloat eMaj_dw = vMax->win[3] - vMin->win[3];
472 const GLfloat eBot_dw = vMid->win[3] - vMin->win[3];
473 span.dwdx = oneOverArea * (eMaj_dw * eBot.dy - eMaj.dy * eBot_dw);
474 span.dwdy = oneOverArea * (eMaj.dx * eBot_dw - eMaj_dw * eBot.dx);
475 }
476 #endif
477 #ifdef INTERP_FOG
478 span.interpMask |= SPAN_FOG;
479 {
480 # ifdef INTERP_W
481 const GLfloat wMax = vMax->win[3], wMin = vMin->win[3], wMid = vMid->win[3];
482 const GLfloat eMaj_dfog = vMax->fog * wMax - vMin->fog * wMin;
483 const GLfloat eBot_dfog = vMid->fog * wMid - vMin->fog * wMin;
484 # else
485 const GLfloat eMaj_dfog = vMax->fog - vMin->fog;
486 const GLfloat eBot_dfog = vMid->fog - vMin->fog;
487 # endif
488 span.dfogdx = oneOverArea * (eMaj_dfog * eBot.dy - eMaj.dy * eBot_dfog);
489 span.dfogdy = oneOverArea * (eMaj.dx * eBot_dfog - eMaj_dfog * eBot.dx);
490 span.fogStep = span.dfogdx;
491 }
492 #endif
493 #ifdef INTERP_RGB
494 span.interpMask |= SPAN_RGBA;
495 if (ctx->Light.ShadeModel == GL_SMOOTH) {
496 GLfloat eMaj_dr = (GLfloat) ((ColorTemp) vMax->color[RCOMP] - (ColorTemp) vMin->color[RCOMP]);
497 GLfloat eBot_dr = (GLfloat) ((ColorTemp) vMid->color[RCOMP] - (ColorTemp) vMin->color[RCOMP]);
498 GLfloat eMaj_dg = (GLfloat) ((ColorTemp) vMax->color[GCOMP] - (ColorTemp) vMin->color[GCOMP]);
499 GLfloat eBot_dg = (GLfloat) ((ColorTemp) vMid->color[GCOMP] - (ColorTemp) vMin->color[GCOMP]);
500 GLfloat eMaj_db = (GLfloat) ((ColorTemp) vMax->color[BCOMP] - (ColorTemp) vMin->color[BCOMP]);
501 GLfloat eBot_db = (GLfloat) ((ColorTemp) vMid->color[BCOMP] - (ColorTemp) vMin->color[BCOMP]);
502 # ifdef INTERP_ALPHA
503 GLfloat eMaj_da = (GLfloat) ((ColorTemp) vMax->color[ACOMP] - (ColorTemp) vMin->color[ACOMP]);
504 GLfloat eBot_da = (GLfloat) ((ColorTemp) vMid->color[ACOMP] - (ColorTemp) vMin->color[ACOMP]);
505 # endif
506 span.drdx = oneOverArea * (eMaj_dr * eBot.dy - eMaj.dy * eBot_dr);
507 span.drdy = oneOverArea * (eMaj.dx * eBot_dr - eMaj_dr * eBot.dx);
508 span.dgdx = oneOverArea * (eMaj_dg * eBot.dy - eMaj.dy * eBot_dg);
509 span.dgdy = oneOverArea * (eMaj.dx * eBot_dg - eMaj_dg * eBot.dx);
510 span.dbdx = oneOverArea * (eMaj_db * eBot.dy - eMaj.dy * eBot_db);
511 span.dbdy = oneOverArea * (eMaj.dx * eBot_db - eMaj_db * eBot.dx);
512 # if CHAN_TYPE == GL_FLOAT
513 span.redStep = span.drdx;
514 span.greenStep = span.dgdx;
515 span.blueStep = span.dbdx;
516 # else
517 span.redStep = SignedFloatToFixed(span.drdx);
518 span.greenStep = SignedFloatToFixed(span.dgdx);
519 span.blueStep = SignedFloatToFixed(span.dbdx);
520 # endif /* GL_FLOAT */
521 # ifdef INTERP_ALPHA
522 span.dadx = oneOverArea * (eMaj_da * eBot.dy - eMaj.dy * eBot_da);
523 span.dady = oneOverArea * (eMaj.dx * eBot_da - eMaj_da * eBot.dx);
524 # if CHAN_TYPE == GL_FLOAT
525 span.alphaStep = span.dadx;
526 # else
527 span.alphaStep = SignedFloatToFixed(span.dadx);
528 # endif /* GL_FLOAT */
529 # endif /* INTERP_ALPHA */
530 }
531 else {
532 ASSERT(ctx->Light.ShadeModel == GL_FLAT);
533 span.interpMask |= SPAN_FLAT;
534 span.drdx = span.drdy = 0.0F;
535 span.dgdx = span.dgdy = 0.0F;
536 span.dbdx = span.dbdy = 0.0F;
537 # if CHAN_TYPE == GL_FLOAT
538 span.redStep = 0.0F;
539 span.greenStep = 0.0F;
540 span.blueStep = 0.0F;
541 # else
542 span.redStep = 0;
543 span.greenStep = 0;
544 span.blueStep = 0;
545 # endif /* GL_FLOAT */
546 # ifdef INTERP_ALPHA
547 span.dadx = span.dady = 0.0F;
548 # if CHAN_TYPE == GL_FLOAT
549 span.alphaStep = 0.0F;
550 # else
551 span.alphaStep = 0;
552 # endif /* GL_FLOAT */
553 # endif
554 }
555 #endif /* INTERP_RGB */
