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Copy pathSDL_RLEaccel.c
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1594 lines (1467 loc) · 71 KB
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/*
Simple DirectMedia Layer
Copyright (C) 1997-2026 Sam Lantinga <slouken@libsdl.org>
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/
#include "../SDL_internal.h"
#if SDL_HAVE_RLE
/*
* RLE encoding for software colorkey and alpha-channel acceleration
*
* Original version by Sam Lantinga
*
* Mattias Engdegård (Yorick): Rewrite. New encoding format, encoder and
* decoder. Added per-surface alpha blitter. Added per-pixel alpha
* format, encoder and blitter.
*
* Many thanks to Xark and johns for hints, benchmarks and useful comments
* leading to this code.
*
* Welcome to Macro Mayhem.
*/
/*
* The encoding translates the image data to a stream of segments of the form
*
* <skip> <run> <data>
*
* where <skip> is the number of transparent pixels to skip,
* <run> is the number of opaque pixels to blit,
* and <data> are the pixels themselves.
*
* This basic structure is used both for colorkeyed surfaces, used for simple
* binary transparency and for per-surface alpha blending, and for surfaces
* with per-pixel alpha. The details differ, however:
*
* Encoding of colorkeyed surfaces:
*
* Encoded pixels always have the same format as the target surface.
* <skip> and <run> are unsigned 8 bit integers, except for 32 bit depth
* where they are 16 bit. This makes the pixel data aligned at all times.
* Segments never wrap around from one scan line to the next.
*
* The end of the sequence is marked by a zero <skip>,<run> pair at the *
* beginning of a line.
*
* Encoding of surfaces with per-pixel alpha:
*
* The sequence begins with a struct RLEDestFormat describing the target
* pixel format, to provide reliable un-encoding.
*
* Each scan line is encoded twice: First all completely opaque pixels,
* encoded in the target format as described above, and then all
* partially transparent (translucent) pixels (where 1 <= alpha <= 254),
* in the following 32-bit format:
*
* For 32-bit targets, each pixel has the target RGB format but with
* the alpha value occupying the highest 8 bits. The <skip> and <run>
* counts are 16 bit.
*
* For 16-bit targets, each pixel has the target RGB format, but with
* the middle component (usually green) shifted 16 steps to the left,
* and the hole filled with the 5 most significant bits of the alpha value.
* i.e. if the target has the format rrrrrggggggbbbbb,
* the encoded pixel will be 00000gggggg00000rrrrr0aaaaabbbbb.
* The <skip> and <run> counts are 8 bit for the opaque lines, 16 bit
* for the translucent lines. Two padding bytes may be inserted
* before each translucent line to keep them 32-bit aligned.
*
* The end of the sequence is marked by a zero <skip>,<run> pair at the
* beginning of an opaque line.
*/
#include "SDL_video.h"
#include "SDL_sysvideo.h"
#include "SDL_blit.h"
#include "SDL_RLEaccel_c.h"
#define PIXEL_COPY(to, from, len, bpp) \
SDL_memcpy(to, from, (size_t)(len) * (bpp))
/*
* Various colorkey blit methods, for opaque and per-surface alpha
*/
#define OPAQUE_BLIT(to, from, length, bpp, alpha) \
PIXEL_COPY(to, from, length, bpp)
/*
* For 32bpp pixels on the form 0x00rrggbb:
* If we treat the middle component separately, we can process the two
* remaining in parallel. This is safe to do because of the gap to the left
* of each component, so the bits from the multiplication don't collide.
* This can be used for any RGB permutation of course.
*/
#define ALPHA_BLIT32_888(to, from, length, bpp, alpha) \
do { \
int i; \
Uint32 *src = (Uint32 *)(from); \
Uint32 *dst = (Uint32 *)(to); \
for (i = 0; i < (int)(length); i++) { \
Uint32 s = *src++; \
Uint32 d = *dst; \
Uint32 s1 = s & 0xff00ff; \
Uint32 d1 = d & 0xff00ff; \
d1 = (d1 + ((s1 - d1) * alpha >> 8)) & 0xff00ff; \
s &= 0xff00; \
d &= 0xff00; \
d = (d + ((s - d) * alpha >> 8)) & 0xff00; \
*dst++ = d1 | d; \
} \
} while (0)
/*
* For 16bpp pixels we can go a step further: put the middle component
* in the high 16 bits of a 32 bit word, and process all three RGB
* components at the same time. Since the smallest gap is here just
* 5 bits, we have to scale alpha down to 5 bits as well.
