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Clarified the code in the pixel format allocation
Added support for direct color 8-bpp modes.
This commit is contained in:
Sam Lantinga
parent
c2113a949a
commit
9afc8f4748
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@ -61,160 +61,45 @@ SDL_PixelFormat *SDL_AllocFormat(int bpp,
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/* Set up the format */
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format->BitsPerPixel = bpp;
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format->BytesPerPixel = (bpp+7)/8;
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switch (bpp) {
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case 1:
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/* Create the 2 color black-white palette */
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format->palette = (SDL_Palette *)malloc(
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sizeof(SDL_Palette));
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if ( format->palette == NULL ) {
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SDL_FreeFormat(format);
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SDL_OutOfMemory();
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return(NULL);
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}
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(format->palette)->ncolors = 2;
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(format->palette)->colors = (SDL_Color *)malloc(
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(format->palette)->ncolors*sizeof(SDL_Color));
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if ( (format->palette)->colors == NULL ) {
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SDL_FreeFormat(format);
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SDL_OutOfMemory();
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return(NULL);
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}
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format->palette->colors[0].r = 0xFF;
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format->palette->colors[0].g = 0xFF;
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format->palette->colors[0].b = 0xFF;
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format->palette->colors[1].r = 0x00;
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format->palette->colors[1].g = 0x00;
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format->palette->colors[1].b = 0x00;
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format->Rloss = 8;
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format->Gloss = 8;
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format->Bloss = 8;
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format->Aloss = 8;
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format->Rshift = 0;
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format->Gshift = 0;
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format->Bshift = 0;
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format->Ashift = 0;
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format->Rmask = 0;
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format->Gmask = 0;
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format->Bmask = 0;
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format->Amask = 0;
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break;
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case 4:
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/* Create the 16 color VGA palette */
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format->palette = (SDL_Palette *)malloc(
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sizeof(SDL_Palette));
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if ( format->palette == NULL ) {
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SDL_FreeFormat(format);
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SDL_OutOfMemory();
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return(NULL);
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}
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(format->palette)->ncolors = 16;
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(format->palette)->colors = (SDL_Color *)malloc(
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(format->palette)->ncolors*sizeof(SDL_Color));
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if ( (format->palette)->colors == NULL ) {
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SDL_FreeFormat(format);
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SDL_OutOfMemory();
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return(NULL);
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}
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/* Punt for now, will this ever be used? */
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memset((format->palette)->colors, 0,
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(format->palette)->ncolors*sizeof(SDL_Color));
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/* Palettized formats have no mask info */
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format->Rloss = 8;
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format->Gloss = 8;
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format->Bloss = 8;
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format->Aloss = 8;
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format->Rshift = 0;
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format->Gshift = 0;
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format->Bshift = 0;
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format->Ashift = 0;
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format->Rmask = 0;
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format->Gmask = 0;
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format->Bmask = 0;
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format->Amask = 0;
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break;
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case 8:
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/* Create an empty 256 color palette */
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format->palette = (SDL_Palette *)malloc(
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sizeof(SDL_Palette));
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if ( format->palette == NULL ) {
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SDL_FreeFormat(format);
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SDL_OutOfMemory();
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return(NULL);
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}
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(format->palette)->ncolors = 256;
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(format->palette)->colors = (SDL_Color *)malloc(
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(format->palette)->ncolors*sizeof(SDL_Color));
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if ( (format->palette)->colors == NULL ) {
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SDL_FreeFormat(format);
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SDL_OutOfMemory();
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return(NULL);
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}
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memset((format->palette)->colors, 0,
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(format->palette)->ncolors*sizeof(SDL_Color));
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/* Palettized formats have no mask info */
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format->Rloss = 8;
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format->Gloss = 8;
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format->Bloss = 8;
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format->Aloss = 8;
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format->Rshift = 0;
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format->Gshift = 0;
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format->Bshift = 0;
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format->Ashift = 0;
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format->Rmask = 0;
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format->Gmask = 0;
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format->Bmask = 0;
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format->Amask = 0;
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break;
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default:
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/* No palette, just packed pixel info */
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format->palette = NULL;
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format->Rshift = 0;
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format->Rloss = 8;
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if ( Rmask ) {
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for ( mask = Rmask; !(mask&0x01); mask >>= 1 )
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++format->Rshift;
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for ( ; (mask&0x01); mask >>= 1 )
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--format->Rloss;
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}
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format->Gshift = 0;
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format->Gloss = 8;
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if ( Gmask ) {
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for ( mask = Gmask; !(mask&0x01); mask >>= 1 )
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++format->Gshift;
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for ( ; (mask&0x01); mask >>= 1 )
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--format->Gloss;
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}
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format->Bshift = 0;
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format->Bloss = 8;
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if ( Bmask ) {
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for ( mask = Bmask; !(mask&0x01); mask >>= 1 )
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++format->Bshift;
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for ( ; (mask&0x01); mask >>= 1 )
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--format->Bloss;
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}
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format->Ashift = 0;
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format->Aloss = 8;
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if ( Amask ) {
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for ( mask = Amask; !(mask&0x01); mask >>= 1 )
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++format->Ashift;
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for ( ; (mask&0x01); mask >>= 1 )
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--format->Aloss;
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}
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format->Rmask = Rmask;
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format->Gmask = Gmask;
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format->Bmask = Bmask;
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format->Amask = Amask;
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break;
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}
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/* Calculate some standard bitmasks, if necessary
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* Note: This could conflict with an alpha mask, if given.