556 #ifdef INTERP_SPEC
557 span.interpMask |= SPAN_SPEC;
558 if (ctx->Light.ShadeModel == GL_SMOOTH) {
559 GLfloat eMaj_dsr = (GLfloat) ((ColorTemp) vMax->specular[RCOMP] - (ColorTemp) vMin->specular[RCOMP]);
560 GLfloat eBot_dsr = (GLfloat) ((ColorTemp) vMid->specular[RCOMP] - (ColorTemp) vMin->specular[RCOMP]);
561 GLfloat eMaj_dsg = (GLfloat) ((ColorTemp) vMax->specular[GCOMP] - (ColorTemp) vMin->specular[GCOMP]);
562 GLfloat eBot_dsg = (GLfloat) ((ColorTemp) vMid->specular[GCOMP] - (ColorTemp) vMin->specular[GCOMP]);
563 GLfloat eMaj_dsb = (GLfloat) ((ColorTemp) vMax->specular[BCOMP] - (ColorTemp) vMin->specular[BCOMP]);
564 GLfloat eBot_dsb = (GLfloat) ((ColorTemp) vMid->specular[BCOMP] - (ColorTemp) vMin->specular[BCOMP]);
565 span.dsrdx = oneOverArea * (eMaj_dsr * eBot.dy - eMaj.dy * eBot_dsr);
566 span.dsrdy = oneOverArea * (eMaj.dx * eBot_dsr - eMaj_dsr * eBot.dx);
567 span.dsgdx = oneOverArea * (eMaj_dsg * eBot.dy - eMaj.dy * eBot_dsg);
568 span.dsgdy = oneOverArea * (eMaj.dx * eBot_dsg - eMaj_dsg * eBot.dx);
569 span.dsbdx = oneOverArea * (eMaj_dsb * eBot.dy - eMaj.dy * eBot_dsb);
570 span.dsbdy = oneOverArea * (eMaj.dx * eBot_dsb - eMaj_dsb * eBot.dx);
571 # if CHAN_TYPE == GL_FLOAT
572 span.specRedStep = span.dsrdx;
573 span.specGreenStep = span.dsgdx;
574 span.specBlueStep = span.dsbdx;
575 # else
576 span.specRedStep = SignedFloatToFixed(span.dsrdx);
577 span.specGreenStep = SignedFloatToFixed(span.dsgdx);
578 span.specBlueStep = SignedFloatToFixed(span.dsbdx);
579 # endif
580 }
581 else {
582 span.dsrdx = span.dsrdy = 0.0F;
583 span.dsgdx = span.dsgdy = 0.0F;
584 span.dsbdx = span.dsbdy = 0.0F;
585 # if CHAN_TYPE == GL_FLOAT
586 span.specRedStep = 0.0F;
587 span.specGreenStep = 0.0F;
588 span.specBlueStep = 0.0F;
589 # else
590 span.specRedStep = 0;
591 span.specGreenStep = 0;
592 span.specBlueStep = 0;
593 # endif
594 }
595 #endif /* INTERP_SPEC */
596 #ifdef INTERP_INDEX
597 span.interpMask |= SPAN_INDEX;
598 if (ctx->Light.ShadeModel == GL_SMOOTH) {
599 GLfloat eMaj_di = vMax->index - vMin->index;
600 GLfloat eBot_di = vMid->index - vMin->index;
601 didx = oneOverArea * (eMaj_di * eBot.dy - eMaj.dy * eBot_di);
602 didy = oneOverArea * (eMaj.dx * eBot_di - eMaj_di * eBot.dx);
603 span.indexStep = SignedFloatToFixed(didx);
604 }
605 else {
606 span.interpMask |= SPAN_FLAT;
607 didx = didy = 0.0F;
608 span.indexStep = 0;
609 }
610 #endif
611 #ifdef INTERP_INT_TEX
612 span.interpMask |= SPAN_INT_TEXTURE;
613 {
614 GLfloat eMaj_ds = (vMax->texcoord[0][0] - vMin->texcoord[0][0]) * S_SCALE;
615 GLfloat eBot_ds = (vMid->texcoord[0][0] - vMin->texcoord[0][0]) * S_SCALE;
616 GLfloat eMaj_dt = (vMax->texcoord[0][1] - vMin->texcoord[0][1]) * T_SCALE;
617 GLfloat eBot_dt = (vMid->texcoord[0][1] - vMin->texcoord[0][1]) * T_SCALE;
618 span.texStepX[0][0] = oneOverArea * (eMaj_ds * eBot.dy - eMaj.dy * eBot_ds);
619 span.texStepY[0][0] = oneOverArea * (eMaj.dx * eBot_ds - eMaj_ds * eBot.dx);
620 span.texStepX[0][1] = oneOverArea * (eMaj_dt * eBot.dy - eMaj.dy * eBot_dt);
621 span.texStepY[0][1] = oneOverArea * (eMaj.dx * eBot_dt - eMaj_dt * eBot.dx);
622 span.intTexStep[0] = SignedFloatToFixed(span.texStepX[0][0]);
623 span.intTexStep[1] = SignedFloatToFixed(span.texStepX[0][1]);
624 }
625 #endif
626 #ifdef INTERP_TEX
627 span.interpMask |= SPAN_TEXTURE;
628 {
629 /* win[3] is 1/W */
630 const GLfloat wMax = vMax->win[3], wMin = vMin->win[3], wMid = vMid->win[3];
631 TEX_UNIT_LOOP(
632 GLfloat eMaj_ds = vMax->texcoord[u][0] * wMax - vMin->texcoord[u][0] * wMin;