*/
#define ALPHA_BLIT16_565(to, from, length, bpp, alpha) \
do { \
int i; \
Uint16 *src = (Uint16 *)(from); \
Uint16 *dst = (Uint16 *)(to); \
Uint32 ALPHA = alpha >> 3; \
for (i = 0; i < (int)(length); i++) { \
Uint32 s = *src++; \
Uint32 d = *dst; \
s = (s | s << 16) & 0x07e0f81f; \
d = (d | d << 16) & 0x07e0f81f; \
d += (s - d) * ALPHA >> 5; \
d &= 0x07e0f81f; \
*dst++ = (Uint16)(d | d >> 16); \
} \
} while (0)
#define ALPHA_BLIT16_555(to, from, length, bpp, alpha) \
do { \
int i; \
Uint16 *src = (Uint16 *)(from); \
Uint16 *dst = (Uint16 *)(to); \
Uint32 ALPHA = alpha >> 3; \
for (i = 0; i < (int)(length); i++) { \
Uint32 s = *src++; \
Uint32 d = *dst; \
s = (s | s << 16) & 0x03e07c1f; \
d = (d | d << 16) & 0x03e07c1f; \
d += (s - d) * ALPHA >> 5; \
d &= 0x03e07c1f; \
*dst++ = (Uint16)(d | d >> 16); \
} \
} while (0)
/*
* The general slow catch-all function, for remaining depths and formats
*/
#define ALPHA_BLIT_ANY(to, from, length, bpp, alpha) \
do { \
int i; \
Uint8 *src = from; \
Uint8 *dst = to; \
for (i = 0; i < (int)(length); i++) { \
Uint32 s, d; \
unsigned rs, gs, bs, rd, gd, bd; \
switch (bpp) { \
case 2: \
s = *(Uint16 *)src; \
d = *(Uint16 *)dst; \
break; \
case 3: \
if (SDL_BYTEORDER == SDL_BIG_ENDIAN) { \
s = (src[0] << 16) | (src[1] << 8) | src[2]; \
d = (dst[0] << 16) | (dst[1] << 8) | dst[2]; \
} else { \
s = (src[2] << 16) | (src[1] << 8) | src[0]; \
d = (dst[2] << 16) | (dst[1] << 8) | dst[0]; \
} \
break; \
case 4: \
s = *(Uint32 *)src; \
d = *(Uint32 *)dst; \
break; \
} \
RGB_FROM_PIXEL(s, fmt, rs, gs, bs); \
RGB_FROM_PIXEL(d, fmt, rd, gd, bd); \
rd += (rs - rd) * alpha >> 8; \
gd += (gs - gd) * alpha >> 8; \
bd += (bs - bd) * alpha >> 8; \
PIXEL_FROM_RGB(d, fmt, rd, gd, bd); \
switch (bpp) { \
case 2: \
*(Uint16 *)dst = (Uint16)d; \
break; \
case 3: \
if (SDL_BYTEORDER == SDL_BIG_ENDIAN) { \
dst[0] = (Uint8)(d >> 16); \
dst[1] = (Uint8)(d >> 8); \
dst[2] = (Uint8)(d); \
} else { \
dst[0] = (Uint8)d; \
dst[1] = (Uint8)(d >> 8); \
dst[2] = (Uint8)(d >> 16); \
} \
break; \
case 4: \
*(Uint32 *)dst = d; \
break; \
} \
src += bpp; \
dst += bpp; \
} \
} while (0)
/*
* Special case: 50% alpha (alpha=128)
* This is treated specially because it can be optimized very well, and
* since it is good for many cases of semi-translucency.
* The theory is to do all three components at the same time:
* First zero the lowest bit of each component, which gives us room to
* add them. Then shift right and add the sum of the lowest bits.
