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1/*
2 Simple DirectMedia Layer
3 Copyright (C) 1997-2025 Sam Lantinga <slouken@libsdl.org>
4
5 This software is provided 'as-is', without any express or implied
6 warranty. In no event will the authors be held liable for any damages
7 arising from the use of this software.
8
9 Permission is granted to anyone to use this software for any purpose,
10 including commercial applications, and to alter it and redistribute it
11 freely, subject to the following restrictions:
12
13 1. The origin of this software must not be misrepresented; you must not
14 claim that you wrote the original software. If you use this software
15 in a product, an acknowledgment in the product documentation would be
16 appreciated but is not required.
17 2. Altered source versions must be plainly marked as such, and must not be
18 misrepresented as being the original software.
19 3. This notice may not be removed or altered from any source distribution.
20*/
21#include "SDL_internal.h"
22
23#ifdef SDL_HAVE_RLE
24
25/*
26 * RLE encoding for software colorkey and alpha-channel acceleration
27 *
28 * Original version by Sam Lantinga
29 *
30 * Mattias Engdegård (Yorick): Rewrite. New encoding format, encoder and
31 * decoder. Added per-surface alpha blitter. Added per-pixel alpha
32 * format, encoder and blitter.
33 *
34 * Many thanks to Xark and johns for hints, benchmarks and useful comments
35 * leading to this code.
36 *
37 * Welcome to Macro Mayhem.
38 */
39
40/*
41 * The encoding translates the image data to a stream of segments of the form
42 *
43 * <skip> <run> <data>
44 *
45 * where <skip> is the number of transparent pixels to skip,
46 * <run> is the number of opaque pixels to blit,
47 * and <data> are the pixels themselves.
48 *
49 * This basic structure is used both for colorkeyed surfaces, used for simple
50 * binary transparency and for per-surface alpha blending, and for surfaces
51 * with per-pixel alpha. The details differ, however:
52 *
53 * Encoding of colorkeyed surfaces:
54 *
55 * Encoded pixels always have the same format as the target surface.
56 * <skip> and <run> are unsigned 8 bit integers, except for 32 bit depth
57 * where they are 16 bit. This makes the pixel data aligned at all times.
58 * Segments never wrap around from one scan line to the next.
59 *
60 * The end of the sequence is marked by a zero <skip>,<run> pair at the *
61 * beginning of a line.
62 *
63 * Encoding of surfaces with per-pixel alpha:
64 *
65 * The sequence begins with an SDL_PixelFormat value describing the target
66 * pixel format, to provide reliable un-encoding.
67 *
68 * Each scan line is encoded twice: First all completely opaque pixels,
69 * encoded in the target format as described above, and then all
70 * partially transparent (translucent) pixels (where 1 <= alpha <= 254),
71 * in the following 32-bit format:
72 *
73 * For 32-bit targets, each pixel has the target RGB format but with
74 * the alpha value occupying the highest 8 bits. The <skip> and <run>
75 * counts are 16 bit.
76 *
77 * For 16-bit targets, each pixel has the target RGB format, but with
78 * the middle component (usually green) shifted 16 steps to the left,
79 * and the hole filled with the 5 most significant bits of the alpha value.
80 * i.e. if the target has the format rrrrrggggggbbbbb,
81 * the encoded pixel will be 00000gggggg00000rrrrr0aaaaabbbbb.
82 * The <skip> and <run> counts are 8 bit for the opaque lines, 16 bit
83 * for the translucent lines. Two padding bytes may be inserted
84 * before each translucent line to keep them 32-bit aligned.
85 *
86 * The end of the sequence is marked by a zero <skip>,<run> pair at the
87 * beginning of an opaque line.
88 */
89
90#include "SDL_sysvideo.h"
91#include "SDL_surface_c.h"
92#include "SDL_RLEaccel_c.h"
93
94#define PIXEL_COPY(to, from, len, bpp) \
95 SDL_memcpy(to, from, (size_t)(len) * (bpp))
96
97/*
98 * Various colorkey blit methods, for opaque and per-surface alpha
99 */
100
101#define OPAQUE_BLIT(to, from, length, bpp, alpha) \
102 PIXEL_COPY(to, from, length, bpp)
103
104/*
105 * For 32bpp pixels on the form 0x00rrggbb:
106 * If we treat the middle component separately, we can process the two
107 * remaining in parallel. This is safe to do because of the gap to the left
108 * of each component, so the bits from the multiplication don't collide.
109 * This can be used for any RGB permutation of course.
110 */
111#define ALPHA_BLIT32_888(to, from, length, bpp, alpha) \
112 do { \
113 int i; \
114 Uint32 *src = (Uint32 *)(from); \
115 Uint32 *dst = (Uint32 *)(to); \
116 for (i = 0; i < (int)(length); i++) { \
117 Uint32 s = *src++; \
118 Uint32 d = *dst; \
119 Uint32 s1 = s & 0xff00ff; \
120 Uint32 d1 = d & 0xff00ff; \
121 d1 = (d1 + ((s1 - d1) * alpha >> 8)) & 0xff00ff; \
122 s &= 0xff00; \
123 d &= 0xff00; \
124 d = (d + ((s - d) * alpha >> 8)) & 0xff00; \
125 *dst++ = d1 | d; \
126 } \
127 } while (0)
128
129/*
130 * For 16bpp pixels we can go a step further: put the middle component
131 * in the high 16 bits of a 32 bit word, and process all three RGB
132 * components at the same time. Since the smallest gap is here just
133 * 5 bits, we have to scale alpha down to 5 bits as well.
134 */
135#define ALPHA_BLIT16_565(to, from, length, bpp, alpha) \
136 do { \
137 int i; \
138 Uint16 *src = (Uint16 *)(from); \
139 Uint16 *dst = (Uint16 *)(to); \
140 Uint32 ALPHA = alpha >> 3; \
141 for (i = 0; i < (int)(length); i++) { \
142 Uint32 s = *src++; \
143 Uint32 d = *dst; \
144 s = (s | s << 16) & 0x07e0f81f; \
145 d = (d | d << 16) & 0x07e0f81f; \
146 d += (s - d) * ALPHA >> 5; \
147 d &= 0x07e0f81f; \
148 *dst++ = (Uint16)(d | d >> 16); \
149 } \
150 } while (0)
151
152#define ALPHA_BLIT16_555(to, from, length, bpp, alpha) \
153 do { \
154 int i; \
155 Uint16 *src = (Uint16 *)(from); \
156 Uint16 *dst = (Uint16 *)(to); \
157 Uint32 ALPHA = alpha >> 3; \
158 for (i = 0; i < (int)(length); i++) { \
159 Uint32 s = *src++; \
160 Uint32 d = *dst; \
161 s = (s | s << 16) & 0x03e07c1f; \
162 d = (d | d << 16) & 0x03e07c1f; \
163 d += (s - d) * ALPHA >> 5; \
164 d &= 0x03e07c1f; \
165 *dst++ = (Uint16)(d | d >> 16); \
166 } \
167 } while (0)
168
169/*
170 * The general slow catch-all function, for remaining depths and formats
171 */
172#define ALPHA_BLIT_ANY(to, from, length, bpp, alpha) \
173 do { \
174 int i; \
175 Uint8 *src = from; \
176 Uint8 *dst = to; \
177 for (i = 0; i < (int)(length); i++) { \
178 Uint32 s = 0, d = 0; \
179 unsigned rs, gs, bs, rd, gd, bd; \
180 switch (bpp) { \
181 case 2: \
182 s = *(Uint16 *)src; \
183 d = *(Uint16 *)dst; \
184 break; \
185 case 3: \
186 if (SDL_BYTEORDER == SDL_BIG_ENDIAN) { \
187 s = (src[0] << 16) | (src[1] << 8) | src[2]; \
188 d = (dst[0] << 16) | (dst[1] << 8) | dst[2]; \
189 } else { \
190 s = (src[2] << 16) | (src[1] << 8) | src[0]; \
191 d = (dst[2] << 16) | (dst[1] << 8) | dst[0]; \
192 } \
193 break; \
194 case 4: \
195 s = *(Uint32 *)src; \
196 d = *(Uint32 *)dst; \
197 break; \
198 } \
199 RGB_FROM_PIXEL(s, fmt, rs, gs, bs); \
200 RGB_FROM_PIXEL(d, fmt, rd, gd, bd); \
201 rd += (rs - rd) * alpha >> 8; \
202 gd += (gs - gd) * alpha >> 8; \
203 bd += (bs - bd) * alpha >> 8; \
204 PIXEL_FROM_RGB(d, fmt, rd, gd, bd); \
205 switch (bpp) { \
206 case 2: \
207 *(Uint16 *)dst = (Uint16)d; \
208 break; \
209 case 3: \
210 if (SDL_BYTEORDER == SDL_BIG_ENDIAN) { \
211 dst[0] = (Uint8)(d >> 16); \
212 dst[1] = (Uint8)(d >> 8); \
213 dst[2] = (Uint8)(d); \
214 } else { \
215 dst[0] = (Uint8)d; \
216 dst[1] = (Uint8)(d >> 8); \
217 dst[2] = (Uint8)(d >> 16); \
218 } \
219 break; \
220 case 4: \
221 *(Uint32 *)dst = d; \
222 break; \
223 } \
224 src += bpp; \
225 dst += bpp; \
226 } \
227 } while (0)
228
229/*
230 * Special case: 50% alpha (alpha=128)
231 * This is treated specially because it can be optimized very well, and
232 * since it is good for many cases of semi-translucency.
