src/video/SDL_blit_A.c
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FUNCTIONS
This source file includes following functions.
- BlitNto1SurfaceAlpha
- BlitNto1PixelAlpha
- BlitNto1SurfaceAlphaKey
- BlitRGBtoRGBSurfaceAlpha
- BlitRGBtoRGBPixelAlpha
- Blit565to565SurfaceAlpha
- Blit555to555SurfaceAlpha
- BlitARGBto565PixelAlpha
- BlitARGBto555PixelAlpha
- BlitNtoNSurfaceAlpha
- BlitNtoNSurfaceAlphaKey
- BlitNtoNPixelAlpha
- SDL_CalculateAlphaBlit
1 /*
2 SDL - Simple DirectMedia Layer
3 Copyright (C) 1997, 1998, 1999, 2000, 2001 Sam Lantinga
4
5 This library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public
7 License as published by the Free Software Foundation; either
8 version 2 of the License, or (at your option) any later version.
9
10 This library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Library General Public License for more details.
14
15 You should have received a copy of the GNU Library General Public
16 License along with this library; if not, write to the Free
17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18
19 Sam Lantinga
20 slouken@devolution.com
21 */
22
23 #ifdef SAVE_RCSID
24 static char rcsid =
25 "@(#) $Id: SDL_blit_A.c,v 1.3.2.9 2001/03/04 17:36:19 hercules Exp $";
26 #endif
27
28 #include <stdio.h>
29
30 #include "SDL_types.h"
31 #include "SDL_video.h"
32 #include "SDL_blit.h"
33
34 /* Functions to perform alpha blended blitting */
35
36 /* N->1 blending with per-surface alpha */
37 static void BlitNto1SurfaceAlpha(SDL_BlitInfo *info)
/* [<][>][^][v][top][bottom][index][help] */
38 {
39 int width = info->d_width;
40 int height = info->d_height;
41 Uint8 *src = info->s_pixels;
42 int srcskip = info->s_skip;
43 Uint8 *dst = info->d_pixels;
44 int dstskip = info->d_skip;
45 Uint8 *palmap = info->table;
46 SDL_PixelFormat *srcfmt = info->src;
47 SDL_PixelFormat *dstfmt = info->dst;
48 int srcbpp = srcfmt->BytesPerPixel;
49
50 const unsigned A = srcfmt->alpha;
51
52 while ( height-- ) {
53 DUFFS_LOOP4(
54 {
55 Uint32 pixel;
56 unsigned sR;
57 unsigned sG;
58 unsigned sB;
59 unsigned dR;
60 unsigned dG;
61 unsigned dB;
62 DISEMBLE_RGB(src, srcbpp, srcfmt, pixel, sR, sG, sB);
63 dR = dstfmt->palette->colors[*dst].r;
64 dG = dstfmt->palette->colors[*dst].g;
65 dB = dstfmt->palette->colors[*dst].b;
66 ALPHA_BLEND(sR, sG, sB, A, dR, dG, dB);
67 dR &= 0xff;
68 dG &= 0xff;
69 dB &= 0xff;
70 /* Pack RGB into 8bit pixel */
71 if ( palmap == NULL ) {
72 *dst =((dR>>5)<<(3+2))|
73 ((dG>>5)<<(2))|
74 ((dB>>6)<<(0));
75 } else {
76 *dst = palmap[((dR>>5)<<(3+2))|
77 ((dG>>5)<<(2)) |
78 ((dB>>6)<<(0))];
79 }
80 dst++;
81 src += srcbpp;
82 },
83 width);
84 src += srcskip;
85 dst += dstskip;
86 }
87 }
88
89 /* N->1 blending with pixel alpha */
90 static void BlitNto1PixelAlpha(SDL_BlitInfo *info)
/* [<][>][^][v][top][bottom][index][help] */
91 {
92 int width = info->d_width;
93 int height = info->d_height;
94 Uint8 *src = info->s_pixels;
95 int srcskip = info->s_skip;
96 Uint8 *dst = info->d_pixels;
97 int dstskip = info->d_skip;
98 Uint8 *palmap = info->table;
99 SDL_PixelFormat *srcfmt = info->src;
