color.xyz = emissive + ambient + diffuse + specular;
The Basic Lighting Model
The Emissive Term 自发光
emissive=ke ； Ke is the material's emissive color.
The Ambient Term
Ambient=Ka*globalAmbient
Ka is the material's ambient reflectance and
globalAmbient is the color of incomming ambient light. 传入的环境光
The Diffuse Term
diffuse=Kd*lightcolor*max(N点乘L,0)
Kd is the material's diffuse color 材质的散射颜色
lightcolor is the color of the incomming diffuse light 传入的散射光
N is the normalized suface normal 归一化表面正常
L is normalized vector toward the light source ,and 归一化向量向光源
P is the point being shaded. 被着色点
The Specular Term
specular = Ks x lightColor x facing x (max(N · H, 0)) shininess
where:
- Ks is the material's specular color,
- lightColor is the color of the incoming specular light,
- N is the normalized surface normal,
- V is the normalized vector toward the viewpoint,
- L is the normalized vector toward the light source,
- H is the normalized vector that is halfway between V and L,
- P is the point being shaded, and
- facing is 1 if N · L is greater than 0, and 0 otherwise.