How does OpenGL, GLX, and Mesa fit into the DRI?
OpenGL is the SGI standard graphics API which has been implemented many times for many different hardware systems. Applications link into OpenGL and cause their graphical output to be displayed on the computer screen by calling functions defined in the OpenGL API. GLX is the graphics library extension to X which allows OpenGL and the X Window System to funtion together. An implementation of GLX is necessary in order to run OpenGL under X. The implementation used in the DRI is the official GLX implementation created by SGI. Mesa 3.1 is an implementation of a very complete 3D drawing library, which exposes a clone of the OpenGL API to applications. It can be used in most cases as a substitute for an official OpenGL implementation, and is used in this project because it can be released in open sourc. That allows it to be included with the XFree86 X Server distribution. The DRI does not alter the OpenGL API, however, it does include modifications to GLX and Mesa 3.1 which are transparant t