*/
#define ALPHA_BLIT32_888_50(to, from, length, bpp, alpha) \
do { \
int i; \
Uint32 *src = (Uint32 *)(from); \
Uint32 *dst = (Uint32 *)(to); \
for (i = 0; i < (int)(length); i++) { \
Uint32 s = *src++; \
Uint32 d = *dst; \
*dst++ = (((s & 0x00fefefe) + (d & 0x00fefefe)) >> 1) + (s & d & 0x00010101); \
} \
} while (0)
/*
* For 16bpp, we can actually blend two pixels in parallel, if we take
* care to shift before we add, not after.
*/
/* helper: blend a single 16 bit pixel at 50% */
#define BLEND16_50(dst, src, mask) \
do { \
Uint32 s = *src++; \
Uint32 d = *dst; \
*dst++ = (Uint16)((((s & mask) + (d & mask)) >> 1) + \
(s & d & (~mask & 0xffff))); \
} while (0)
/* basic 16bpp blender. mask is the pixels to keep when adding. */
#define ALPHA_BLIT16_50(to, from, length, bpp, alpha, mask) \
do { \
unsigned n = (length); \
Uint16 *src = (Uint16 *)(from); \
Uint16 *dst = (Uint16 *)(to); \
if (((uintptr_t)src ^ (uintptr_t)dst) & 3) { \
/* source and destination not in phase, blit one by one */ \
while (n--) \
BLEND16_50(dst, src, mask); \
} else { \
if ((uintptr_t)src & 3) { \
/* first odd pixel */ \
BLEND16_50(dst, src, mask); \
n--; \
} \
for (; n > 1; n -= 2) { \
Uint32 s = *(Uint32 *)src; \
Uint32 d = *(Uint32 *)dst; \
*(Uint32 *)dst = ((s & (mask | mask << 16)) >> 1) + ((d & (mask | mask << 16)) >> 1) + (s & d & (~(mask | mask << 16))); \
src += 2; \
dst += 2; \
} \
if (n) \
BLEND16_50(dst, src, mask); /* last odd pixel */ \
} \
} while (0)
#define ALPHA_BLIT16_565_50(to, from, length, bpp, alpha) \
ALPHA_BLIT16_50(to, from, length, bpp, alpha, 0xf7deU)
#define ALPHA_BLIT16_555_50(to, from, length, bpp, alpha) \
ALPHA_BLIT16_50(to, from, length, bpp, alpha, 0xfbdeU)
#define CHOOSE_BLIT(blitter, alpha, fmt) \
do { \
if (alpha == 255) { \
switch (fmt->BytesPerPixel) { \
case 1: \
blitter(1, Uint8, OPAQUE_BLIT); \
break; \
case 2: \
blitter(2, Uint8, OPAQUE_BLIT); \
break; \
case 3: \
blitter(3, Uint8, OPAQUE_BLIT); \
break; \
case 4: \
blitter(4, Uint16, OPAQUE_BLIT); \
break; \
} \
} else { \
switch (fmt->BytesPerPixel) { \
case 1: \
/* No 8bpp alpha blitting */ \
break; \
\
case 2: \
switch (fmt->Rmask | fmt->Gmask | fmt->Bmask) { \
case 0xffff: \
if (fmt->Gmask == 0x07e0 || fmt->Rmask == 0x07e0 || fmt->Bmask == 0x07e0) { \
if (alpha == 128) { \
blitter(2, Uint8, ALPHA_BLIT16_565_50); \
} else { \
blitter(2, Uint8, ALPHA_BLIT16_565); \
} \
} else { \
goto general16; \
} \
break; \
\
case 0x7fff: \
if (fmt->Gmask == 0x03e0 || fmt->Rmask == 0x03e0 || fmt->Bmask == 0x03e0) { \
if (alpha == 128) { \
blitter(2, Uint8, ALPHA_BLIT16_555_50); \
} else { \
blitter(2, Uint8, ALPHA_BLIT16_555); \
} \
break; \
} else { \
goto general16; \
} \
break; \
\
default: \
general16: \
blitter(2, Uint8, ALPHA_BLIT_ANY); \
} \
break; \
\
case 3: \
blitter(3, Uint8, ALPHA_BLIT_ANY); \
break; \
\
case 4: \
if ((fmt->Rmask | fmt->Gmask | fmt->Bmask) == 0x00ffffff && (fmt->Gmask == 0xff00 || fmt->Rmask == 0xff00 || fmt->Bmask == 0xff00)) { \
if (alpha == 128) { \
blitter(4, Uint16, ALPHA_BLIT32_888_50); \
} else { \
blitter(4, Uint16, ALPHA_BLIT32_888); \
} \
} else { \
blitter(4, Uint16, ALPHA_BLIT_ANY); \
} \
break; \
} \
} \
} while (0)
/*
* Set a pixel value using the given format, except that the alpha value is
* placed in the top byte. This is the format used for RLE with alpha.
