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Support returning <8bpp surfaces in SDL_LoadBMP_RW

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This commit is contained in:
Cameron Cawley
2023-11-17 14:10:32 +00:00
committed by Sam Lantinga
parent 773ec1cfcb
commit 05e7dcf8f8
3 changed files with 40 additions and 79 deletions
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105
src/video/SDL_bmp.c
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@@ -197,7 +197,6 @@ SDL_Surface *SDL_LoadBMP_RW(SDL_RWops *src, SDL_bool freesrc)
{
SDL_bool was_error = SDL_TRUE;
Sint64 fp_offset = 0;
int bmpPitch;
int i, pad;
SDL_Surface *surface;
Uint32 Rmask = 0;
@@ -208,7 +207,6 @@ SDL_Surface *SDL_LoadBMP_RW(SDL_RWops *src, SDL_bool freesrc)
Uint8 *bits;
Uint8 *top, *end;
SDL_bool topDown;
int ExpandBMP;
SDL_bool haveRGBMasks = SDL_FALSE;
SDL_bool haveAlphaMask = SDL_FALSE;
SDL_bool correctAlpha = SDL_FALSE;
@@ -365,14 +363,8 @@ SDL_Surface *SDL_LoadBMP_RW(SDL_RWops *src, SDL_bool freesrc)
goto done;
}
/* Expand 1, 2 and 4 bit bitmaps to 8 bits per pixel */
/* Reject invalid bit depths */
switch (biBitCount) {
case 1:
case 2:
case 4:
ExpandBMP = biBitCount;
biBitCount = 8;
break;
case 0:
case 3:
case 5:
@@ -381,7 +373,6 @@ SDL_Surface *SDL_LoadBMP_RW(SDL_RWops *src, SDL_bool freesrc)
SDL_SetError("%d-bpp BMP images are not supported", biBitCount);
goto done;
default:
ExpandBMP = 0;
break;
}
@@ -514,89 +505,49 @@ SDL_Surface *SDL_LoadBMP_RW(SDL_RWops *src, SDL_bool freesrc)
}
top = (Uint8 *)surface->pixels;
end = (Uint8 *)surface->pixels + (surface->h * surface->pitch);
switch (ExpandBMP) {
case 1:
bmpPitch = (biWidth + 7) >> 3;
pad = (((bmpPitch) % 4) ? (4 - ((bmpPitch) % 4)) : 0);
break;
case 2:
bmpPitch = (biWidth + 3) >> 2;
pad = (((bmpPitch) % 4) ? (4 - ((bmpPitch) % 4)) : 0);
break;
case 4:
bmpPitch = (biWidth + 1) >> 1;
pad = (((bmpPitch) % 4) ? (4 - ((bmpPitch) % 4)) : 0);
break;
default:
pad = ((surface->pitch % 4) ? (4 - (surface->pitch % 4)) : 0);
break;
}
pad = ((surface->pitch % 4) ? (4 - (surface->pitch % 4)) : 0);
if (topDown) {
bits = top;
} else {
bits = end - surface->pitch;
}
while (bits >= top && bits < end) {
switch (ExpandBMP) {
case 1:
case 2:
case 4:
{
Uint8 pixel = 0;
int shift = (8 - ExpandBMP);
if (SDL_RWread(src, bits, surface->pitch) != (size_t)surface->pitch) {
goto done;
}
if (biBitCount == 8 && palette && biClrUsed < (1u << biBitCount)) {
for (i = 0; i < surface->w; ++i) {
if (i % (8 / ExpandBMP) == 0) {
if (!SDL_ReadU8(src, &pixel)) {
goto done;
}
}
bits[i] = (pixel >> shift);
if (bits[i] >= biClrUsed) {
SDL_SetError("A BMP image contains a pixel with a color out of the palette");
goto done;
}
pixel <<= ExpandBMP;
}
} break;
default:
if (SDL_RWread(src, bits, surface->pitch) != (size_t)surface->pitch) {
goto done;
}
if (biBitCount == 8 && palette && biClrUsed < (1u << biBitCount)) {
for (i = 0; i < surface->w; ++i) {
if (bits[i] >= biClrUsed) {
SDL_SetError("A BMP image contains a pixel with a color out of the palette");
goto done;
}
}
}
}
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
/* Byte-swap the pixels if needed. Note that the 24bpp
case has already been taken care of above. */
switch (biBitCount) {
case 15:
case 16:
{
Uint16 *pix = (Uint16 *)bits;
for (i = 0; i < surface->w; i++) {
pix[i] = SDL_Swap16(pix[i]);
}
break;
/* Byte-swap the pixels if needed. Note that the 24bpp
case has already been taken care of above. */
switch (biBitCount) {
case 15:
case 16:
{
Uint16 *pix = (Uint16 *)bits;
for (i = 0; i < surface->w; i++) {
pix[i] = SDL_Swap16(pix[i]);
}
case 32:
{
Uint32 *pix = (Uint32 *)bits;
for (i = 0; i < surface->w; i++) {
pix[i] = SDL_Swap32(pix[i]);
}
break;
}
}
#endif
break;
}
case 32:
{
Uint32 *pix = (Uint32 *)bits;
for (i = 0; i < surface->w; i++) {
pix[i] = SDL_Swap32(pix[i]);
}
break;
}
}
#endif
/* Skip padding bytes, ugh */
if (pad) {
Uint8 padbyte;