100 SDL_PixelFormat *dstfmt = info->dst;
101 int srcbpp = srcfmt->BytesPerPixel;
102
103 /* FIXME: fix alpha bit field expansion here too? */
104 while ( height-- ) {
105 DUFFS_LOOP4(
106 {
107 Uint32 pixel;
108 unsigned sR;
109 unsigned sG;
110 unsigned sB;
111 unsigned sA;
112 unsigned dR;
113 unsigned dG;
114 unsigned dB;
115 DISEMBLE_RGBA(src,srcbpp,srcfmt,pixel,sR,sG,sB,sA);
116 dR = dstfmt->palette->colors[*dst].r;
117 dG = dstfmt->palette->colors[*dst].g;
118 dB = dstfmt->palette->colors[*dst].b;
119 ALPHA_BLEND(sR, sG, sB, sA, dR, dG, dB);
120 dR &= 0xff;
121 dG &= 0xff;
122 dB &= 0xff;
123 /* Pack RGB into 8bit pixel */
124 if ( palmap == NULL ) {
125 *dst =((dR>>5)<<(3+2))|
126 ((dG>>5)<<(2))|
127 ((dB>>6)<<(0));
128 } else {
129 *dst = palmap[((dR>>5)<<(3+2))|
130 ((dG>>5)<<(2)) |
131 ((dB>>6)<<(0)) ];
132 }
133 dst++;
134 src += srcbpp;
135 },
136 width);
137 src += srcskip;
138 dst += dstskip;
139 }
140 }
141
142 /* colorkeyed N->1 blending with per-surface alpha */
143 static void BlitNto1SurfaceAlphaKey(SDL_BlitInfo *info)
/* [<][>][^][v][top][bottom][index][help] */
144 {
145 int width = info->d_width;
146 int height = info->d_height;
147 Uint8 *src = info->s_pixels;
148 int srcskip = info->s_skip;
149 Uint8 *dst = info->d_pixels;
150 int dstskip = info->d_skip;
151 Uint8 *palmap = info->table;
152 SDL_PixelFormat *srcfmt = info->src;
153 SDL_PixelFormat *dstfmt = info->dst;
154 int srcbpp = srcfmt->BytesPerPixel;
155 Uint32 ckey = srcfmt->colorkey;
156
157 const int A = srcfmt->alpha;
158
159 while ( height-- ) {
160 DUFFS_LOOP(
161 {
162 Uint32 pixel;
163 unsigned sR;
164 unsigned sG;
165 unsigned sB;
166 unsigned dR;
167 unsigned dG;
168 unsigned dB;
169 DISEMBLE_RGB(src, srcbpp, srcfmt, pixel, sR, sG, sB);
170 if ( pixel != ckey ) {
171 dR = dstfmt->palette->colors[*dst].r;
172 dG = dstfmt->palette->colors[*dst].g;
173 dB = dstfmt->palette->colors[*dst].b;
174 ALPHA_BLEND(sR, sG, sB, A, dR, dG, dB);
175 dR &= 0xff;
176 dG &= 0xff;
177 dB &= 0xff;
178 /* Pack RGB into 8bit pixel */
179 if ( palmap == NULL ) {
180 *dst =((dR>>5)<<(3+2))|
181 ((dG>>5)<<(2)) |
182 ((dB>>6)<<(0));
183 } else {
184 *dst = palmap[((dR>>5)<<(3+2))|
185 ((dG>>5)<<(2)) |
186 ((dB>>6)<<(0)) ];
187 }
188 }
189 dst++;
190 src += srcbpp;
191 },
192 width);
193 src += srcskip;
194 dst += dstskip;
195 }
196 }
197
198 /* fast RGB888->(A)RGB888 blending with surface alpha */
199 static void BlitRGBtoRGBSurfaceAlpha(SDL_BlitInfo *info)
/* [<][>][^][v][top][bottom][index][help] */
200 {
201 int width = info->d_width;
202 int height = info->d_height;
203 Uint32 *srcp = (Uint32 *)info->s_pixels;
204 int srcskip = info->s_skip >> 2;
205 Uint32 *dstp = (Uint32 *)info->d_pixels;
206 int dstskip = info->d_skip >> 2;
207 SDL_PixelFormat *srcfmt = info->src;
208 unsigned alpha = srcfmt->alpha;
209
210 while(height--) {
211 DUFFS_LOOP4({
212 Uint32 s;
213 Uint32 d;
214 Uint32 s1;
215 Uint32 d1;
216 s = *srcp;
217 d = *dstp;
218 s1 = s & 0xff00ff;
219 d1 = d & 0xff00ff;
220 d1 = (d1 + ((s1 - d1) * alpha >> 8)) & 0xff00ff;
221 s &= 0xff00;
222 d &= 0xff00;
223 d = (d + ((s - d) * alpha >> 8)) & 0xff00;