*/
#define RLEPIXEL_FROM_RGBA(Pixel, fmt, r, g, b, a) \
{ \
Pixel = ((r >> fmt->Rloss) << fmt->Rshift) | \
((g >> fmt->Gloss) << fmt->Gshift) | \
((b >> fmt->Bloss) << fmt->Bshift) | \
(a << 24); \
}
/*
* This takes care of the case when the surface is clipped on the left and/or
* right. Top clipping has already been taken care of.
*/
#define RLECLIPBLIT(bpp, Type, do_blit) \
do { \
int linecount = srcrect->h; \
int ofs = 0; \
int left = srcrect->x; \
int right = left + srcrect->w; \
dstbuf -= left * bpp; \
for (;;) { \
int run; \
ofs += *(Type *)srcbuf; \
run = ((Type *)srcbuf)[1]; \
srcbuf += 2 * sizeof(Type); \
if (run) { \
/* clip to left and right borders */ \
if (ofs < right) { \
int start = 0; \
int len = run; \
int startcol; \
if (left - ofs > 0) { \
start = left - ofs; \
len -= start; \
if (len <= 0) \
goto nocopy##bpp##do_blit; \
} \
startcol = ofs + start; \
if (len > right - startcol) \
len = right - startcol; \
do_blit(dstbuf + startcol * bpp, srcbuf + start * bpp, \
len, bpp, alpha); \
} \
nocopy##bpp##do_blit : srcbuf += run * bpp; \
ofs += run; \
} else if (!ofs) { \
break; \
} \
\
if (ofs == w) { \
ofs = 0; \
dstbuf += surf_dst->pitch; \
if (!--linecount) { \
break; \
} \
} \
} \
} while (0)
static void RLEClipBlit(int w, Uint8 *srcbuf, SDL_Surface *surf_dst,
Uint8 *dstbuf, SDL_Rect *srcrect, unsigned alpha)
{
SDL_PixelFormat *fmt = surf_dst->format;
CHOOSE_BLIT(RLECLIPBLIT, alpha, fmt);
}
#undef RLECLIPBLIT
/* blit a colorkeyed RLE surface */
static int SDLCALL SDL_RLEBlit(SDL_Surface *surf_src, SDL_Rect *srcrect,
SDL_Surface *surf_dst, SDL_Rect *dstrect)
{
Uint8 *dstbuf;
Uint8 *srcbuf;
int x, y;
int w = surf_src->w;
unsigned alpha;
/* Lock the destination if necessary */
if (SDL_MUSTLOCK(surf_dst)) {
if (SDL_LockSurface(surf_dst) < 0) {
return -1;
}
}
/* Set up the source and destination pointers */
x = dstrect->x;
y = dstrect->y;
dstbuf = (Uint8 *)surf_dst->pixels + y * surf_dst->pitch + x * surf_src->format->BytesPerPixel;
srcbuf = (Uint8 *)surf_src->map->data;
{
/* skip lines at the top if necessary */
int vskip = srcrect->y;
int ofs = 0;
if (vskip) {
#define RLESKIP(bpp, Type) \
for (;;) { \
int run; \
ofs += *(Type *)srcbuf; \
run = ((Type *)srcbuf)[1]; \
srcbuf += sizeof(Type) * 2; \
if (run) { \
srcbuf += run * bpp; \
ofs += run; \
} else if (!ofs) \
goto done; \
if (ofs == w) { \
ofs = 0; \
if (!--vskip) \
break; \
} \
}
switch (surf_src->format->BytesPerPixel) {
case 1:
RLESKIP(1, Uint8);
break;
case 2:
RLESKIP(2, Uint8);
break;
case 3:
RLESKIP(3, Uint8);
break;
case 4:
RLESKIP(4, Uint16);
break;
}
#undef RLESKIP
}
}
alpha = surf_src->map->info.a;
/* if left or right edge clipping needed, call clip blit */
if (srcrect->x || srcrect->w != surf_src->w) {
