Ive read various papers on deferred shading, some blend lighting directly into back buffer, others build a summed lighting buffer to be used later in post processing, plus an additional specular buffer.
What are some options for providing these intermediate lighting buffers when using a framebuffer object gbuffer, assuming the gbuffer already has a depth texture, and 3 - 4 render targets attached and being used. I ask because the number of fullscreen texture buffers seems to be mounting the more I read, which obviously gets worse as the screen res goes up.
DepthTexture, RenderTexture0, RenderTexture1, RenderTexture2, RenderTexture3, SummedLightingTarget, SpecularLightingTarget
Would it be an expensive operation to detach a couple of the gbuffer rendertextures temporarily and replace them with lighting textures to fill? Then reattach the orginal buffers.
Or would it make more sense to use a entirely different FBO for the intermediate lighting? Or something else?