TinyGL 0.4.1 for MinGW
ztriangle.c
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1#include <stdlib.h>
2#include "zbuffer.h"
3
4#define ZCMP(z,zpix) ((z) >= (zpix))
5
6void ZB_fillTriangleFlat(ZBuffer *zb,
7 ZBufferPoint *p0,ZBufferPoint *p1,ZBufferPoint *p2)
8{
9#if TGL_FEATURE_RENDER_BITS == 24
10 unsigned char colorR, colorG, colorB;
11#else
12 int color;
13#endif
14
15#define INTERP_Z
16
17#if TGL_FEATURE_RENDER_BITS == 24
18
19#define DRAW_INIT() \
20{ \
21 colorR=p2->r>>8; \
22 colorG=p2->g>>8; \
23 colorB=p2->b>>8; \
24}
25
26#define PUT_PIXEL(_a) \
27{ \
28 zz=z >> ZB_POINT_Z_FRAC_BITS; \
29 if (ZCMP(zz,pz[_a])) { \
30 pp[3 * _a]=colorR;\
31 pp[3 * _a + 1]=colorG;\
32 pp[3 * _a + 2]=colorB;\
33 pz[_a]=zz; \
34 }\
35 z+=dzdx; \
36}
37
38#else
39
40#define DRAW_INIT() \
41{ \
42 color=RGB_TO_PIXEL(p2->r,p2->g,p2->b); \
43}
44
45#define PUT_PIXEL(_a) \
46{ \
47 zz=z >> ZB_POINT_Z_FRAC_BITS; \
48 if (ZCMP(zz,pz[_a])) { \
49 pp[_a]=color; \
50 pz[_a]=zz; \
51 } \
52 z+=dzdx; \
53}
54#endif /* TGL_FEATURE_RENDER_BITS == 24 */
55
56#include "ztriangle.h"
57}
58
59/*
60 * Smooth filled triangle.
61 * The code below is very tricky :)
62 */
63
64void ZB_fillTriangleSmooth(ZBuffer *zb,
65 ZBufferPoint *p0,ZBufferPoint *p1,ZBufferPoint *p2)
66{
67#if TGL_FEATURE_RENDER_BITS == 16
68 int _drgbdx;
69#endif
70
71#define INTERP_Z
72#define INTERP_RGB
73
74#define SAR_RND_TO_ZERO(v,n) (v / (1<<n))
75
76#if TGL_FEATURE_RENDER_BITS == 24
77
78#define DRAW_INIT() \
79{ \
80}
81
82#define PUT_PIXEL(_a) \
83{ \
84 zz=z >> ZB_POINT_Z_FRAC_BITS; \
85 if (ZCMP(zz,pz[_a])) { \
86 pp[3 * _a]=or1 >> 8;\
87 pp[3 * _a + 1]=og1 >> 8;\
88 pp[3 * _a + 2]=ob1 >> 8;\
89 pz[_a]=zz; \
90 }\
91 z+=dzdx; \
92 og1+=dgdx; \
93 or1+=drdx; \
94 ob1+=dbdx; \
95}
96
97#elif TGL_FEATURE_RENDER_BITS == 16
98
99#define DRAW_INIT() \
100{ \
101 _drgbdx=(SAR_RND_TO_ZERO(drdx,6) << 22) & 0xFFC00000; \
102 _drgbdx|=SAR_RND_TO_ZERO(dgdx,5) & 0x000007FF; \
103 _drgbdx|=(SAR_RND_TO_ZERO(dbdx,7) << 12) & 0x001FF000; \
104}
105
106
107#define PUT_PIXEL(_a) \
108{ \
109 zz=z >> ZB_POINT_Z_FRAC_BITS; \
110 if (ZCMP(zz,pz[_a])) { \
111 tmp=rgb & 0xF81F07E0; \
112 pp[_a]=tmp | (tmp >> 16); \
113 pz[_a]=zz; \
114 } \
115 z+=dzdx; \
116 rgb=(rgb+drgbdx) & ( ~ 0x00200800); \
117}
118
119#define DRAW_LINE() \
120{ \
121 register unsigned short *pz; \
122 register PIXEL *pp; \
123 register unsigned int tmp,z,zz,rgb,drgbdx; \
124 register int n; \
125 n=(x2 >> 16) - x1; \
126 pp=pp1+x1; \
127 pz=pz1+x1; \
128 z=z1; \
129 rgb=(r1 << 16) & 0xFFC00000; \
130 rgb|=(g1 >> 5) & 0x000007FF; \
131 rgb|=(b1 << 5) & 0x001FF000; \
132 drgbdx=_drgbdx; \
133 while (n>=3) { \
134 PUT_PIXEL(0); \
135 PUT_PIXEL(1); \
136 PUT_PIXEL(2); \
137 PUT_PIXEL(3); \
138 pz+=4; \
139 pp+=4; \
140 n-=4; \
141 } \
142 while (n>=0) { \
143 PUT_PIXEL(0); \
144 pz+=1; \