RLEClipBlit(w, srcbuf, surf_dst, dstbuf, srcrect, alpha);
} else {
SDL_PixelFormat *fmt = surf_src->format;
#define RLEBLIT(bpp, Type, do_blit) \
do { \
int linecount = srcrect->h; \
int ofs = 0; \
for (;;) { \
unsigned run; \
ofs += *(Type *)srcbuf; \
run = ((Type *)srcbuf)[1]; \
srcbuf += 2 * sizeof(Type); \
if (run) { \
do_blit(dstbuf + ofs * bpp, srcbuf, run, bpp, alpha); \
srcbuf += run * bpp; \
ofs += run; \
} else if (!ofs) \
break; \
if (ofs == w) { \
ofs = 0; \
dstbuf += surf_dst->pitch; \
if (!--linecount) \
break; \
} \
} \
} while (0)
CHOOSE_BLIT(RLEBLIT, alpha, fmt);
#undef RLEBLIT
}
done:
/* Unlock the destination if necessary */
if (SDL_MUSTLOCK(surf_dst)) {
SDL_UnlockSurface(surf_dst);
}
return 0;
}
#undef OPAQUE_BLIT
/*
* Per-pixel blitting macros for translucent pixels:
* These use the same techniques as the per-surface blitting macros
*/
/*
* For 32bpp pixels, we have made sure the alpha is stored in the top
* 8 bits, so proceed as usual
*/
#define BLIT_TRANSL_888(src, dst) \
do { \
Uint32 s = src; \
Uint32 d = dst; \
unsigned alpha = s >> 24; \
Uint32 s1 = s & 0xff00ff; \
Uint32 d1 = d & 0xff00ff; \
d1 = (d1 + ((s1 - d1) * alpha >> 8)) & 0xff00ff; \
s &= 0xff00; \
d &= 0xff00; \
d = (d + ((s - d) * alpha >> 8)) & 0xff00; \
dst = d1 | d | 0xff000000; \
} while (0)
/*
* For 16bpp pixels, we have stored the 5 most significant alpha bits in
* bits 5-10. As before, we can process all 3 RGB components at the same time.
*/
#define BLIT_TRANSL_565(src, dst) \
do { \
Uint32 s = src; \
Uint32 d = dst; \
unsigned alpha = (s & 0x3e0) >> 5; \
s &= 0x07e0f81f; \
d = (d | d << 16) & 0x07e0f81f; \
d += (s - d) * alpha >> 5; \
d &= 0x07e0f81f; \
dst = (Uint16)(d | d >> 16); \
} while (0)
#define BLIT_TRANSL_555(src, dst) \
do { \
Uint32 s = src; \
Uint32 d = dst; \
unsigned alpha = (s & 0x3e0) >> 5; \
s &= 0x03e07c1f; \
d = (d | d << 16) & 0x03e07c1f; \
d += (s - d) * alpha >> 5; \
d &= 0x03e07c1f; \
dst = (Uint16)(d | d >> 16); \
} while (0)
/* used to save the destination format in the encoding. Designed to be
macro-compatible with SDL_PixelFormat but without the unneeded fields */
typedef struct
{
Uint8 BytesPerPixel;
Uint8 padding[3];
Uint32 Rmask;
Uint32 Gmask;
Uint32 Bmask;
Uint32 Amask;
Uint8 Rloss;
Uint8 Gloss;
Uint8 Bloss;
Uint8 Aloss;
Uint8 Rshift;
Uint8 Gshift;
Uint8 Bshift;
Uint8 Ashift;
} RLEDestFormat;
/* blit a pixel-alpha RLE surface clipped at the right and/or left edges */
static void RLEAlphaClipBlit(int w, Uint8 *srcbuf, SDL_Surface *surf_dst,
Uint8 *dstbuf, SDL_Rect *srcrect)
<
10BC8
div>
{
SDL_PixelFormat *df = surf_dst->format;
/*
* clipped blitter: Ptype is the destination pixel type,
* Ctype the translucent count type, and do_blend the macro
* to blend one pixel.
