Hello, right now im porting my engine from DX to OpenGL and I have encountered some difficulties with glBlendfunc.
Primarily I have 2 questions
From the docs:
glBlendFunc defines the operation of blending for all draw buffers when it is enabled. glBlendFunci defines the operation of blending for a single draw buffer specified by buf when enabled for that draw buffer.
which of the two calls is dominating the other one? Or how will my rendertarget in slot 0 be blended if I set glBlendFunc (GL_ZERO, GL_ONE) AND glBlendFunci (0, GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)? Is this behaviour well defined?
I have tested a simple scene using blending. Configuring the pipeline state with glBlendFunci instead of glBlendFunc causes serious performace issues dropping fps from >250 to 0.5. I find it hard to explain, since the funcionality should be supported (I'm running a 3.3 core context on a GeForce 9800 GT). I'd like to know if someone here knows any hints regarding this.
Thanks in advance!