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[mesa.git] / src / mesa / swrast / s_accum.c
1
2 /*
3 * Mesa 3-D graphics library
4 * Version: 4.1
5 *
6 * Copyright (C) 1999-2002 Brian Paul All Rights Reserved.
7 *
8 * Permission is hereby granted, free of charge, to any person obtaining a
9 * copy of this software and associated documentation files (the "Software"),
10 * to deal in the Software without restriction, including without limitation
11 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
12 * and/or sell copies of the Software, and to permit persons to whom the
13 * Software is furnished to do so, subject to the following conditions:
14 *
15 * The above copyright notice and this permission notice shall be included
16 * in all copies or substantial portions of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
21 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
22 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
23 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
24 */
25
26
27 #include "glheader.h"
28 #include "context.h"
29 #include "macros.h"
30 #include "imports.h"
31
32 #include "s_accum.h"
33 #include "s_alphabuf.h"
34 #include "s_context.h"
35 #include "s_masking.h"
36 #include "s_span.h"
37
38
39 /*
40 * Accumulation buffer notes
41 *
42 * Normally, accumulation buffer values are GLshorts with values in
43 * [-32767, 32767] which represent floating point colors in [-1, 1],
44 * as suggested by the OpenGL specification.
45 *
46 * We optimize for the common case used for full-scene antialiasing:
47 * // start with accum buffer cleared to zero
48 * glAccum(GL_LOAD, w); // or GL_ACCUM the first image
49 * glAccum(GL_ACCUM, w);
50 * ...
51 * glAccum(GL_ACCUM, w);
52 * glAccum(GL_RETURN, 1.0);
53 * That is, we start with an empty accumulation buffer and accumulate
54 * n images, each with weight w = 1/n.
55 * In this scenario, we can simply store unscaled integer values in
56 * the accum buffer instead of scaled integers. We'll also keep track
57 * of the w value so when we do GL_RETURN we simply divide the accumulated
58 * values by n (=1/w).
59 * This lets us avoid _many_ int->float->int conversions.
60 */
61
62
63 #if CHAN_BITS == 8 && ACCUM_BITS < 32
64 #define USE_OPTIMIZED_ACCUM /* enable the optimization */
65 #endif
66
67
68 void
69 _swrast_alloc_accum_buffer( GLframebuffer *buffer )
70 {
71 GET_CURRENT_CONTEXT(ctx);
72 GLint n;
73
74 if (buffer->Accum) {
75 MESA_PBUFFER_FREE( buffer->Accum );
76 buffer->Accum = NULL;
77 }
78
79 /* allocate accumulation buffer if not already present */
80 n = buffer->Width * buffer->Height * 4 * sizeof(GLaccum);
81 buffer->Accum = (GLaccum *) MESA_PBUFFER_ALLOC( n );
82 if (!buffer->Accum) {
83 /* unable to setup accumulation buffer */
84 _mesa_error( NULL, GL_OUT_OF_MEMORY, "glAccum" );
85 }
86
87 if (ctx) {
88 SWcontext *swrast = SWRAST_CONTEXT(ctx);
89 /* XXX these fields should probably be in the GLframebuffer */
90 #ifdef USE_OPTIMIZED_ACCUM
91 swrast->_IntegerAccumMode = GL_TRUE;
92 #else
93 swrast->_IntegerAccumMode = GL_FALSE;
94 #endif
95 swrast->_IntegerAccumScaler = 0.0;
96 }
97 }
98
99
100 /*
101 * This is called when we fall out of optimized/unscaled accum buffer mode.
102 * That is, we convert each unscaled accum buffer value into a scaled value
103 * representing the range[-1, 1].
104 */
105 static void rescale_accum( GLcontext *ctx )
106 {
107 SWcontext *swrast = SWRAST_CONTEXT(ctx);
108 const GLuint n = ctx->DrawBuffer->Width * ctx->DrawBuffer->Height * 4;
109 const GLfloat s = swrast->_IntegerAccumScaler * (32767.0F / CHAN_MAXF);
110 GLaccum *accum = ctx->DrawBuffer->Accum;
111 GLuint i;
112
113 assert(swrast->_IntegerAccumMode);
114 assert(accum);
115
116 for (i = 0; i < n; i++) {
117 accum[i] = (GLaccum) (accum[i] * s);
118 }
119
120 swrast->_IntegerAccumMode = GL_FALSE;
121 }
122
123
124
125
126
127
128 /*
129 * Clear the accumulation Buffer.
