src/video/SDL_blit.h
changeset 3625 83910f4c373f
parent 3437 dc2911c207e4
child 3631 76667e288846
equal deleted inserted replaced
3624:9b1af1049f66 3625:83910f4c373f
   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)