233 * The theory is to do all three components at the same time:
234 * First zero the lowest bit of each component, which gives us room to
235 * add them. Then shift right and add the sum of the lowest bits.
236 */
237#define ALPHA_BLIT32_888_50(to, from, length, bpp, alpha) \
238 do { \
239 int i; \
240 Uint32 *src = (Uint32 *)(from); \
241 Uint32 *dst = (Uint32 *)(to); \
242 for (i = 0; i < (int)(length); i++) { \
243 Uint32 s = *src++; \
244 Uint32 d = *dst; \
245 *dst++ = (((s & 0x00fefefe) + (d & 0x00fefefe)) >> 1) + (s & d & 0x00010101); \
246 } \
247 } while (0)
248
249/*
250 * For 16bpp, we can actually blend two pixels in parallel, if we take
251 * care to shift before we add, not after.
252 */
253
254// helper: blend a single 16 bit pixel at 50%
255#define BLEND16_50(dst, src, mask) \
256 do { \
257 Uint32 s = *src++; \
258 Uint32 d = *dst; \
259 *dst++ = (Uint16)((((s & mask) + (d & mask)) >> 1) + \
260 (s & d & (~mask & 0xffff))); \
261 } while (0)
262
263// basic 16bpp blender. mask is the pixels to keep when adding.
264#define ALPHA_BLIT16_50(to, from, length, bpp, alpha, mask) \
265 do { \
266 unsigned n = (length); \
267 Uint16 *src = (Uint16 *)(from); \
268 Uint16 *dst = (Uint16 *)(to); \
269 if (((uintptr_t)src ^ (uintptr_t)dst) & 3) { \
270 /* source and destination not in phase, blit one by one */ \
271 while (n--) \
272 BLEND16_50(dst, src, mask); \
273 } else { \
274 if ((uintptr_t)src & 3) { \
275 /* first odd pixel */ \
276 BLEND16_50(dst, src, mask); \
277 n--; \
278 } \
279 for (; n > 1; n -= 2) { \
280 Uint32 s = *(Uint32 *)src; \
281 Uint32 d = *(Uint32 *)dst; \
282 *(Uint32 *)dst = ((s & (mask | mask << 16)) >> 1) + ((d & (mask | mask << 16)) >> 1) + (s & d & (~(mask | mask << 16))); \
283 src += 2; \
284 dst += 2; \
285 } \
286 if (n) \
287 BLEND16_50(dst, src, mask); /* last odd pixel */ \
288 } \
289 } while (0)
290
291#define ALPHA_BLIT16_565_50(to, from, length, bpp, alpha) \
292 ALPHA_BLIT16_50(to, from, length, bpp, alpha, 0xf7deU)
293
294#define ALPHA_BLIT16_555_50(to, from, length, bpp, alpha) \
295 ALPHA_BLIT16_50(to, from, length, bpp, alpha, 0xfbdeU)
296
297#define CHOOSE_BLIT(blitter, alpha, fmt) \
298 do { \
299 if (alpha == 255) { \
300 switch (fmt->bytes_per_pixel) { \
301 case 1: \
302 blitter(1, Uint8, OPAQUE_BLIT); \
303 break; \
304 case 2: \
305 blitter(2, Uint8, OPAQUE_BLIT); \
306 break; \
307 case 3: \
308 blitter(3, Uint8, OPAQUE_BLIT); \
309 break; \
310 case 4: \
311 blitter(4, Uint16, OPAQUE_BLIT); \
312 break; \
313 } \
314 } else { \
315 switch (fmt->bytes_per_pixel) { \
316 case 1: \
317 /* No 8bpp alpha blitting */ \
318 break; \
319 \
320 case 2: \
321 switch (fmt->Rmask | fmt->Gmask | fmt->Bmask) { \
322 case 0xffff: \
323 if (fmt->Gmask == 0x07e0 || fmt->Rmask == 0x07e0 || fmt->Bmask == 0x07e0) { \
324 if (alpha == 128) { \
325 blitter(2, Uint8, ALPHA_BLIT16_565_50); \
326 } else { \
327 blitter(2, Uint8, ALPHA_BLIT16_565); \
328 } \
329 } else { \
330 goto general16; \
331 } \
332 break; \
333 \
334 case 0x7fff: \
335 if (fmt->Gmask == 0x03e0 || fmt->Rmask == 0x03e0 || fmt->Bmask == 0x03e0) { \
336 if (alpha == 128) { \
337 blitter(2, Uint8, ALPHA_BLIT16_555_50); \
338 } else { \
339 blitter(2, Uint8, ALPHA_BLIT16_555); \
340 } \
341 break; \
342 } else { \
343 goto general16; \
344 } \
345 break; \
346 \
347 default: \
348 general16: \
349 blitter(2, Uint8, ALPHA_BLIT_ANY); \
350 } \
351 break; \
352 \
353 case 3: \
354 blitter(3, Uint8, ALPHA_BLIT_ANY); \
355 break; \
356 \
357 case 4: \
358 if ((fmt->Rmask | fmt->Gmask | fmt->Bmask) == 0x00ffffff && (fmt->Gmask == 0xff00 || fmt->Rmask == 0xff00 || fmt->Bmask == 0xff00)) { \
359 if (alpha == 128) { \
360 blitter(4, Uint16, ALPHA_BLIT32_888_50); \
361 } else { \
362 blitter(4, Uint16, ALPHA_BLIT32_888); \
363 } \
364 } else { \
365 blitter(4, Uint16, ALPHA_BLIT_ANY); \
366 } \
367 break; \
368 } \
369 } \
370 } while (0)
371
372/*
373 * Set a pixel value using the given format, except that the alpha value is
374 * placed in the top byte. This is the format used for RLE with alpha.
