[SDL] Blit only alpha component

Amir Cicak krib at lappasoft.com
Sun Sep 11 12:23:05 PDT 2005


Hello,

I want to make hole in one surface by blitting aplha from another surface on 
that surface, so when I blit first surface to display aplha mask from 2. 
surface apears transparent. All my surfaces are per pixel alpha. So basicaly I 
need to copy alpha component from one surface to another one, but using Blit, 
not by locking surfaces and going through pixels, since I noticed this is too 
slow even if my both surfaces are in sys memory. Is there fast way to do this 
(if its not possible to blit) because I must do it in runtime (I cant do it in 
load time).

Thank you in advance...





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