clean-ups, re-org in preparation for fragment program work
[mesa.git] / src / mesa / swrast / s_tritemp.h
1 /* $Id: s_tritemp.h,v 1.45 2003/03/16 18:42:13 brianp Exp $ */
2
3 /*
4 * Mesa 3-D graphics library
5 * Version: 5.1
6 *
7 * Copyright (C) 1999-2003 Brian Paul All Rights Reserved.
8 *
9 * Permission is hereby granted, free of charge, to any person obtaining a
10 * copy of this software and associated documentation files (the "Software"),
11 * to deal in the Software without restriction, including without limitation
12 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
13 * and/or sell copies of the Software, and to permit persons to whom the
14 * Software is furnished to do so, subject to the following conditions:
15 *
16 * The above copyright notice and this permission notice shall be included
17 * in all copies or substantial portions of the Software.
18 *
19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
20 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
22 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
23 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
24 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25 */
26 /* $XFree86: xc/extras/Mesa/src/swrast/s_tritemp.h,v 1.2 2002/02/27 21:07:54 tsi Exp $ */
27
28 /*
29 * Triangle Rasterizer Template
30 *
31 * This file is #include'd to generate custom triangle rasterizers.
32 *
33 * The following macros may be defined to indicate what auxillary information
34 * must be interplated across the triangle:
35 * INTERP_Z - if defined, interpolate Z values
36 * INTERP_FOG - if defined, interpolate fog values
37 * INTERP_RGB - if defined, interpolate RGB values
38 * INTERP_ALPHA - if defined, interpolate Alpha values (req's INTERP_RGB)
39 * INTERP_SPEC - if defined, interpolate specular RGB values
40 * INTERP_INDEX - if defined, interpolate color index values
41 * INTERP_INT_TEX - if defined, interpolate integer ST texcoords
42 * (fast, simple 2-D texture mapping)
43 * INTERP_TEX - if defined, interpolate set 0 float STRQ texcoords
44 * NOTE: OpenGL STRQ = Mesa STUV (R was taken for red)
45 * INTERP_MULTITEX - if defined, interpolate N units of STRQ texcoords
46 *
47 * When one can directly address pixels in the color buffer the following
48 * macros can be defined and used to compute pixel addresses during
49 * rasterization (see pRow):
50 * PIXEL_TYPE - the datatype of a pixel (GLubyte, GLushort, GLuint)
51 * BYTES_PER_ROW - number of bytes per row in the color buffer
52 * PIXEL_ADDRESS(X,Y) - returns the address of pixel at (X,Y) where
53 * Y==0 at bottom of screen and increases upward.
54 *
55 * Similarly, for direct depth buffer access, this type is used for depth
56 * buffer addressing:
57 * DEPTH_TYPE - either GLushort or GLuint
58 *
59 * Optionally, one may provide one-time setup code per triangle:
60 * SETUP_CODE - code which is to be executed once per triangle
61 * CLEANUP_CODE - code to execute at end of triangle
62 *
63 * The following macro MUST be defined:
64 * RENDER_SPAN(span) - code to write a span of pixels.
65 *
66 * This code was designed for the origin to be in the lower-left corner.
67 *
68 * Inspired by triangle rasterizer code written by Allen Akin. Thanks Allen!
69 */
70
71
72 /*
73 * ColorTemp is used for intermediate color values.
74 */
75 #if CHAN_TYPE == GL_FLOAT
76 #define ColorTemp GLfloat
77 #else
78 #define ColorTemp GLint /* same as GLfixed */
79 #endif
80
81
82
83 static void NAME(GLcontext *ctx, const SWvertex *v0,
84 const SWvertex *v1,
85 const SWvertex *v2 )
86 {
87 typedef struct {
88 const SWvertex *v0, *v1; /* Y(v0) < Y(v1) */
89 GLfloat dx; /* X(v1) - X(v0) */
90 GLfloat dy; /* Y(v1) - Y(v0) */
91 GLfixed fdxdy; /* dx/dy in fixed-point */
92 GLfixed fsx; /* first sample point x coord */
93 GLfixed fsy;
94 GLfloat adjy; /* adjust from v[0]->fy to fsy, scaled */
95 GLint lines; /* number of lines to be sampled on this edge */
96 GLfixed fx0; /* fixed pt X of lower endpoint */
97 } EdgeT;
98
99 #ifdef INTERP_Z
100 const GLint depthBits = ctx->Visual.depthBits;
101 const GLint fixedToDepthShift = depthBits <= 16 ? FIXED_SHIFT : 0;
102 const GLfloat maxDepth = ctx->DepthMaxF;
103 #define FixedToDepth(F) ((F) >> fixedToDepthShift)
104 #endif
105 EdgeT eMaj, eTop, eBot;
106 GLfloat oneOverArea;
107 const SWvertex *vMin, *vMid, *vMax; /* Y(vMin)<=Y(vMid)<=Y(vMax) */
108 float bf = SWRAST_CONTEXT(ctx)->_backface_sign;
109 const GLint snapMask = ~((FIXED_ONE / (1 << SUB_PIXEL_BITS)) - 1); /* for x/y coord snapping */
110 GLfixed vMin_fx, vMin_fy, vMid_fx, vMid_fy, vMax_fx, vMax_fy;
111
112 struct sw_span span;
113
114 INIT_SPAN(span, GL_POLYGON, 0, 0, 0);
115
116 #ifdef INTERP_Z
117 (void) fixedToDepthShift;
118 #endif
119
120 /*
121 printf("%s()\n", __FUNCTION__);
122 printf(" %g, %g, %g\n", v0->win[0], v0->win[1], v0->win[2]);
123 printf(" %g, %g, %g\n", v1->win[0], v1->win[1], v1->win[2]);
124 printf(" %g, %g, %g\n", v2->win[0], v2->win[1], v2->win[2]);
125 */
126
127 /* Compute fixed point x,y coords w/ half-pixel offsets and snapping.
128 * And find the order of the 3 vertices along the Y axis.
