2 * Mesa 3-D graphics library
5 * Copyright (C) 1999-2004 Brian Paul All Rights Reserved.
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:
14 * The above copyright notice and this permission notice shall be included
15 * in all copies or substantial portions of the Software.
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.
27 * Antialiased Triangle Rasterizer Template
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
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_RGBA - if defined, compute RGBA values
37 * DO_INDEX - if defined, compute color index values
38 * DO_SPEC - if defined, compute specular RGB values
39 * DO_TEX - if defined, compute unit 0 STRQ texcoords
40 * DO_MULTITEX - if defined, compute all unit's STRQ texcoords
43 /*void triangle( GLcontext *ctx, GLuint v0, GLuint v1, GLuint v2, GLuint pv )*/
45 const GLfloat
*p0
= v0
->win
;
46 const GLfloat
*p1
= v1
->win
;
47 const GLfloat
*p2
= v2
->win
;
48 const SWvertex
*vMin
, *vMid
, *vMax
;
52 GLfloat majDx
, majDy
; /* major (i.e. long) edge dx and dy */
65 GLfloat rPlane
[4], gPlane
[4], bPlane
[4], aPlane
[4];
71 GLfloat srPlane
[4], sgPlane
[4], sbPlane
[4];
74 GLfloat sPlane
[4], tPlane
[4], uPlane
[4], vPlane
[4];
75 GLfloat texWidth
, texHeight
;
76 #elif defined(DO_MULTITEX)
77 GLfloat sPlane
[MAX_TEXTURE_COORD_UNITS
][4]; /* texture S */
78 GLfloat tPlane
[MAX_TEXTURE_COORD_UNITS
][4]; /* texture T */
79 GLfloat uPlane
[MAX_TEXTURE_COORD_UNITS
][4]; /* texture R */
80 GLfloat vPlane
[MAX_TEXTURE_COORD_UNITS
][4]; /* texture Q */
81 GLfloat texWidth
[MAX_TEXTURE_COORD_UNITS
];
82 GLfloat texHeight
[MAX_TEXTURE_COORD_UNITS
];
84 GLfloat bf
= SWRAST_CONTEXT(ctx
)->_BackfaceSign
;
87 INIT_SPAN(span
, GL_POLYGON
, 0, 0, SPAN_COVERAGE
);
89 /* determine bottom to top order of vertices */
91 GLfloat y0
= v0
->win
[1];
92 GLfloat y1
= v1
->win
[1];
93 GLfloat y2
= v2
->win
[1];
96 vMin
= v0
; vMid
= v1
; vMax
= v2
; /* y0<=y1<=y2 */
99 vMin
= v2
; vMid
= v0
; vMax
= v1
; /* y2<=y0<=y1 */
102 vMin
= v0
; vMid
= v2
; vMax
= v1
; bf
= -bf
; /* y0<=y2<=y1 */
107 vMin
= v1
; vMid
= v0
; vMax
= v2
; bf
= -bf
; /* y1<=y0<=y2 */
110 vMin
= v2
; vMid
= v1
; vMax
= v0
; bf
= -bf
; /* y2<=y1<=y0 */
113 vMin
= v1
; vMid
= v2
; vMax
= v0
; /* y1<=y2<=y0 */
118 majDx
= vMax
->win
[0] - vMin
->win
[0];
119 majDy
= vMax
->win
[1] - vMin
->win
[1];
122 const GLfloat botDx
= vMid
->win
[0] - vMin
->win
[0];
123 const GLfloat botDy
= vMid
->win
[1] - vMin
->win
[1];
124 const GLfloat area
= majDx
* botDy
- botDx
* majDy
;
125 /* Do backface culling */
126 if (area
* bf
< 0 || area
== 0 || IS_INF_OR_NAN(area
))
128 ltor
= (GLboolean
) (area
< 0.0F
);
131 #ifndef DO_OCCLUSION_TEST
132 ctx
->OcclusionResult
= GL_TRUE
;
135 /* Plane equation setup:
136 * We evaluate plane equations at window (x,y) coordinates in order
137 * to compute color, Z, fog, texcoords, etc. This isn't terribly
138 * efficient but it's easy and reliable.