375 */
376#define RLEPIXEL_FROM_RGBA(Pixel, fmt, r, g, b, a) \
377 { \
378 Pixel = ((r >> (8 - fmt->Rbits)) << fmt->Rshift) | \
379 ((g >> (8 - fmt->Gbits)) << fmt->Gshift) | \
380 ((b >> (8 - fmt->Bbits)) << fmt->Bshift) | \
381 (a << 24); \
382 }
383
384/*
385 * This takes care of the case when the surface is clipped on the left and/or
386 * right. Top clipping has already been taken care of.
387 */
388#define RLECLIPBLIT(bpp, Type, do_blit) \
389 do { \
390 int linecount = srcrect->h; \
391 int ofs = 0; \
392 int left = srcrect->x; \
393 int right = left + srcrect->w; \
394 dstbuf -= left * bpp; \
395 for (;;) { \
396 int run; \
397 ofs += *(Type *)srcbuf; \
398 run = ((Type *)srcbuf)[1]; \
399 srcbuf += 2 * sizeof(Type); \
400 if (run) { \
401 /* clip to left and right borders */ \
402 if (ofs < right) { \
403 int start = 0; \
404 int len = run; \
405 int startcol; \
406 if (left - ofs > 0) { \
407 start = left - ofs; \
408 len -= start; \
409 if (len <= 0) \
410 goto nocopy##bpp##do_blit; \
411 } \
412 startcol = ofs + start; \
413 if (len > right - startcol) \
414 len = right - startcol; \
415 do_blit(dstbuf + startcol * bpp, srcbuf + start * bpp, \
416 len, bpp, alpha); \
417 } \
418 nocopy##bpp##do_blit : srcbuf += run * bpp; \
419 ofs += run; \
420 } else if (!ofs) { \
421 break; \
422 } \
423 \
424 if (ofs == w) { \
425 ofs = 0; \
426 dstbuf += surf_dst->pitch; \
427 if (!--linecount) { \
428 break; \
429 } \
430 } \
431 } \
432 } while (0)
433
434static void RLEClipBlit(int w, Uint8 *srcbuf, SDL_Surface *surf_dst,
435 Uint8 *dstbuf, const SDL_Rect *srcrect, unsigned alpha)
436{
437 const SDL_PixelFormatDetails *fmt = surf_dst->fmt;
438
439 CHOOSE_BLIT(RLECLIPBLIT, alpha, fmt);
440}
441
442#undef RLECLIPBLIT
443
444// blit a colorkeyed RLE surface
445static bool SDLCALL SDL_RLEBlit(SDL_Surface *surf_src, const SDL_Rect *srcrect,
446 SDL_Surface *surf_dst, const SDL_Rect *dstrect)
447{
448 Uint8 *dstbuf;
449 Uint8 *srcbuf;
450 int x, y;
451 int w = surf_src->w;
452 unsigned alpha;
453
454 // Lock the destination if necessary
455 if (SDL_MUSTLOCK(surf_dst)) {
456 if (!SDL_LockSurface(surf_dst)) {
457 return false;
458 }
459 }
460
461 // Set up the source and destination pointers
462 x = dstrect->x;
463 y = dstrect->y;
464 dstbuf = (Uint8 *)surf_dst->pixels + y * surf_dst->pitch + x * surf_src->fmt->bytes_per_pixel;
465 srcbuf = (Uint8 *)surf_src->map.data + sizeof(SDL_PixelFormat);
466
467 {
468 // skip lines at the top if necessary
469 int vskip = srcrect->y;
470 int ofs = 0;
471 if (vskip) {
472
473#define RLESKIP(bpp, Type) \
474 for (;;) { \
475 int run; \
476 ofs += *(Type *)srcbuf; \
477 run = ((Type *)srcbuf)[1]; \
478 srcbuf += sizeof(Type) * 2; \
479 if (run) { \
480 srcbuf += run * bpp; \
481 ofs += run; \
482 } else if (!ofs) \
483 goto done; \
484 if (ofs == w) { \
485 ofs = 0; \
486 if (!--vskip) \
487 break; \
488 } \
489 }
490
491 switch (surf_src->fmt->bytes_per_pixel) {
492 case 1:
493 RLESKIP(1, Uint8);
494 break;
495 case 2:
496 RLESKIP(2, Uint8);
497 break;
498 case 3:
499 RLESKIP(3, Uint8);
500 break;
501 case 4:
502 RLESKIP(4, Uint16);
503 break;
504 }
505
506#undef RLESKIP
507 }
508 }
509
510 alpha = surf_src->map.info.a;
511 // if left or right edge clipping needed, call clip blit
512 if (srcrect->x || srcrect->w != surf_src->w) {
513 RLEClipBlit(w, srcbuf, surf_dst, dstbuf, srcrect, alpha);
514 } else {
515 const SDL_PixelFormatDetails *fmt = surf_src->fmt;
516
517#define RLEBLIT(bpp, Type, do_blit) \
518 do { \
519 int linecount = srcrect->h; \
520 int ofs = 0; \
521 for (;;) { \
522 unsigned run; \
523 ofs += *(Type *)srcbuf; \
524 run = ((Type *)srcbuf)[1]; \
525 srcbuf += 2 * sizeof(Type); \
526 if (run) { \
527 do_blit(dstbuf + ofs * bpp, srcbuf, run, bpp, alpha); \
528 srcbuf += run * bpp; \
529 ofs += run; \
530 } else if (!ofs) \
531 break; \
532 if (ofs == w) { \
533 ofs = 0; \
534 dstbuf += surf_dst->pitch; \
535 if (!--linecount) \
536 break; \
537 } \
538 } \
539 } while (0)
540
541 CHOOSE_BLIT(RLEBLIT, alpha, fmt);
542
543#undef RLEBLIT
544 }
545
546done:
547 // Unlock the destination if necessary
548 if (SDL_MUSTLOCK(surf_dst)) {
549 SDL_UnlockSurface(surf_dst);
550 }
551 return true;
552}
553
554#undef OPAQUE_BLIT
555
556/*
557 * Per-pixel blitting macros for translucent pixels:
558 * These use the same techniques as the per-surface blitting macros
559 */
560
561/*
562 * For 32bpp pixels, we have made sure the alpha is stored in the top
563 * 8 bits, so proceed as usual
564 */
565#define BLIT_TRANSL_888(src, dst) \
566 do { \
567 Uint32 s = src; \
568 Uint32 d = dst; \
569 unsigned alpha = s >> 24; \
570 Uint32 s1 = s & 0xff00ff; \
571 Uint32 d1 = d & 0xff00ff; \
572 d1 = (d1 + ((s1 - d1) * alpha >> 8)) & 0xff00ff; \
573 s &= 0xff00; \
574 d &= 0xff00; \
575 d = (d + ((s - d) * alpha >> 8)) & 0xff00; \
576 dst = d1 | d | 0xff000000; \
577 } while (0)
578
579/*
580 * For 16bpp pixels, we have stored the 5 most significant alpha bits in
581 * bits 5-10. As before, we can process all 3 RGB components at the same time.