*/
#define RLEALPHACLIPBLIT(Ptype, Ctype, do_blend) \
do { \
int linecount = srcrect->h; \
int left = srcrect->x; \
int right = left + srcrect->w; \
dstbuf -= left * sizeof(Ptype); \
do { \
int ofs = 0; \
/* blit opaque pixels on one line */ \
do { \
unsigned run; \
ofs += ((Ctype *)srcbuf)[0]; \
run = ((Ctype *)srcbuf)[1]; \
srcbuf += 2 * sizeof(Ctype); \
if (run) { \
/* clip to left and right borders */ \
int cofs = ofs; \
int crun = run; \
if (left - cofs > 0) { \
crun -= left - cofs; \
cofs = left; \
} \
if (crun > right - cofs) \
crun = right - cofs; \
if (crun > 0) \
PIXEL_COPY(dstbuf + cofs * sizeof(Ptype), \
srcbuf + (cofs - ofs) * sizeof(Ptype), \
(unsigned)crun, sizeof(Ptype)); \
srcbuf += run * sizeof(Ptype); \
ofs += run; \
} else if (!ofs) \
return; \
} while (ofs < w); \
/* skip padding if necessary */ \
if (sizeof(Ptype) == 2) \
srcbuf += (uintptr_t)srcbuf & 2; \
/* blit translucent pixels on the same line */ \
ofs = 0; \
do { \
unsigned run; \
ofs += ((Uint16 *)srcbuf)[0]; \
run = ((Uint16 *)srcbuf)[1]; \
srcbuf += 4; \
if (run) { \
/* clip to left and right borders */ \
int cofs = ofs; \
int crun = run; \
if (left - cofs > 0) { \
crun -= left - cofs; \
cofs = left; \
} \
if (crun > right - cofs) \
crun = right - cofs; \
if (crun > 0) { \
Ptype *dst = (Ptype *)dstbuf + cofs; \
Uint32 *src = (Uint32 *)srcbuf + (cofs - ofs); \
int i; \
for (i = 0; i < crun; i++) \
do_blend(src[i], dst[i]); \
} \
srcbuf += run * 4; \
ofs += run; \
} \
} while (ofs < w); \
dstbuf += surf_dst->pitch; \
} while (--linecount); \
} while (0)
switch (df->BytesPerPixel) {
case 2:
if (df->Gmask == 0x07e0 || df->Rmask == 0x07e0 || df->Bmask == 0x07e0) {
RLEALPHACLIPBLIT(Uint16, Uint8, BLIT_TRANSL_565);
} else {
RLEALPHACLIPBLIT(Uint16, Uint8, BLIT_TRANSL_555);
}
break;
case 4:
RLEALPHACLIPBLIT(Uint32, Uint16, BLIT_TRANSL_888);
break;
}
}
/* blit a pixel-alpha RLE surface */
static int SDLCALL SDL_RLEAlphaBlit(SDL_Surface *surf_src, SDL_Rect *srcrect,
SDL_Surface *surf_dst, SDL_Rect *dstrect)
{
int x, y;
int w = surf_src->w;
Uint8 *srcbuf, *dstbuf;
SDL_PixelFormat *df = surf_dst->format;
/* Lock the destination if necessary */
if (SDL_MUSTLOCK(surf_dst)) {
if (SDL_LockSurface(surf_dst) < 0) {
return -1;
}
}
x = dstrect->x;
y = dstrect->y;
dstbuf = (Uint8 *)surf_dst->pixels + y * surf_dst->pitch + x * df->BytesPerPixel;
srcbuf = (Uint8 *)surf_src->map->data + sizeof(RLEDestFormat);
{
/* skip lines at the top if necessary */
int vskip = srcrect->y;
if (vskip) {
int ofs;
if (df->BytesPerPixel == 2) {
/* the 16/32 interleaved format */
do {
/* skip opaque line */
ofs = 0;
do {
int run;
ofs += srcbuf[0];
run = srcbuf[1];
srcbuf += 2;
if (run) {