145 pp+=1; \
146 n-=1; \
147 } \
148}
149
150#else
151
152#define DRAW_INIT() \
153{ \
154}
155
156#define PUT_PIXEL(_a) \
157{ \
158 zz=z >> ZB_POINT_Z_FRAC_BITS; \
159 if (ZCMP(zz,pz[_a])) { \
160 pp[_a] = RGB_TO_PIXEL(or1, og1, ob1);\
161 pz[_a]=zz; \
162 }\
163 z+=dzdx; \
164 og1+=dgdx; \
165 or1+=drdx; \
166 ob1+=dbdx; \
167}
168
169#endif /* TGL_FEATURE_RENDER_BITS */
170
171#include "ztriangle.h"
172}
173
174void ZB_setTexture(ZBuffer *zb,PIXEL *texture)
175{
176 zb->current_texture=texture;
177}
178
179void ZB_fillTriangleMapping(ZBuffer *zb,
180 ZBufferPoint *p0,ZBufferPoint *p1,ZBufferPoint *p2)
181{
182 PIXEL *texture;
183
184#define INTERP_Z
185#define INTERP_ST
186
187#define DRAW_INIT() \
188{ \
189 texture=zb->current_texture; \
190}
191
192#if TGL_FEATURE_RENDER_BITS == 24
193
194#define PUT_PIXEL(_a) \
195{ \
196 unsigned char *ptr;\
197 zz=z >> ZB_POINT_Z_FRAC_BITS; \
198 if (ZCMP(zz,pz[_a])) { \
199 ptr = texture + (((t & 0x3FC00000) | s) >> 14) * 3; \
200 pp[3 * _a]= ptr[0];\
201 pp[3 * _a + 1]= ptr[1];\
202 pp[3 * _a + 2]= ptr[2];\
203 pz[_a]=zz; \
204 } \
205 z+=dzdx; \
206 s+=dsdx; \
207 t+=dtdx; \
208}
209
210#else
211
212#define PUT_PIXEL(_a) \
213{ \
214 zz=z >> ZB_POINT_Z_FRAC_BITS; \
215 if (ZCMP(zz,pz[_a])) { \
216 pp[_a]=texture[((t & 0x3FC00000) | s) >> 14]; \
217 pz[_a]=zz; \
218 } \
219 z+=dzdx; \
220 s+=dsdx; \
221 t+=dtdx; \
222}
223
224#endif
225
226#include "ztriangle.h"
227}
228
229/*
230 * Texture mapping with perspective correction.
231 * We use the gradient method to make less divisions.
232 * TODO: pipeline the division
233 */
234#if 1
235
236void ZB_fillTriangleMappingPerspective(ZBuffer *zb,
237 ZBufferPoint *p0,ZBufferPoint *p1,ZBufferPoint *p2)
238{
239 PIXEL *texture;
240 float fdzdx,fndzdx,ndszdx,ndtzdx;
241
242#define INTERP_Z
243#define INTERP_STZ
244
245#define NB_INTERP 8
246
247#define DRAW_INIT() \
248{ \
249 texture=zb->current_texture;\
250 fdzdx=(float)dzdx;\
251 fndzdx=NB_INTERP * fdzdx;\
252 ndszdx=NB_INTERP * dszdx;\
253 ndtzdx=NB_INTERP * dtzdx;\
254}
255
256
257#if TGL_FEATURE_RENDER_BITS == 24
258
259#define PUT_PIXEL(_a) \
260{ \
261 unsigned char *ptr;\
262 zz=z >> ZB_POINT_Z_FRAC_BITS; \
263 if (ZCMP(zz,pz[_a])) { \
264 ptr = texture + (((t & 0x3FC00000) | (s & 0x003FC000)) >> 14) * 3;\
265 pp[3 * _a]= ptr[0];\
266 pp[3 * _a + 1]= ptr[1];\
267 pp[3 * _a + 2]= ptr[2];\
268 pz[_a]=zz; \
269 } \
270 z+=dzdx; \
271 s+=dsdx; \
272 t+=dtdx; \
273}
274
275#else
276
277#define PUT_PIXEL(_a) \
278{ \
279 zz=z >> ZB_POINT_Z_FRAC_BITS; \
280 if (ZCMP(zz,pz[_a])) { \
281 pp[_a]=*(PIXEL *)((char *)texture+ \
282 (((t & 0x3FC00000) | (s & 0x003FC000)) >> (17 - PSZSH)));\
283 pz[_a]=zz; \
284 } \
285 z+=dzdx; \
286 s+=dsdx; \
287 t+=dtdx; \
288}
289
290#endif
291
292#define DRAW_LINE() \
293{ \
294 register unsigned short *pz; \