141 compute_plane(p0
, p1
, p2
, p0
[2], p1
[2], p2
[2], zPlane
);
142 span
.arrayMask
|= SPAN_Z
;
145 compute_plane(p0
, p1
, p2
, v0
->fog
, v1
->fog
, v2
->fog
, fogPlane
);
146 span
.arrayMask
|= SPAN_FOG
;
149 if (ctx
->Light
.ShadeModel
== GL_SMOOTH
) {
150 compute_plane(p0
, p1
, p2
, v0
->color
[RCOMP
], v1
->color
[RCOMP
], v2
->color
[RCOMP
], rPlane
);
151 compute_plane(p0
, p1
, p2
, v0
->color
[GCOMP
], v1
->color
[GCOMP
], v2
->color
[GCOMP
], gPlane
);
152 compute_plane(p0
, p1
, p2
, v0
->color
[BCOMP
], v1
->color
[BCOMP
], v2
->color
[BCOMP
], bPlane
);
153 compute_plane(p0
, p1
, p2
, v0
->color
[ACOMP
], v1
->color
[ACOMP
], v2
->color
[ACOMP
], aPlane
);
156 constant_plane(v2
->color
[RCOMP
], rPlane
);
157 constant_plane(v2
->color
[GCOMP
], gPlane
);
158 constant_plane(v2
->color
[BCOMP
], bPlane
);
159 constant_plane(v2
->color
[ACOMP
], aPlane
);
161 span
.arrayMask
|= SPAN_RGBA
;
164 if (ctx
->Light
.ShadeModel
== GL_SMOOTH
) {
165 compute_plane(p0
, p1
, p2
, (GLfloat
) v0
->index
,
166 v1
->index
, v2
->index
, iPlane
);
169 constant_plane(v2
->index
, iPlane
);
171 span
.arrayMask
|= SPAN_INDEX
;
174 if (ctx
->Light
.ShadeModel
== GL_SMOOTH
) {
175 compute_plane(p0
, p1
, p2
, v0
->specular
[RCOMP
], v1
->specular
[RCOMP
], v2
->specular
[RCOMP
], srPlane
);
176 compute_plane(p0
, p1
, p2
, v0
->specular
[GCOMP
], v1
->specular
[GCOMP
], v2
->specular
[GCOMP
], sgPlane
);
177 compute_plane(p0
, p1
, p2
, v0
->specular
[BCOMP
], v1
->specular
[BCOMP
], v2
->specular
[BCOMP
], sbPlane
);
180 constant_plane(v2
->specular
[RCOMP
], srPlane
);
181 constant_plane(v2
->specular
[GCOMP
], sgPlane
);
182 constant_plane(v2
->specular
[BCOMP
], sbPlane
);
184 span
.arrayMask
|= SPAN_SPEC
;
188 const struct gl_texture_object
*obj
= ctx
->Texture
.Unit
[0]._Current
;
189 const struct gl_texture_image
*texImage
= obj
->Image
[0][obj
->BaseLevel
];
190 const GLfloat invW0
= v0
->win
[3];
191 const GLfloat invW1
= v1
->win
[3];
192 const GLfloat invW2
= v2
->win
[3];
193 const GLfloat s0
= v0
->texcoord
[0][0] * invW0
;
194 const GLfloat s1
= v1
->texcoord
[0][0] * invW1
;
195 const GLfloat s2
= v2
->texcoord
[0][0] * invW2
;
196 const GLfloat t0
= v0
->texcoord
[0][1] * invW0
;
197 const GLfloat t1
= v1
->texcoord
[0][1] * invW1
;
198 const GLfloat t2
= v2
->texcoord
[0][1] * invW2
;
199 const GLfloat r0
= v0
->texcoord
[0][2] * invW0
;
200 const GLfloat r1
= v1
->texcoord
[0][2] * invW1
;
201 const GLfloat r2
= v2
->texcoord
[0][2] * invW2
;
202 const GLfloat q0
= v0
->texcoord
[0][3] * invW0
;
203 const GLfloat q1
= v1
->texcoord
[0][3] * invW1
;
204 const GLfloat q2
= v2
->texcoord
[0][3] * invW2
;
205 compute_plane(p0
, p1
, p2
, s0
, s1
, s2
, sPlane
);
206 compute_plane(p0
, p1
, p2
, t0
, t1
, t2
, tPlane
);
207 compute_plane(p0
, p1
, p2
, r0
, r1
, r2
, uPlane
);
208 compute_plane(p0
, p1
, p2
, q0
, q1
, q2
, vPlane
);
209 texWidth
= (GLfloat
) texImage
->Width
;
210 texHeight
= (GLfloat
) texImage
->Height
;
212 span
.arrayMask
