Games101: Computer Graphics-Week 4
Recap and supplement
对于旋转变换，逆时针旋转θ角度和顺时针旋转θ角度的矩阵恰好为正交矩阵，此时矩阵的转置和矩阵的逆相等。
为了统一平移变换和线性变换的书写形式，引入齐次坐标的概念，实质是增加一个维度；
3D Transformations
On homogeneous coordinates, 3D points/vectors can be described as :
- 3D point = $ (x, y, z, 1)^T$
- 3D vector = $ (x, y, z, 0)^T $
- In general, if $ (x, y, z, w)^T $ ($ w \neq 0$ and $w \neq 1$), which refers the same point $(x/w, y/w, z/w, 1)^T $