130 */
131 void
132 _swarst_clear_accum_buffer( GLcontext *ctx )
133 {
134 SWcontext *swrast = SWRAST_CONTEXT(ctx);
135 GLuint buffersize;
136 GLfloat acc_scale;
137
138 if (ctx->Visual.accumRedBits==0) {
139 /* No accumulation buffer! */
140 return;
141 }
142
143 if (sizeof(GLaccum)==1) {
144 acc_scale = 127.0;
145 }
146 else if (sizeof(GLaccum)==2) {
147 acc_scale = 32767.0;
148 }
149 else {
150 acc_scale = 1.0F;
151 }
152
153 /* number of pixels */
154 buffersize = ctx->DrawBuffer->Width * ctx->DrawBuffer->Height;
155
156 if (!ctx->DrawBuffer->Accum) {
157 /* try to alloc accumulation buffer */
158 ctx->DrawBuffer->Accum = (GLaccum *)
159 MALLOC( buffersize * 4 * sizeof(GLaccum) );
160 }
161
162 if (ctx->DrawBuffer->Accum) {
163 if (ctx->Scissor.Enabled) {
164 /* Limit clear to scissor box */
165 const GLaccum r = (GLaccum) (ctx->Accum.ClearColor[0] * acc_scale);
166 const GLaccum g = (GLaccum) (ctx->Accum.ClearColor[1] * acc_scale);
167 const GLaccum b = (GLaccum) (ctx->Accum.ClearColor[2] * acc_scale);
168 const GLaccum a = (GLaccum) (ctx->Accum.ClearColor[3] * acc_scale);
169 GLint i, j;
170 GLint width, height;
171 GLaccum *row;
172 /* size of region to clear */
173 width = 4 * (ctx->DrawBuffer->_Xmax - ctx->DrawBuffer->_Xmin);
174 height = ctx->DrawBuffer->_Ymax - ctx->DrawBuffer->_Ymin;
175 /* ptr to first element to clear */
176 row = ctx->DrawBuffer->Accum
177 + 4 * (ctx->DrawBuffer->_Ymin * ctx->DrawBuffer->Width
178 + ctx->DrawBuffer->_Xmin);
179 for (j=0;j<height;j++) {
180 for (i=0;i<width;i+=4) {
181 row[i+0] = r;
182 row[i+1] = g;
183 row[i+2] = b;
184 row[i+3] = a;
185 }
186 row += 4 * ctx->DrawBuffer->Width;
187 }
188 }
189 else {
190 /* clear whole buffer */
191 if (ctx->Accum.ClearColor[0]==0.0 &&
192 ctx->Accum.ClearColor[1]==0.0 &&
193 ctx->Accum.ClearColor[2]==0.0 &&
194 ctx->Accum.ClearColor[3]==0.0) {
195 /* Black */
196 _mesa_bzero( ctx->DrawBuffer->Accum,
197 buffersize * 4 * sizeof(GLaccum) );
198 }
199 else {
200 /* Not black */
201 const GLaccum r = (GLaccum) (ctx->Accum.ClearColor[0] * acc_scale);
202 const GLaccum g = (GLaccum) (ctx->Accum.ClearColor[1] * acc_scale);
203 const GLaccum b = (GLaccum) (ctx->Accum.ClearColor[2] * acc_scale);
204 const GLaccum a = (GLaccum) (ctx->Accum.ClearColor[3] * acc_scale);
205 GLaccum *acc = ctx->DrawBuffer->Accum;
206 GLuint i;
207 for (i=0;i<buffersize;i++) {
208 *acc++ = r;
209 *acc++ = g;
210 *acc++ = b;
211 *acc++ = a;
212 }
213 }
214 }
215
216 /* update optimized accum state vars */
217 if (ctx->Accum.ClearColor[0] == 0.0 && ctx->Accum.ClearColor[1] == 0.0 &&
218 ctx->Accum.ClearColor[2] == 0.0 && ctx->Accum.ClearColor[3] == 0.0) {
219 #ifdef USE_OPTIMIZED_ACCUM
220 swrast->_IntegerAccumMode = GL_TRUE;
221 #else
222 swrast->_IntegerAccumMode = GL_FALSE;
223 #endif
224 swrast->_IntegerAccumScaler = 0.0; /* denotes empty accum buffer */
225 }
226 else {
227 swrast->_IntegerAccumMode = GL_FALSE;
228 }
229 }
230 }
231
232
233 void
234 _swrast_Accum( GLcontext *ctx, GLenum op, GLfloat value,