|= (SPAN_TEXTURE
| SPAN_LAMBDA
);
213 #elif defined(DO_MULTITEX)
216 for (u
= 0; u
< ctx
->Const
.MaxTextureUnits
; u
++) {
217 if (ctx
->Texture
.Unit
[u
]._ReallyEnabled
) {
218 const struct gl_texture_object
*obj
= ctx
->Texture
.Unit
[u
]._Current
;
219 const struct gl_texture_image
*texImage
= obj
->Image
[0][obj
->BaseLevel
];
220 const GLfloat invW0
= v0
->win
[3];
221 const GLfloat invW1
= v1
->win
[3];
222 const GLfloat invW2
= v2
->win
[3];
223 const GLfloat s0
= v0
->texcoord
[u
][0] * invW0
;
224 const GLfloat s1
= v1
->texcoord
[u
][0] * invW1
;
225 const GLfloat s2
= v2
->texcoord
[u
][0] * invW2
;
226 const GLfloat t0
= v0
->texcoord
[u
][1] * invW0
;
227 const GLfloat t1
= v1
->texcoord
[u
][1] * invW1
;
228 const GLfloat t2
= v2
->texcoord
[u
][1] * invW2
;
229 const GLfloat r0
= v0
->texcoord
[u
][2] * invW0
;
230 const GLfloat r1
= v1
->texcoord
[u
][2] * invW1
;
231 const GLfloat r2
= v2
->texcoord
[u
][2] * invW2
;
232 const GLfloat q0
= v0
->texcoord
[u
][3] * invW0
;
233 const GLfloat q1
= v1
->texcoord
[u
][3] * invW1
;
234 const GLfloat q2
= v2
->texcoord
[u
][3] * invW2
;
235 compute_plane(p0
, p1
, p2
, s0
, s1
, s2
, sPlane
[u
]);
236 compute_plane(p0
, p1
, p2
, t0
, t1
, t2
, tPlane
[u
]);
237 compute_plane(p0
, p1
, p2
, r0
, r1
, r2
, uPlane
[u
]);
238 compute_plane(p0
, p1
, p2
, q0
, q1
, q2
, vPlane
[u
]);
239 texWidth
[u
] = (GLfloat
) texImage
->Width
;
240 texHeight
[u
] = (GLfloat
) texImage
->Height
;
244 span
.arrayMask
|= (SPAN_TEXTURE
| SPAN_LAMBDA
);
247 /* Begin bottom-to-top scan over the triangle.
248 * The long edge will either be on the left or right side of the
249 * triangle. We always scan from the long edge toward the shorter
250 * edges, stopping when we find that coverage = 0. If the long edge
251 * is on the left we scan left-to-right. Else, we scan right-to-left.
255 iyMin
= (GLint
) yMin
;
256 iyMax
= (GLint
) yMax
+ 1;
259 /* scan left to right */
260 const GLfloat
*pMin
= vMin
->win
;
261 const GLfloat
*pMid
= vMid
->win
;
262 const GLfloat
*pMax
= vMax
->win
;
263 const GLfloat dxdy
= majDx
/ majDy
;
264 const GLfloat xAdj
= dxdy
< 0.0F
? -dxdy
: 0.0F
;
265 GLfloat x
= pMin
[0] - (yMin
- iyMin
) * dxdy
;
267 for (iy
= iyMin
; iy
< iyMax
; iy
++, x
+= dxdy
) {
268 GLint ix
, startX
= (GLint
) (x
- xAdj
);
270 GLfloat coverage
= 0.0F
;
272 /* skip over fragments with zero coverage */
273 while (startX
< MAX_WIDTH
) {
274 coverage
= compute_coveragef(pMin
, pMid
, pMax
, startX
, iy
);
280 /* enter interior of triangle */
283 while (coverage
> 0.0F
) {
284 /* (cx,cy) = center of fragment */
285 const GLfloat cx
= ix
+ 0.5F
, cy
= iy
+ 0.5F
;
286 struct span_arrays
*array
= span
.array
;
288 array
->coverage
[count
] = (GLfloat
) compute_coveragei(pMin
, pMid
, pMax
, ix
, iy
);
290 array
->coverage
[count
] = coverage
;
293 array
->z
[count
] = (GLdepth
) IROUND(solve_plane(cx
, cy
, zPlane
));
296 array
->fog
[count
] = solve_plane(cx
, cy
, fogPlane
);
299 array
->rgba
[count
][RCOMP