srcbuf += 2 * run;
ofs += run;
} else if (ofs == 0) {
goto done;
}
} while (ofs < w);
/* skip padding */
srcbuf += (uintptr_t)srcbuf & 2;
/* skip translucent line */
ofs = 0;
do {
int run;
ofs += ((Uint16 *)srcbuf)[0];
run = ((Uint16 *)srcbuf)[1];
srcbuf += 4 * (run + 1);
ofs += run;
} while (ofs < w);
} while (--vskip);
} else {
/* the 32/32 interleaved format */
vskip <<= 1; /* opaque and translucent have same format */
do {
ofs = 0;
do {
int run;
ofs += ((Uint16 *)srcbuf)[0];
run = ((Uint16 *)srcbuf)[1];
srcbuf += 4;
if (run) {
srcbuf += 4 * run;
ofs += run;
} else if (ofs == 0) {
goto done;
}
} while (ofs < w);
} while (--vskip);
}
}
}
/* if left or right edge clipping needed, call clip blit */
if (srcrect->x || srcrect->w != surf_src->w) {
RLEAlphaClipBlit(w, srcbuf, surf_dst, dstbuf, srcrect);
} else {
/*
* non-clipped blitter. Ptype is the destination pixel type,
* Ctype the translucent count type, and do_blend the
* macro to blend one pixel.
*/
#define RLEALPHABLIT(Ptype, Ctype, do_blend) \
do { \
int linecount = srcrect->h; \
do { \
int ofs = 0; \
/* blit opaque pixels on one line */ \
do { \
unsigned run; \
ofs += ((Ctype *)srcbuf)[0]; \
run = ((Ctype *)srcbuf)[1]; \
srcbuf += 2 * sizeof(Ctype); \
if (run) { \
PIXEL_COPY(dstbuf + ofs * sizeof(Ptype), srcbuf, \
run, sizeof(Ptype)); \
srcbuf += run * sizeof(Ptype); \
ofs += run; \
} else if (!ofs) \
goto done; \
} while (ofs < w); \
/* skip padding if necessary */ \
if (sizeof(Ptype) == 2) \
srcbuf += (uintptr_t)srcbuf & 2; \
/* blit translucent pixels on the same line */ \
ofs = 0; \
do { \
unsigned run; \
ofs += ((Uint16 *)srcbuf)[0]; \
run = ((Uint16 *)srcbuf)[1]; \
srcbuf += 4; \
if (run) { \
Ptype *dst = (Ptype *)dstbuf + ofs; \
unsigned i; \
for (i = 0; i < run; i++) { \
Uint32 src = *(Uint32 *)srcbuf; \
do_blend(src, *dst); \
srcbuf += 4; \
dst++; \
} \
ofs += run; \
} \
} while (ofs < w); \
dstbuf += surf_dst->pitch; \
} while (--linecount); \
} while (0)
switch (df->BytesPerPixel) {
case 2:
if (df->Gmask == 0x07e0 || df->Rmask == 0x07e0 || df->Bmask == 0x07e0) {
RLEALPHABLIT(Uint16, Uint8, BLIT_TRANSL_565);
} else {
RLEALPHABLIT(Uint16, Uint8, BLIT_TRANSL_555);
}
break;
case 4:
RLEALPHABLIT(Uint32, Uint16, BLIT_TRANSL_888);
break;
}
}
done:
/* Unlock the destination if necessary */
if (SDL_MUSTLOCK(surf_dst)) {
SDL_UnlockSurface(surf_dst);
}
return 0;
}
/*
* Auxiliary functions:
* The encoding functions take 32bpp rgb + a, and
* return the number of bytes copied to the destination.
* The decoding functions copy to 32bpp rgb + a, and
* return the number of bytes copied from the source.
* These are only used in the encoder and un-RLE code and are therefore not
* highly optimised.