582 */
583#define BLIT_TRANSL_565(src, dst) \
584 do { \
585 Uint32 s = src; \
586 Uint32 d = dst; \
587 unsigned alpha = (s & 0x3e0) >> 5; \
588 s &= 0x07e0f81f; \
589 d = (d | d << 16) & 0x07e0f81f; \
590 d += (s - d) * alpha >> 5; \
591 d &= 0x07e0f81f; \
592 dst = (Uint16)(d | d >> 16); \
593 } while (0)
594
595#define BLIT_TRANSL_555(src, dst) \
596 do { \
597 Uint32 s = src; \
598 Uint32 d = dst; \
599 unsigned alpha = (s & 0x3e0) >> 5; \
600 s &= 0x03e07c1f; \
601 d = (d | d << 16) & 0x03e07c1f; \
602 d += (s - d) * alpha >> 5; \
603 d &= 0x03e07c1f; \
604 dst = (Uint16)(d | d >> 16); \
605 } while (0)
606
607// blit a pixel-alpha RLE surface clipped at the right and/or left edges
608static void RLEAlphaClipBlit(int w, Uint8 *srcbuf, SDL_Surface *surf_dst,
609 Uint8 *dstbuf, const SDL_Rect *srcrect)
610{
611 const SDL_PixelFormatDetails *df = surf_dst->fmt;
612 /*
613 * clipped blitter: Ptype is the destination pixel type,
614 * Ctype the translucent count type, and do_blend the macro
615 * to blend one pixel.
616 */
617#define RLEALPHACLIPBLIT(Ptype, Ctype, do_blend) \
618 do { \
619 int linecount = srcrect->h; \
620 int left = srcrect->x; \
621 int right = left + srcrect->w; \
622 dstbuf -= left * sizeof(Ptype); \
623 do { \
624 int ofs = 0; \
625 /* blit opaque pixels on one line */ \
626 do { \
627 unsigned run; \
628 ofs += ((Ctype *)srcbuf)[0]; \
629 run = ((Ctype *)srcbuf)[1]; \
630 srcbuf += 2 * sizeof(Ctype); \
631 if (run) { \
632 /* clip to left and right borders */ \
633 int cofs = ofs; \
634 int crun = run; \
635 if (left - cofs > 0) { \
636 crun -= left - cofs; \
637 cofs = left; \
638 } \
639 if (crun > right - cofs) \
640 crun = right - cofs; \
641 if (crun > 0) \
642 PIXEL_COPY(dstbuf + cofs * sizeof(Ptype), \
643 srcbuf + (cofs - ofs) * sizeof(Ptype), \
644 (unsigned)crun, sizeof(Ptype)); \
645 srcbuf += run * sizeof(Ptype); \
646 ofs += run; \
647 } else if (!ofs) \
648 return; \
649 } while (ofs < w); \
650 /* skip padding if necessary */ \
651 if (sizeof(Ptype) == 2) \
652 srcbuf += (uintptr_t)srcbuf & 2; \
653 /* blit translucent pixels on the same line */ \
654 ofs = 0; \
655 do { \
656 unsigned run; \
657 ofs += ((Uint16 *)srcbuf)[0]; \
658 run = ((Uint16 *)srcbuf)[1]; \
659 srcbuf += 4; \
660 if (run) { \
661 /* clip to left and right borders */ \
662 int cofs = ofs; \
663 int crun = run; \
664 if (left - cofs > 0) { \
665 crun -= left - cofs; \
666 cofs = left; \
667 } \
668 if (crun > right - cofs) \
669 crun = right - cofs; \
670 if (crun > 0) { \
671 Ptype *dst = (Ptype *)dstbuf + cofs; \
672 Uint32 *src = (Uint32 *)srcbuf + (cofs - ofs); \
673 int i; \
674 for (i = 0; i < crun; i++) \
675 do_blend(src[i], dst[i]); \
676 } \
677 srcbuf += run * 4; \
678 ofs += run; \
679 } \
680 } while (ofs < w); \
681 dstbuf += surf_dst->pitch; \
682 } while (--linecount); \
683 } while (0)
684
685 switch (df->bytes_per_pixel) {
686 case 2:
687 if (df->Gmask == 0x07e0 || df->Rmask == 0x07e0 || df->Bmask == 0x07e0) {
688 RLEALPHACLIPBLIT(Uint16, Uint8, BLIT_TRANSL_565);
689 } else {
690 RLEALPHACLIPBLIT(Uint16, Uint8, BLIT_TRANSL_555);
691 }
692 break;
693 case 4:
694 RLEALPHACLIPBLIT(Uint32, Uint16, BLIT_TRANSL_888);
695 break;
696 }
697}
698
699// blit a pixel-alpha RLE surface
700static bool SDLCALL SDL_RLEAlphaBlit(SDL_Surface *surf_src, const SDL_Rect *srcrect,
701 SDL_Surface *surf_dst, const SDL_Rect *dstrect)
702{
703 int x, y;
704 int w = surf_src->w;
705 Uint8 *srcbuf, *dstbuf;
706 const SDL_PixelFormatDetails *df = surf_dst->fmt;
707
708 // Lock the destination if necessary
709 if (SDL_MUSTLOCK(surf_dst)) {
710 if (!SDL_LockSurface(surf_dst)) {
711 return false;
712 }
713 }
714
715 x = dstrect->x;
716 y = dstrect->y;
717 dstbuf = (Uint8 *)surf_dst->pixels + y * surf_dst->pitch + x * df->bytes_per_pixel;
718 srcbuf = (Uint8 *)surf_src->map.data + sizeof(SDL_PixelFormat);
719
720 {
721 // skip lines at the top if necessary
722 int vskip = srcrect->y;
723 if (vskip) {
724 int ofs;
725 if (df->bytes_per_pixel == 2) {
726 // the 16/32 interleaved format
727 do {
728 // skip opaque line
729 ofs = 0;
730 do {
731 int run;
732 ofs += srcbuf[0];
733 run = srcbuf[1];
734 srcbuf += 2;
735 if (run) {
736 srcbuf += 2 * run;
737 ofs += run;
738 } else if (ofs == 0) {
739 goto done;
740 }
741 } while (ofs < w);
742
743 // skip padding
744 srcbuf += (uintptr_t)srcbuf & 2;
745
746 // skip translucent line
747 ofs = 0;
748 do {
749 int run;
750 ofs += ((Uint16 *)srcbuf)[0];
751 run = ((Uint16 *)srcbuf)[1];
752 srcbuf += 4 * (run + 1);
753 ofs += run;
754 } while (ofs < w);
755 } while (--vskip);
756 } else {
757 // the 32/32 interleaved format
758 vskip <<= 1; // opaque and translucent have same format
759 do {
760 ofs = 0;
761 do {
762 int run;
763 ofs += ((Uint16 *)srcbuf)[0];
764 run = ((Uint16 *)srcbuf)[1];
765 srcbuf += 4;
766 if (run) {
767 srcbuf += 4 * run;
768 ofs += run;
769 } else if (ofs == 0) {
770 goto done;
771 }
772 } while (ofs < w);
773 } while (--vskip);
774 }
775 }
776 }
777
778 // if left or right edge clipping needed, call clip blit
779 if (srcrect->x || srcrect->w != surf_src->w) {
780 RLEAlphaClipBlit(w, srcbuf, surf_dst, dstbuf, srcrect);
781 } else {
782
783 /*
784 * non-clipped blitter. Ptype is the destination pixel type,
785 * Ctype the translucent count type, and do_blend the
786 * macro to blend one pixel.
