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SDL_ConvertColorkeyToAlpha: remove and clarify a FIXME 

This function doesn't handle bpp 1 or 3 case, because those formats never have an alpha channel
This commit is contained in:
Sylvain Becker 2021-02-03 09:32:09 +01:00
parent 85235985fb
commit c0166a29b7
1 changed files with 55 additions and 62 deletions
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117
src/video/SDL_surface.c
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@ -326,11 +326,12 @@ SDL_GetColorKey(SDL_Surface * surface, Uint32 * key)
return 0;
}
/* This is a fairly slow function to switch from colorkey to alpha */
/* This is a fairly slow function to switch from colorkey to alpha
NB: it doesn't handle bpp 1 or 3, because they have no alpha channel */
static void
SDL_ConvertColorkeyToAlpha(SDL_Surface * surface, SDL_bool ignore_alpha)
{
int x, y;
int x, y, bpp;
if (!surface) {
return;
@ -341,82 +342,74 @@ SDL_ConvertColorkeyToAlpha(SDL_Surface * surface, SDL_bool ignore_alpha)
return;
}
bpp = surface->format->BytesPerPixel;
SDL_LockSurface(surface);
switch (surface->format->BytesPerPixel) {
case 2:
{
Uint16 *row, *spot;
Uint16 ckey = (Uint16) surface->map->info.colorkey;
Uint16 mask = (Uint16) (~surface->format->Amask);
if (bpp == 2) {
Uint16 *row, *spot;
Uint16 ckey = (Uint16) surface->map->info.colorkey;
Uint16 mask = (Uint16) (~surface->format->Amask);
/* Ignore, or not, alpha in colorkey comparison */
if (ignore_alpha) {
ckey &= mask;
row = (Uint16 *) surface->pixels;
for (y = surface->h; y--;) {
spot = row;
for (x = surface->w; x--;) {
if ((*spot & mask) == ckey) {
*spot &= mask;
}
++spot;
/* Ignore, or not, alpha in colorkey comparison */
if (ignore_alpha) {
ckey &= mask;
row = (Uint16 *) surface->pixels;
for (y = surface->h; y--;) {
spot = row;
for (x = surface->w; x--;) {
if ((*spot & mask) == ckey) {
*spot &= mask;
}
row += surface->pitch / 2;
++spot;
}
} else {
row = (Uint16 *) surface->pixels;
for (y = surface->h; y--;) {
spot = row;
for (x = surface->w; x--;) {
if (*spot == ckey) {
*spot &= mask;
}
++spot;
row += surface->pitch / 2;
}
} else {
row = (Uint16 *) surface->pixels;
for (y = surface->h; y--;) {
spot = row;
for (x = surface->w; x--;) {
if (*spot == ckey) {
*spot &= mask;
}
row += surface->pitch / 2;
++spot;
}
row += surface->pitch / 2;
}
}
break;
case 3:
/* FIXME */
break;
case 4:
{
Uint32 *row, *spot;
Uint32 ckey = surface->map->info.colorkey;
Uint32 mask = ~surface->format->Amask;
} else if (bpp == 4) {
Uint32 *row, *spot;
Uint32 ckey = surface->map->info.colorkey;
Uint32 mask = ~surface->format->Amask;
/* Ignore, or not, alpha in colorkey comparison */
if (ignore_alpha) {
ckey &= mask;
row = (Uint32 *) surface->pixels;
for (y = surface->h; y--;) {
spot = row;
for (x = surface->w; x--;) {
if ((*spot & mask) == ckey) {
*spot &= mask;
}
++spot;
/* Ignore, or not, alpha in colorkey comparison */
if (ignore_alpha) {
ckey &= mask;
row = (Uint32 *) surface->pixels;
for (y = surface->h; y--;) {
spot = row;
for (x = surface->w; x--;) {
if ((*spot & mask) == ckey) {
*spot &= mask;
}
row += surface->pitch / 4;
++spot;
}
} else {
row = (Uint32 *) surface->pixels;
for (y = surface->h; y--;) {
spot = row;
for (x = surface->w; x--;) {
if (*spot == ckey) {
*spot &= mask;
}
++spot;
row += surface->pitch / 4;
}
} else {
row = (Uint32 *) surface->pixels;
for (y = surface->h; y--;) {
spot = row;
for (x = surface->w; x--;) {
if (*spot == ckey) {
*spot &= mask;
}
row += surface->pitch / 4;
++spot;
}
row += surface->pitch / 4;
}
}
break;
}
SDL_UnlockSurface(surface);