1. 概念
矢量表示的是方向与大小，并不表示位置
1）矢量的分量--components
2）矢量--vector
3）矢量的模--magnitude
The magnitude or length of a vector r is written
4）位置矢量--Position Vectors
Given any point P(x, y, z), a position vector p is created by assuming that P is the vector’s head and the origin is its tail. As the tail coordinates are (0, 0, 0) the vector’s components are x, y, z
5）单位矢量--Unit Vectors
2. 操作
1）缩放--Scaling a Vector
2）加减--Vector Addition and Subtraction
3）单位化
4）笛卡尔矢量--Cartesian Vectors
A Cartesian vector is constructed from three unit vectors: i, j and k, aligned with the x-, y- and z-axis, respectively:
By employing the rules of vector addition and subtraction, we can compose a vector r by summing three scaled Cartesian unit vectors as follows：
相等于
5）标量积--Scalar Product/Dot Product
在计算机图形学中的应用点：
(1) 计算灯光与表面的法线之间的夹角
(2) 判断三角面的朝向是正面，还是背面
(3) 三维空间中的三角形面积计算
6）叉积--Vector Product/Cross Product
注意：叉积不满足交换律
叉积在三维世界中需要遵守右手规则
在计算机图形学中的应用点：
(1) 三角形表面的法线计算
(2) 二维空间中的三角形面积计算
