Blendmodes(specifically BLENDMODE_SCREEN) - what open gl functions do they translate to?

Hey all!

Hope everyone had a good holiday and is ready for the new year ahead!

To my question - I was curious if I was looking in the right spot in regards as to what the various blendmode enums translate to in terms of OpenGL calls.

I’m trying to port some bits of code into a non oF environment and looking at the source, for OF_BLENDMODE_SCREEN, it should, I believe , translate to the following -
(note - code I’m porting is using the programmable renderer)

glEnable(GL_BLEND); glBlendEquation(GL_FUNC_ADD); glBlendFunc(GL_ONE_MINUS_DST_COLOR, GL_ONE);

However, when trying to use these functions, the result in the codebase I’m porting to is the same as if I had used OF_BLENDMODE_ALPHA.

Not sure if the problem lies elsewhere, but I just wanted to at least confirm those are the right GL calls to make sure I’m re-creating OF_BLENDMODE_SCREEN correctly.


Ah! never mind.

I’m dealing with a buncha FBOs and shaders so I thought that the issues I’m having had something to do with incorrect values being written to the fbos through blending, but it looks like the problem more likely lies in a surprisingly unexpected other area.