633 GLfloat eBot_ds = vMid->texcoord[u][0] * wMid - vMin->texcoord[u][0] * wMin;
634 GLfloat eMaj_dt = vMax->texcoord[u][1] * wMax - vMin->texcoord[u][1] * wMin;
635 GLfloat eBot_dt = vMid->texcoord[u][1] * wMid - vMin->texcoord[u][1] * wMin;
636 GLfloat eMaj_du = vMax->texcoord[u][2] * wMax - vMin->texcoord[u][2] * wMin;
637 GLfloat eBot_du = vMid->texcoord[u][2] * wMid - vMin->texcoord[u][2] * wMin;
638 GLfloat eMaj_dv = vMax->texcoord[u][3] * wMax - vMin->texcoord[u][3] * wMin;
639 GLfloat eBot_dv = vMid->texcoord[u][3] * wMid - vMin->texcoord[u][3] * wMin;
640 span.texStepX[u][0] = oneOverArea * (eMaj_ds * eBot.dy - eMaj.dy * eBot_ds);
641 span.texStepY[u][0] = oneOverArea * (eMaj.dx * eBot_ds - eMaj_ds * eBot.dx);
642 span.texStepX[u][1] = oneOverArea * (eMaj_dt * eBot.dy - eMaj.dy * eBot_dt);
643 span.texStepY[u][1] = oneOverArea * (eMaj.dx * eBot_dt - eMaj_dt * eBot.dx);
644 span.texStepX[u][2] = oneOverArea * (eMaj_du * eBot.dy - eMaj.dy * eBot_du);
645 span.texStepY[u][2] = oneOverArea * (eMaj.dx * eBot_du - eMaj_du * eBot.dx);
646 span.texStepX[u][3] = oneOverArea * (eMaj_dv * eBot.dy - eMaj.dy * eBot_dv);
647 span.texStepY[u][3] = oneOverArea * (eMaj.dx * eBot_dv - eMaj_dv * eBot.dx);
648 )
649 }
650 #endif
651
652 /*
653 * We always sample at pixel centers. However, we avoid
654 * explicit half-pixel offsets in this code by incorporating
655 * the proper offset in each of x and y during the
656 * transformation to window coordinates.
657 *
658 * We also apply the usual rasterization rules to prevent
659 * cracks and overlaps. A pixel is considered inside a
660 * subtriangle if it meets all of four conditions: it is on or
661 * to the right of the left edge, strictly to the left of the
662 * right edge, on or below the top edge, and strictly above
663 * the bottom edge. (Some edges may be degenerate.)
664 *
665 * The following discussion assumes left-to-right scanning
666 * (that is, the major edge is on the left); the right-to-left
667 * case is a straightforward variation.
668 *
669 * We start by finding the half-integral y coordinate that is
670 * at or below the top of the triangle. This gives us the
671 * first scan line that could possibly contain pixels that are
672 * inside the triangle.
673 *
674 * Next we creep down the major edge until we reach that y,
675 * and compute the corresponding x coordinate on the edge.
676 * Then we find the half-integral x that lies on or just
677 * inside the edge. This is the first pixel that might lie in
678 * the interior of the triangle. (We won't know for sure
679 * until we check the other edges.)
680 *
681 * As we rasterize the triangle, we'll step down the major
682 * edge. For each step in y, we'll move an integer number
683 * of steps in x. There are two possible x step sizes, which
684 * we'll call the ``inner'' step (guaranteed to land on the
685 * edge or inside it) and the ``outer'' step (guaranteed to
686 * land on the edge or outside it). The inner and outer steps
687 * differ by one. During rasterization we maintain an error
688 * term that indicates our distance from the true edge, and
689 * select either the inner step or the outer step, whichever
690 * gets us to the first pixel that falls inside the triangle.
691 *
692 * All parameters (z, red, etc.) as well as the buffer
693 * addresses for color and z have inner and outer step values,
694 * so that we can increment them appropriately. This method
695 * eliminates the need to adjust parameters by creeping a
696 * sub-pixel amount into the triangle at each scanline.
