I want to create an effect of a circular light - no projections, no OpenGL, thank you - in my game, much like the Zelda:
I was able to create the effect with a single light source. I have a dark surface and one with a transparent gradient circle that I blend on the first using SDL_BLENDMODE_NONE, then I blend the dark texture into the screen:
The problem is that, when I have two of them, the intersection if mixed:
So, my idea is to create an image with a white circle using gradient to transparent, and subtract the alpha, in my black surface, from the white pixels in the image.
But I could not figure out how to do that. I tried different combinations of custom blend, and still I am unable to do so.
So, in short my question is:
Given a dark texture, I want to use custom blend to make transparent all white pixels from a second texture, respecting its alpha level. Do anyone knows how to do that?
Thanks in advance.