224 *dstp = d1 | d | 0xff000000;
225 ++srcp;
226 ++dstp;
227 }, width);
228 srcp += srcskip;
229 dstp += dstskip;
230 }
231 }
232
233 /* fast ARGB888->(A)RGB888 blending with pixel alpha */
234 static void BlitRGBtoRGBPixelAlpha(SDL_BlitInfo *info)
/* [<][>][^][v][top][bottom][index][help] */
235 {
236 int width = info->d_width;
237 int height = info->d_height;
238 Uint32 *srcp = (Uint32 *)info->s_pixels;
239 int srcskip = info->s_skip >> 2;
240 Uint32 *dstp = (Uint32 *)info->d_pixels;
241 int dstskip = info->d_skip >> 2;
242
243 while(height--) {
244 DUFFS_LOOP4({
245 Uint32 dalpha;
246 Uint32 d;
247 Uint32 s1;
248 Uint32 d1;
249 Uint32 s = *srcp;
250 Uint32 alpha = s >> 24;
251 /* FIXME: Here we special-case opaque alpha since the
252 compositioning used (>>8 instead of /255) doesn't handle
253 it correctly. Also special-case alpha=0 for speed?
254 Benchmark this! */
255 if(alpha == SDL_ALPHA_OPAQUE) {
256 *dstp = (s & 0x00ffffff) | (*dstp & 0xff000000);
257 } else {
258 /*
259 * take out the middle component (green), and process
260 * the other two in parallel. One multiply less.
261 */
262 d = *dstp;
263 dalpha = d & 0xff000000;
264 s1 = s & 0xff00ff;
265 d1 = d & 0xff00ff;
266 d1 = (d1 + ((s1 - d1) * alpha >> 8)) & 0xff00ff;
267 s &= 0xff00;
268 d &= 0xff00;
269 d = (d + ((s - d) * alpha >> 8)) & 0xff00;
270 *dstp = d1 | d | dalpha;
271 }
272 ++srcp;
273 ++dstp;
274 }, width);
275 srcp += srcskip;
276 dstp += dstskip;
277 }
278 }
279
280 /* fast RGB565->RGB565 blending with surface alpha */
281 static void Blit565to565SurfaceAlpha(SDL_BlitInfo *info)
/* [<][>][^][v][top][bottom][index][help] */
282 {
283 int width = info->d_width;
284 int height = info->d_height;
285 Uint16 *srcp = (Uint16 *)info->s_pixels;
286 int srcskip = info->s_skip >> 1;
287 Uint16 *dstp = (Uint16 *)info->d_pixels;
288 int dstskip = info->d_skip >> 1;
289 unsigned alpha = info->src->alpha >> 3; /* downscale alpha to 5 bits */
290
291 while(height--) {
292 DUFFS_LOOP4({
293 Uint32 s = *srcp++;
294 Uint32 d = *dstp;
295 /*
296 * shift out the middle component (green) to the high 16
297 * bits, and process all three RGB components at the same
298 * time.
299 */
300 s = (s | s << 16) & 0x07e0f81f;
301 d = (d | d << 16) & 0x07e0f81f;
302 d += (s - d) * alpha >> 5;
303 d &= 0x07e0f81f;
304 *dstp++ = d | d >> 16;
305 }, width);
306 srcp += srcskip;
307 dstp += dstskip;
308 }
309 }
310
311 /* fast RGB555->RGB555 blending with surface alpha */
312 static void Blit555to555SurfaceAlpha(SDL_BlitInfo *info)
/* [<][>][^][v][top][bottom][index][help] */
313 {
314 int width = info->d_width;
315 int height = info->d_height;
316 Uint16 *srcp = (Uint16 *)info->s_pixels;
317 int srcskip = info->s_skip >> 1;
318 Uint16 *dstp = (Uint16 *)info->d_pixels;
319 int dstskip = info->d_skip >> 1;
320 unsigned alpha = info->src->alpha >> 3; /* downscale alpha to 5 bits */
321
322 while(height--) {
323 DUFFS_LOOP4({
324 Uint32 s = *srcp++;
325 Uint32 d = *dstp;
326 /*
327 * shift out the middle component (green) to the high 16
328 * bits, and process all three RGB components at the same
329 * time.
