Reflective Shadow Mapping (RSM)

基本思想:

Shadow Map 可以告诉我们这些信息,对上面所有的点对 $p$ 点的贡献求和。上面的任何一个像素,对应一个小片(small surface patch / like an area light)。

Limit:

Assumption:

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注意 $p$ 点是 shading point,$q$ 点在 shadow map 上。我们假设的是 $q$ 点是 diffuse reflector。

Reflective Flux = Li

Reflective Flux = Li

$$ L_o(p,w_o) =\int_{\Omega_{patch}}L_i(p,w_i)f_r(p,w_i,w_o)\cos\theta_i\mathrm{d}w_i\\ = \int_{A_{patch}}L_i(q \rightarrow p)f_r(p, q\rightarrow p, w_o)\frac{\cos\theta_p\cos\theta_q}{||q - p||^2}\mathrm{d}A\\ $$

Precomputation:

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