] = solve_plane_chan(cx
, cy
, rPlane
);
300 array
->rgba
[count
][GCOMP
] = solve_plane_chan(cx
, cy
, gPlane
);
301 array
->rgba
[count
][BCOMP
] = solve_plane_chan(cx
, cy
, bPlane
);
302 array
->rgba
[count
][ACOMP
] = solve_plane_chan(cx
, cy
, aPlane
);
305 array
->index
[count
] = (GLint
) solve_plane(cx
, cy
, iPlane
);
308 array
->spec
[count
][RCOMP
] = solve_plane_chan(cx
, cy
, srPlane
);
309 array
->spec
[count
][GCOMP
] = solve_plane_chan(cx
, cy
, sgPlane
);
310 array
->spec
[count
][BCOMP
] = solve_plane_chan(cx
, cy
, sbPlane
);
314 const GLfloat invQ
= solve_plane_recip(cx
, cy
, vPlane
);
315 array
->texcoords
[0][count
][0] = solve_plane(cx
, cy
, sPlane
) * invQ
;
316 array
->texcoords
[0][count
][1] = solve_plane(cx
, cy
, tPlane
) * invQ
;
317 array
->texcoords
[0][count
][2] = solve_plane(cx
, cy
, uPlane
) * invQ
;
318 array
->lambda
[0][count
] = compute_lambda(sPlane
, tPlane
, vPlane
,
320 texWidth
, texHeight
);
322 #elif defined(DO_MULTITEX)
325 for (unit
= 0; unit
< ctx
->Const
.MaxTextureUnits
; unit
++) {
326 if (ctx
->Texture
.Unit
[unit
]._ReallyEnabled
) {
327 GLfloat invQ
= solve_plane_recip(cx
, cy
, vPlane
[unit
]);
328 array
->texcoords
[unit
][count
][0] = solve_plane(cx
, cy
, sPlane
[unit
]) * invQ
;
329 array
->texcoords
[unit
][count
][1] = solve_plane(cx
, cy
, tPlane
[unit
]) * invQ
;
330 array
->texcoords
[unit
][count
][2] = solve_plane(cx
, cy
, uPlane
[unit
]) * invQ
;
331 array
->lambda
[unit
][count
] = compute_lambda(sPlane
[unit
],
332 tPlane
[unit
], vPlane
[unit
], cx
, cy
, invQ
,
333 texWidth
[unit
], texHeight
[unit
]);
340 coverage
= compute_coveragef(pMin
, pMid
, pMax
, ix
, iy
);
348 span
.end
= (GLuint
) ix
- (GLuint
) startX
;
349 ASSERT(span
.interpMask
== 0);
351 _swrast_write_rgba_span(ctx
, &span
);
353 _swrast_write_index_span(ctx
, &span
);
358 /* scan right to left */
359 const GLfloat
*pMin
= vMin
->win
;
360 const GLfloat
*pMid
= vMid
->win
;
361 const GLfloat
*pMax
= vMax
->win
;
362 const GLfloat dxdy
= majDx
/ majDy
;
363 const GLfloat xAdj
= dxdy
> 0 ? dxdy
: 0.0F
;
364 GLfloat x
= pMin
[0] - (yMin
- iyMin
) * dxdy
;
366 for (iy
= iyMin
; iy
< iyMax
; iy
++, x
+= dxdy
) {
367 GLint ix
, left
, startX
= (GLint
) (x
+ xAdj
);
369 GLfloat coverage
= 0.0F
;
371 /* make sure we're not past the window edge */
372 if (startX
>= ctx
->DrawBuffer
->_Xmax
) {
373 startX
= ctx
->DrawBuffer
->_Xmax
- 1;
376 /* skip fragments with zero coverage */
377 while (startX
>= 0) {
378 coverage
= compute_coveragef(pMin
, pMax
, pMid
, startX
, iy
);
384 /* enter interior of triangle */
387 while (coverage
> 0.0F
) {
388 /* (cx,cy) = center of fragment */
389 const GLfloat cx
= ix
+ 0.5F
, cy
= iy
+ 0.5F
;
390 struct span_arrays
*array
= span
.array
;
392 array
->coverage
[ix
] = (GLfloat
) compute_coveragei(pMin
, pMax
, pMid
, ix
, iy
);
394 array
->coverage
[ix
] = coverage
;
397 array
->z
[ix
] = (GLdepth
) IROUND(solve_plane(cx
, cy
, zPlane
));
400 array
->fog
[ix
] = solve_plane(cx
, cy
, fogPlane
);