129 */
130 {
131 const GLfixed fy0 = FloatToFixed(v0->win[1] - 0.5F) & snapMask;
132 const GLfixed fy1 = FloatToFixed(v1->win[1] - 0.5F) & snapMask;
133 const GLfixed fy2 = FloatToFixed(v2->win[1] - 0.5F) & snapMask;
134
135 if (fy0 <= fy1) {
136 if (fy1 <= fy2) {
137 /* y0 <= y1 <= y2 */
138 vMin = v0; vMid = v1; vMax = v2;
139 vMin_fy = fy0; vMid_fy = fy1; vMax_fy = fy2;
140 }
141 else if (fy2 <= fy0) {
142 /* y2 <= y0 <= y1 */
143 vMin = v2; vMid = v0; vMax = v1;
144 vMin_fy = fy2; vMid_fy = fy0; vMax_fy = fy1;
145 }
146 else {
147 /* y0 <= y2 <= y1 */
148 vMin = v0; vMid = v2; vMax = v1;
149 vMin_fy = fy0; vMid_fy = fy2; vMax_fy = fy1;
150 bf = -bf;
151 }
152 }
153 else {
154 if (fy0 <= fy2) {
155 /* y1 <= y0 <= y2 */
156 vMin = v1; vMid = v0; vMax = v2;
157 vMin_fy = fy1; vMid_fy = fy0; vMax_fy = fy2;
158 bf = -bf;
159 }
160 else if (fy2 <= fy1) {
161 /* y2 <= y1 <= y0 */
162 vMin = v2; vMid = v1; vMax = v0;
163 vMin_fy = fy2; vMid_fy = fy1; vMax_fy = fy0;
164 bf = -bf;
165 }
166 else {
167 /* y1 <= y2 <= y0 */
168 vMin = v1; vMid = v2; vMax = v0;
169 vMin_fy = fy1; vMid_fy = fy2; vMax_fy = fy0;
170 }
171 }
172
173 /* fixed point X coords */
174 vMin_fx = FloatToFixed(vMin->win[0] + 0.5F) & snapMask;
175 vMid_fx = FloatToFixed(vMid->win[0] + 0.5F) & snapMask;
176 vMax_fx = FloatToFixed(vMax->win[0] + 0.5F) & snapMask;
177 }
178
179 /* vertex/edge relationship */
180 eMaj.v0 = vMin; eMaj.v1 = vMax; /*TODO: .v1's not needed */
181 eTop.v0 = vMid; eTop.v1 = vMax;
182 eBot.v0 = vMin; eBot.v1 = vMid;
183
184 /* compute deltas for each edge: vertex[upper] - vertex[lower] */
185 eMaj.dx = FixedToFloat(vMax_fx - vMin_fx);
186 eMaj.dy = FixedToFloat(vMax_fy - vMin_fy);
187 eTop.dx = FixedToFloat(vMax_fx - vMid_fx);
188 eTop.dy = FixedToFloat(vMax_fy - vMid_fy);
189 eBot.dx = FixedToFloat(vMid_fx - vMin_fx);
190 eBot.dy = FixedToFloat(vMid_fy - vMin_fy);
191
192 /* compute area, oneOverArea and perform backface culling */
193 {
194 const GLfloat area = eMaj.dx * eBot.dy - eBot.dx * eMaj.dy;
195
196 /* Do backface culling */
197 if (area * bf < 0.0)
198 return;
199
200 if (IS_INF_OR_NAN(area) || area == 0.0F)
201 return;
202
203 oneOverArea = 1.0F / area;
204 }
205
206 #ifndef DO_OCCLUSION_TEST
207 ctx->OcclusionResult = GL_TRUE;
208 #endif
209 span.facing = ctx->_Facing; /* for 2-sided stencil test */
210
211 /* Edge setup. For a triangle strip these could be reused... */
212 {
213 eMaj.fsy = FixedCeil(vMin_fy);
214 eMaj.lines = FixedToInt(FixedCeil(vMax_fy - eMaj.fsy));
215 if (eMaj.lines > 0) {
216 GLfloat dxdy = eMaj.dx / eMaj.dy;
217 eMaj.fdxdy = SignedFloatToFixed(dxdy);
218 eMaj.adjy = (GLfloat) (eMaj.fsy - vMin_fy); /* SCALED! */
219 eMaj.fx0 = vMin_fx;
220 eMaj.fsx = eMaj.fx0 + (GLfixed) (eMaj.adjy * dxdy);
221 }
222 else {
223 return; /*CULLED*/
224 }
225
226 eTop.fsy = FixedCeil(vMid_fy);
227 eTop.lines = FixedToInt(FixedCeil(vMax_fy - eTop.fsy));
228 if (eTop.lines > 0) {
229 GLfloat dxdy = eTop.dx / eTop.dy;
230 eTop.fdxdy = SignedFloatToFixed(dxdy);
231 eTop.adjy = (GLfloat) (eTop.fsy - vMid_fy); /* SCALED! */
232 eTop.fx0 = vMid_fx;
233 eTop.fsx = eTop.fx0 + (GLfixed) (eTop.adjy * dxdy);
234 }
235
236 eBot.fsy = FixedCeil(vMin_fy);
237 eBot.lines = FixedToInt(FixedCeil(vMid_fy - eBot.fsy));
238 if (eBot.lines > 0) {
239 GLfloat dxdy = eBot.dx / eBot.dy;
240 eBot.fdxdy = SignedFloatToFixed(dxdy);
241 eBot.adjy = (GLfloat) (eBot.fsy - vMin_fy); /* SCALED! */
242 eBot.fx0 = vMin_fx;
243 eBot.fsx = eBot.fx0 + (GLfixed) (eBot.adjy * dxdy);
244 }
245 }
246
247 /*
248 * Conceptually, we view a triangle as two subtriangles
249 * separated by a perfectly horizontal line. The edge that is
250 * intersected by this line is one with maximal absolute dy; we
251 * call it a ``major'' edge. The other two edges are the
252 * ``top'' edge (for the upper subtriangle) and the ``bottom''
253 * edge (for the lower subtriangle). If either of these two
254 * edges is horizontal or very close to horizontal, the
255 * corresponding subtriangle might cover zero sample points;
256 * we take care to handle such cases, for performance as well
257 * as correctness.
258 *
259 * By stepping rasterization parameters along the major edge,
260 * we can avoid recomputing them at the discontinuity where
261 * the top and bottom edges meet. However, this forces us to
262 * be able to scan both left-to-right and right-to-left.
263 * Also, we must determine whether the major edge is at the
264 * left or right side of the triangle. We do this by
265 * computing the magnitude of the cross-product of the major
266 * and top edges. Since this magnitude depends on the sine of
267 * the angle between the two edges, its sign tells us whether
268 * we turn to the left or to the right when travelling along
269 * the major edge to the top edge, and from this we infer
270 * whether the major edge is on the left or the right.
271 *
272 * Serendipitously, this cross-product magnitude is also a
273 * value we need to compute the iteration parameter
274 * derivatives for the triangle, and it can be used to perform
275 * backface culling because its sign tells us whether the
276 * triangle is clockwise or counterclockwise. In this code we
277 * refer to it as ``area'' because it's also proportional to
278 * the pixel area of the triangle.
