Experimenting with compositing images in SDL2, I get a dark edge
around my textures. In the image below, you can see the top
example where I composite the cyan image on top of the
blue/magenta image looks correct but the bottom example, which is
done using SDL_RenderCopy is not correct.
http://a4.pbase.com/o10/09/605909/1/166698494.lCoVTgcI.example.png
I tried premultiplying the the colors in the cyan image and
setting the blend function as such...
SDL_SetTextureBlendMode(texture, SDL_ComposeCustomBlendMode(
SDL_BlendFactor.SDL_BLENDFACTOR_ONE,
SDL_BlendFactor.SDL_BLENDFACTOR_ONE_MINUS_SRC_ALPHA,
SDL_BlendOperation.SDL_BLENDOPERATION_ADD,
SDL_BlendFactor.SDL_BLENDFACTOR_ONE,
SDL_BlendFactor.SDL_BLENDFACTOR_ONE,
SDL_BlendOperation.SDL_BLENDOPERATION_ADD));
...but that produces the exact same thing.
Any SDL experts out there that can give me a clue?
