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Fix regression: when a palette + colorkey is converted, it needs a blend mode. 

- Regression of test_1.c of bug 3827, after fix from bug 4798.
- Blending is also needed when the palette contains alpha value, but not necessarily colorkey.
- Clean up SDL_ConvertColorkeyToAlpha which doesn't seem to need 'ignore_alpha' parameter any-more.

(see bug 3827)
This commit is contained in:
Sylvain Becker 2020-02-23 22:38:08 +01:00
parent 094655cff9
commit bf8aa1edae
1 changed files with 16 additions and 5 deletions
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21
src/video/SDL_surface.c
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@ -964,6 +964,7 @@ SDL_ConvertSurface(SDL_Surface * surface, const SDL_PixelFormat * format,
int ret; int ret;
int palette_ck_transform = 0; int palette_ck_transform = 0;
int palette_ck_value = 0; int palette_ck_value = 0;
int palette_has_alpha = SDL_FALSE;
if (!surface) { if (!surface) {
SDL_InvalidParamError("surface"); SDL_InvalidParamError("surface");
@ -1029,6 +1030,7 @@ SDL_ConvertSurface(SDL_Surface * surface, const SDL_PixelFormat * format,
if (copy_flags & SDL_COPY_COLORKEY) { if (copy_flags & SDL_COPY_COLORKEY) {
if (surface->format->palette && !format->palette) { if (surface->format->palette && !format->palette) {
palette_ck_transform = 1; palette_ck_transform = 1;
palette_has_alpha = SDL_TRUE;
palette_ck_value = surface->format->palette->colors[surface->map->info.colorkey].a; palette_ck_value = surface->format->palette->colors[surface->map->info.colorkey].a;
surface->format->palette->colors[surface->map->info.colorkey].a = SDL_ALPHA_TRANSPARENT; surface->format->palette->colors[surface->map->info.colorkey].a = SDL_ALPHA_TRANSPARENT;
} }
@ -1066,7 +1068,6 @@ SDL_ConvertSurface(SDL_Surface * surface, const SDL_PixelFormat * format,
if (copy_flags & SDL_COPY_COLORKEY) { if (copy_flags & SDL_COPY_COLORKEY) {
SDL_bool set_colorkey_by_color = SDL_FALSE; SDL_bool set_colorkey_by_color = SDL_FALSE;
SDL_bool ignore_alpha = SDL_TRUE; /* Ignore, or not, alpha in colorkey comparison */
if (surface->format->palette) { if (surface->format->palette) {
if (format->palette && if (format->palette &&
@ -1077,9 +1078,6 @@ SDL_ConvertSurface(SDL_Surface * surface, const SDL_PixelFormat * format,
SDL_SetColorKey(convert, 1, surface->map->info.colorkey); SDL_SetColorKey(convert, 1, surface->map->info.colorkey);
} else if (!format->palette) { } else if (!format->palette) {
/* Was done by 'palette_ck_transform' */ /* Was done by 'palette_ck_transform' */
}else if (format->Amask) {
set_colorkey_by_color = SDL_TRUE;
ignore_alpha = SDL_FALSE;
} else { } else {
set_colorkey_by_color = SDL_TRUE; set_colorkey_by_color = SDL_TRUE;
} }
@ -1120,14 +1118,27 @@ SDL_ConvertSurface(SDL_Surface * surface, const SDL_PixelFormat * format,
SDL_SetColorKey(convert, 1, converted_colorkey); SDL_SetColorKey(convert, 1, converted_colorkey);
/* This is needed when converting for 3D texture upload */ /* This is needed when converting for 3D texture upload */
SDL_ConvertColorkeyToAlpha(convert, ignore_alpha); SDL_ConvertColorkeyToAlpha(convert, SDL_TRUE);
} }
} }
SDL_SetClipRect(convert, &surface->clip_rect); SDL_SetClipRect(convert, &surface->clip_rect);
/* Source surface has a palette with alpha. Will need blend mode */
if (palette_has_alpha == SDL_FALSE && surface->format->palette) {
int i;
for (i = 0; i < surface->format->palette->ncolors; i++) {
Uint8 alpha_value = surface->format->palette->colors[i].a;
if (alpha_value != 0 && alpha_value != SDL_ALPHA_OPAQUE) {
palette_has_alpha = SDL_TRUE;
break;
}
}
}
/* Enable alpha blending by default if the new surface has an /* Enable alpha blending by default if the new surface has an
* alpha channel or alpha modulation */ * alpha channel or alpha modulation */
if ((surface->format->Amask && format->Amask) || if ((surface->format->Amask && format->Amask) ||
(palette_has_alpha && format->Amask) ||
(copy_flags & SDL_COPY_MODULATE_ALPHA)) { (copy_flags & SDL_COPY_MODULATE_ALPHA)) {
SDL_SetSurfaceBlendMode(convert, SDL_BLENDMODE_BLEND); SDL_SetSurfaceBlendMode(convert, SDL_BLENDMODE_BLEND);
} }