787 */
788#define RLEALPHABLIT(Ptype, Ctype, do_blend) \
789 do { \
790 int linecount = srcrect->h; \
791 do { \
792 int ofs = 0; \
793 /* blit opaque pixels on one line */ \
794 do { \
795 unsigned run; \
796 ofs += ((Ctype *)srcbuf)[0]; \
797 run = ((Ctype *)srcbuf)[1]; \
798 srcbuf += 2 * sizeof(Ctype); \
799 if (run) { \
800 PIXEL_COPY(dstbuf + ofs * sizeof(Ptype), srcbuf, \
801 run, sizeof(Ptype)); \
802 srcbuf += run * sizeof(Ptype); \
803 ofs += run; \
804 } else if (!ofs) \
805 goto done; \
806 } while (ofs < w); \
807 /* skip padding if necessary */ \
808 if (sizeof(Ptype) == 2) \
809 srcbuf += (uintptr_t)srcbuf & 2; \
810 /* blit translucent pixels on the same line */ \
811 ofs = 0; \
812 do { \
813 unsigned run; \
814 ofs += ((Uint16 *)srcbuf)[0]; \
815 run = ((Uint16 *)srcbuf)[1]; \
816 srcbuf += 4; \
817 if (run) { \
818 Ptype *dst = (Ptype *)dstbuf + ofs; \
819 unsigned i; \
820 for (i = 0; i < run; i++) { \
821 Uint32 src = *(Uint32 *)srcbuf; \
822 do_blend(src, *dst); \
823 srcbuf += 4; \
824 dst++; \
825 } \
826 ofs += run; \
827 } \
828 } while (ofs < w); \
829 dstbuf += surf_dst->pitch; \
830 } while (--linecount); \
831 } while (0)
832
833 switch (df->bytes_per_pixel) {
834 case 2:
835 if (df->Gmask == 0x07e0 || df->Rmask == 0x07e0 || df->Bmask == 0x07e0) {
836 RLEALPHABLIT(Uint16, Uint8, BLIT_TRANSL_565);
837 } else {
838 RLEALPHABLIT(Uint16, Uint8, BLIT_TRANSL_555);
839 }
840 break;
841 case 4:
842 RLEALPHABLIT(Uint32, Uint16, BLIT_TRANSL_888);
843 break;
844 }
845 }
846
847done:
848 // Unlock the destination if necessary
849 if (SDL_MUSTLOCK(surf_dst)) {
850 SDL_UnlockSurface(surf_dst);
851 }
852 return true;
853}
854
855/*
856 * Auxiliary functions:
857 * The encoding functions take 32bpp rgb + a, and
858 * return the number of bytes copied to the destination.
859 * The decoding functions copy to 32bpp rgb + a, and
860 * return the number of bytes copied from the source.
861 * These are only used in the encoder and un-RLE code and are therefore not
862 * highly optimised.
863 */
864
865// encode 32bpp rgb + a into 16bpp rgb, losing alpha
866static int copy_opaque_16(void *dst, const Uint32 *src, int n,
867 const SDL_PixelFormatDetails *sfmt, const SDL_PixelFormatDetails *dfmt)
868{
869 int i;
870 Uint16 *d = (Uint16 *)dst;
871 for (i = 0; i < n; i++) {
872 unsigned r, g, b;
873 RGB_FROM_PIXEL(*src, sfmt, r, g, b);
874 PIXEL_FROM_RGB(*d, dfmt, r, g, b);
875 src++;
876 d++;
877 }
878 return n * 2;
879}
880
881// decode opaque pixels from 16bpp to 32bpp rgb + a
882static int uncopy_opaque_16(Uint32 *dst, const void *src, int n,
883 const SDL_PixelFormatDetails *sfmt, const SDL_PixelFormatDetails *dfmt)
884{
885 int i;
886 const Uint16 *s = (const Uint16 *)src;
887 unsigned alpha = dfmt->Amask ? 255 : 0;
888 for (i = 0; i < n; i++) {
889 unsigned r, g, b;
890 RGB_FROM_PIXEL(*s, sfmt, r, g, b);
891 PIXEL_FROM_RGBA(*dst, dfmt, r, g, b, alpha);
892 s++;
893 dst++;
894 }
895 return n * 2;
896}
897
898// encode 32bpp rgb + a into 32bpp G0RAB format for blitting into 565
899static int copy_transl_565(void *dst, const Uint32 *src, int n,
900 const SDL_PixelFormatDetails *sfmt, const SDL_PixelFormatDetails *dfmt)
901{
902 int i;
903 Uint32 *d = (Uint32 *)dst;
904 for (i = 0; i < n; i++) {
905 unsigned r, g, b, a;
906 Uint16 pix;
907 RGBA_FROM_8888(*src, sfmt, r, g, b, a);
908 PIXEL_FROM_RGB(pix, dfmt, r, g, b);
909 *d = ((pix & 0x7e0) << 16) | (pix & 0xf81f) | ((a << 2) & 0x7e0);
910 src++;
911 d++;
912 }
913 return n * 4;
914}
915
916// encode 32bpp rgb + a into 32bpp G0RAB format for blitting into 555
917static int copy_transl_555(void *dst, const Uint32 *src, int n,
918 const SDL_PixelFormatDetails *sfmt, const SDL_PixelFormatDetails *dfmt)
919{
920 int i;
921 Uint32 *d = (Uint32 *)dst;
922 for (i = 0; i < n; i++) {
923 unsigned r, g, b, a;
924 Uint16 pix;
925 RGBA_FROM_8888(*src, sfmt, r, g, b, a);
926 PIXEL_FROM_RGB(pix, dfmt, r, g, b);
927 *d = ((pix & 0x3e0) << 16) | (pix & 0xfc1f) | ((a << 2) & 0x3e0);
928 src++;
929 d++;
930 }
931 return n * 4;
932}
933
934// decode translucent pixels from 32bpp GORAB to 32bpp rgb + a
935static int uncopy_transl_16(Uint32 *dst, const void *src, int n,
936 const SDL_PixelFormatDetails *sfmt, const SDL_PixelFormatDetails *dfmt)
937{
938 int i;
939 const Uint32 *s = (const Uint32 *)src;
940 for (i = 0; i < n; i++) {
941 unsigned r, g, b, a;
942 Uint32 pix = *s++;
943 a = (pix & 0x3e0) >> 2;
944 pix = (pix & ~0x3e0) | pix >> 16;
945 RGB_FROM_PIXEL(pix, sfmt, r, g, b);
946 PIXEL_FROM_RGBA(*dst, dfmt, r, g, b, a);
947 dst++;
948 }
949 return n * 4;
950}
951
952// encode 32bpp rgba into 32bpp rgba, keeping alpha (dual purpose)
953static int copy_32(void *dst, const Uint32 *src, int n,
954 const SDL_PixelFormatDetails *sfmt, const SDL_PixelFormatDetails *dfmt)
955{
956 int i;
957 Uint32 *d = (Uint32 *)dst;
958 for (i = 0; i < n; i++) {
959 unsigned r, g, b, a;
960 RGBA_FROM_8888(*src, sfmt, r, g, b, a);
961 RLEPIXEL_FROM_RGBA(*d, dfmt, r, g, b, a);
962 d++;
963 src++;
964 }
965 return n * 4;
966}
967
968// decode 32bpp rgba into 32bpp rgba, keeping alpha (dual purpose)
969static int uncopy_32(Uint32 *dst, const void *src, int n,
970 const SDL_PixelFormatDetails *sfmt, const SDL_PixelFormatDetails *dfmt)
971{
972 int i;
973 const Uint32 *s = (const Uint32 *)src;
974 for (i = 0; i < n; i++) {
975 unsigned r, g, b, a;
976 Uint32 pixel = *s++;
977 RGB_FROM_PIXEL(pixel, sfmt, r, g, b);
978 a = pixel >> 24;
979 PIXEL_FROM_RGBA(*dst, dfmt, r, g, b, a);
980 dst++;
981 }
982 return n * 4;
983}
984
985#define ISOPAQUE(pixel, fmt) ((((pixel)&fmt->Amask) >> fmt->Ashift) == 255)
986
987#define ISTRANSL(pixel, fmt) \
988 ((unsigned)((((pixel)&fmt->Amask) >> fmt->Ashift) - 1U) < 254U)
