Date: Thu, 4 Nov 1999 15:33:40 +0100

I am new to graphics programming and have some problems.

When displaying png’s with alpha channel things get really slow.


  • If ‘flag’ is (SDL_SRCALPHA|SDL_MULACCEL), alpha blending is enabled
  • with alpha pre-multiplication enabled.*
  • Alpha blend premultiplication is an optimization that cuts the actual
  • alpha blend operation in half. There are a couple of drawbacks however.

SDL_MULACCEL is not defined anywhere.
Is this a feature not implemented yet?

Is ther any other way to speed up alpha blending?

Robert Hopland