In Figure 1. and Figure 2. Render Manages operations used to create 2D picture, sends informations about avatar's position and view direction to global shader, updates frame-buffer etc. GlobalShader Solves global illumination. This object usually prepares informations for local shader. LocalShader Computes color of entire patch.
Computation uses informations taken from light model.
LightModel Computes color of one point. Light Light source. Can be dot light, directional light or spot light. Instance of this class returns light intensity in given 3D point. GeomArch Geometric architecture.