295 register PIXEL *pp; \
296 register unsigned int s,t,z,zz; \
297 register int n,dsdx,dtdx; \
298 float sz,tz,fz,zinv; \
299 n=(x2>>16)-x1; \
300 fz=(float)z1;\
301 zinv=1.0 / fz;\
302 pp=(PIXEL *)((char *)pp1 + x1 * PSZB); \
303 pz=pz1+x1; \
304 z=z1; \
305 sz=sz1;\
306 tz=tz1;\
307 while (n>=(NB_INTERP-1)) { \
308 {\
309 float ss,tt;\
310 ss=(sz * zinv);\
311 tt=(tz * zinv);\
312 s=(int) ss;\
313 t=(int) tt;\
314 dsdx= (int)( (dszdx - ss*fdzdx)*zinv );\
315 dtdx= (int)( (dtzdx - tt*fdzdx)*zinv );\
316 fz+=fndzdx;\
317 zinv=1.0 / fz;\
318 }\
319 PUT_PIXEL(0); \
320 PUT_PIXEL(1); \
321 PUT_PIXEL(2); \
322 PUT_PIXEL(3); \
323 PUT_PIXEL(4); \
324 PUT_PIXEL(5); \
325 PUT_PIXEL(6); \
326 PUT_PIXEL(7); \
327 pz+=NB_INTERP; \
328 pp=(PIXEL *)((char *)pp + NB_INTERP * PSZB);\
329 n-=NB_INTERP; \
330 sz+=ndszdx;\
331 tz+=ndtzdx;\
332 } \
333 {\
334 float ss,tt;\
335 ss=(sz * zinv);\
336 tt=(tz * zinv);\
337 s=(int) ss;\
338 t=(int) tt;\
339 dsdx= (int)( (dszdx - ss*fdzdx)*zinv );\
340 dtdx= (int)( (dtzdx - tt*fdzdx)*zinv );\
341 }\
342 while (n>=0) { \
343 PUT_PIXEL(0); \
344 pz+=1; \
345 pp=(PIXEL *)((char *)pp + PSZB);\
346 n-=1; \
347 } \
348}
349
350#include "ztriangle.h"
351}
352
353#endif
354
355#if 0
356
357/* slow but exact version (only there for reference, incorrect for 24
358 bits) */
359
360void ZB_fillTriangleMappingPerspective(ZBuffer *zb,
361 ZBufferPoint *p0,ZBufferPoint *p1,ZBufferPoint *p2)
362{
363 PIXEL *texture;
364
365#define INTERP_Z
366#define INTERP_STZ
367
368#define DRAW_INIT() \
369{ \
370 texture=zb->current_texture; \
371}
372
373#define PUT_PIXEL(_a) \
374{ \
375 float zinv; \
376 int s,t; \
377 zz=z >> ZB_POINT_Z_FRAC_BITS; \
378 if (ZCMP(zz,pz[_a])) { \
379 zinv= 1.0 / (float) z; \
380 s= (int) (sz * zinv); \
381 t= (int) (tz * zinv); \
382 pp[_a]=texture[((t & 0x3FC00000) | s) >> 14]; \
383 pz[_a]=zz; \
384 } \
385 z+=dzdx; \
386 sz+=dszdx; \
387 tz+=dtzdx; \
388}
389
390#include "ztriangle.h"
391}
392
393
394#endif
ZBuffer::current_texture
PIXEL * current_texture
Definition: zbuffer.h:86
PIXEL
unsigned short PIXEL
Definition: zbuffer.h:48
ZB_setTexture
void ZB_setTexture(ZBuffer *zb, PIXEL *texture)
Definition: ztriangle.c:174
ZB_fillTriangleMappingPerspective
void ZB_fillTriangleMappingPerspective(ZBuffer *zb, ZBufferPoint *p0, ZBufferPoint *p1, ZBufferPoint *p2)
Definition: ztriangle.c:236
ZB_fillTriangleSmooth
void ZB_fillTriangleSmooth(ZBuffer *zb, ZBufferPoint *p0, ZBufferPoint *p1, ZBufferPoint *p2)
Definition: ztriangle.c:64
ZB_fillTriangleMapping
void ZB_fillTriangleMapping(ZBuffer *zb, ZBufferPoint *p0, ZBufferPoint *p1, ZBufferPoint *p2)
Definition: ztriangle.c:179
ZB_fillTriangleFlat
void ZB_fillTriangleFlat(ZBuffer *zb, ZBufferPoint *p0, ZBufferPoint *p1, ZBufferPoint *p2)
Definition: ztriangle.c:6
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