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draw: corrections to allow for different cliptest cases
[mesa.git] / src / mesa / swrast / s_aatritemp.h
1 /*
2 * Mesa 3-D graphics library
3 * Version: 7.0.3
4 *
5 * Copyright (C) 1999-2007 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 /*
27 * Antialiased Triangle Rasterizer Template
28 *
29 * This file is #include'd to generate custom AA triangle rasterizers.
30 * NOTE: this code hasn't been optimized yet. That'll come after it
31 * works correctly.
32 *
33 * The following macros may be defined to indicate what auxillary information
34 * must be copmuted across the triangle:
35 * DO_Z - if defined, compute Z values
36 * DO_ATTRIBS - if defined, compute texcoords, varying, etc.
37 */
38
39 /*void triangle( GLcontext *ctx, GLuint v0, GLuint v1, GLuint v2, GLuint pv )*/
40 {
41 const SWcontext *swrast = SWRAST_CONTEXT(ctx);
42 const GLfloat *p0 = v0->attrib[FRAG_ATTRIB_WPOS];
43 const GLfloat *p1 = v1->attrib[FRAG_ATTRIB_WPOS];
44 const GLfloat *p2 = v2->attrib[FRAG_ATTRIB_WPOS];
45 const SWvertex *vMin, *vMid, *vMax;
46 GLint iyMin, iyMax;
47 GLfloat yMin, yMax;
48 GLboolean ltor;
49 GLfloat majDx, majDy; /* major (i.e. long) edge dx and dy */
50
51 SWspan span;
52
53 #ifdef DO_Z
54 GLfloat zPlane[4];
55 #endif
56 GLfloat rPlane[4], gPlane[4], bPlane[4], aPlane[4];
57 #if defined(DO_ATTRIBS)
58 GLfloat attrPlane[FRAG_ATTRIB_MAX][4][4];
59 GLfloat wPlane[4]; /* win[3] */
60 #endif
61 GLfloat bf = SWRAST_CONTEXT(ctx)->_BackfaceCullSign;
62
63 (void) swrast;
64
65 INIT_SPAN(span, GL_POLYGON);
66 span.arrayMask = SPAN_COVERAGE;
67
68 /* determine bottom to top order of vertices */
69 {
70 GLfloat y0 = v0->attrib[FRAG_ATTRIB_WPOS][1];
71 GLfloat y1 = v1->attrib[FRAG_ATTRIB_WPOS][1];
72 GLfloat y2 = v2->attrib[FRAG_ATTRIB_WPOS][1];
73 if (y0 <= y1) {
74 if (y1 <= y2) {
75 vMin = v0; vMid = v1; vMax = v2; /* y0<=y1<=y2 */
76 }
77 else if (y2 <= y0) {
78 vMin = v2; vMid = v0; vMax = v1; /* y2<=y0<=y1 */
79 }
80 else {
81 vMin = v0; vMid = v2; vMax = v1; bf = -bf; /* y0<=y2<=y1 */
82 }
83 }
84 else {
85 if (y0 <= y2) {
86 vMin = v1; vMid = v0; vMax = v2; bf = -bf; /* y1<=y0<=y2 */
87 }
88 else if (y2 <= y1) {
89 vMin = v2; vMid = v1; vMax = v0; bf = -bf; /* y2<=y1<=y0 */
90 }
91 else {
92 vMin = v1; vMid = v2; vMax = v0; /* y1<=y2<=y0 */
93 }
94 }
95 }
96
97 majDx = vMax->attrib[FRAG_ATTRIB_WPOS][0] - vMin->attrib[FRAG_ATTRIB_WPOS][0];
98 majDy = vMax->attrib[FRAG_ATTRIB_WPOS][1] - vMin->attrib[FRAG_ATTRIB_WPOS][1];
99
100 /* front/back-face determination and cullling */
101 {
102 const GLfloat botDx = vMid->attrib[FRAG_ATTRIB_WPOS][0] - vMin->attrib[FRAG_ATTRIB_WPOS][0];
103 const GLfloat botDy = vMid->attrib[FRAG_ATTRIB_WPOS][1] - vMin->attrib[FRAG_ATTRIB_WPOS][1];
104 const GLfloat area = majDx * botDy - botDx * majDy;
105 /* Do backface culling */
106 if (area * bf < 0 || area == 0 || IS_INF_OR_NAN(area))
107 return;
108 ltor = (GLboolean) (area < 0.0F);
109
110 span.facing = area * swrast->_BackfaceSign > 0.0F;
111 }
112
113 /* Plane equation setup:
114 * We evaluate plane equations at window (x,y) coordinates in order
115 * to compute color, Z, fog, texcoords, etc. This isn't terribly
116 * efficient but it's easy and reliable.
