kc3-lang/SDL

2020-01-16T08:52:59

Fixed bug 4903 - Lack of color multiply with alpha (SDL_BLENDMODE_MOD + SDL_BLENDMODE_BLEND) blending mode for all renderers Konrad This kind of blending is rather quite useful and in my opinion should be available for all renderers. I do need it myself, but since I didn't want to use a custom blending mode which is supported only by certain renderers (e.g. not in software which is quite important for me) I did write implementation of SDL_BLENDMODE_MUL for all renderers altogether. SDL_BLENDMODE_MUL implements following equation: dstRGB = (srcRGB * dstRGB) + (dstRGB * (1-srcA)) dstA = (srcA * dstA) + (dstA * (1-srcA)) Background: https://i.imgur.com/UsYhydP.png Blended texture: https://i.imgur.com/0juXQcV.png Result for SDL_BLENDMODE_MOD: https://i.imgur.com/wgNSgUl.png Result for SDL_BLENDMODE_MUL: https://i.imgur.com/Veokzim.png I think I did cover all possibilities within included patch, but I didn't write any tests for SDL_BLENDMODE_MUL, so it would be lovely if someone could do it.