697 */
698
699 {
700 GLint subTriangle;
701 GLinterp fxLeftEdge = 0, fxRightEdge = 0;
702 GLinterp fdxLeftEdge = 0, fdxRightEdge = 0;
703 GLinterp fError = 0, fdError = 0;
704 #ifdef PIXEL_ADDRESS
705 PIXEL_TYPE *pRow = NULL;
706 GLint dPRowOuter = 0, dPRowInner; /* offset in bytes */
707 #endif
708 #ifdef INTERP_Z
709 # ifdef DEPTH_TYPE
710 struct gl_renderbuffer *zrb
711 = ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer;
712 DEPTH_TYPE *zRow = NULL;
713 GLint dZRowOuter = 0, dZRowInner; /* offset in bytes */
714 # endif
715 GLuint zLeft = 0;
716 GLfixed fdzOuter = 0, fdzInner;
717 #endif
718 #ifdef INTERP_W
719 GLfloat wLeft = 0, dwOuter = 0, dwInner;
720 #endif
721 #ifdef INTERP_FOG
722 GLfloat fogLeft = 0, dfogOuter = 0, dfogInner;
723 #endif
724 #ifdef INTERP_RGB
725 ColorTemp rLeft = 0, fdrOuter = 0, fdrInner;
726 ColorTemp gLeft = 0, fdgOuter = 0, fdgInner;
727 ColorTemp bLeft = 0, fdbOuter = 0, fdbInner;
728 #endif
729 #ifdef INTERP_ALPHA
730 ColorTemp aLeft = 0, fdaOuter = 0, fdaInner;
731 #endif
732 #ifdef INTERP_SPEC
733 ColorTemp srLeft=0, dsrOuter=0, dsrInner;
734 ColorTemp sgLeft=0, dsgOuter=0, dsgInner;
735 ColorTemp sbLeft=0, dsbOuter=0, dsbInner;
736 #endif
737 #ifdef INTERP_INDEX
738 GLfixed iLeft=0, diOuter=0, diInner;
739 #endif
740 #ifdef INTERP_INT_TEX
741 GLfixed sLeft=0, dsOuter=0, dsInner;
742 GLfixed tLeft=0, dtOuter=0, dtInner;
743 #endif
744 #ifdef INTERP_TEX
745 GLfloat sLeft[MAX_TEXTURE_COORD_UNITS];
746 GLfloat tLeft[MAX_TEXTURE_COORD_UNITS];
747 GLfloat uLeft[MAX_TEXTURE_COORD_UNITS];
748 GLfloat vLeft[MAX_TEXTURE_COORD_UNITS];
749 GLfloat dsOuter[MAX_TEXTURE_COORD_UNITS], dsInner[MAX_TEXTURE_COORD_UNITS];
750 GLfloat dtOuter[MAX_TEXTURE_COORD_UNITS], dtInner[MAX_TEXTURE_COORD_UNITS];
751 GLfloat duOuter[MAX_TEXTURE_COORD_UNITS], duInner[MAX_TEXTURE_COORD_UNITS];
752 GLfloat dvOuter[MAX_TEXTURE_COORD_UNITS], dvInner[MAX_TEXTURE_COORD_UNITS];
753 #endif
754
755 for (subTriangle=0; subTriangle<=1; subTriangle++) {
756 EdgeT *eLeft, *eRight;
757 int setupLeft, setupRight;
758 int lines;
759
760 if (subTriangle==0) {
761 /* bottom half */
762 if (scan_from_left_to_right) {
763 eLeft = &eMaj;
764 eRight = &eBot;
765 lines = eRight->lines;
766 setupLeft = 1;
767 setupRight = 1;
768 }
769 else {
770 eLeft = &eBot;
771 eRight = &eMaj;
772 lines = eLeft->lines;
773 setupLeft = 1;
774 setupRight = 1;
775 }
776 }
777 else {
778 /* top half */
779 if (scan_from_left_to_right) {
780 eLeft = &eMaj;
781 eRight = &eTop;
782 lines = eRight->lines;
783 setupLeft = 0;
784 setupRight = 1;
785 }
786 else {
787 eLeft = &eTop;
788 eRight = &eMaj;
789 lines = eLeft->lines;
790 setupLeft = 1;
791 setupRight = 0;
792 }
793 if (lines == 0)
794 return;
795 }
796
797 if (setupLeft && eLeft->lines > 0) {
798 const SWvertex *vLower = eLeft->v0;
799 #if TRIANGLE_WALK_DOUBLE
800 const GLdouble fsy = eLeft->fsy;
801 const GLdouble fsx = eLeft->fsx;
802 const GLdouble fx = CEILF(fsx);
803 const GLdouble adjx = (fx - eLeft->fx0) * FIXED_SCALE; /* SCALED! */
804 #else
805 const GLfixed fsy = eLeft->fsy;
806 const GLfixed fsx = eLeft->fsx; /* no fractional part */
807 const GLfixed fx = FixedCeil(fsx); /* no fractional part */
808 const GLfixed adjx = (GLinterp) (fx - eLeft->fx0); /* SCALED! */
809 #endif
810 const GLinterp adjy = (GLinterp) eLeft->adjy; /* SCALED! */
811 GLint idxOuter;
812 #if TRIANGLE_WALK_DOUBLE
813 GLdouble dxOuter;
814
815 fError = fx - fsx - 1.0;
816 fxLeftEdge = fsx;
817 fdxLeftEdge = eLeft->dxdy;
818 dxOuter = FLOORF(fdxLeftEdge);
819 fdError = dxOuter - fdxLeftEdge + 1.0;
820 idxOuter = (GLint) dxOuter;
821 span.y = (GLint) fsy;
822 #else
823 GLfloat dxOuter;
824 GLfixed fdxOuter;
825
826 fError = fx - fsx - FIXED_ONE;
827 fxLeftEdge = fsx - FIXED_EPSILON;
828 fdxLeftEdge = eLeft->fdxdy;
829 fdxOuter = FixedFloor(fdxLeftEdge - FIXED_EPSILON);
830 fdError = fdxOuter - fdxLeftEdge + FIXED_ONE;
831 idxOuter = FixedToInt(fdxOuter);
832 dxOuter = (GLfloat) idxOuter;
833 span.y = FixedToInt(fsy);
834 #endif
835
836 /* silence warnings on some compilers */
837 (void) dxOuter;
838 (void) adjx;
839 (void) adjy;
840 (void) vLower;
841
842 #ifdef PIXEL_ADDRESS
843 {
844 pRow = (PIXEL_TYPE *) PIXEL_ADDRESS(InterpToInt(fxLeftEdge), span.y);
845 dPRowOuter = -((int)BYTES_PER_ROW) + idxOuter * sizeof(PIXEL_TYPE);
846 /* negative because Y=0 at bottom and increases upward */
847 }
848 #endif
849 /*
850 * Now we need the set of parameter (z, color, etc.) values at
851 * the point (fx, fsy). This gives us properly-sampled parameter
852 * values that we can step from pixel to pixel. Furthermore,
853 * although we might have intermediate results that overflow
854 * the normal parameter range when we step temporarily outside
855 * the triangle, we shouldn't overflow or underflow for any
856 * pixel that's actually inside the triangle.
