Really Basic OpenGL Post-Processing C++ Class for my Half-Life mod that can process multiple PP shaders

Hello. I need a really basic post-processing class (C++ and OpenGL) for my Half-Life mod for multiple PP shaders with dynamic intensities. If you need to hardcode them, grayscale and chromatic aberration. But shaders are optional, I just need the class. (An example shader for understanding/testing the system would be great) Git Repo: [login to view URL] Framebuffers are not present within the Half-Life engine itself, so rendering the screen to texture in the Half-Life engine can be found in this tutorial: [login to view URL] Ignore the obsolete CG stuff in the article and don't use CG please. GLUT would be easier since it's already used in the project.