403 array
->rgba
[ix
][RCOMP
] = solve_plane_chan(cx
, cy
, rPlane
);
404 array
->rgba
[ix
][GCOMP
] = solve_plane_chan(cx
, cy
, gPlane
);
405 array
->rgba
[ix
][BCOMP
] = solve_plane_chan(cx
, cy
, bPlane
);
406 array
->rgba
[ix
][ACOMP
] = solve_plane_chan(cx
, cy
, aPlane
);
409 array
->index
[ix
] = (GLint
) solve_plane(cx
, cy
, iPlane
);
412 array
->spec
[ix
][RCOMP
] = solve_plane_chan(cx
, cy
, srPlane
);
413 array
->spec
[ix
][GCOMP
] = solve_plane_chan(cx
, cy
, sgPlane
);
414 array
->spec
[ix
][BCOMP
] = solve_plane_chan(cx
, cy
, sbPlane
);
418 const GLfloat invQ
= solve_plane_recip(cx
, cy
, vPlane
);
419 array
->texcoords
[0][ix
][0] = solve_plane(cx
, cy
, sPlane
) * invQ
;
420 array
->texcoords
[0][ix
][1] = solve_plane(cx
, cy
, tPlane
) * invQ
;
421 array
->texcoords
[0][ix
][2] = solve_plane(cx
, cy
, uPlane
) * invQ
;
422 array
->lambda
[0][ix
] = compute_lambda(sPlane
, tPlane
, vPlane
,
423 cx
, cy
, invQ
, texWidth
, texHeight
);
425 #elif defined(DO_MULTITEX)
428 for (unit
= 0; unit
< ctx
->Const
.MaxTextureUnits
; unit
++) {
429 if (ctx
->Texture
.Unit
[unit
]._ReallyEnabled
) {
430 GLfloat invQ
= solve_plane_recip(cx
, cy
, vPlane
[unit
]);
431 array
->texcoords
[unit
][ix
][0] = solve_plane(cx
, cy
, sPlane
[unit
]) * invQ
;
432 array
->texcoords
[unit
][ix
][1] = solve_plane(cx
, cy
, tPlane
[unit
]) * invQ
;
433 array
->texcoords
[unit
][ix
][2] = solve_plane(cx
, cy
, uPlane
[unit
]) * invQ
;
434 array
->lambda
[unit
][ix
] = compute_lambda(sPlane
[unit
],
446 coverage
= compute_coveragef(pMin
, pMax
, pMid
, ix
, iy
);
452 n
= (GLuint
) startX
- (GLuint
) ix
;
456 /* shift all values to the left */
457 /* XXX this is temporary */
459 struct span_arrays
*array
= span
.array
;
461 for (j
= 0; j
< (GLint
) n
; j
++) {
463 COPY_CHAN4(array
->rgba
[j
], array
->rgba
[j
+ left
]);
466 COPY_CHAN4(array
->spec
[j
], array
->spec
[j
+ left
]);
469 array
->index
[j
] = array
->index
[j
+ left
];
472 array
->z
[j
] = array
->z
[j
+ left
];
475 array
->fog
[j
] = array
->fog
[j
+ left
];
478 COPY_4V(array
->texcoords
[0][j
], array
->texcoords
[0][j
+ left
]);
480 #if defined(DO_MULTITEX) || defined(DO_TEX)
481 array
->lambda
[0][j
] = array
->lambda
[0][j
+ left
];
483 array
->coverage
[j
] = array
->coverage
[j
+ left
];
487 /* shift texcoords */
489 struct span_arrays
*array
= span
.array
;
491 for (unit
= 0; unit
< ctx
->Const
.MaxTextureUnits
; unit
++) {
492 if (ctx
->Texture
.Unit
[unit
]._ReallyEnabled
) {
494 for (j
= 0; j
< (GLint
) n
; j
++) {
495 array
->texcoords
[unit
][j
][0] = array
->texcoords
[unit
][j
+ left
][0];
496 array
->texcoords
[unit
][j
][1] = array
->texcoords
[unit
][j
+ left
][1];
497 array
->texcoords
[unit
][j
][2] = array
->texcoords
[unit
][j
+ left
][2];
498 array
->lambda
[unit
][j
] = array
->lambda
[unit
][j
+ left
];
508 ASSERT(span
.interpMask
== 0);
510 _swrast_write_rgba_span(ctx
, &span
);
512 _swrast_write_index_span(ctx
, &span
);
547 #ifdef DO_OCCLUSION_TEST
548 #undef DO_OCCLUSION_TEST