$L_0(\mathbf{v})=\pi\rho(\mathbf{l_c},\mathbf{v})\otimes\mathbf{c}_{light}(\mathbf{n}\cdot\mathbf{l_c})$

## 对比

$L_{o}(\mathbf{v})=(\mathbf{c}_{diff}(\mathbf{n}\cdot\mathbf{l_c})+\mathbf{c}_{spec}(\mathbf{r_v}\cdot\mathbf{l_c})^{\alpha})\otimes\mathbf{c}_{light}$

$L_{o}(\mathbf{v})=(\mathbf{c}_{diff}+\mathbf{c}_{spec}(\mathbf{r_v}\cdot\mathbf{l_c})^{\alpha})\otimes\mathbf{c}_{light}(\mathbf{n}\cdot\mathbf{l_c})$

$L_{o}(\mathbf{v})=(\mathbf{c}_{diff}+\pi\mathbf{c}_{spec}(\mathbf{n}\cdot\mathbf{h})^{\alpha})\otimes\mathbf{c}_{light}(\mathbf{n}\cdot\mathbf{l_c})$

$\mathbf{c}_{diff}=\pi\frac{\mathbf{c}_{diff}}{\pi}$

$L_{o}(\mathbf{v})=\pi(\mathbf{n}\cdot\mathbf{h})^{\alpha}\mathbf{c}_{spec}\otimes\mathbf{c}_{light}(\mathbf{n}\cdot\mathbf{l_c})$

$L_{o}(\mathbf{v})=\pi\frac{D(\mathbf{h})G(\mathbf{l_c},\mathbf{v},\mathbf{h})}{4(\mathbf{n}\cdot\mathbf{l_c})(\mathbf{n}\cdot\mathbf{v})}F(\mathbf{c}_{spec},\mathbf{l_c},\mathbf{h})\otimes\mathbf{c}_{light}(\mathbf{n}\cdot\mathbf{l_c})$

$(\mathbf{v}\cdot\mathbf{n})=\int_{\Theta}D(\mathbf{m})(\mathbf{v}\cdot\mathbf{m})\domega_m$

$1=\int_{\Theta}D(\mathbf{m})(\mathbf{n}\cdot\mathbf{m})\domega_m$

Blinn-Phong的项如果也要满足这个方程，就得乘上一个归一化系数：

$D_{BP}=\frac{\alpha+2}{2\pi}(\mathbf{n}\cdot\mathbf{m})^{\alpha}$

$\frac{G(\mathbf{l_c},\mathbf{v},\mathbf{h})}{(\mathbf{n}\cdot\mathbf{l_c})(\mathbf{n}\cdot\mathbf{v})}$

$G_{implicit}(\mathbf{l_c},\mathbf{v},\mathbf{h})=(\mathbf{n}\cdot\mathbf{l_c})(\mathbf{n}\cdot\mathbf{v})$

$L_{o}(\mathbf{v})=\frac{\alpha+2}{8}(\mathbf{n}\cdot\mathbf{h})^{\alpha}F(\mathbf{c}_{spec},\mathbf{l_c},\mathbf{h})\otimes\mathbf{c}_{light}(\mathbf{n}\cdot\mathbf{l_c})$

$L_{o}(\mathbf{v})=(\mathbf{c}_{diff}+\frac{\alpha+2}{8}(\mathbf{n}\cdot\mathbf{h})^{\alpha}F(\mathbf{c}_{spec},\mathbf{l_c},\mathbf{h}))\otimes\mathbf{c}_{light}(\mathbf{n}\cdot\mathbf{l_c})$