330 */
331 s = (s | s << 16) & 0x03e07c1f;
332 d = (d | d << 16) & 0x03e07c1f;
333 d += (s - d) * alpha >> 5;
334 d &= 0x03e07c1f;
335 *dstp++ = d | d >> 16;
336 }, width);
337 srcp += srcskip;
338 dstp += dstskip;
339 }
340 }
341
342 /* fast ARGB8888->RGB565 blending with pixel alpha */
343 static void BlitARGBto565PixelAlpha(SDL_BlitInfo *info)
/* [<][>][^][v][top][bottom][index][help] */
344 {
345 int width = info->d_width;
346 int height = info->d_height;
347 Uint32 *srcp = (Uint32 *)info->s_pixels;
348 int srcskip = info->s_skip >> 2;
349 Uint16 *dstp = (Uint16 *)info->d_pixels;
350 int dstskip = info->d_skip >> 1;
351
352 while(height--) {
353 DUFFS_LOOP4({
354 Uint32 s = *srcp;
355 unsigned alpha = s >> 27; /* downscale alpha to 5 bits */
356 /* FIXME: Here we special-case opaque alpha since the
357 compositioning used (>>8 instead of /255) doesn't handle
358 it correctly. Also special-case alpha=0 for speed?
359 Benchmark this! */
360 if(alpha == (SDL_ALPHA_OPAQUE >> 3)) {
361 *dstp = (s >> 8 & 0xf800) + (s >> 5 & 0x7e0)
362 + (s >> 3 & 0x1f);
363 } else {
364 Uint32 d = *dstp;
365 /*
366 * convert source and destination to G0RAB65565
367 * and blend all components at the same time
368 */
369 s = ((s & 0xfc00) << 11) + (s >> 8 & 0xf800)
370 + (s >> 3 & 0x1f);
371 d = (d | d << 16) & 0x07e0f81f;
372 d += (s - d) * alpha >> 5;
373 d &= 0x07e0f81f;
374 *dstp = d | d >> 16;
375 }
376 srcp++;
377 dstp++;
378 }, width);
379 srcp += srcskip;
380 dstp += dstskip;
381 }
382 }
383
384 /* fast ARGB8888->RGB555 blending with pixel alpha */
385 static void BlitARGBto555PixelAlpha(SDL_BlitInfo *info)
/* [<][>][^][v][top][bottom][index][help] */
386 {
387 int width = info->d_width;
388 int height = info->d_height;
389 Uint32 *srcp = (Uint32 *)info->s_pixels;
390 int srcskip = info->s_skip >> 2;
391 Uint16 *dstp = (Uint16 *)info->d_pixels;
392 int dstskip = info->d_skip >> 1;
393
394 while(height--) {
395 DUFFS_LOOP4({
396 unsigned alpha;
397 Uint32 s = *srcp;
398 alpha = s >> 27; /* downscale alpha to 5 bits */
399 /* FIXME: Here we special-case opaque alpha since the
400 compositioning used (>>8 instead of /255) doesn't handle
401 it correctly. Also special-case alpha=0 for speed?