117 */
118 #ifdef DO_Z
119 compute_plane(p0, p1, p2, p0[2], p1[2], p2[2], zPlane);
120 span.arrayMask |= SPAN_Z;
121 #endif
122 if (ctx->Light.ShadeModel == GL_SMOOTH) {
123 compute_plane(p0, p1, p2, v0->color[RCOMP], v1->color[RCOMP], v2->color[RCOMP], rPlane);
124 compute_plane(p0, p1, p2, v0->color[GCOMP], v1->color[GCOMP], v2->color[GCOMP], gPlane);
125 compute_plane(p0, p1, p2, v0->color[BCOMP], v1->color[BCOMP], v2->color[BCOMP], bPlane);
126 compute_plane(p0, p1, p2, v0->color[ACOMP], v1->color[ACOMP], v2->color[ACOMP], aPlane);
127 }
128 else {
129 constant_plane(v2->color[RCOMP], rPlane);
130 constant_plane(v2->color[GCOMP], gPlane);
131 constant_plane(v2->color[BCOMP], bPlane);
132 constant_plane(v2->color[ACOMP], aPlane);
133 }
134 span.arrayMask |= SPAN_RGBA;
135 #if defined(DO_ATTRIBS)
136 {
137 const GLfloat invW0 = v0->attrib[FRAG_ATTRIB_WPOS][3];
138 const GLfloat invW1 = v1->attrib[FRAG_ATTRIB_WPOS][3];
139 const GLfloat invW2 = v2->attrib[FRAG_ATTRIB_WPOS][3];
140 compute_plane(p0, p1, p2, invW0, invW1, invW2, wPlane);
141 span.attrStepX[FRAG_ATTRIB_WPOS][3] = plane_dx(wPlane);
142 span.attrStepY[FRAG_ATTRIB_WPOS][3] = plane_dy(wPlane);
143 ATTRIB_LOOP_BEGIN
144 GLuint c;
145 if (swrast->_InterpMode[attr] == GL_FLAT) {
146 for (c = 0; c < 4; c++) {
147 constant_plane(v2->attrib[attr][c] * invW2, attrPlane[attr][c]);
148 }
149 }
150 else {
151 for (c = 0; c < 4; c++) {
152 const GLfloat a0 = v0->attrib[attr][c] * invW0;
153 const GLfloat a1 = v1->attrib[attr][c] * invW1;
154 const GLfloat a2 = v2->attrib[attr][c] * invW2;
155 compute_plane(p0, p1, p2, a0, a1, a2, attrPlane[attr][c]);
156 }
157 }
158 for (c = 0; c < 4; c++) {
159 span.attrStepX[attr][c] = plane_dx(attrPlane[attr][c]);
160 span.attrStepY[attr][c] = plane_dy(attrPlane[attr][c]);
161 }
162 ATTRIB_LOOP_END
163 }
164 #endif
165
166 /* Begin bottom-to-top scan over the triangle.
167 * The long edge will either be on the left or right side of the
168 * triangle. We always scan from the long edge toward the shorter
169 * edges, stopping when we find that coverage = 0. If the long edge
170 * is on the left we scan left-to-right. Else, we scan right-to-left.
171 */
172 yMin = vMin->attrib[FRAG_ATTRIB_WPOS][1];
173 yMax = vMax->attrib[FRAG_ATTRIB_WPOS][1];
174 iyMin = (GLint) yMin;
175 iyMax = (GLint) yMax + 1;
176
177 if (ltor) {
178 /* scan left to right */
179 const GLfloat *pMin = vMin->attrib[FRAG_ATTRIB_WPOS];
180 const GLfloat *pMid = vMid->attrib[FRAG_ATTRIB_WPOS];
181 const GLfloat *pMax = vMax->attrib[FRAG_ATTRIB_WPOS];
182 const GLfloat dxdy = majDx / majDy;
183 const GLfloat xAdj = dxdy < 0.0F ? -dxdy : 0.0F;
184 GLfloat x = pMin[0] - (yMin - iyMin) * dxdy;
185 GLint iy;
186 for (iy = iyMin; iy < iyMax; iy++, x += dxdy) {
187 GLint ix, startX = (GLint) (x - xAdj);
188 GLuint count;
189 GLfloat coverage = 0.0F;
190
191 /* skip over fragments with zero coverage */
192 while (startX < MAX_WIDTH) {
193 coverage = compute_coveragef(pMin, pMid, pMax, startX, iy);
194 if (coverage > 0.0F)
195 break;
196 startX++;
197 }
198
199 /* enter interior of triangle */
200 ix = startX;
201
202 #if defined(DO_ATTRIBS)
203 /* compute attributes at left-most fragment */
204 span.attrStart[FRAG_ATTRIB_WPOS][3] = solve_plane(ix + 0.5F, iy + 0.5F, wPlane);
205 ATTRIB_LOOP_BEGIN
206 GLuint c;
207 for (c = 0; c < 4; c++) {
208 span.attrStart[attr][c] = solve_plane(ix + 0.5F, iy + 0.5F, attrPlane[attr][c]);
209 }