857 */
858
859 #ifdef INTERP_Z
860 {
861 GLfloat z0 = vLower->win[2];
862 if (depthBits <= 16) {
863 /* interpolate fixed-pt values */
864 GLfloat tmp = (z0 * FIXED_SCALE + span.dzdx * adjx
865 + span.dzdy * adjy) + FIXED_HALF;
866 if (tmp < MAX_GLUINT / 2)
867 zLeft = (GLfixed) tmp;
868 else
869 zLeft = MAX_GLUINT / 2;
870 fdzOuter = SignedFloatToFixed(span.dzdy + dxOuter * span.dzdx);
871 }
872 else {
873 /* interpolate depth values w/out scaling */
874 zLeft = (GLuint) (z0 + span.dzdx * FixedToFloat(adjx)
875 + span.dzdy * FixedToFloat(adjy));
876 fdzOuter = (GLint) (span.dzdy + dxOuter * span.dzdx);
877 }
878 # ifdef DEPTH_TYPE
879 zRow = (DEPTH_TYPE *)
880 zrb->GetPointer(ctx, zrb, InterpToInt(fxLeftEdge), span.y);
881 dZRowOuter = (ctx->DrawBuffer->Width + idxOuter) * sizeof(DEPTH_TYPE);
882 # endif
883 }
884 #endif
885 #ifdef INTERP_W
886 wLeft = vLower->win[3] + (span.dwdx * adjx + span.dwdy * adjy) * (1.0F/FIXED_SCALE);
887 dwOuter = span.dwdy + dxOuter * span.dwdx;
888 #endif
889 #ifdef INTERP_FOG
890 # ifdef INTERP_W
891 fogLeft = vLower->fog * vLower->win[3] + (span.dfogdx * adjx + span.dfogdy * adjy) * (1.0F/FIXED_SCALE);
892 # else
893 fogLeft = vLower->fog + (span.dfogdx * adjx + span.dfogdy * adjy) * (1.0F/FIXED_SCALE);
894 # endif
895 dfogOuter = span.dfogdy + dxOuter * span.dfogdx;
896 #endif
897 #ifdef INTERP_RGB
898 if (ctx->Light.ShadeModel == GL_SMOOTH) {
899 # if CHAN_TYPE == GL_FLOAT
900 rLeft = vLower->color[RCOMP] + (span.drdx * adjx + span.drdy * adjy) * (1.0F / FIXED_SCALE);
901 gLeft = vLower->color[GCOMP] + (span.dgdx * adjx + span.dgdy * adjy) * (1.0F / FIXED_SCALE);
902 bLeft = vLower->color[BCOMP] + (span.dbdx * adjx + span.dbdy * adjy) * (1.0F / FIXED_SCALE);
903 fdrOuter = span.drdy + dxOuter * span.drdx;
904 fdgOuter = span.dgdy + dxOuter * span.dgdx;
905 fdbOuter = span.dbdy + dxOuter * span.dbdx;
906 # else
907 rLeft = (GLint)(ChanToFixed(vLower->color[RCOMP]) + span.drdx * adjx + span.drdy * adjy) + FIXED_HALF;
908 gLeft = (GLint)(ChanToFixed(vLower->color[GCOMP]) + span.dgdx * adjx + span.dgdy * adjy) + FIXED_HALF;
909 bLeft = (GLint)(ChanToFixed(vLower->color[BCOMP]) + span.dbdx * adjx + span.dbdy * adjy) + FIXED_HALF;
910 fdrOuter = SignedFloatToFixed(span.drdy + dxOuter * span.drdx);
911 fdgOuter = SignedFloatToFixed(span.dgdy + dxOuter * span.dgdx);
912 fdbOuter = SignedFloatToFixed(span.dbdy + dxOuter * span.dbdx);
913 # endif
914 # ifdef INTERP_ALPHA
915 # if CHAN_TYPE == GL_FLOAT
916 aLeft = vLower->color[ACOMP] + (span.dadx * adjx + span.dady * adjy) * (1.0F / FIXED_SCALE);
917 fdaOuter = span.dady + dxOuter * span.dadx;
918 # else
919 aLeft = (GLint)(ChanToFixed(vLower->color[ACOMP]) + span.dadx * adjx + span.dady * adjy) + FIXED_HALF;
920 fdaOuter = SignedFloatToFixed(span.dady + dxOuter * span.dadx);
921 # endif
922 # endif
923 }
924 else {
925 ASSERT(ctx->Light.ShadeModel == GL_FLAT);
926 # if CHAN_TYPE == GL_FLOAT
927 rLeft = v2->color[RCOMP];
928 gLeft = v2->color[GCOMP];
929 bLeft = v2->color[BCOMP];
930 fdrOuter = fdgOuter = fdbOuter = 0.0F;
931 # else
932 rLeft = ChanToFixed(v2->color[RCOMP]);
933 gLeft = ChanToFixed(v2->color[GCOMP]);
934 bLeft = ChanToFixed(v2->color[BCOMP]);
935 fdrOuter = fdgOuter = fdbOuter = 0;
936 # endif
937 # ifdef INTERP_ALPHA
938 # if CHAN_TYPE == GL_FLOAT
939 aLeft = v2->color[ACOMP];
940 fdaOuter = 0.0F;
941 # else
942 aLeft = ChanToFixed(v2->color[ACOMP]);
943 fdaOuter = 0;
944 # endif
945 # endif
946 }
947 #endif /* INTERP_RGB */
948
949
950 #ifdef INTERP_SPEC
951 if (ctx->Light.ShadeModel == GL_SMOOTH) {
952 # if CHAN_TYPE == GL_FLOAT
