‘Advanced Global Illumination’reading notes 4-优快云博客

本文链接：https://blog.youkuaiyun.com/saintony/article/details/5562006

本文探讨了多种混合全局光照算法，包括结合光线追踪与光子映射的方法，利用辐射缓存加速计算的技术，以及使用即时辐射度等创新方案。此外还介绍了由康奈尔大学Kavita Bala教授提出的Lightcuts算法，该算法通过简化场景中的光源来大幅提升性能。

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Chapter 7 covers a wide range of hybrid algorithms of GI, which are more interesting and subtle. With the former single pass techniques as the base weapon, this chapter broadens my brain with creative combinations of the one-pass algorithms.

For example:

1. you can finish the first pass by regular ray-tracing, and conduct the second pass focusing on caustics generation by light-tracing;

2. you can speed up the GI calculation using irradiance caching for some specific locations and use interpolation for the pixels between the locations - this will result a high speed up for some situations;

3. Photon mapping, the powerful tool to generate caustics, and it is also helpful for global diffuse illumination;

4. Instant Radiosity - it is quite naughty algorithm: it just puts a point light on the hit points on the specular surfaces...

5. Lightcuts: this is a cutting-edge performance boost algorithm proposed by Prof. Kavita Bala from Cornell University. Since we have so complex scenes, we have simplify the lights - the most important factor for GI - by simulating many lights into a single light...and the result images are almost the same while the time cost is much much less now...

All right, the last chapter will discuss some current research on GI (including the famous Ambient Occlusion)- I think it will be more interesting.