402 Benchmark this! */
403 if(alpha == (SDL_ALPHA_OPAQUE >> 3)) {
404 *dstp = (s >> 9 & 0x7c00) + (s >> 6 & 0x3e0)
405 + (s >> 3 & 0x1f);
406 } else {
407 Uint32 d = *dstp;
408 /*
409 * convert source and destination to G0RAB65565
410 * and blend all components at the same time
411 */
412 s = ((s & 0xf800) << 10) + (s >> 9 & 0x7c00)
413 + (s >> 3 & 0x1f);
414 d = (d | d << 16) & 0x03e07c1f;
415 d += (s - d) * alpha >> 5;
416 d &= 0x03e07c1f;
417 *dstp = d | d >> 16;
418 }
419 srcp++;
420 dstp++;
421 }, width);
422 srcp += srcskip;
423 dstp += dstskip;
424 }
425 }
426
427 /* General (slow) N->N blending with per-surface alpha */
428 static void BlitNtoNSurfaceAlpha(SDL_BlitInfo *info)
/* [<][>][^][v][top][bottom][index][help] */
429 {
430 int width = info->d_width;
431 int height = info->d_height;
432 Uint8 *src = info->s_pixels;
433 int srcskip = info->s_skip;
434 Uint8 *dst = info->d_pixels;
435 int dstskip = info->d_skip;
436 SDL_PixelFormat *srcfmt = info->src;
437 SDL_PixelFormat *dstfmt = info->dst;
438 int srcbpp = srcfmt->BytesPerPixel;
439 int dstbpp = dstfmt->BytesPerPixel;
440 unsigned sA = srcfmt->alpha;
441 unsigned dA = dstfmt->Amask ? SDL_ALPHA_OPAQUE : 0;
442
443 while ( height-- ) {
444 DUFFS_LOOP4(
445 {
446 Uint32 pixel;
447 unsigned sR;
448 unsigned sG;
449 unsigned sB;
450 unsigned dR;
451 unsigned dG;
452 unsigned dB;
453 DISEMBLE_RGB(src, srcbpp, srcfmt, pixel, sR, sG, sB);
454 DISEMBLE_RGB(dst, dstbpp, dstfmt, pixel, dR, dG, dB);
455 ALPHA_BLEND(sR, sG, sB, sA, dR, dG, dB);
456 ASSEMBLE_RGBA(dst, dstbpp, dstfmt, dR, dG, dB, dA);
457 src += srcbpp;
458 dst += dstbpp;
459 },
460 width);
461 src += srcskip;
462 dst += dstskip;
463 }
464 }
465
466 /* General (slow) colorkeyed N->N blending with per-surface alpha */
467 static void BlitNtoNSurfaceAlphaKey(SDL_BlitInfo *info)
/* [<][>][^][v][top][bottom][index][help] */
468 {
469 int width = info->d_width;
470 int height = info->d_height;
471 Uint8 *src = info->s_pixels;
472 int srcskip = info->s_skip;
473 Uint8 *dst = info->d_pixels;
474 int dstskip = info->d_skip;
475 SDL_PixelFormat *srcfmt = info->src;
476 SDL_PixelFormat *dstfmt = info->dst;
477 Uint32 ckey = srcfmt->colorkey;
478 int srcbpp = srcfmt->BytesPerPixel;
479 int dstbpp = dstfmt->BytesPerPixel;
480 unsigned sA = srcfmt->alpha;
481 unsigned dA = dstfmt->Amask ? SDL_ALPHA_OPAQUE : 0;
482
483 while ( height-- ) {
484 DUFFS_LOOP4(
485 {
486 Uint32 pixel;
487 unsigned sR;
488 unsigned sG;
489 unsigned sB;
490 unsigned dR;
491 unsigned dG;
492 unsigned dB;
493 RETRIEVE_RGB_PIXEL(src, srcbpp, pixel);
494 if(pixel != ckey) {
495 RGB_FROM_PIXEL(pixel, srcfmt, sR, sG, sB);
496 DISEMBLE_RGB(dst, dstbpp, dstfmt, pixel, dR, dG, dB);
497 ALPHA_BLEND(sR, sG, sB, sA, dR, dG, dB);
498 ASSEMBLE_RGBA(dst, dstbpp, dstfmt, dR, dG, dB, dA);
499 }
500 src += srcbpp;
501 dst += dstbpp;
502 },
503 width);
504 src += srcskip;
505 dst += dstskip;
506 }
507 }
508
509 /* General (slow) N->N blending with pixel alpha */
510 static void BlitNtoNPixelAlpha(SDL_BlitInfo *info)
/* [<][>][^][v][top][bottom][index][help] */
511 {
512 int width = info->d_width;
513 int height = info->d_height;
514 Uint8 *src = info->s_pixels;
515 int srcskip = info->s_skip;
516 Uint8 *dst = info->d_pixels;
517 int dstskip = info->d_skip;
518 SDL_PixelFormat *srcfmt = info->src;
519 SDL_PixelFormat *dstfmt = info->dst;
520
521 int srcbpp;
522 int dstbpp;
523
524 /* Set up some basic variables */
525 srcbpp = srcfmt->BytesPerPixel;
526 dstbpp = dstfmt->BytesPerPixel;
527
528 /* FIXME: for 8bpp source alpha, this doesn't get opaque values
529 quite right. for <8bpp source alpha, it gets them very wrong
530 (check all macros!)
