I am implementing deferred shading and tring to blend the results of each light into an FBO. My goal is to end up with an FBO that contains the contribution for each light in the scene.
The problem I am having is when I turn on blending, it seams that everything runs in software… I get below 3 FPS…
Is it possible to do GL_BLEND + glBlendFunc(GL_ONE, GL_ONE) in FBO’s??
Sounds like you are using blending with a floating point render target on a hardware that doesn´t support it.
nVidia supports this since the 6000’ series, ATI since the Xxxx series.
nVidia used to add “ForceSW” (or something similar) to the value returned when you got the Vendor string using glGetString(). I don’t know if they still do this.
It seems, the Quadro FX4000 is based on Geforce6800-like chips (NV40), so your card should at least support blending on FP16 render targets. Check, if you are maybe using FP32…