Mercurial > sdl-ios-xcode
changeset 431:41cadcba32e8
Fixed SDL_DisplayFormatAlpha() on RGB surfaces with alpha
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Thu, 01 Aug 2002 23:06:39 +0000 |
| parents | 60effdbf14ee |
| children | 80a35d43a58f |
| files | docs.html include/SDL_video.h src/video/SDL_blit_N.c src/video/SDL_surface.c |
| diffstat | 4 files changed, 63 insertions(+), 6 deletions(-) [+] |
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--- a/docs.html Thu Aug 01 05:16:38 2002 +0000 +++ b/docs.html Thu Aug 01 23:06:39 2002 +0000 @@ -16,6 +16,7 @@ Major changes since SDL 1.0.0: </H2> <UL> + <LI> 1.2.5: Fixed SDL_DisplayFormatAlpha() on RGB surfaces with alpha <LI> 1.2.5: Fixed setting OpenGL mode multiple times on Windows <LI> 1.2.5: Added support for Qtopia on embedded systems (thanks David!) <LI> 1.2.4: Added initial support for Atari (thanks Patrice!)
--- a/include/SDL_video.h Thu Aug 01 05:16:38 2002 +0000 +++ b/include/SDL_video.h Thu Aug 01 23:06:39 2002 +0000 @@ -645,7 +645,7 @@ * alpha-blend (using the source per-surface alpha value); * set destination alpha to opaque. * SDL_SRCALPHA not set: - * copy RGB, set destination alpha to opaque. + * copy RGB, set destination alpha to source per-surface alpha value. * both: * if SDL_SRCCOLORKEY set, only copy the pixels matching the * source colour key.
--- a/src/video/SDL_blit_N.c Thu Aug 01 05:16:38 2002 +0000 +++ b/src/video/SDL_blit_N.c Thu Aug 01 23:06:39 2002 +0000 @@ -1202,7 +1202,7 @@ int srcbpp = srcfmt->BytesPerPixel; SDL_PixelFormat *dstfmt = info->dst; int dstbpp = dstfmt->BytesPerPixel; - unsigned alpha = dstfmt->Amask ? SDL_ALPHA_OPAQUE : 0; + unsigned alpha = dstfmt->Amask ? srcfmt->alpha : 0; while ( height-- ) { DUFFS_LOOP( @@ -1358,7 +1358,7 @@ SDL_PixelFormat *dstfmt = info->dst; int srcbpp = srcfmt->BytesPerPixel; int dstbpp = dstfmt->BytesPerPixel; - unsigned alpha = dstfmt->Amask ? SDL_ALPHA_OPAQUE : 0; + unsigned alpha = dstfmt->Amask ? srcfmt->alpha : 0; while ( height-- ) { DUFFS_LOOP(
--- a/src/video/SDL_surface.c Thu Aug 01 05:16:38 2002 +0000 +++ b/src/video/SDL_surface.c Thu Aug 01 23:06:39 2002 +0000 @@ -211,6 +211,7 @@ SDL_InvalidateMap(surface->map); return(0); } +/* This function sets the alpha channel of a surface */ int SDL_SetAlpha (SDL_Surface *surface, Uint32 flag, Uint8 value) { Uint32 oldflags = surface->flags; @@ -269,6 +270,52 @@ SDL_InvalidateMap(surface->map); return(0); } +int SDL_SetAlphaChannel(SDL_Surface *surface, Uint8 value) +{ + int row, col; + int offset; + Uint8 *buf; + + if ( (surface->format->Amask != 0xFF000000) && + (surface->format->Amask != 0x000000FF) ) { + SDL_SetError("Unsupported surface alpha mask format"); + return -1; + } + +#if SDL_BYTEORDER == SDL_LIL_ENDIAN + if ( surface->format->Amask == 0xFF000000 ) { + offset = 3; + } else { + offset = 0; + } +#else + if ( surface->format->Amask == 0xFF000000 ) { + offset = 0; + } else { + offset = 3; + } +#endif /* Byte ordering */ + + /* Quickly set the alpha channel of an RGBA or ARGB surface */ + if ( SDL_MUSTLOCK(surface) ) { + if ( SDL_LockSurface(surface) < 0 ) { + return -1; + } + } + row = surface->h; + while (row--) { + col = surface->w; + buf = (Uint8 *)surface->pixels + row * surface->pitch + offset; + while(col--) { + *buf = value; + buf += 4; + } + } + if ( SDL_MUSTLOCK(surface) ) { + SDL_UnlockSurface(surface); + } + return 0; +} /* * A function to calculate the intersection of two rectangles: @@ -748,8 +795,13 @@ } } if ( (surface_flags & SDL_SRCALPHA) == SDL_SRCALPHA ) { - alpha = surface->format->alpha; - SDL_SetAlpha(surface, 0, 0); + /* Copy over the alpha channel to RGBA if requested */ + if ( format->Amask ) { + surface->flags &= ~SDL_SRCALPHA; + } else { + alpha = surface->format->alpha; + SDL_SetAlpha(surface, 0, 0); + } } /* Copy over the image data */ @@ -780,7 +832,11 @@ SDL_SetAlpha(convert, aflags|(flags&SDL_RLEACCELOK), alpha); } - SDL_SetAlpha(surface, aflags, alpha); + if ( format->Amask ) { + surface->flags |= SDL_SRCALPHA; + } else { + SDL_SetAlpha(surface, aflags, alpha); + } } /* We're ready to go! */