531 It is unclear whether there is a good general solution that doesn't
532 need a branch (or a divide). */
533 while ( height-- ) {
534 DUFFS_LOOP4(
535 {
536 Uint32 pixel;
537 unsigned sR;
538 unsigned sG;
539 unsigned sB;
540 unsigned dR;
541 unsigned dG;
542 unsigned dB;
543 unsigned sA;
544 unsigned dA;
545 DISEMBLE_RGBA(src, srcbpp, srcfmt, pixel, sR, sG, sB, sA);
546 DISEMBLE_RGBA(dst, dstbpp, dstfmt, pixel, dR, dG, dB, dA);
547 ALPHA_BLEND(sR, sG, sB, sA, dR, dG, dB);
548 ASSEMBLE_RGBA(dst, dstbpp, dstfmt, dR, dG, dB, dA);
549 src += srcbpp;
550 dst += dstbpp;
551 },
552 width);
553 src += srcskip;
554 dst += dstskip;
555 }
556 }
557
558
559 SDL_loblit SDL_CalculateAlphaBlit(SDL_Surface *surface, int blit_index)
/* [<][>][^][v][top][bottom][index][help] */
560 {
561 SDL_PixelFormat *sf = surface->format;
562 SDL_PixelFormat *df = surface->map->dst->format;
563
564 if(sf->Amask == 0) {
565 if((surface->flags & SDL_SRCCOLORKEY) == SDL_SRCCOLORKEY) {
566 if(df->BytesPerPixel == 1)
567 return BlitNto1SurfaceAlphaKey;
568 else
569 return BlitNtoNSurfaceAlphaKey;
570 } else {
571 /* Per-surface alpha blits */
572 switch(df->BytesPerPixel) {
573 case 1:
574 return BlitNto1SurfaceAlpha;
575
576 case 2:
577 if(surface->map->identity) {
578 if(df->Gmask == 0x7e0)
579 return Blit565to565SurfaceAlpha;
580 else if(df->Gmask == 0x3e0)
581 return Blit555to555SurfaceAlpha;
582 }
583 return BlitNtoNSurfaceAlpha;
584
585 case 4:
586 if(sf->Rmask == df->Rmask
587 && sf->Gmask == df->Gmask
588 && sf->Bmask == df->Bmask
589 && (sf->Rmask | sf->Gmask | sf->Bmask) == 0xffffff
590 && sf->BytesPerPixel == 4)
591 return BlitRGBtoRGBSurfaceAlpha;
592 else
593 return BlitNtoNSurfaceAlpha;
594
595 case 3:
596 default:
597 return BlitNtoNSurfaceAlpha;
598 }
599 }
600 } else {
601 /* Per-pixel alpha blits */
602 switch(df->BytesPerPixel) {
603 case 1:
604 return BlitNto1PixelAlpha;
605
606 case 2:
607 if(sf->BytesPerPixel == 4 && sf->Amask == 0xff000000
608 && sf->Gmask == 0xff00
609 && ((sf->Rmask == 0xff && df->Rmask == 0x1f)
610 || (sf->Bmask == 0xff && df->Bmask == 0x1f))) {
611 if(df->Gmask == 0x7e0)
612 return BlitARGBto565PixelAlpha;
613 else if(df->Gmask == 0x3e0)
614 return BlitARGBto555PixelAlpha;
615 }
616 return BlitNtoNPixelAlpha;
617
618 case 4:
619 if(sf->Amask == 0xff000000
620 && sf->Rmask == df->Rmask
621 && sf->Gmask == df->Gmask
622 && sf->Bmask == df->Bmask
623 && sf->BytesPerPixel == 4)
624 return BlitRGBtoRGBPixelAlpha;
625 return BlitNtoNPixelAlpha;
626
627 case 3:
628 default:
629 return BlitNtoNPixelAlpha;
630 }
631 }
632 }
633