279 */
280
281 {
282 GLint scan_from_left_to_right; /* true if scanning left-to-right */
283 #ifdef INTERP_Z
284 GLfloat dzdx, dzdy;
285 #endif
286 #ifdef INTERP_FOG
287 GLfloat dfogdy;
288 #endif
289 #if defined(INTERP_RGB)
290 GLfloat drdx, drdy;
291 GLfloat dgdx, dgdy;
292 GLfloat dbdx, dbdy;
293 #endif
294 #if defined(INTERP_ALPHA)
295 GLfloat dadx, dady;
296 #endif
297 #if defined(INTERP_SPEC)
298 GLfloat dsrdx, dsrdy;
299 GLfloat dsgdx, dsgdy;
300 GLfloat dsbdx, dsbdy;
301 #endif
302 #ifdef INTERP_INDEX
303 GLfloat didx, didy;
304 #endif
305
306 /*
307 * Execute user-supplied setup code
308 */
309 #ifdef SETUP_CODE
310 SETUP_CODE
311 #endif
312
313 scan_from_left_to_right = (oneOverArea < 0.0F);
314
315
316 /* compute d?/dx and d?/dy derivatives */
317 #ifdef INTERP_Z
318 span.interpMask |= SPAN_Z;
319 {
320 GLfloat eMaj_dz, eBot_dz;
321 eMaj_dz = vMax->win[2] - vMin->win[2];
322 eBot_dz = vMid->win[2] - vMin->win[2];
323 dzdx = oneOverArea * (eMaj_dz * eBot.dy - eMaj.dy * eBot_dz);
324 if (dzdx > maxDepth || dzdx < -maxDepth) {
325 /* probably a sliver triangle */
326 dzdx = 0.0;
327 dzdy = 0.0;
328 }
329 else {
330 dzdy = oneOverArea * (eMaj.dx * eBot_dz - eMaj_dz * eBot.dx);
331 }
332 if (depthBits <= 16)
333 span.zStep = SignedFloatToFixed(dzdx);
334 else
335 span.zStep = (GLint) dzdx;
336 }
337 #endif
338 #ifdef INTERP_FOG
339 span.interpMask |= SPAN_FOG;
340 {
341 const GLfloat eMaj_dfog = vMax->fog - vMin->fog;
342 const GLfloat eBot_dfog = vMid->fog - vMin->fog;
343 span.fogStep = oneOverArea * (eMaj_dfog * eBot.dy - eMaj.dy * eBot_dfog);
344 dfogdy = oneOverArea * (eMaj.dx * eBot_dfog - eMaj_dfog * eBot.dx);
345 }
346 #endif
347 #ifdef INTERP_RGB
348 span.interpMask |= SPAN_RGBA;
349 if (ctx->Light.ShadeModel == GL_SMOOTH) {
350 GLfloat eMaj_dr = (GLfloat) ((ColorTemp) vMax->color[RCOMP] - vMin->color[RCOMP]);
351 GLfloat eBot_dr = (GLfloat) ((ColorTemp) vMid->color[RCOMP] - vMin->color[RCOMP]);
352 GLfloat eMaj_dg = (GLfloat) ((ColorTemp) vMax->color[GCOMP] - vMin->color[GCOMP]);
353 GLfloat eBot_dg = (GLfloat) ((ColorTemp) vMid->color[GCOMP] - vMin->color[GCOMP]);
354 GLfloat eMaj_db = (GLfloat) ((ColorTemp) vMax->color[BCOMP] - vMin->color[BCOMP]);
355 GLfloat eBot_db = (GLfloat) ((ColorTemp) vMid->color[BCOMP] - vMin->color[BCOMP]);
356 # ifdef INTERP_ALPHA
357 GLfloat eMaj_da = (GLfloat) ((ColorTemp) vMax->color[ACOMP] - vMin->color[ACOMP]);
358 GLfloat eBot_da = (GLfloat) ((ColorTemp) vMid->color[ACOMP] - vMin->color[ACOMP]);
359 # endif
360 drdx = oneOverArea * (eMaj_dr * eBot.dy - eMaj.dy * eBot_dr);
361 drdy = oneOverArea * (eMaj.dx * eBot_dr - eMaj_dr * eBot.dx);
362 dgdx = oneOverArea * (eMaj_dg * eBot.dy - eMaj.dy * eBot_dg);
363 dgdy = oneOverArea * (eMaj.dx * eBot_dg - eMaj_dg * eBot.dx);
364 dbdx = oneOverArea * (eMaj_db * eBot.dy - eMaj.dy * eBot_db);
365 dbdy = oneOverArea * (eMaj.dx * eBot_db - eMaj_db * eBot.dx);
366 # if CHAN_TYPE == GL_FLOAT
367 span.redStep = drdx;
368 span.greenStep = dgdx;
369 span.blueStep = dbdx;
370 # else
371 span.redStep = SignedFloatToFixed(drdx);
372 span.greenStep = SignedFloatToFixed(dgdx);
373 span.blueStep = SignedFloatToFixed(dbdx);
374 # endif /* GL_FLOAT */
375 # ifdef INTERP_ALPHA
376 dadx = oneOverArea * (eMaj_da * eBot.dy - eMaj.dy * eBot_da);
377 dady = oneOverArea * (eMaj.dx * eBot_da - eMaj_da * eBot.dx);
378 # if CHAN_TYPE == GL_FLOAT
379 span.alphaStep = dadx;
380 # else
381 span.alphaStep = SignedFloatToFixed(dadx);
382 # endif /* GL_FLOAT */
383 # endif /* INTERP_ALPHA */
384 }
385 else {
386 ASSERT (ctx->Light.ShadeModel == GL_FLAT);
387 span.interpMask |= SPAN_FLAT;
388 drdx = drdy = span.redStep = 0;
389 dgdx = dgdy = span.greenStep = 0;
390 dbdx = dbdy = span.blueStep = 0;
391 # ifdef INTERP_ALPHA
392 dadx = dady = span.alphaStep = 0;
393 # endif
394 }
395 #endif /* INTERP_RGB */
396 #ifdef INTERP_SPEC
397 span.interpMask |= SPAN_SPEC;
398 if (ctx->Light.ShadeModel == GL_SMOOTH) {
399 GLfloat eMaj_dsr = (GLfloat) ((ColorTemp) vMax->specular[RCOMP] - vMin->specular[RCOMP]);
400 GLfloat eBot_dsr = (GLfloat) ((ColorTemp) vMid->specular[RCOMP] - vMin->specular[RCOMP]);
401 GLfloat eMaj_dsg = (GLfloat) ((ColorTemp) vMax->specular[GCOMP] - vMin->specular[GCOMP]);
402 GLfloat eBot_dsg = (GLfloat) ((ColorTemp) vMid->specular[GCOMP] - vMin->specular[GCOMP]);
403 GLfloat eMaj_dsb = (GLfloat) ((ColorTemp) vMax->specular[BCOMP] - vMin->specular[BCOMP]);
404 GLfloat eBot_dsb = (GLfloat) ((ColorTemp) vMid->specular[BCOMP] - vMin->specular[BCOMP]);
405 dsrdx = oneOverArea * (eMaj_dsr * eBot.dy - eMaj.dy * eBot_dsr);
406 dsrdy = oneOverArea * (eMaj.dx * eBot_dsr - eMaj_dsr * eBot.dx);
407 dsgdx = oneOverArea * (eMaj_dsg * eBot.dy - eMaj.dy * eBot_dsg);
408 dsgdy = oneOverArea * (eMaj.dx * eBot_dsg - eMaj_dsg * eBot.dx);
409 dsbdx = oneOverArea * (eMaj_dsb * eBot.dy - eMaj.dy * eBot_dsb);
410 dsbdy = oneOverArea * (eMaj.dx * eBot_dsb - eMaj_dsb * eBot.dx);
411 # if CHAN_TYPE == GL_FLOAT
412 span.specRedStep = dsrdx;
413 span.specGreenStep = dsgdx;
414 span.specBlueStep = dsbdx;
415 # else
416 span.specRedStep = SignedFloatToFixed(dsrdx);
417 span.specGreenStep = SignedFloatToFixed(dsgdx);
418 span.specBlueStep = SignedFloatToFixed(dsbdx);
419 # endif
420 }
421 else {
422 dsrdx = dsrdy = span.specRedStep = 0;
423 dsgdx = dsgdy = span.specGreenStep = 0;
424 dsbdx = dsbdy = span.specBlueStep = 0;
425 }
426 #endif /* INTERP_SPEC */
427 #ifdef INTERP_INDEX
428 span.interpMask |= SPAN_INDEX;
429 if (ctx->Light.ShadeModel == GL_SMOOTH) {
430 GLfloat eMaj_di = (GLfloat) ((GLint) vMax->index - (GLint) vMin->index);
431 GLfloat eBot_di = (GLfloat) ((GLint) vMid->index - (GLint) vMin->index);
432 didx = oneOverArea * (eMaj_di * eBot.dy - eMaj.dy * eBot_di);
433 didy = oneOverArea * (eMaj.dx * eBot_di - eMaj_di * eBot.dx);
434 span.indexStep = SignedFloatToFixed(didx);
435 }
436 else {
437 span.interpMask |= SPAN_FLAT;
438 didx = didy = 0.0F;
439 span.indexStep = 0;
