Mercurial > sdl-ios-xcode
comparison src/video/SDL_blit.h @ 3625:83910f4c373f
Merged r4992:4993 from branches/SDL-1.2: increased alpha blend accuracy.
author | Ryan C. Gordon <icculus@icculus.org> |
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date | Sun, 10 Jan 2010 06:18:39 +0000 |
parents | dc2911c207e4 |
children | 76667e288846 |
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3624:9b1af1049f66 | 3625:83910f4c373f |
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442 } | 442 } |
443 | 443 |
444 /* Blend the RGB values of two Pixels based on a source alpha value */ | 444 /* Blend the RGB values of two Pixels based on a source alpha value */ |
445 #define ALPHA_BLEND(sR, sG, sB, A, dR, dG, dB) \ | 445 #define ALPHA_BLEND(sR, sG, sB, A, dR, dG, dB) \ |
446 do { \ | 446 do { \ |
447 dR = ((((int)(sR-dR)*(int)A)/255)+dR); \ | 447 dR = (((((int)(sR-dR)*((int)A))+255)/255)+dR); \ |
448 dG = ((((int)(sG-dG)*(int)A)/255)+dG); \ | 448 dG = (((((int)(sG-dG)*((int)A))+255)/255)+dG); \ |
449 dB = ((((int)(sB-dB)*(int)A)/255)+dB); \ | 449 dB = (((((int)(sB-dB)*((int)A))+255)/255)+dB); \ |
450 } while(0) | 450 } while(0) |
451 | 451 |
452 | 452 |
453 /* This is a very useful loop for optimizing blitters */ | 453 /* This is a very useful loop for optimizing blitters */ |
454 #if defined(_MSC_VER) && (_MSC_VER == 1300) | 454 #if defined(_MSC_VER) && (_MSC_VER == 1300) |