[SDL] color key broken in glSDL?

[David Olofson]

On Friday 13 October 2006 13:32, James Gregory wrote:
[...]
> I ran into this problem doing this (pseudo code):
> 
> surface1 = load_image();
> image_processing(surface1);
> surface2 = create_rgba_surface();
> blit(from surface1, to surface2);
> set_color_key(surface2);
> display_format(surface2);
> 
> I could remove the blitting across step, but then I would need to
> reload the image each time I want to do some processing and create a
> surface from it.

I see. But, why are you creating surface2 as an RGBA surface?

The correct way of doing it would be to create the surface2 using the 
pixelformat struct from surface1. Unfortunately, that doesn't quite 
cover it as a general solution, as blitting from one surface to 
another doesn't create a copy of the original, except in a few 
special cases. You need to fiddle with the colorkey and alpha 
settings of the source surface to make sure the blitter actually just 
copies pixels, without keying or blending.


//David Olofson - Programmer, Composer, Open Source Advocate

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