953 srLeft = vLower->specular[RCOMP] + (span.dsrdx * adjx + span.dsrdy * adjy) * (1.0F / FIXED_SCALE);
954 sgLeft = vLower->specular[GCOMP] + (span.dsgdx * adjx + span.dsgdy * adjy) * (1.0F / FIXED_SCALE);
955 sbLeft = vLower->specular[BCOMP] + (span.dsbdx * adjx + span.dsbdy * adjy) * (1.0F / FIXED_SCALE);
956 dsrOuter = span.dsrdy + dxOuter * span.dsrdx;
957 dsgOuter = span.dsgdy + dxOuter * span.dsgdx;
958 dsbOuter = span.dsbdy + dxOuter * span.dsbdx;
959 # else
960 srLeft = (GLfixed) (ChanToFixed(vLower->specular[RCOMP]) + span.dsrdx * adjx + span.dsrdy * adjy) + FIXED_HALF;
961 sgLeft = (GLfixed) (ChanToFixed(vLower->specular[GCOMP]) + span.dsgdx * adjx + span.dsgdy * adjy) + FIXED_HALF;
962 sbLeft = (GLfixed) (ChanToFixed(vLower->specular[BCOMP]) + span.dsbdx * adjx + span.dsbdy * adjy) + FIXED_HALF;
963 dsrOuter = SignedFloatToFixed(span.dsrdy + dxOuter * span.dsrdx);
964 dsgOuter = SignedFloatToFixed(span.dsgdy + dxOuter * span.dsgdx);
965 dsbOuter = SignedFloatToFixed(span.dsbdy + dxOuter * span.dsbdx);
966 # endif
967 }
968 else {
969 ASSERT(ctx->Light.ShadeModel == GL_FLAT);
970 #if CHAN_TYPE == GL_FLOAT
971 srLeft = v2->specular[RCOMP];
972 sgLeft = v2->specular[GCOMP];
973 sbLeft = v2->specular[BCOMP];
974 dsrOuter = dsgOuter = dsbOuter = 0.0F;
975 # else
976 srLeft = ChanToFixed(v2->specular[RCOMP]);
977 sgLeft = ChanToFixed(v2->specular[GCOMP]);
978 sbLeft = ChanToFixed(v2->specular[BCOMP]);
979 dsrOuter = dsgOuter = dsbOuter = 0;
980 # endif
981 }
982 #endif
983
984 #ifdef INTERP_INDEX
985 if (ctx->Light.ShadeModel == GL_SMOOTH) {
986 iLeft = (GLfixed)(vLower->index * FIXED_SCALE
987 + didx * adjx + didy * adjy) + FIXED_HALF;
988 diOuter = SignedFloatToFixed(didy + dxOuter * didx);
989 }
990 else {
991 ASSERT(ctx->Light.ShadeModel == GL_FLAT);
992 iLeft = FloatToFixed(v2->index);
993 diOuter = 0;
994 }
995 #endif
996 #ifdef INTERP_INT_TEX
997 {
998 GLfloat s0, t0;
999 s0 = vLower->texcoord[0][0] * S_SCALE;
1000 sLeft = (GLfixed)(s0 * FIXED_SCALE + span.texStepX[0][0] * adjx
1001 + span.texStepY[0][0] * adjy) + FIXED_HALF;
1002 dsOuter = SignedFloatToFixed(span.texStepY[0][0] + dxOuter * span.texStepX[0][0]);
1003
1004 t0 = vLower->texcoord[0][1] * T_SCALE;
1005 tLeft = (GLfixed)(t0 * FIXED_SCALE + span.texStepX[0][1] * adjx
1006 + span.texStepY[0][1] * adjy) + FIXED_HALF;
1007 dtOuter = SignedFloatToFixed(span.texStepY[0][1] + dxOuter * span.texStepX[0][1]);
1008 }
1009 #endif
1010 #ifdef INTERP_TEX
1011 TEX_UNIT_LOOP(
1012 const GLfloat invW = vLower->win[3];
1013 const GLfloat s0 = vLower->texcoord[u][0] * invW;
1014 const GLfloat t0 = vLower->texcoord[u][1] * invW;
1015 const GLfloat u0 = vLower->texcoord[u][2] * invW;
1016 const GLfloat v0 = vLower->texcoord[u][3] * invW;
1017 sLeft[u] = s0 + (span.texStepX[u][0] * adjx + span.texStepY[u][0] * adjy) * (1.0F/FIXED_SCALE);
1018 tLeft[u] = t0 + (span.texStepX[u][1] * adjx + span.texStepY[u][1] * adjy) * (1.0F/FIXED_SCALE);
1019 uLeft[u] = u0 + (span.texStepX[u][2] * adjx + span.texStepY[u][2] * adjy) * (1.0F/FIXED_SCALE);
1020 vLeft[u] = v0 + (span.texStepX[u][3] * adjx + span.texStepY[u][3] * adjy) * (1.0F/FIXED_SCALE);
1021 dsOuter[u] = span.texStepY[u][0] + dxOuter * span.texStepX[u][0];
1022 dtOuter[u] = span.texStepY[u][1] + dxOuter * span.texStepX[u][1];
1023 duOuter[u] = span.texStepY[u][2] + dxOuter * span.texStepX[u][2];
1024 dvOuter[u] = span.texStepY[u][3] + dxOuter * span.texStepX[u][3];
1025 )
1026 #endif
1027 } /*if setupLeft*/
1028
1029
1030 if (setupRight && eRight->lines>0) {
1031 #if TRIANGLE_WALK_DOUBLE
1032 fxRightEdge = eRight->fsx;
1033 fdxRightEdge = eRight->dxdy;
1034 #else
1035 fxRightEdge = eRight->fsx - FIXED_EPSILON;