440 }
441 #endif
442 #ifdef INTERP_INT_TEX
443 span.interpMask |= SPAN_INT_TEXTURE;
444 {
445 GLfloat eMaj_ds = (vMax->texcoord[0][0] - vMin->texcoord[0][0]) * S_SCALE;
446 GLfloat eBot_ds = (vMid->texcoord[0][0] - vMin->texcoord[0][0]) * S_SCALE;
447 GLfloat eMaj_dt = (vMax->texcoord[0][1] - vMin->texcoord[0][1]) * T_SCALE;
448 GLfloat eBot_dt = (vMid->texcoord[0][1] - vMin->texcoord[0][1]) * T_SCALE;
449 span.texStepX[0][0] = oneOverArea * (eMaj_ds * eBot.dy - eMaj.dy * eBot_ds);
450 span.texStepY[0][0] = oneOverArea * (eMaj.dx * eBot_ds - eMaj_ds * eBot.dx);
451 span.texStepX[0][1] = oneOverArea * (eMaj_dt * eBot.dy - eMaj.dy * eBot_dt);
452 span.texStepY[0][1] = oneOverArea * (eMaj.dx * eBot_dt - eMaj_dt * eBot.dx);
453 span.intTexStep[0] = SignedFloatToFixed(span.texStepX[0][0]);
454 span.intTexStep[1] = SignedFloatToFixed(span.texStepX[0][1]);
455 }
456 #endif
457 #ifdef INTERP_TEX
458 span.interpMask |= SPAN_TEXTURE;
459 {
460 const GLfloat wMax = vMax->win[3], wMin = vMin->win[3], wMid = vMid->win[3];
461 GLfloat eMaj_ds = vMax->texcoord[0][0] * wMax - vMin->texcoord[0][0] * wMin;
462 GLfloat eBot_ds = vMid->texcoord[0][0] * wMid - vMin->texcoord[0][0] * wMin;
463 GLfloat eMaj_dt = vMax->texcoord[0][1] * wMax - vMin->texcoord[0][1] * wMin;
464 GLfloat eBot_dt = vMid->texcoord[0][1] * wMid - vMin->texcoord[0][1] * wMin;
465 GLfloat eMaj_du = vMax->texcoord[0][2] * wMax - vMin->texcoord[0][2] * wMin;
466 GLfloat eBot_du = vMid->texcoord[0][2] * wMid - vMin->texcoord[0][2] * wMin;
467 GLfloat eMaj_dv = vMax->texcoord[0][3] * wMax - vMin->texcoord[0][3] * wMin;
468 GLfloat eBot_dv = vMid->texcoord[0][3] * wMid - vMin->texcoord[0][3] * wMin;
469 span.texStepX[0][0] = oneOverArea * (eMaj_ds * eBot.dy - eMaj.dy * eBot_ds);
470 span.texStepY[0][0] = oneOverArea * (eMaj.dx * eBot_ds - eMaj_ds * eBot.dx);
471 span.texStepX[0][1] = oneOverArea * (eMaj_dt * eBot.dy - eMaj.dy * eBot_dt);
472 span.texStepY[0][1] = oneOverArea * (eMaj.dx * eBot_dt - eMaj_dt * eBot.dx);
473 span.texStepX[0][2] = oneOverArea * (eMaj_du * eBot.dy - eMaj.dy * eBot_du);
474 span.texStepY[0][2] = oneOverArea * (eMaj.dx * eBot_du - eMaj_du * eBot.dx);
475 span.texStepX[0][3] = oneOverArea * (eMaj_dv * eBot.dy - eMaj.dy * eBot_dv);
476 span.texStepY[0][3] = oneOverArea * (eMaj.dx * eBot_dv - eMaj_dv * eBot.dx);
477 }
478 #endif
479 #ifdef INTERP_MULTITEX
480 span.interpMask |= SPAN_TEXTURE;
481 {
482 const GLfloat wMax = vMax->win[3], wMin = vMin->win[3], wMid = vMid->win[3];
483 GLuint u;
484 for (u = 0; u < ctx->Const.MaxTextureUnits; u++) {
485 if (ctx->Texture.Unit[u]._ReallyEnabled) {
486 GLfloat eMaj_ds = vMax->texcoord[u][0] * wMax - vMin->texcoord[u][0] * wMin;
487 GLfloat eBot_ds = vMid->texcoord[u][0] * wMid - vMin->texcoord[u][0] * wMin;
488 GLfloat eMaj_dt = vMax->texcoord[u][1] * wMax - vMin->texcoord[u][1] * wMin;
489 GLfloat eBot_dt = vMid->texcoord[u][1] * wMid - vMin->texcoord[u][1] * wMin;
490 GLfloat eMaj_du = vMax->texcoord[u][2] * wMax - vMin->texcoord[u][2] * wMin;
491 GLfloat eBot_du = vMid->texcoord[u][2] * wMid - vMin->texcoord[u][2] * wMin;
492 GLfloat eMaj_dv = vMax->texcoord[u][3] * wMax - vMin->texcoord[u][3] * wMin;
493 GLfloat eBot_dv = vMid->texcoord[u][3] * wMid - vMin->texcoord[u][3] * wMin;
494 span.texStepX[u][0] = oneOverArea * (eMaj_ds * eBot.dy - eMaj.dy * eBot_ds);
495 span.texStepY[u][0] = oneOverArea * (eMaj.dx * eBot_ds - eMaj_ds * eBot.dx);
496 span.texStepX[u][1] = oneOverArea * (eMaj_dt * eBot.dy - eMaj.dy * eBot_dt);
497 span.texStepY[u][1] = oneOverArea * (eMaj.dx * eBot_dt - eMaj_dt * eBot.dx);
498 span.texStepX[u][2] = oneOverArea * (eMaj_du * eBot.dy - eMaj.dy * eBot_du);
499 span.texStepY[u][2] = oneOverArea * (eMaj.dx * eBot_du - eMaj_du * eBot.dx);
500 span.texStepX[u][3] = oneOverArea * (eMaj_dv * eBot.dy - eMaj.dy * eBot_dv);
501 span.texStepY[u][3] = oneOverArea * (eMaj.dx * eBot_dv - eMaj_dv * eBot.dx);
502 }
503 }
504 }
505 #endif
506
507 /*
508 * We always sample at pixel centers. However, we avoid
509 * explicit half-pixel offsets in this code by incorporating
510 * the proper offset in each of x and y during the
511 * transformation to window coordinates.
512 *
513 * We also apply the usual rasterization rules to prevent
514 * cracks and overlaps. A pixel is considered inside a
515 * subtriangle if it meets all of four conditions: it is on or
516 * to the right of the left edge, strictly to the left of the
517 * right edge, on or below the top edge, and strictly above
518 * the bottom edge. (Some edges may be degenerate.)
519 *
520 * The following discussion assumes left-to-right scanning
521 * (that is, the major edge is on the left); the right-to-left
522 * case is a straightforward variation.
523 *
524 * We start by finding the half-integral y coordinate that is
525 * at or below the top of the triangle. This gives us the
526 * first scan line that could possibly contain pixels that are
527 * inside the triangle.
528 *
529 * Next we creep down the major edge until we reach that y,
530 * and compute the corresponding x coordinate on the edge.
531 * Then we find the half-integral x that lies on or just
532 * inside the edge. This is the first pixel that might lie in
533 * the interior of the triangle. (We won't know for sure
534 * until we check the other edges.)
535 *
536 * As we rasterize the triangle, we'll step down the major
537 * edge. For each step in y, we'll move an integer number
538 * of steps in x. There are two possible x step sizes, which
539 * we'll call the ``inner'' step (guaranteed to land on the
540 * edge or inside it) and the ``outer'' step (guaranteed to
541 * land on the edge or outside it). The inner and outer steps
542 * differ by one. During rasterization we maintain an error
543 * term that indicates our distance from the true edge, and
544 * select either the inner step or the outer step, whichever
545 * gets us to the first pixel that falls inside the triangle.