235 GLint xpos, GLint ypos,
236 GLint width, GLint height )
237
238 {
239 SWcontext *swrast = SWRAST_CONTEXT(ctx);
240 GLuint width4;
241 GLfloat acc_scale;
242 GLchan rgba[MAX_WIDTH][4];
243 const GLuint colorMask = *((GLuint *) &ctx->Color.ColorMask);
244
245
246 if (SWRAST_CONTEXT(ctx)->NewState)
247 _swrast_validate_derived( ctx );
248
249 if (!ctx->DrawBuffer->Accum) {
250 _mesa_warning(ctx,
251 "Calling glAccum() without an accumulation "
252 "buffer (low memory?)");
253 return;
254 }
255
256 if (sizeof(GLaccum)==1) {
257 acc_scale = 127.0;
258 }
259 else if (sizeof(GLaccum)==2) {
260 acc_scale = 32767.0;
261 }
262 else {
263 acc_scale = 1.0F;
264 }
265
266 width4 = 4 * width;
267
268 switch (op) {
269 case GL_ADD:
270 if (value != 0.0F) {
271 const GLaccum val = (GLaccum) (value * acc_scale);
272 GLint j;
273 /* Leave optimized accum buffer mode */
274 if (swrast->_IntegerAccumMode)
275 rescale_accum(ctx);
276 for (j = 0; j < height; j++) {
277 GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + 4*xpos;
278 GLuint i;
279 for (i = 0; i < width4; i++) {
280 acc[i] += val;
281 }
282 ypos++;
283 }
284 }
285 break;
286
287 case GL_MULT:
288 if (value != 1.0F) {
289 GLint j;
290 /* Leave optimized accum buffer mode */
291 if (swrast->_IntegerAccumMode)
292 rescale_accum(ctx);
293 for (j = 0; j < height; j++) {
294 GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + 4 * xpos;
295 GLuint i;
296 for (i = 0; i < width4; i++) {
297 acc[i] = (GLaccum) ( (GLfloat) acc[i] * value );
298 }
299 ypos++;
300 }
301 }
302 break;
303
304 case GL_ACCUM:
305 if (value == 0.0F)
306 return;
307
308 _swrast_use_read_buffer(ctx);
309
310 /* May have to leave optimized accum buffer mode */
311 if (swrast->_IntegerAccumScaler == 0.0 && value > 0.0 && value <= 1.0)
312 swrast->_IntegerAccumScaler = value;
313 if (swrast->_IntegerAccumMode && value != swrast->_IntegerAccumScaler)
314 rescale_accum(ctx);
315
316 RENDER_START(swrast,ctx);
317
318 if (swrast->_IntegerAccumMode) {
319 /* simply add integer color values into accum buffer */
320 GLint j;
321 GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + xpos * 4;
322 assert(swrast->_IntegerAccumScaler > 0.0);
323 assert(swrast->_IntegerAccumScaler <= 1.0);
324 for (j = 0; j < height; j++) {
325
326 GLint i, i4;
327 _swrast_read_rgba_span(ctx, ctx->DrawBuffer, width, xpos, ypos, rgba);
328 for (i = i4 = 0; i < width; i++, i4+=4) {
329 acc[i4+0] += rgba[i][RCOMP];
330 acc[i4+1] += rgba[i][GCOMP];
331 acc[i4+2] += rgba[i][BCOMP];
332 acc[i4+3] += rgba[i][ACOMP];
333 }
334 acc += width4;
335 ypos++;
336 }
337 }
338 else {
339 /* scaled integer (or float) accum buffer */
340 const GLfloat rscale = value * acc_scale / CHAN_MAXF;
341 const GLfloat gscale = value * acc_scale / CHAN_MAXF;
342 const GLfloat bscale = value * acc_scale / CHAN_MAXF;
343 const GLfloat ascale = value * acc_scale / CHAN_MAXF;
344 GLint j;
345 for (j=0;j<height;j++) {
346 GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + xpos * 4;
347 GLint i;