1036 fdxRightEdge = eRight->fdxdy;
1037 #endif
1038 }
1039
1040 if (lines==0) {
1041 continue;
1042 }
1043
1044
1045 /* Rasterize setup */
1046 #ifdef PIXEL_ADDRESS
1047 dPRowInner = dPRowOuter + sizeof(PIXEL_TYPE);
1048 #endif
1049 #ifdef INTERP_Z
1050 # ifdef DEPTH_TYPE
1051 dZRowInner = dZRowOuter + sizeof(DEPTH_TYPE);
1052 # endif
1053 fdzInner = fdzOuter + span.zStep;
1054 #endif
1055 #ifdef INTERP_W
1056 dwInner = dwOuter + span.dwdx;
1057 #endif
1058 #ifdef INTERP_FOG
1059 dfogInner = dfogOuter + span.dfogdx;
1060 #endif
1061 #ifdef INTERP_RGB
1062 fdrInner = fdrOuter + span.redStep;
1063 fdgInner = fdgOuter + span.greenStep;
1064 fdbInner = fdbOuter + span.blueStep;
1065 #endif
1066 #ifdef INTERP_ALPHA
1067 fdaInner = fdaOuter + span.alphaStep;
1068 #endif
1069 #ifdef INTERP_SPEC
1070 dsrInner = dsrOuter + span.specRedStep;
1071 dsgInner = dsgOuter + span.specGreenStep;
1072 dsbInner = dsbOuter + span.specBlueStep;
1073 #endif
1074 #ifdef INTERP_INDEX
1075 diInner = diOuter + span.indexStep;
1076 #endif
1077 #ifdef INTERP_INT_TEX
1078 dsInner = dsOuter + span.intTexStep[0];
1079 dtInner = dtOuter + span.intTexStep[1];
1080 #endif
1081 #ifdef INTERP_TEX
1082 TEX_UNIT_LOOP(
1083 dsInner[u] = dsOuter[u] + span.texStepX[u][0];
1084 dtInner[u] = dtOuter[u] + span.texStepX[u][1];
1085 duInner[u] = duOuter[u] + span.texStepX[u][2];
1086 dvInner[u] = dvOuter[u] + span.texStepX[u][3];
1087 )
1088 #endif
1089
1090 while (lines > 0) {
1091 /* initialize the span interpolants to the leftmost value */
1092 /* ff = fixed-pt fragment */
1093 const GLint right = InterpToInt(fxRightEdge);
1094 span.x = InterpToInt(fxLeftEdge);
1095 if (right <= span.x)
1096 span.end = 0;
1097 else
1098 span.end = right - span.x;
1099
1100 #ifdef INTERP_Z
1101 span.z = zLeft;
1102 #endif
1103 #ifdef INTERP_W
1104 span.w = wLeft;
1105 #endif
1106 #ifdef INTERP_FOG
1107 span.fog = fogLeft;
1108 #endif
1109 #ifdef INTERP_RGB
1110 span.red = rLeft;
1111 span.green = gLeft;
1112 span.blue = bLeft;
1113 #endif
1114 #ifdef INTERP_ALPHA
1115 span.alpha = aLeft;
1116 #endif
1117 #ifdef INTERP_SPEC
1118 span.specRed = srLeft;
1119 span.specGreen = sgLeft;
1120 span.specBlue = sbLeft;
1121 #endif
1122 #ifdef INTERP_INDEX
1123 span.index = iLeft;
1124 #endif
1125 #ifdef INTERP_INT_TEX
1126 span.intTex[0] = sLeft;
1127 span.intTex[1] = tLeft;
1128 #endif
1129
1130 #ifdef INTERP_TEX
1131 TEX_UNIT_LOOP(
1132 span.tex[u][0] = sLeft[u];
1133 span.tex[u][1] = tLeft[u];
1134 span.tex[u][2] = uLeft[u];
1135 span.tex[u][3] = vLeft[u];
1136 )
1137 #endif
1138
1139 /* This is where we actually generate fragments */
1140 /* XXX the test for span.y > 0 _shouldn't_ be needed but
1141 * it fixes a problem on 64-bit Opterons (bug 4842).
1142 */
1143 if (span.end > 0 && span.y >= 0) {
1144 const GLint len = span.end - 1;
1145 (void) len;
1146 #ifdef INTERP_RGB
1147 CLAMP_INTERPOLANT(red, redStep, len);
1148 CLAMP_INTERPOLANT(green, greenStep, len);
1149 CLAMP_INTERPOLANT(blue, blueStep, len);
1150 #endif
1151 #ifdef INTERP_ALPHA
1152 CLAMP_INTERPOLANT(alpha, alphaStep, len);
1153 #endif
1154 #ifdef INTERP_SPEC
1155 CLAMP_INTERPOLANT(specRed, specRedStep, len);
1156 CLAMP_INTERPOLANT(specGreen, specGreenStep, len);
1157 CLAMP_INTERPOLANT(specBlue, specBlueStep, len);
1158 #endif
1159 #ifdef INTERP_INDEX
1160 CLAMP_INTERPOLANT(index, indexStep, len);
1161 #endif
1162 {
1163 RENDER_SPAN( span );
1164 }
1165 }
1166
1167 /*
1168 * Advance to the next scan line. Compute the
1169 * new edge coordinates, and adjust the
1170 * pixel-center x coordinate so that it stays
1171 * on or inside the major edge.