546 *
547 * All parameters (z, red, etc.) as well as the buffer
548 * addresses for color and z have inner and outer step values,
549 * so that we can increment them appropriately. This method
550 * eliminates the need to adjust parameters by creeping a
551 * sub-pixel amount into the triangle at each scanline.
552 */
553
554 {
555 int subTriangle;
556 GLfixed fx;
557 GLfixed fxLeftEdge = 0, fxRightEdge = 0;
558 GLfixed fdxLeftEdge = 0, fdxRightEdge = 0;
559 GLfixed fdxOuter;
560 int idxOuter;
561 float dxOuter;
562 GLfixed fError = 0, fdError = 0;
563 float adjx, adjy;
564 GLfixed fy;
565 #ifdef PIXEL_ADDRESS
566 PIXEL_TYPE *pRow = NULL;
567 int dPRowOuter = 0, dPRowInner; /* offset in bytes */
568 #endif
569 #ifdef INTERP_Z
570 # ifdef DEPTH_TYPE
571 DEPTH_TYPE *zRow = NULL;
572 int dZRowOuter = 0, dZRowInner; /* offset in bytes */
573 # endif
574 GLfixed fz = 0, fdzOuter = 0, fdzInner;
575 #endif
576 #ifdef INTERP_FOG
577 GLfloat fogLeft = 0, dfogOuter = 0, dfogInner;
578 #endif
579 #ifdef INTERP_RGB
580 ColorTemp fr = 0, fdrOuter = 0, fdrInner;
581 ColorTemp fg = 0, fdgOuter = 0, fdgInner;
582 ColorTemp fb = 0, fdbOuter = 0, fdbInner;
583 #endif
584 #ifdef INTERP_ALPHA
585 ColorTemp fa = 0, fdaOuter = 0, fdaInner;
586 #endif
587 #ifdef INTERP_SPEC
588 ColorTemp fsr=0, fdsrOuter=0, fdsrInner;
589 ColorTemp fsg=0, fdsgOuter=0, fdsgInner;
590 ColorTemp fsb=0, fdsbOuter=0, fdsbInner;
591 #endif
592 #ifdef INTERP_INDEX
593 GLfixed fi=0, fdiOuter=0, fdiInner;
594 #endif
595 #ifdef INTERP_INT_TEX
596 GLfixed fs=0, fdsOuter=0, fdsInner;
597 GLfixed ft=0, fdtOuter=0, fdtInner;
598 #endif
599 #ifdef INTERP_TEX
600 GLfloat sLeft=0, dsOuter=0, dsInner;
601 GLfloat tLeft=0, dtOuter=0, dtInner;
602 GLfloat uLeft=0, duOuter=0, duInner;
603 GLfloat vLeft=0, dvOuter=0, dvInner;
604 #endif
605 #ifdef INTERP_MULTITEX
606 GLfloat sLeft[MAX_TEXTURE_COORD_UNITS];
607 GLfloat tLeft[MAX_TEXTURE_COORD_UNITS];
608 GLfloat uLeft[MAX_TEXTURE_COORD_UNITS];
609 GLfloat vLeft[MAX_TEXTURE_COORD_UNITS];
610 GLfloat dsOuter[MAX_TEXTURE_COORD_UNITS], dsInner[MAX_TEXTURE_COORD_UNITS];
611 GLfloat dtOuter[MAX_TEXTURE_COORD_UNITS], dtInner[MAX_TEXTURE_COORD_UNITS];
612 GLfloat duOuter[MAX_TEXTURE_COORD_UNITS], duInner[MAX_TEXTURE_COORD_UNITS];
613 GLfloat dvOuter[MAX_TEXTURE_COORD_UNITS], dvInner[MAX_TEXTURE_COORD_UNITS];
614 #endif
615
616 for (subTriangle=0; subTriangle<=1; subTriangle++) {
617 EdgeT *eLeft, *eRight;
618 int setupLeft, setupRight;
619 int lines;
620
621 if (subTriangle==0) {
622 /* bottom half */
623 if (scan_from_left_to_right) {
624 eLeft = &eMaj;
625 eRight = &eBot;
626 lines = eRight->lines;
627 setupLeft = 1;
628 setupRight = 1;
629 }
630 else {
631 eLeft = &eBot;
632 eRight = &eMaj;
633 lines = eLeft->lines;
634 setupLeft = 1;
635 setupRight = 1;
636 }
637 }
638 else {
639 /* top half */
640 if (scan_from_left_to_right) {
641 eLeft = &eMaj;
642 eRight = &eTop;
643 lines = eRight->lines;
644 setupLeft = 0;
645 setupRight = 1;
646 }
647 else {
648 eLeft = &eTop;
649 eRight = &eMaj;
650 lines = eLeft->lines;
651 setupLeft = 1;
652 setupRight = 0;
653 }
654 if (lines == 0)
655 return;
656 }
657
658 if (setupLeft && eLeft->lines > 0) {
659 const SWvertex *vLower;
660 GLfixed fsx = eLeft->fsx;
661 fx = FixedCeil(fsx);
662 fError = fx - fsx - FIXED_ONE;
663 fxLeftEdge = fsx - FIXED_EPSILON;
664 fdxLeftEdge = eLeft->fdxdy;
665 fdxOuter = FixedFloor(fdxLeftEdge - FIXED_EPSILON);
666 fdError = fdxOuter - fdxLeftEdge + FIXED_ONE;
667 idxOuter = FixedToInt(fdxOuter);
668 dxOuter = (float) idxOuter;
669 (void) dxOuter;
670
671 fy = eLeft->fsy;
672 span.y = FixedToInt(fy);
673
674 adjx = (float)(fx - eLeft->fx0); /* SCALED! */
675 adjy = eLeft->adjy; /* SCALED! */
676 #ifndef __IBMCPP__
677 (void) adjx; /* silence compiler warnings */
678 (void) adjy; /* silence compiler warnings */
679 #endif
680 vLower = eLeft->v0;
681 #ifndef __IBMCPP__
682 (void) vLower; /* silence compiler warnings */
683 #endif
684
685 #ifdef PIXEL_ADDRESS
686 {
687 pRow = (PIXEL_TYPE *) PIXEL_ADDRESS(FixedToInt(fxLeftEdge), span.y);
688 dPRowOuter = -((int)BYTES_PER_ROW) + idxOuter * sizeof(PIXEL_TYPE);
689 /* negative because Y=0 at bottom and increases upward */
690 }
691 #endif
692 /*
693 * Now we need the set of parameter (z, color, etc.) values at
694 * the point (fx, fy). This gives us properly-sampled parameter
695 * values that we can step from pixel to pixel. Furthermore,
696 * although we might have intermediate results that overflow
697 * the normal parameter range when we step temporarily outside
698 * the triangle, we shouldn't overflow or underflow for any
699 * pixel that's actually inside the triangle.