989
990// convert surface to be quickly alpha-blittable onto dest, if possible
991static bool RLEAlphaSurface(SDL_Surface *surface)
992{
993 SDL_Surface *dest;
994 const SDL_PixelFormatDetails *df;
995 int maxsize = 0;
996 int max_opaque_run;
997 int max_transl_run = 65535;
998 unsigned masksum;
999 Uint8 *rlebuf, *dst;
1000 int (*copy_opaque)(void *, const Uint32 *, int,
1001 const SDL_PixelFormatDetails *, const SDL_PixelFormatDetails *);
1002 int (*copy_transl)(void *, const Uint32 *, int,
1003 const SDL_PixelFormatDetails *, const SDL_PixelFormatDetails *);
1004
1005 dest = surface->map.info.dst_surface;
1006 if (!dest) {
1007 return false;
1008 }
1009 df = dest->fmt;
1010 if (surface->fmt->bits_per_pixel != 32) {
1011 return false; // only 32bpp source supported
1012 }
1013
1014 /* find out whether the destination is one we support,
1015 and determine the max size of the encoded result */
1016 masksum = df->Rmask | df->Gmask | df->Bmask;
1017 switch (df->bytes_per_pixel) {
1018 case 2:
1019 // 16bpp: only support 565 and 555 formats
1020 switch (masksum) {
1021 case 0xffff:
1022 if (df->Gmask == 0x07e0 || df->Rmask == 0x07e0 || df->Bmask == 0x07e0) {
1023 copy_opaque = copy_opaque_16;
1024 copy_transl = copy_transl_565;
1025 } else {
1026 return false;
1027 }
1028 break;
1029 case 0x7fff:
1030 if (df->Gmask == 0x03e0 || df->Rmask == 0x03e0 || df->Bmask == 0x03e0) {
1031 copy_opaque = copy_opaque_16;
1032 copy_transl = copy_transl_555;
1033 } else {
1034 return false;
1035 }
1036 break;
1037 default:
1038 return false;
1039 }
1040 max_opaque_run = 255; // runs stored as bytes
1041
1042 /* worst case is alternating opaque and translucent pixels,
1043 with room for alignment padding between lines */
1044 maxsize = surface->h * (2 + (4 + 2) * (surface->w + 1)) + 2;
1045 break;
1046 case 4:
1047 if (masksum != 0x00ffffff) {
1048 return false; // requires unused high byte
1049 }
1050 copy_opaque = copy_32;
1051 copy_transl = copy_32;
1052 max_opaque_run = 255; // runs stored as short ints
1053
1054 // worst case is alternating opaque and translucent pixels
1055 maxsize = surface->h * 2 * 4 * (surface->w + 1) + 4;
1056 break;
1057 default:
1058 return false; // anything else unsupported right now
1059 }
1060
1061 maxsize += sizeof(SDL_PixelFormat);
1062 rlebuf = (Uint8 *)SDL_malloc(maxsize);
1063 if (!rlebuf) {
1064 return false;
1065 }
1066 // save the destination format so we can undo the encoding later
1067 *(SDL_PixelFormat *)rlebuf = dest->format;
1068 dst = rlebuf + sizeof(SDL_PixelFormat);
1069
1070 // Do the actual encoding
1071 {
1072 int x, y;
1073 int h = surface->h, w = surface->w;
1074 const SDL_PixelFormatDetails *sf = surface->fmt;
1075 Uint32 *src = (Uint32 *)surface->pixels;
1076 Uint8 *lastline = dst; // end of last non-blank line
1077
1078 // opaque counts are 8 or 16 bits, depending on target depth
1079#define ADD_OPAQUE_COUNTS(n, m) \
1080 if (df->bytes_per_pixel == 4) { \
1081 ((Uint16 *)dst)[0] = (Uint16)n; \
1082 ((Uint16 *)dst)[1] = (Uint16)m; \
1083 dst += 4; \
1084 } else { \
1085 dst[0] = (Uint8)n; \
1086 dst[1] = (Uint8)m; \
1087 dst += 2; \
1088 }
1089
1090 // translucent counts are always 16 bit
1091#define ADD_TRANSL_COUNTS(n, m) \
1092 (((Uint16 *)dst)[0] = (Uint16)n, ((Uint16 *)dst)[1] = (Uint16)m, dst += 4)
1093
1094 for (y = 0; y < h; y++) {
1095 int runstart, skipstart;
1096 int blankline = 0;
1097 // First encode all opaque pixels of a scan line
1098 x = 0;
1099 do {
1100 int run, skip, len;
1101 skipstart = x;
1102 while (x < w && !ISOPAQUE(src[x], sf)) {
1103 x++;
1104 }
1105 runstart = x;
1106 while (x < w && ISOPAQUE(src[x], sf)) {
1107 x++;
1108 }
1109 skip = runstart - skipstart;
1110 if (skip == w) {
1111 blankline = 1;
1112 }
1113 run = x - runstart;
1114 while (skip > max_opaque_run) {
1115 ADD_OPAQUE_COUNTS(max_opaque_run, 0);
1116 skip -= max_opaque_run;
1117 }
1118 len = SDL_min(run, max_opaque_run);
1119 ADD_OPAQUE_COUNTS(skip, len);
1120 dst += copy_opaque(dst, src + runstart, len, sf, df);
1121 runstart += len;
1122 run -= len;
1123 while (run) {
1124 len = SDL_min(run, max_opaque_run);
1125 ADD_OPAQUE_COUNTS(0, len);
1126 dst += copy_opaque(dst, src + runstart, len, sf, df);
1127 runstart += len;
1128 run -= len;
1129 }
1130 } while (x < w);
1131
1132 // Make sure the next output address is 32-bit aligned
1133 dst += (uintptr_t)dst & 2;
1134
1135 // Next, encode all translucent pixels of the same scan line
1136 x = 0;
1137 do {
1138 int run, skip, len;
1139 skipstart = x;
1140 while (x < w && !ISTRANSL(src[x], sf)) {
1141 x++;
1142 }
1143 runstart = x;
1144 while (x < w && ISTRANSL(src[x], sf)) {
1145 x++;
1146 }
1147 skip = runstart - skipstart;
1148 blankline &= (skip == w);
1149 run = x - runstart;
1150 while (skip > max_transl_run) {
1151 ADD_TRANSL_COUNTS(max_transl_run, 0);
1152 skip -= max_transl_run;
1153 }
1154 len = SDL_min(run, max_transl_run);
1155 ADD_TRANSL_COUNTS(skip, len);
1156 dst += copy_transl(dst, src + runstart, len, sf, df);
1157 runstart += len;
1158 run -= len;
1159 while (run) {
1160 len = SDL_min(run, max_transl_run);
1161 ADD_TRANSL_COUNTS(0, len);
1162 dst += copy_transl(dst, src + runstart, len, sf, df);
1163 runstart += len;
1164 run -= len;
1165 }
1166 if (!blankline) {
1167 lastline = dst;
1168 }
1169 } while (x < w);
1170
1171 src += surface->pitch >> 2;
1172 }
1173 dst = lastline; // back up past trailing blank lines
1174 ADD_OPAQUE_COUNTS(0, 0);
1175 }
1176
1177#undef ADD_OPAQUE_COUNTS
1178#undef ADD_TRANSL_COUNTS
1179
1180 // Now that we have it encoded, release the original pixels
1181 if (!(surface->flags & SDL_SURFACE_PREALLOCATED)) {
1182 if (surface->flags & SDL_SURFACE_SIMD_ALIGNED) {
