Thank you for your answers. I've abandoned the idea of using that particular blend mode. I have come to understand more about shaders, so it was not for naught.

Thank you for replying. After looking at slime's bloom shader and Photoshop math , I came up with this: #define BlendScreenf(base, blend) (1.0 - ((1.0 - base) * (1.0 - blend))) #define Blend(base, blend, funcf) vec3(funcf(base.r, blend.r), funcf(base.g, blend.g), funcf(base.b, blend.b)) #define Blen...

Is is possible in 0.8 to set the blend mode to what in Photoshop is known as screen (GL_ONE, GL_ONE_MINUS_SRC_COLOR)? Painting grey (0.5) over grey (0.5) should result in grey-white (0.75).