700 */
701
702 #ifdef INTERP_Z
703 {
704 GLfloat z0 = vLower->win[2];
705 if (depthBits <= 16) {
706 /* interpolate fixed-pt values */
707 GLfloat tmp = (z0 * FIXED_SCALE + dzdx * adjx + dzdy * adjy) + FIXED_HALF;
708 if (tmp < MAX_GLUINT / 2)
709 fz = (GLfixed) tmp;
710 else
711 fz = MAX_GLUINT / 2;
712 fdzOuter = SignedFloatToFixed(dzdy + dxOuter * dzdx);
713 }
714 else {
715 /* interpolate depth values exactly */
716 fz = (GLint) (z0 + dzdx * FixedToFloat(adjx) + dzdy * FixedToFloat(adjy));
717 fdzOuter = (GLint) (dzdy + dxOuter * dzdx);
718 }
719 # ifdef DEPTH_TYPE
720 zRow = (DEPTH_TYPE *)
721 _mesa_zbuffer_address(ctx, FixedToInt(fxLeftEdge), span.y);
722 dZRowOuter = (ctx->DrawBuffer->Width + idxOuter) * sizeof(DEPTH_TYPE);
723 # endif
724 }
725 #endif
726 #ifdef INTERP_FOG
727 fogLeft = vLower->fog + (span.fogStep * adjx + dfogdy * adjy)
728 * (1.0F/FIXED_SCALE);
729 dfogOuter = dfogdy + dxOuter * span.fogStep;
730 #endif
731 #ifdef INTERP_RGB
732 if (ctx->Light.ShadeModel == GL_SMOOTH) {
733 # if CHAN_TYPE == GL_FLOAT
734 fr = vLower->color[RCOMP] + (drdx * adjx + drdy * adjy) * (1.0F / FIXED_SCALE);
735 fg = vLower->color[GCOMP] + (dgdx * adjx + dgdy * adjy) * (1.0F / FIXED_SCALE);
736 fb = vLower->color[BCOMP] + (dbdx * adjx + dbdy * adjy) * (1.0F / FIXED_SCALE);
737 fdrOuter = drdy + dxOuter * drdx;
738 fdgOuter = dgdy + dxOuter * dgdx;
739 fdbOuter = dbdy + dxOuter * dbdx;
740 # else
741 fr = (ChanToFixed(vLower->color[RCOMP]) + drdx * adjx + drdy * adjy) + FIXED_HALF;
742 fg = (ChanToFixed(vLower->color[GCOMP]) + dgdx * adjx + dgdy * adjy) + FIXED_HALF;
743 fb = (ChanToFixed(vLower->color[BCOMP]) + dbdx * adjx + dbdy * adjy) + FIXED_HALF;
744 fdrOuter = SignedFloatToFixed(drdy + dxOuter * drdx);
745 fdgOuter = SignedFloatToFixed(dgdy + dxOuter * dgdx);
746 fdbOuter = SignedFloatToFixed(dbdy + dxOuter * dbdx);
747 # endif
748 # ifdef INTERP_ALPHA
749 # if CHAN_TYPE == GL_FLOAT
750 fa = vLower->color[ACOMP] + (dadx * adjx + dady * adjy) * (1.0F / FIXED_SCALE);
751 fdaOuter = dady + dxOuter * dadx;
752 # else
753 fa = (ChanToFixed(vLower->color[ACOMP]) + dadx * adjx + dady * adjy) + FIXED_HALF;
754 fdaOuter = SignedFloatToFixed(dady + dxOuter * dadx);
755 # endif
756 # endif
757 }
758 else {
759 ASSERT (ctx->Light.ShadeModel == GL_FLAT);
760 # if CHAN_TYPE == GL_FLOAT
761 fr = v2->color[RCOMP];
762 fg = v2->color[GCOMP];
763 fb = v2->color[BCOMP];
764 fdrOuter = fdgOuter = fdbOuter = 0.0F;
765 # else
766 fr = ChanToFixed(v2->color[RCOMP]);
767 fg = ChanToFixed(v2->color[GCOMP]);
768 fb = ChanToFixed(v2->color[BCOMP]);
769 fdrOuter = fdgOuter = fdbOuter = 0;
770 # endif
771 # ifdef INTERP_ALPHA
772 # if CHAN_TYPE == GL_FLOAT
773 fa = v2->color[ACOMP];
774 fdaOuter = 0.0F;
775 # else
776 fa = ChanToFixed(v2->color[ACOMP]);
777 fdaOuter = 0;
778 # endif
779 # endif
780 }
781 #endif
782
783 #ifdef INTERP_SPEC
784 if (ctx->Light.ShadeModel == GL_SMOOTH) {
785 # if CHAN_TYPE == GL_FLOAT
786 fsr = vLower->specular[RCOMP] + (dsrdx * adjx + dsrdy * adjy) * (1.0F / FIXED_SCALE);
787 fsg = vLower->specular[GCOMP] + (dsgdx * adjx + dsgdy * adjy) * (1.0F / FIXED_SCALE);
788 fsb = vLower->specular[BCOMP] + (dsbdx * adjx + dsbdy * adjy) * (1.0F / FIXED_SCALE);
789 fdsrOuter = dsrdy + dxOuter * dsrdx;
790 fdsgOuter = dsgdy + dxOuter * dsgdx;
791 fdsbOuter = dsbdy + dxOuter * dsbdx;
792 # else
793 fsr = (GLfixed) (ChanToFixed(vLower->specular[RCOMP]) + dsrdx * adjx + dsrdy * adjy) + FIXED_HALF;
794 fsg = (GLfixed) (ChanToFixed(vLower->specular[GCOMP]) + dsgdx * adjx + dsgdy * adjy) + FIXED_HALF;
795 fsb = (GLfixed) (ChanToFixed(vLower->specular[BCOMP]) + dsbdx * adjx + dsbdy * adjy) + FIXED_HALF;
796 fdsrOuter = SignedFloatToFixed(dsrdy + dxOuter * dsrdx);
797 fdsgOuter = SignedFloatToFixed(dsgdy + dxOuter * dsgdx);
798 fdsbOuter = SignedFloatToFixed(dsbdy + dxOuter * dsbdx);
799 # endif
800 }
801 else {
802 #if CHAN_TYPE == GL_FLOAT
803 fsr = v2->specular[RCOMP];
804 fsg = v2->specular[GCOMP];
805 fsb = v2->specular[BCOMP];
806 fdsrOuter = fdsgOuter = fdsbOuter = 0.0F;
807 # else
808 fsr = ChanToFixed(v2->specular[RCOMP]);
809 fsg = ChanToFixed(v2->specular[GCOMP]);
810 fsb = ChanToFixed(v2->specular[BCOMP]);
811 fdsrOuter = fdsgOuter = fdsbOuter = 0;
812 # endif
813 }
814 #endif
815
816 #ifdef INTERP_INDEX
817 if (ctx->Light.ShadeModel == GL_SMOOTH) {
818 fi = (GLfixed)(vLower->index * FIXED_SCALE
819 + didx * adjx + didy * adjy) + FIXED_HALF;
820 fdiOuter = SignedFloatToFixed(didy + dxOuter * didx);
821 }
822 else {
823 fi = (GLfixed) (v2->index * FIXED_SCALE);
824 fdiOuter = 0;
825 }
826 #endif
827 #ifdef INTERP_INT_TEX
828 {
829 GLfloat s0, t0;
830 s0 = vLower->texcoord[0][0] * S_SCALE;
831 fs = (GLfixed)(s0 * FIXED_SCALE + span.texStepX[0][0] * adjx
832 + span.texStepY[0][0] * adjy) + FIXED_HALF;
833 fdsOuter = SignedFloatToFixed(span.texStepY[0][0] + dxOuter * span.texStepX[0][0]);
834
835 t0 = vLower->texcoord[0][1] * T_SCALE;
836 ft = (GLfixed)(t0 * FIXED_SCALE + span.texStepX[0][1] * adjx
837 + span.texStepY[0][1] * adjy) + FIXED_HALF;
838 fdtOuter = SignedFloatToFixed(span.texStepY[0][1] + dxOuter * span.texStepX[0][1]);
839 }
840 #endif