1183 SDL_aligned_free(surface->pixels);
1184 surface->flags &= ~SDL_SURFACE_SIMD_ALIGNED;
1185 } else {
1186 SDL_free(surface->pixels);
1187 }
1188 surface->pixels = NULL;
1189 }
1190
1191 // reallocate the buffer to release unused memory
1192 {
1193 Uint8 *p = (Uint8 *)SDL_realloc(rlebuf, dst - rlebuf);
1194 if (!p) {
1195 p = rlebuf;
1196 }
1197 surface->map.data = p;
1198 }
1199
1200 return true;
1201}
1202
1203static Uint32 getpix_8(const Uint8 *srcbuf)
1204{
1205 return *srcbuf;
1206}
1207
1208static Uint32 getpix_16(const Uint8 *srcbuf)
1209{
1210 return *(const Uint16 *)srcbuf;
1211}
1212
1213static Uint32 getpix_24(const Uint8 *srcbuf)
1214{
1215#if SDL_BYTEORDER == SDL_LIL_ENDIAN
1216 return srcbuf[0] + (srcbuf[1] << 8) + (srcbuf[2] << 16);
1217#else
1218 return (srcbuf[0] << 16) + (srcbuf[1] << 8) + srcbuf[2];
1219#endif
1220}
1221
1222static Uint32 getpix_32(const Uint8 *srcbuf)
1223{
1224 return *(const Uint32 *)srcbuf;
1225}
1226
1227typedef Uint32 (*getpix_func)(const Uint8 *);
1228
1229static const getpix_func getpixes[4] = {
1230 getpix_8, getpix_16, getpix_24, getpix_32
1231};
1232
1233static bool RLEColorkeySurface(SDL_Surface *surface)
1234{
1235 SDL_Surface *dest;
1236 Uint8 *rlebuf, *dst;
1237 int maxn;
1238 int y;
1239 Uint8 *srcbuf, *lastline;
1240 int maxsize = 0;
1241 const int bpp = surface->fmt->bytes_per_pixel;
1242 getpix_func getpix;
1243 Uint32 ckey, rgbmask;
1244 int w, h;
1245
1246 dest = surface->map.info.dst_surface;
1247 if (!dest) {
1248 return false;
1249 }
1250
1251 // calculate the worst case size for the compressed surface
1252 switch (bpp) {
1253 case 1:
1254 /* worst case is alternating opaque and transparent pixels,
1255 starting with an opaque pixel */
1256 maxsize = surface->h * 3 * (surface->w / 2 + 1) + 2;
1257 break;
1258 case 2:
1259 case 3:
1260 // worst case is solid runs, at most 255 pixels wide
1261 maxsize = surface->h * (2 * (surface->w / 255 + 1) + surface->w * bpp) + 2;
1262 break;
1263 case 4:
1264 // worst case is solid runs, at most 65535 pixels wide
1265 maxsize = surface->h * (4 * (surface->w / 65535 + 1) + surface->w * 4) + 4;
1266 break;
1267
1268 default:
1269 return false;
1270 }
1271
1272 maxsize += sizeof(SDL_PixelFormat);
1273 rlebuf = (Uint8 *)SDL_malloc(maxsize);
1274 if (!rlebuf) {
1275 return false;
1276 }
1277 // save the destination format so we can undo the encoding later
1278 *(SDL_PixelFormat *)rlebuf = dest->format;
1279
1280 // Set up the conversion
1281 srcbuf = (Uint8 *)surface->pixels;
1282 maxn = bpp == 4 ? 65535 : 255;
1283 dst = rlebuf + sizeof(SDL_PixelFormat);
1284 rgbmask = ~surface->fmt->Amask;
1285 ckey = surface->map.info.colorkey & rgbmask;
1286 lastline = dst;
1287 getpix = getpixes[bpp - 1];
1288 w = surface->w;
1289 h = surface->h;
1290
1291#define ADD_COUNTS(n, m) \
1292 if (bpp == 4) { \
1293 ((Uint16 *)dst)[0] = (Uint16)n; \
1294 ((Uint16 *)dst)[1] = (Uint16)m; \
1295 dst += 4; \
1296 } else { \
1297 dst[0] = (Uint8)n; \
1298 dst[1] = (Uint8)m; \
1299 dst += 2; \
1300 }
1301
1302 for (y = 0; y < h; y++) {
1303 int x = 0;
1304 int blankline = 0;
1305 do {
1306 int run, skip;
1307 int len;
1308 int runstart;
1309 int skipstart = x;
1310
1311 // find run of transparent, then opaque pixels
1312 while (x < w && (getpix(srcbuf + x * bpp) & rgbmask) == ckey) {
1313 x++;
1314 }
1315 runstart = x;
1316 while (x < w && (getpix(srcbuf + x * bpp) & rgbmask) != ckey) {
1317 x++;
1318 }
1319 skip = runstart - skipstart;
1320 if (skip == w) {
1321 blankline = 1;
1322 }
1323 run = x - runstart;
1324
1325 // encode segment
1326 while (skip > maxn) {
1327 ADD_COUNTS(maxn, 0);
1328 skip -= maxn;
1329 }
1330 len = SDL_min(run, maxn);
1331 ADD_COUNTS(skip, len);
1332 SDL_memcpy(dst, srcbuf + runstart * bpp, (size_t)len * bpp);
1333 dst += len * bpp;
1334 run -= len;
1335 runstart += len;
1336 while (run) {
1337 len = SDL_min(run, maxn);
1338 ADD_COUNTS(0, len);
1339 SDL_memcpy(dst, srcbuf + runstart * bpp, (size_t)len * bpp);
1340 dst += len * bpp;
1341 runstart += len;
1342 run -= len;
1343 }
1344 if (!blankline) {
1345 lastline = dst;
1346 }
1347 } while (x < w);
1348
1349 srcbuf += surface->pitch;
1350 }
1351 dst = lastline; // back up bast trailing blank lines
1352 ADD_COUNTS(0, 0);
1353
1354#undef ADD_COUNTS
1355
1356 // Now that we have it encoded, release the original pixels
1357 if (!(surface->flags & SDL_SURFACE_PREALLOCATED)) {
1358 if (surface->flags & SDL_SURFACE_SIMD_ALIGNED) {
1359 SDL_aligned_free(surface->pixels);
1360 surface->flags &= ~SDL_SURFACE_SIMD_ALIGNED;
1361 } else {
1362 SDL_free(surface->pixels);
1363 }
1364 surface->pixels = NULL;
1365 }
1366
1367 // reallocate the buffer to release unused memory
1368 {
1369 // If SDL_realloc returns NULL, the original block is left intact
1370 Uint8 *p = (Uint8 *)SDL_realloc(rlebuf, dst - rlebuf);
1371 if (!p) {
1372 p = rlebuf;
1373 }
1374 surface->map.data = p;
1375 }
1376
1377 return true;
1378}
1379
1380bool SDL_RLESurface(SDL_Surface *surface)
1381{
1382 int flags;
1383
1384 // Clear any previous RLE conversion
1385 if (surface->internal_flags & SDL_INTERNAL_SURFACE_RLEACCEL) {
1386 SDL_UnRLESurface(surface, true);
1387 }
1388
1389 // We don't support RLE encoding of bitmaps
1390 if (SDL_BITSPERPIXEL(surface->format) < 8) {
1391 return false;
1392 }
1393
1394 // Make sure the pixels are available
1395 if (!surface->pixels) {
1396 return false;
1397 }
1398
1399 flags = surface->map.info.flags;
1400 if (flags & SDL_COPY_COLORKEY) {
1401 // ok
1402 } else if ((flags & SDL_COPY_BLEND) && SDL_ISPIXELFORMAT_ALPHA(surface->format)) {
1403 // ok
1404 } else {
1405 // If we don't have colorkey or blending, nothing to do...