348 _swrast_read_rgba_span(ctx, ctx->DrawBuffer, width, xpos, ypos, rgba);
349 for (i=0;i<width;i++) {
350 acc[0] += (GLaccum) ( (GLfloat) rgba[i][RCOMP] * rscale );
351 acc[1] += (GLaccum) ( (GLfloat) rgba[i][GCOMP] * gscale );
352 acc[2] += (GLaccum) ( (GLfloat) rgba[i][BCOMP] * bscale );
353 acc[3] += (GLaccum) ( (GLfloat) rgba[i][ACOMP] * ascale );
354 acc += 4;
355 }
356 ypos++;
357 }
358 }
359 /* restore read buffer = draw buffer (the default) */
360 _swrast_use_draw_buffer(ctx);
361
362 RENDER_FINISH(swrast,ctx);
363 break;
364
365 case GL_LOAD:
366 _swrast_use_read_buffer(ctx);
367
368 /* This is a change to go into optimized accum buffer mode */
369 if (value > 0.0 && value <= 1.0) {
370 #ifdef USE_OPTIMIZED_ACCUM
371 swrast->_IntegerAccumMode = GL_TRUE;
372 #else
373 swrast->_IntegerAccumMode = GL_FALSE;
374 #endif
375 swrast->_IntegerAccumScaler = value;
376 }
377 else {
378 swrast->_IntegerAccumMode = GL_FALSE;
379 swrast->_IntegerAccumScaler = 0.0;
380 }
381
382 RENDER_START(swrast,ctx);
383 if (swrast->_IntegerAccumMode) {
384 /* just copy values into accum buffer */
385 GLint j;
386 GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + xpos * 4;
387 assert(swrast->_IntegerAccumScaler > 0.0);
388 assert(swrast->_IntegerAccumScaler <= 1.0);
389 for (j = 0; j < height; j++) {
390 GLint i, i4;
391 _swrast_read_rgba_span(ctx, ctx->DrawBuffer, width, xpos, ypos, rgba);
392 for (i = i4 = 0; i < width; i++, i4 += 4) {
393 acc[i4+0] = rgba[i][RCOMP];
394 acc[i4+1] = rgba[i][GCOMP];
395 acc[i4+2] = rgba[i][BCOMP];
396 acc[i4+3] = rgba[i][ACOMP];
397 }
398 acc += width4;
399 ypos++;
400 }
401 }
402 else {
403 /* scaled integer (or float) accum buffer */
404 const GLfloat rscale = value * acc_scale / CHAN_MAXF;
405 const GLfloat gscale = value * acc_scale / CHAN_MAXF;
406 const GLfloat bscale = value * acc_scale / CHAN_MAXF;
407 const GLfloat ascale = value * acc_scale / CHAN_MAXF;
408 #if 0
409 const GLfloat d = 3.0 / acc_scale; /* XXX what's this? */
410 #endif
411 GLint i, j;
412 for (j = 0; j < height; j++) {
413 GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + xpos * 4;
414 _swrast_read_rgba_span(ctx, ctx->DrawBuffer, width, xpos, ypos, rgba);
415 for (i=0;i<width;i++) {
416 #if 0
417 *acc++ = (GLaccum) ((GLfloat) rgba[i][RCOMP] * rscale + d);
418 *acc++ = (GLaccum) ((GLfloat) rgba[i][GCOMP] * gscale + d);
419 *acc++ = (GLaccum) ((GLfloat) rgba[i][BCOMP] * bscale + d);
420 *acc++ = (GLaccum) ((GLfloat) rgba[i][ACOMP] * ascale + d);
421 #else
422 *acc++ = (GLaccum) ((GLfloat) rgba[i][RCOMP] * rscale);
423 *acc++ = (GLaccum) ((GLfloat) rgba[i][GCOMP] * gscale);
424 *acc++ = (GLaccum) ((GLfloat) rgba[i][BCOMP] * bscale);
425 *acc++ = (GLaccum) ((GLfloat) rgba[i][ACOMP] * ascale);
426 #endif
427 }
428 ypos++;
429 }
430 }
431
432 /* restore read buffer = draw buffer (the default) */
433 _swrast_use_draw_buffer(ctx);
434
435 RENDER_FINISH(swrast,ctx);
436 break;
437
438 case GL_RETURN:
439 /* May have to leave optimized accum buffer mode */
