OpenGL FrameBuffer Object 101
by Rob 'phantom' Jones

Contents   Introduction   Adding a Depth Buffer   Adding a Texture To Render To   Rendering to Texture   Using The Rendered To Texture   Cleaning Up   Source code   Printable version   Discuss this article The Series   OpenGL Frame Buffer Object 101   OpenGL Frame Buffer Object 201

Introduction

The Frame Buffer Object (FBO) extension was introduced to make Render to Texture objects much more efficient and much easier to perform when compared with the copying or pbuffer alternatives.

In this little article I’m going to give you a quick over view of how to use this extension and some things to keep in mind when using it so you can add faster Render to Texture functionality to your OpenGL programs.

Setting Up

As with the other objects in OpenGL (texture object, pixel buffer objects and vertex buffer object) before you can use a FBO you have to create a valid handle to it:

GLuint fbo;
glGenFramebuffersEXT(1, &fbo);

To perform any operations on a FBO you need to bind it, much like you would a VBO or texture, so that the operations can be performed on it, this is done via the following code

glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo);

The first parameter is the ‘target’ you wish to bind the framebuffer to, right now the only target you can use is the one indicated above however it is possible future extensions might allow you to bind it somewhere else. The fbo variable holds the handle to the FBO we requested earlier. To perform any FBO related operations you need to have a FBO bound or the calls will fail.

Adding a Depth Buffer