1172 */
1173 span.y++;
1174 lines--;
1175
1176 fxLeftEdge += fdxLeftEdge;
1177 fxRightEdge += fdxRightEdge;
1178
1179 fError += fdError;
1180 if (fError >= 0) {
1181 fError -= INTERP_ONE;
1182
1183 #ifdef PIXEL_ADDRESS
1184 pRow = (PIXEL_TYPE *) ((GLubyte *) pRow + dPRowOuter);
1185 #endif
1186 #ifdef INTERP_Z
1187 # ifdef DEPTH_TYPE
1188 zRow = (DEPTH_TYPE *) ((GLubyte *) zRow + dZRowOuter);
1189 # endif
1190 zLeft += fdzOuter;
1191 #endif
1192 #ifdef INTERP_W
1193 wLeft += dwOuter;
1194 #endif
1195 #ifdef INTERP_FOG
1196 fogLeft += dfogOuter;
1197 #endif
1198 #ifdef INTERP_RGB
1199 rLeft += fdrOuter;
1200 gLeft += fdgOuter;
1201 bLeft += fdbOuter;
1202 #endif
1203 #ifdef INTERP_ALPHA
1204 aLeft += fdaOuter;
1205 #endif
1206 #ifdef INTERP_SPEC
1207 srLeft += dsrOuter;
1208 sgLeft += dsgOuter;
1209 sbLeft += dsbOuter;
1210 #endif
1211 #ifdef INTERP_INDEX
1212 iLeft += diOuter;
1213 #endif
1214 #ifdef INTERP_INT_TEX
1215 sLeft += dsOuter;
1216 tLeft += dtOuter;
1217 #endif
1218 #ifdef INTERP_TEX
1219 TEX_UNIT_LOOP(
1220 sLeft[u] += dsOuter[u];
1221 tLeft[u] += dtOuter[u];
1222 uLeft[u] += duOuter[u];
1223 vLeft[u] += dvOuter[u];
1224 )
1225 #endif
1226 }
1227 else {
1228 #ifdef PIXEL_ADDRESS
1229 pRow = (PIXEL_TYPE *) ((GLubyte *) pRow + dPRowInner);
1230 #endif
1231 #ifdef INTERP_Z
1232 # ifdef DEPTH_TYPE
1233 zRow = (DEPTH_TYPE *) ((GLubyte *) zRow + dZRowInner);
1234 # endif
1235 zLeft += fdzInner;
1236 #endif
1237 #ifdef INTERP_W
1238 wLeft += dwInner;
1239 #endif
1240 #ifdef INTERP_FOG
1241 fogLeft += dfogInner;
1242 #endif
1243 #ifdef INTERP_RGB
1244 rLeft += fdrInner;
1245 gLeft += fdgInner;
1246 bLeft += fdbInner;
1247 #endif
1248 #ifdef INTERP_ALPHA
1249 aLeft += fdaInner;
1250 #endif
1251 #ifdef INTERP_SPEC
1252 srLeft += dsrInner;
1253 sgLeft += dsgInner;
1254 sbLeft += dsbInner;
1255 #endif
1256 #ifdef INTERP_INDEX
1257 iLeft += diInner;
1258 #endif
1259 #ifdef INTERP_INT_TEX
1260 sLeft += dsInner;
1261 tLeft += dtInner;
1262 #endif
1263 #ifdef INTERP_TEX
1264 TEX_UNIT_LOOP(
1265 sLeft[u] += dsInner[u];
1266 tLeft[u] += dtInner[u];
1267 uLeft[u] += duInner[u];
1268 vLeft[u] += dvInner[u];
1269 )
1270 #endif
1271 }
1272 } /*while lines>0*/
1273
1274 } /* for subTriangle */
1275
1276 }
1277 #ifdef CLEANUP_CODE
1278 CLEANUP_CODE
1279 #endif
1280 }
1281 }
1282
1283 #undef SETUP_CODE
1284 #undef CLEANUP_CODE
1285 #undef RENDER_SPAN
1286
1287 #undef PIXEL_TYPE
1288 #undef BYTES_PER_ROW
1289 #undef PIXEL_ADDRESS
1290 #undef DEPTH_TYPE
1291
1292 #undef INTERP_Z
1293 #undef INTERP_W
1294 #undef INTERP_FOG
1295 #undef INTERP_RGB
1296 #undef INTERP_ALPHA
1297 #undef INTERP_SPEC
1298 #undef INTERP_INDEX
1299 #undef INTERP_INT_TEX
1300 #undef INTERP_TEX
1301 #undef INTERP_MULTITEX
1302 #undef TEX_UNIT_LOOP
1303
1304 #undef S_SCALE
1305 #undef T_SCALE
1306
1307 #undef FixedToDepth
1308 #undef ColorTemp
1309 #undef GLinterp
1310 #undef InterpToInt
1311 #undef INTERP_ONE
1312
1313 #undef NAME