Because you can do so many things with OpenGL, an OpenGL program can potentially be large and complicated. However, the basic structure of all OpenGL applications is usually similar to the following:
• Initialize the state associated with how objects should be rendered.
• Specify those objects to be rendered.
Before you look at some code, let’s introduce some commonly used graphics terms. Rendering, which we’ve already used without defining previously, is the process by which a computer creates an image from models. OpenGL is just one example of a rendering system; there are many others. OpenGL is a rasterization-based system, but there are other methods for generating images as well, such as ray tracing ...