440 if (swrast->_IntegerAccumMode && value != 1.0)
441 rescale_accum(ctx);
442
443 RENDER_START(swrast,ctx);
444 #ifdef USE_OPTIMIZED_ACCUM
445 if (swrast->_IntegerAccumMode && swrast->_IntegerAccumScaler > 0) {
446 /* build lookup table to avoid many floating point multiplies */
447 static GLchan multTable[32768];
448 static GLfloat prevMult = 0.0;
449 const GLfloat mult = swrast->_IntegerAccumScaler;
450 const GLint max = MIN2((GLint) (256 / mult), 32767);
451 GLint j;
452 if (mult != prevMult) {
453 for (j = 0; j < max; j++)
454 multTable[j] = IROUND((GLfloat) j * mult);
455 prevMult = mult;
456 }
457
458 assert(swrast->_IntegerAccumScaler > 0.0);
459 assert(swrast->_IntegerAccumScaler <= 1.0);
460 for (j = 0; j < height; j++) {
461 const GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + xpos*4;
462 GLint i, i4;
463 for (i = i4 = 0; i < width; i++, i4 += 4) {
464 ASSERT(acc[i4+0] < max);
465 ASSERT(acc[i4+1] < max);
466 ASSERT(acc[i4+2] < max);
467 ASSERT(acc[i4+3] < max);
468 rgba[i][RCOMP] = multTable[acc[i4+0]];
469 rgba[i][GCOMP] = multTable[acc[i4+1]];
470 rgba[i][BCOMP] = multTable[acc[i4+2]];
471 rgba[i][ACOMP] = multTable[acc[i4+3]];
472 }
473 if (colorMask != 0xffffffff) {
474 _swrast_mask_rgba_array( ctx, width, xpos, ypos, rgba );
475 }
476 (*swrast->Driver.WriteRGBASpan)( ctx, width, xpos, ypos,
477 (const GLchan (*)[4])rgba, NULL );
478 if (ctx->DrawBuffer->UseSoftwareAlphaBuffers
479 && ctx->Color.ColorMask[ACOMP]) {
480 _swrast_write_alpha_span(ctx, width, xpos, ypos,
481 (CONST GLchan (*)[4]) rgba, NULL);
482 }
483 ypos++;
484 }
485 }
486 else
487 #endif /* USE_OPTIMIZED_ACCUM */
488 {
489 /* scaled integer (or float) accum buffer */
490 const GLfloat rscale = value / acc_scale * CHAN_MAXF;
491 const GLfloat gscale = value / acc_scale * CHAN_MAXF;
492 const GLfloat bscale = value / acc_scale * CHAN_MAXF;
493 const GLfloat ascale = value / acc_scale * CHAN_MAXF;
494 GLint i, j;
495 for (j=0;j<height;j++) {
496 const GLaccum *acc = ctx->DrawBuffer->Accum + ypos * width4 + xpos*4;
497 for (i=0;i<width;i++) {
498 GLint r = IROUND( (GLfloat) (acc[0]) * rscale );
499 GLint g = IROUND( (GLfloat) (acc[1]) * gscale );
500 GLint b = IROUND( (GLfloat) (acc[2]) * bscale );
501 GLint a = IROUND( (GLfloat) (acc[3]) * ascale );
502 acc += 4;
503 rgba[i][RCOMP] = CLAMP( r, 0, CHAN_MAX );
504 rgba[i][GCOMP] = CLAMP( g, 0, CHAN_MAX );
505 rgba[i][BCOMP] = CLAMP( b, 0, CHAN_MAX );
506 rgba[i][ACOMP] = CLAMP( a, 0, CHAN_MAX );
507 }
508 if (colorMask != 0xffffffff) {
509 _swrast_mask_rgba_array( ctx, width, xpos, ypos, rgba );
510 }
511 (*swrast->Driver.WriteRGBASpan)( ctx, width, xpos, ypos,
512 (const GLchan (*)[4])rgba, NULL );
513 if (ctx->DrawBuffer->UseSoftwareAlphaBuffers
514 && ctx->Color.ColorMask[ACOMP]) {
515 _swrast_write_alpha_span(ctx, width, xpos, ypos,
516 (CONST GLchan (*)[4]) rgba, NULL);
517 }
518 ypos++;
519 }
520 }
521 RENDER_FINISH(swrast,ctx);
522 break;
523
524 default:
525 _mesa_error( ctx, GL_INVALID_ENUM, "glAccum" );
526 }
527 }