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*/
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if ( (bpp > 8) && !format->Rmask && !format->Gmask && !format->Bmask ) {
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if ( Rmask || Bmask || Gmask ) { /* Packed pixels with custom mask */
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format->palette = NULL;
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format->Rshift = 0;
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format->Rloss = 8;
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if ( Rmask ) {
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for ( mask = Rmask; !(mask&0x01); mask >>= 1 )
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++format->Rshift;
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for ( ; (mask&0x01); mask >>= 1 )
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--format->Rloss;
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}
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format->Gshift = 0;
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format->Gloss = 8;
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if ( Gmask ) {
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for ( mask = Gmask; !(mask&0x01); mask >>= 1 )
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++format->Gshift;
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for ( ; (mask&0x01); mask >>= 1 )
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--format->Gloss;
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}
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format->Bshift = 0;
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format->Bloss = 8;
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if ( Bmask ) {
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for ( mask = Bmask; !(mask&0x01); mask >>= 1 )
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++format->Bshift;
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for ( ; (mask&0x01); mask >>= 1 )
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--format->Bloss;
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}
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format->Ashift = 0;
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format->Aloss = 8;
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if ( Amask ) {
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for ( mask = Amask; !(mask&0x01); mask >>= 1 )
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++format->Ashift;
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for ( ; (mask&0x01); mask >>= 1 )
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--format->Aloss;
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}
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format->Rmask = Rmask;
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format->Gmask = Gmask;
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format->Bmask = Bmask;
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format->Amask = Amask;
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} else if ( bpp > 8 ) { /* Packed pixels with standard mask */
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/* R-G-B */
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if ( bpp > 24 )
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bpp = 24;
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@ -227,6 +112,52 @@ SDL_PixelFormat *SDL_AllocFormat(int bpp,
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format->Rmask = ((0xFF>>format->Rloss)<<format->Rshift);
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format->Gmask = ((0xFF>>format->Gloss)<<format->Gshift);
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format->Bmask = ((0xFF>>format->Bloss)<<format->Bshift);
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} else { /* Palettized mode */
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int i, ncolors = 1;
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for ( i = 0; i < bpp; ++i ) {
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ncolors *= 2;
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}
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format->palette = (SDL_Palette *)malloc(sizeof(SDL_Palette));
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if ( format->palette == NULL ) {
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SDL_FreeFormat(format);
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SDL_OutOfMemory();
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return(NULL);
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}
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(format->palette)->ncolors = ncolors;
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(format->palette)->colors = (SDL_Color *)malloc(
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(format->palette)->ncolors*sizeof(SDL_Color));
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if ( (format->palette)->colors == NULL ) {
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SDL_FreeFormat(format);
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SDL_OutOfMemory();
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return(NULL);
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}
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if ( ncolors == 2 ) {
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/* Create a black and white bitmap palette */
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format->palette->colors[0].r = 0xFF;
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format->palette->colors[0].g = 0xFF;
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format->palette->colors[0].b = 0xFF;
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format->palette->colors[1].r = 0x00;
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format->palette->colors[1].g = 0x00;
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format->palette->colors[1].b = 0x00;
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} else {
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/* Create an empty palette */
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memset((format->palette)->colors, 0,
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(format->palette)->ncolors*sizeof(SDL_Color));
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}
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/* Palettized formats have no mask info */
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format->Rloss = 8;
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format->Gloss = 8;
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format->Bloss = 8;
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format->Aloss = 8;
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format->Rshift = 0;
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format->Gshift = 0;
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format->Bshift = 0;
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format->Ashift = 0;
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format->Rmask = 0;
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format->Gmask = 0;
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format->Bmask = 0;
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format->Amask = 0;
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}
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return(format);
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}
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