Let's summarize what we have learned in this chapter:
There is no camera object in WebGL. However, we can build one using the Model-View matrix.
3D objects undergo several transformations to be displayed on a 2D screen. These transformations are represented as 4x4 matrices.
Scene transformations are affine. Affine transformations are constituted by a linear transformation followed by a translation. WebGL groups affine transforms in three matrices: the Model-View matrix, the Perspective matrix, and the Normal matrix and one WebGL operation: gl.viewport().
Affine transforms are applied in projective space so they can be represented by 4x4 matrices. To work in projective space, vertices need to be augmented to contain an extra term, namely, w, which is called the perspective coordinate. The 4-tuple (x,y,z,w) is called homogeneous coordinates. Homogeneous coordinates allows representation of lines that intersect on infinity by making the perspective coordinate w = 0. Vectors always have...