*/
/* encode 32bpp rgb + a into 16bpp rgb, losing alpha */
static int copy_opaque_16(void *dst, Uint32 *src, int n,
SDL_PixelFormat *sfmt, SDL_PixelFormat *dfmt)
{
int i;
Uint16 *d = dst;
for (i = 0; i < n; i++) {
unsigned r, g, b;
RGB_FROM_PIXEL(*src, sfmt, r, g, b);
PIXEL_FROM_RGB(*d, dfmt, r, g, b);
src++;
d++;
}
return n * 2;
}
/* decode opaque pixels from 16bpp to 32bpp rgb + a */
static int uncopy_opaque_16(Uint32 *dst, void *src, int n,
RLEDestFormat *sfmt, SDL_PixelFormat *dfmt)
{
int i;
Uint16 *s = src;
unsigned alpha = dfmt->Amask ? 255 : 0;
for (i = 0; i < n; i++) {
unsigned r, g, b;
RGB_FROM_PIXEL(*s, sfmt, r, g, b);
PIXEL_FROM_RGBA(*dst, dfmt, r, g, b, alpha);
s++;
dst++;
}
return n * 2;
}
/* encode 32bpp rgb + a into 32bpp G0RAB format for blitting into 565 */
static int copy_transl_565(void *dst, Uint32 *src, int n,
SDL_PixelFormat *sfmt, SDL_PixelFormat *dfmt)
{
int i;
Uint32 *d = dst;
for (i = 0; i < n; i++) {
unsigned r, g, b, a;
Uint16 pix;
RGBA_FROM_8888(*src, sfmt, r, g, b, a);
PIXEL_FROM_RGB(pix, dfmt, r, g, b);
*d = ((pix & 0x7e0) << 16) | (pix & 0xf81f) | ((a << 2) & 0x7e0);
src++;
d++;
}
return n * 4;
}
/* encode 32bpp rgb + a into 32bpp G0RAB format for blitting into 555 */
static int copy_transl_555(void *dst, Uint32 *src, int n,
SDL_PixelFormat *sfmt, SDL_PixelFormat *dfmt)
{
int i;
Uint32 *d = dst;
for (i = 0; i < n; i++) {
unsigned r, g, b, a;
Uint16 pix;
RGBA_FROM_8888(*src, sfmt, r, g, b, a);
PIXEL_FROM_RGB(pix, dfmt, r, g, b);
*d = ((pix & 0x3e0) << 16) | (pix & 0xfc1f) | ((a << 2) & 0x3e0);
src++;
d++;
}
return n * 4;
}
/* decode translucent pixels from 32bpp GORAB to 32bpp rgb + a */
static int uncopy_transl_16(Uint32 *dst, void *src, int n,
RLEDestFormat *sfmt, SDL_PixelFormat *dfmt)
{
int i;
Uint32 *s = src;
for (i = 0; i < n; i++) {
unsigned r, g, b, a;
Uint32 pix = *s++;
a = (pix & 0x3e0) >> 2;
pix = (pix & ~0x3e0) | pix >> 16;
RGB_FROM_PIXEL(pix, sfmt, r, g, b);
PIXEL_FROM_RGBA(*dst, dfmt, r, g, b, a);
dst++;
}
return n * 4;
}
/* encode 32bpp rgba into 32bpp rgba, keeping alpha (dual purpose) */
static int copy_32(void *dst, Uint32 *src, int n,
SDL_PixelFormat *sfmt, SDL_PixelFormat *dfmt)
{
int i;
Uint32 *d = dst;
for (i = 0; i < n; i++) {
unsigned r, g, b, a;
RGBA_FROM_8888(*src, sfmt, r, g, b, a);
RLEPIXEL_FROM_RGBA(*d, dfmt, r, g, b, a);
d++;
src++;
}
return n * 4;
}
/* decode 32bpp rgba into 32bpp rgba, keeping alpha (dual purpose) */
static int uncopy_32(Uint32 *dst, void *src, int n,
RLEDestFormat *sfmt, SDL_PixelFormat *dfmt)
{
int i;
Uint32 *s = src;
for (i = 0; i < n; i++) {
unsigned r, g, b, a;
Uint32 pixel = *s++;
RGB_FROM_PIXEL(pixel, sfmt, r, g, b);
a = pixel >> 24;
PIXEL_FROM_RGBA(*dst, dfmt, r, g, b, a);