How do I create a downscaled copy of an FBO in OpenGL?
- by Jasper Bekkers
Hi,
In order to speed up some post-processing shaders I'm using, I need to perform these operations on a framebuffer that is smaller in size than the actual window (about 1/4th or more). Most of the effects I want to optimize are simple blurring operations that could be replaced (for a large part) by smaller kernel and bilinear filtering. Thus, I need to create a copy of the current FBO into another one. However, I couldn't find anything, that works, on how to do this.
I've tried using glBlitframebufferEXT and rendering a fullscreen quad into the other framebuffer, but both paths result in a black texture as output. How do I go about solving this problem?