841 #ifdef INTERP_TEX
842 {
843 const GLfloat invW = vLower->win[3];
844 const GLfloat s0 = vLower->texcoord[0][0] * invW;
845 const GLfloat t0 = vLower->texcoord[0][1] * invW;
846 const GLfloat u0 = vLower->texcoord[0][2] * invW;
847 const GLfloat v0 = vLower->texcoord[0][3] * invW;
848 sLeft = s0 + (span.texStepX[0][0] * adjx + span.texStepY[0][0] * adjy) * (1.0F/FIXED_SCALE);
849 tLeft = t0 + (span.texStepX[0][1] * adjx + span.texStepY[0][1] * adjy) * (1.0F/FIXED_SCALE);
850 uLeft = u0 + (span.texStepX[0][2] * adjx + span.texStepY[0][2] * adjy) * (1.0F/FIXED_SCALE);
851 vLeft = v0 + (span.texStepX[0][3] * adjx + span.texStepY[0][3] * adjy) * (1.0F/FIXED_SCALE);
852 dsOuter = span.texStepY[0][0] + dxOuter * span.texStepX[0][0];
853 dtOuter = span.texStepY[0][1] + dxOuter * span.texStepX[0][1];
854 duOuter = span.texStepY[0][2] + dxOuter * span.texStepX[0][2];
855 dvOuter = span.texStepY[0][3] + dxOuter * span.texStepX[0][3];
856 }
857 #endif
858 #ifdef INTERP_MULTITEX
859 {
860 GLuint u;
861 for (u = 0; u < ctx->Const.MaxTextureUnits; u++) {
862 if (ctx->Texture.Unit[u]._ReallyEnabled) {
863 const GLfloat invW = vLower->win[3];
864 const GLfloat s0 = vLower->texcoord[u][0] * invW;
865 const GLfloat t0 = vLower->texcoord[u][1] * invW;
866 const GLfloat u0 = vLower->texcoord[u][2] * invW;
867 const GLfloat v0 = vLower->texcoord[u][3] * invW;
868 sLeft[u] = s0 + (span.texStepX[u][0] * adjx + span.texStepY[u][0] * adjy) * (1.0F/FIXED_SCALE);
869 tLeft[u] = t0 + (span.texStepX[u][1] * adjx + span.texStepY[u][1] * adjy) * (1.0F/FIXED_SCALE);
870 uLeft[u] = u0 + (span.texStepX[u][2] * adjx + span.texStepY[u][2] * adjy) * (1.0F/FIXED_SCALE);
871 vLeft[u] = v0 + (span.texStepX[u][3] * adjx + span.texStepY[u][3] * adjy) * (1.0F/FIXED_SCALE);
872 dsOuter[u] = span.texStepY[u][0] + dxOuter * span.texStepX[u][0];
873 dtOuter[u] = span.texStepY[u][1] + dxOuter * span.texStepX[u][1];
874 duOuter[u] = span.texStepY[u][2] + dxOuter * span.texStepX[u][2];
875 dvOuter[u] = span.texStepY[u][3] + dxOuter * span.texStepX[u][3];
876 }
877 }
878 }
879 #endif
880
881 } /*if setupLeft*/
882
883
884 if (setupRight && eRight->lines>0) {
885 fxRightEdge = eRight->fsx - FIXED_EPSILON;
886 fdxRightEdge = eRight->fdxdy;
887 }
888
889 if (lines==0) {
890 continue;
891 }
892
893
894 /* Rasterize setup */
895 #ifdef PIXEL_ADDRESS
896 dPRowInner = dPRowOuter + sizeof(PIXEL_TYPE);
897 #endif
898 #ifdef INTERP_Z
899 # ifdef DEPTH_TYPE
900 dZRowInner = dZRowOuter + sizeof(DEPTH_TYPE);
901 # endif
902 fdzInner = fdzOuter + span.zStep;
903 #endif
904 #ifdef INTERP_FOG
905 dfogInner = dfogOuter + span.fogStep;
906 #endif
907 #if defined(INTERP_RGB)
908 fdrInner = fdrOuter + span.redStep;
909 fdgInner = fdgOuter + span.greenStep;
910 fdbInner = fdbOuter + span.blueStep;
911 #endif
912 #if defined(INTERP_ALPHA)
913 fdaInner = fdaOuter + span.alphaStep;
914 #endif
915 #if defined(INTERP_SPEC)
916 fdsrInner = fdsrOuter + span.specRedStep;
917 fdsgInner = fdsgOuter + span.specGreenStep;
918 fdsbInner = fdsbOuter + span.specBlueStep;
919 #endif
920 #ifdef INTERP_INDEX
921 fdiInner = fdiOuter + span.indexStep;
922 #endif
923 #ifdef INTERP_INT_TEX
924 fdsInner = fdsOuter + span.intTexStep[0];
925 fdtInner = fdtOuter + span.intTexStep[1];
926 #endif
927 #ifdef INTERP_TEX
928 dsInner = dsOuter + span.texStepX[0][0];
929 dtInner = dtOuter + span.texStepX[0][1];
930 duInner = duOuter + span.texStepX[0][2];
931 dvInner = dvOuter + span.texStepX[0][3];
932 #endif
933 #ifdef INTERP_MULTITEX
934 {
935 GLuint u;
936 for (u = 0; u < ctx->Const.MaxTextureUnits; u++) {
937 if (ctx->Texture.Unit[u]._ReallyEnabled) {
938 dsInner[u] = dsOuter[u] + span.texStepX[u][0];
939 dtInner[u] = dtOuter[u] + span.texStepX[u][1];
940 duInner[u] = duOuter[u] + span.texStepX[u][2];
941 dvInner[u] = dvOuter[u] + span.texStepX[u][3];
942 }
943 }
944 }
945 #endif
946
947 while (lines > 0) {
948 /* initialize the span interpolants to the leftmost value */
949 /* ff = fixed-pt fragment */
950 const GLint right = FixedToInt(fxRightEdge);
951
952 span.x = FixedToInt(fxLeftEdge);
953
954 if (right <= span.x)
955 span.end = 0;
956 else
957 span.end = right - span.x;
958
959 #ifdef INTERP_Z
960 span.z = fz;
961 #endif
962 #ifdef INTERP_FOG
963 span.fog = fogLeft;
964 #endif
965 #if defined(INTERP_RGB)
966 span.red = fr;
967 span.green = fg;
968 span.blue = fb;
969 #endif
970 #if defined(INTERP_ALPHA)
971 span.alpha = fa;
972 #endif
973 #if defined(INTERP_SPEC)
974 span.specRed = fsr;
975 span.specGreen = fsg;
976 span.specBlue = fsb;
977 #endif
978 #ifdef INTERP_INDEX
979 span.index = fi;
980 #endif
981 #ifdef INTERP_INT_TEX
982 span.intTex[0] = fs;
983 span.intTex[1] = ft;
984 #endif
985
986 #ifdef INTERP_TEX
987 span.tex[0][0] = sLeft;
988 span.tex[0][1] = tLeft;
989 span.tex[0][2] = uLeft;
990 span.tex[0][3] = vLeft;
991 #endif
992
993 #ifdef INTERP_MULTITEX
994 {
995 GLuint u;
996 for (u = 0; u < ctx->Const.MaxTextureUnits; u++) {
997 if (ctx->Texture.Unit[u]._ReallyEnabled) {
998 span.tex[u][0] = sLeft[u];
999 span.tex[u][1] = tLeft[u];
1000 span.tex[u][2] = uLeft[u];
1001 span.tex[u][3] = vLeft[u];
1002 }
1003 }
1004 }
