Real-Time 3D Graphics with WebGL 2 - Second Edition

Perspective Division

Once it has been determined how much of the viewing space will be rendered, the frustum is mapped into the near plane in order to produce a 2D image. The near plane is what is going to be rendered on your computer screen.

Different operative systems and displaying devices can have mechanisms to represent 2D information on screen. To provide robustness for all possible cases, WebGL and OpenGL ES provide an intermediate coordinate system that is independent from any specific hardware. This space is known as the Normalized Device Coordinates (NDC).

Normalized device coordinates are obtained by dividing the clipping coordinates by the w component. This is why this step is known as perspective division. Also, please remember ...