210 ATTRIB_LOOP_END
211 #endif
212
213 count = 0;
214 while (coverage > 0.0F) {
215 /* (cx,cy) = center of fragment */
216 const GLfloat cx = ix + 0.5F, cy = iy + 0.5F;
217 SWspanarrays *array = span.array;
218 array->coverage[count] = coverage;
219 #ifdef DO_Z
220 array->z[count] = (GLuint) solve_plane(cx, cy, zPlane);
221 #endif
222 array->rgba[count][RCOMP] = solve_plane_chan(cx, cy, rPlane);
223 array->rgba[count][GCOMP] = solve_plane_chan(cx, cy, gPlane);
224 array->rgba[count][BCOMP] = solve_plane_chan(cx, cy, bPlane);
225 array->rgba[count][ACOMP] = solve_plane_chan(cx, cy, aPlane);
226 ix++;
227 count++;
228 coverage = compute_coveragef(pMin, pMid, pMax, ix, iy);
229 }
230
231 if (ix <= startX)
232 continue;
233
234 span.x = startX;
235 span.y = iy;
236 span.end = (GLuint) ix - (GLuint) startX;
237 _swrast_write_rgba_span(ctx, &span);
238 }
239 }
240 else {
241 /* scan right to left */
242 const GLfloat *pMin = vMin->attrib[FRAG_ATTRIB_WPOS];
243 const GLfloat *pMid = vMid->attrib[FRAG_ATTRIB_WPOS];
244 const GLfloat *pMax = vMax->attrib[FRAG_ATTRIB_WPOS];
245 const GLfloat dxdy = majDx / majDy;
246 const GLfloat xAdj = dxdy > 0 ? dxdy : 0.0F;
247 GLfloat x = pMin[0] - (yMin - iyMin) * dxdy;
248 GLint iy;
249 for (iy = iyMin; iy < iyMax; iy++, x += dxdy) {
250 GLint ix, left, startX = (GLint) (x + xAdj);
251 GLuint count, n;
252 GLfloat coverage = 0.0F;
253
254 /* make sure we're not past the window edge */
255 if (startX >= ctx->DrawBuffer->_Xmax) {
256 startX = ctx->DrawBuffer->_Xmax - 1;
257 }
258
259 /* skip fragments with zero coverage */
260 while (startX > 0) {
261 coverage = compute_coveragef(pMin, pMax, pMid, startX, iy);
262 if (coverage > 0.0F)
263 break;
264 startX--;
265 }
266
267 /* enter interior of triangle */
268 ix = startX;
269 count = 0;
270 while (coverage > 0.0F) {
271 /* (cx,cy) = center of fragment */
272 const GLfloat cx = ix + 0.5F, cy = iy + 0.5F;
273 SWspanarrays *array = span.array;
274 ASSERT(ix >= 0);
275 array->coverage[ix] = coverage;
276 #ifdef DO_Z
277 array->z[ix] = (GLuint) solve_plane(cx, cy, zPlane);
278 #endif
279 array->rgba[ix][RCOMP] = solve_plane_chan(cx, cy, rPlane);
280 array->rgba[ix][GCOMP] = solve_plane_chan(cx, cy, gPlane);
281 array->rgba[ix][BCOMP] = solve_plane_chan(cx, cy, bPlane);
282 array->rgba[ix][ACOMP] = solve_plane_chan(cx, cy, aPlane);
283 ix--;
284 count++;
285 coverage = compute_coveragef(pMin, pMax, pMid, ix, iy);
286 }
287
288 #if defined(DO_ATTRIBS)
289 /* compute attributes at left-most fragment */
290 span.attrStart[FRAG_ATTRIB_WPOS][3] = solve_plane(ix + 1.5F, iy + 0.5F, wPlane);
291 ATTRIB_LOOP_BEGIN
292 GLuint c;
293 for (c = 0; c < 4; c++) {
294 span.attrStart[attr][c] = solve_plane(ix + 1.5F, iy + 0.5F, attrPlane[attr][c]);
295 }
296 ATTRIB_LOOP_END
297 #endif
298
299 if (startX <= ix)
300 continue;
301
302 n = (GLuint) startX - (GLuint) ix;
303
304 left = ix + 1;
305
306 /* shift all values to the left */
307 /* XXX this is temporary */
308 {
309 SWspanarrays *array = span.array;
310 GLint j;
311 for (j = 0; j < (GLint) n; j++) {
312 array->coverage[j] = array->coverage[j + left];
313 COPY_CHAN4(array->rgba[j], array->rgba[j + left]);
314 #ifdef DO_Z
315 array->z[j] = array->z[j + left];
316 #endif
317 }
318 }
319
320 span.x = left;
321 span.y = iy;
322 span.end = n;
323 _swrast_write_rgba_span(ctx, &span);
324 }
325 }
326 }
327
328
329 #undef DO_Z
330 #undef DO_ATTRIBS
331 #undef DO_OCCLUSION_TEST