1005 #endif
1006
1007 #ifdef INTERP_RGB
1008 {
1009 /* need this to accomodate round-off errors */
1010 const GLint len = right - span.x - 1;
1011 GLfixed ffrend = span.red + len * span.redStep;
1012 GLfixed ffgend = span.green + len * span.greenStep;
1013 GLfixed ffbend = span.blue + len * span.blueStep;
1014 if (ffrend < 0) {
1015 span.red -= ffrend;
1016 if (span.red < 0)
1017 span.red = 0;
1018 }
1019 if (ffgend < 0) {
1020 span.green -= ffgend;
1021 if (span.green < 0)
1022 span.green = 0;
1023 }
1024 if (ffbend < 0) {
1025 span.blue -= ffbend;
1026 if (span.blue < 0)
1027 span.blue = 0;
1028 }
1029 }
1030 #endif
1031 #ifdef INTERP_ALPHA
1032 {
1033 const GLint len = right - span.x - 1;
1034 GLfixed ffaend = span.alpha + len * span.alphaStep;
1035 if (ffaend < 0) {
1036 span.alpha -= ffaend;
1037 if (span.alpha < 0)
1038 span.alpha = 0;
1039 }
1040 }
1041 #endif
1042 #ifdef INTERP_SPEC
1043 {
1044 /* need this to accomodate round-off errors */
1045 const GLint len = right - span.x - 1;
1046 GLfixed ffsrend = span.specRed + len * span.specRedStep;
1047 GLfixed ffsgend = span.specGreen + len * span.specGreenStep;
1048 GLfixed ffsbend = span.specBlue + len * span.specBlueStep;
1049 if (ffsrend < 0) {
1050 span.specRed -= ffsrend;
1051 if (span.specRed < 0)
1052 span.specRed = 0;
1053 }
1054 if (ffsgend < 0) {
1055 span.specGreen -= ffsgend;
1056 if (span.specGreen < 0)
1057 span.specGreen = 0;
1058 }
1059 if (ffsbend < 0) {
1060 span.specBlue -= ffsbend;
1061 if (span.specBlue < 0)
1062 span.specBlue = 0;
1063 }
1064 }
1065 #endif
1066 #ifdef INTERP_INDEX
1067 if (span.index < 0) span.index = 0;
1068 #endif
1069
1070 /* This is where we actually generate fragments */
1071 if (span.end > 0) {
1072 RENDER_SPAN( span );
1073 }
1074
1075 /*
1076 * Advance to the next scan line. Compute the
1077 * new edge coordinates, and adjust the
1078 * pixel-center x coordinate so that it stays
1079 * on or inside the major edge.
1080 */
1081 (span.y)++;
1082 lines--;
1083
1084 fxLeftEdge += fdxLeftEdge;
1085 fxRightEdge += fdxRightEdge;
1086
1087
1088 fError += fdError;
1089 if (fError >= 0) {
1090 fError -= FIXED_ONE;
1091 #ifdef PIXEL_ADDRESS
1092 pRow = (PIXEL_TYPE *) ((GLubyte *) pRow + dPRowOuter);
1093 #endif
1094 #ifdef INTERP_Z
1095 # ifdef DEPTH_TYPE
1096 zRow = (DEPTH_TYPE *) ((GLubyte *) zRow + dZRowOuter);
1097 # endif
1098 fz += fdzOuter;
1099 #endif
1100 #ifdef INTERP_FOG
1101 fogLeft += dfogOuter;
1102 #endif
1103 #if defined(INTERP_RGB)
1104 fr += fdrOuter;
1105 fg += fdgOuter;
1106 fb += fdbOuter;
1107 #endif
1108 #if defined(INTERP_ALPHA)
1109 fa += fdaOuter;
1110 #endif
1111 #if defined(INTERP_SPEC)
1112 fsr += fdsrOuter;
1113 fsg += fdsgOuter;
1114 fsb += fdsbOuter;
1115 #endif
1116 #ifdef INTERP_INDEX
1117 fi += fdiOuter;
1118 #endif
1119 #ifdef INTERP_INT_TEX
1120 fs += fdsOuter;
1121 ft += fdtOuter;
1122 #endif
1123 #ifdef INTERP_TEX
1124 sLeft += dsOuter;
1125 tLeft += dtOuter;
1126 uLeft += duOuter;
1127 vLeft += dvOuter;
1128 #endif
1129 #ifdef INTERP_MULTITEX
1130 {
1131 GLuint u;
1132 for (u = 0; u < ctx->Const.MaxTextureUnits; u++) {
1133 if (ctx->Texture.Unit[u]._ReallyEnabled) {
1134 sLeft[u] += dsOuter[u];
1135 tLeft[u] += dtOuter[u];
1136 uLeft[u] += duOuter[u];
1137 vLeft[u] += dvOuter[u];
1138 }
1139 }
1140 }
1141 #endif
1142 }
1143 else {
1144 #ifdef PIXEL_ADDRESS
1145 pRow = (PIXEL_TYPE *) ((GLubyte *) pRow + dPRowInner);
1146 #endif
1147 #ifdef INTERP_Z
1148 # ifdef DEPTH_TYPE
1149 zRow = (DEPTH_TYPE *) ((GLubyte *) zRow + dZRowInner);
1150 # endif
1151 fz += fdzInner;
1152 #endif
1153 #ifdef INTERP_FOG
1154 fogLeft += dfogInner;
1155 #endif
1156 #if defined(INTERP_RGB)
1157 fr += fdrInner;
1158 fg += fdgInner;
1159 fb += fdbInner;
1160 #endif
1161 #if defined(INTERP_ALPHA)
1162 fa += fdaInner;
1163 #endif
1164 #if defined(INTERP_SPEC)
1165 fsr += fdsrInner;
1166 fsg += fdsgInner;
1167 fsb += fdsbInner;
1168 #endif
1169 #ifdef INTERP_INDEX
1170 fi += fdiInner;
1171 #endif
1172 #ifdef INTERP_INT_TEX
1173 fs += fdsInner;
1174 ft += fdtInner;
1175 #endif
1176 #ifdef INTERP_TEX
1177 sLeft += dsInner;
1178 tLeft += dtInner;
1179 uLeft += duInner;
1180 vLeft += dvInner;
1181 #endif
1182 #ifdef INTERP_MULTITEX
1183 {
1184 GLuint u;
1185 for (u = 0; u < ctx->Const.MaxTextureUnits; u++) {
1186 if (ctx->Texture.Unit[u]._ReallyEnabled) {
1187 sLeft[u] += dsInner[u];
1188 tLeft[u] += dtInner[u];
1189 uLeft[u] += duInner[u];
1190 vLeft[u] += dvInner[u];
1191 }
1192 }
1193 }
1194 #endif
1195 }
1196 } /*while lines>0*/
1197
1198 } /* for subTriangle */
1199
1200 }
1201 #ifdef CLEANUP_CODE
1202 CLEANUP_CODE
1203 #endif
1204 }
1205 }
1206
1207 #undef SETUP_CODE
1208 #undef CLEANUP_CODE
1209 #undef RENDER_SPAN
1210
1211 #undef PIXEL_TYPE
1212 #undef BYTES_PER_ROW
1213 #undef PIXEL_ADDRESS
1214
1215 #undef INTERP_Z
1216 #undef INTERP_FOG
1217 #undef INTERP_RGB
1218 #undef INTERP_ALPHA
1219 #undef INTERP_SPEC
1220 #undef INTERP_INDEX
1221 #undef INTERP_INT_TEX
1222 #undef INTERP_TEX
1223 #undef INTERP_MULTITEX
1224
1225 #undef S_SCALE
1226 #undef T_SCALE
1227
1228 #undef FixedToDepth
1229
1230 #undef DO_OCCLUSION_TEST
1231 #undef NAME