1406 return false;
1407 }
1408
1409 // Pass on combinations not supported
1410 if ((flags & SDL_COPY_MODULATE_COLOR) ||
1411 ((flags & SDL_COPY_MODULATE_ALPHA) && SDL_ISPIXELFORMAT_ALPHA(surface->format)) ||
1412 (flags & (SDL_COPY_BLEND_PREMULTIPLIED | SDL_COPY_ADD | SDL_COPY_ADD_PREMULTIPLIED | SDL_COPY_MOD | SDL_COPY_MUL)) ||
1413 (flags & SDL_COPY_NEAREST)) {
1414 return false;
1415 }
1416
1417 // Encode and set up the blit
1418 if (!SDL_ISPIXELFORMAT_ALPHA(surface->format) || !(flags & SDL_COPY_BLEND)) {
1419 if (!surface->map.identity) {
1420 return false;
1421 }
1422 if (!RLEColorkeySurface(surface)) {
1423 return false;
1424 }
1425 surface->map.blit = SDL_RLEBlit;
1426 surface->map.info.flags |= SDL_COPY_RLE_COLORKEY;
1427 } else {
1428 if (!RLEAlphaSurface(surface)) {
1429 return false;
1430 }
1431 surface->map.blit = SDL_RLEAlphaBlit;
1432 surface->map.info.flags |= SDL_COPY_RLE_ALPHAKEY;
1433 }
1434
1435 // The surface is now accelerated
1436 surface->internal_flags |= SDL_INTERNAL_SURFACE_RLEACCEL;
1437
1438 return true;
1439}
1440
1441/*
1442 * Un-RLE a surface with pixel alpha
1443 * This may not give back exactly the image before RLE-encoding; all
1444 * completely transparent pixels will be lost, and color and alpha depth
1445 * may have been reduced (when encoding for 16bpp targets).
1446 */
1447static bool UnRLEAlpha(SDL_Surface *surface)
1448{
1449 Uint8 *srcbuf;
1450 Uint32 *dst;
1451 const SDL_PixelFormatDetails *sf = surface->fmt;
1452 const SDL_PixelFormatDetails *df = SDL_GetPixelFormatDetails(*(SDL_PixelFormat *)surface->map.data);
1453 int (*uncopy_opaque)(Uint32 *, const void *, int,
1454 const SDL_PixelFormatDetails *, const SDL_PixelFormatDetails *);
1455 int (*uncopy_transl)(Uint32 *, const void *, int,
1456 const SDL_PixelFormatDetails *, const SDL_PixelFormatDetails *);
1457 int w = surface->w;
1458 int bpp = df->bytes_per_pixel;
1459 size_t size;
1460
1461 if (bpp == 2) {
1462 uncopy_opaque = uncopy_opaque_16;
1463 uncopy_transl = uncopy_transl_16;
1464 } else {
1465 uncopy_opaque = uncopy_transl = uncopy_32;
1466 }
1467
1468 if (!SDL_size_mul_check_overflow(surface->h, surface->pitch, &size)) {
1469 return false;
1470 }
1471
1472 surface->pixels = SDL_aligned_alloc(SDL_GetSIMDAlignment(), size);
1473 if (!surface->pixels) {
1474 return false;
1475 }
1476 surface->flags |= SDL_SURFACE_SIMD_ALIGNED;
1477 // fill background with transparent pixels
1478 SDL_memset(surface->pixels, 0, (size_t)surface->h * surface->pitch);
1479
1480 dst = (Uint32 *)surface->pixels;
1481 srcbuf = (Uint8 *)surface->map.data + sizeof(SDL_PixelFormat);
1482 for (;;) {
1483 // copy opaque pixels
1484 int ofs = 0;
1485 do {
1486 unsigned run;
1487 if (bpp == 2) {
1488 ofs += srcbuf[0];
1489 run = srcbuf[1];
1490 srcbuf += 2;
1491 } else {
1492 ofs += ((Uint16 *)srcbuf)[0];
1493 run = ((Uint16 *)srcbuf)[1];
1494 srcbuf += 4;
1495 }
1496 if (run) {
1497 srcbuf += uncopy_opaque(dst + ofs, srcbuf, run, df, sf);
1498 ofs += run;
1499 } else if (!ofs) {
1500 goto end_function;
1501 }
1502 } while (ofs < w);
1503
1504 // skip padding if needed
1505 if (bpp == 2) {
1506 srcbuf += (uintptr_t)srcbuf & 2;
1507 }
1508
1509 // copy translucent pixels
1510 ofs = 0;
1511 do {
1512 unsigned run;
1513 ofs += ((Uint16 *)srcbuf)[0];
1514 run = ((Uint16 *)srcbuf)[1];
1515 srcbuf += 4;
1516 if (run) {
1517 srcbuf += uncopy_transl(dst + ofs, srcbuf, run, df, sf);
1518 ofs += run;
1519 }
1520 } while (ofs < w);
1521 dst += surface->pitch >> 2;
1522 }
1523
1524end_function:
1525 return true;
1526}
1527
1528void SDL_UnRLESurface(SDL_Surface *surface, bool recode)
1529{
1530 if (surface->internal_flags & SDL_INTERNAL_SURFACE_RLEACCEL) {
1531 surface->internal_flags &= ~SDL_INTERNAL_SURFACE_RLEACCEL;
1532
1533 if (recode && !(surface->flags & SDL_SURFACE_PREALLOCATED)) {
1534 if (surface->map.info.flags & SDL_COPY_RLE_COLORKEY) {
1535 SDL_Rect full;
1536 size_t size;
1537
1538 // re-create the original surface
1539 if (!SDL_size_mul_check_overflow(surface->h, surface->pitch, &size)) {
1540 // Memory corruption?
1541 surface->internal_flags |= SDL_INTERNAL_SURFACE_RLEACCEL;
1542 return;
1543 }
1544 surface->pixels = SDL_aligned_alloc(SDL_GetSIMDAlignment(), size);
1545 if (!surface->pixels) {
1546 // Oh crap...
1547 surface->internal_flags |= SDL_INTERNAL_SURFACE_RLEACCEL;
1548 return;
1549 }
1550 surface->flags |= SDL_SURFACE_SIMD_ALIGNED;
1551
1552 // fill it with the background color
1553 SDL_FillSurfaceRect(surface, NULL, surface->map.info.colorkey);
1554
1555 // now render the encoded surface
1556 full.x = full.y = 0;
1557 full.w = surface->w;
1558 full.h = surface->h;
1559 SDL_RLEBlit(surface, &full, surface, &full);
1560 } else {
1561 if (!UnRLEAlpha(surface)) {
1562 // Oh crap...
1563 surface->internal_flags |= SDL_INTERNAL_SURFACE_RLEACCEL;
1564 return;
1565 }
1566 }
1567 }
1568 surface->map.info.flags &=
1569 ~(SDL_COPY_RLE_COLORKEY | SDL_COPY_RLE_ALPHAKEY);
1570
1571 SDL_free(surface->map.data);
1572 surface->map.data = NULL;
1573 }
1574}
1575
1576#endif // SDL_HAVE_RLE
generated by cgit v1.2.3 (git 2.25.1) at 2025-12-30 03:34:35 +0000