[WIP] 50 Years of Ray Tracing

用代码叙述光线追踪技术对发展历程：从1968年它诞生到2018年实时光线追踪发布

• 以历史的发展的眼光学习光线追踪技术，将其中的一些关键对推进作用对文章找出来，并进行代码实践&练习
• 提供尽量简单，直观的 CPU 算法实现；代码的简单/易理解为首位，不太考虑性能优化
• 使用现代 C++ 编程
• 一个基础库 RTKit
  • 1.0 版是完全自己在这个 repo 了一点点写起来的
  • 2.0 版将底层改用 Intel Embree 用来进行光线与场景求交

文章列表

算法名称	文件夹	作者	文章标题
Ray Casting	1968.Appel	Arthur Appel	Some techniques for shading machine renderings of solids
Recursive Ray Tracing	1979.Whitted	Turner Whitted	An improved illumination model for shaded display
Distributed Ray Tracing	1984.Cook	Robert Cook et al.	Distributed ray tracing
Path Tracing	1986.Kajiya	James Kajiya	The rendering equation
Bidirectional Light Transport	1994.Veach.BDPT	Eric Veach	Bidirectional Estimators for Light Transport
Analytic Direct Lighting	1995.Arvo	James Richard Arvo	Analytic Methods for Simulated Light Transport
Multiple Importance Sampling	1995.Veach.MIS	Eric Veach et al.	Optimally Combining Sampling Techniques for Monte Carlo Rendering
Photon Mapping	1996.Henrik	Henrik Wann Jensen	Global Illumination using Photon Maps
Monte Carlo Direct Lighting	1996.Shirley	Peter Shirley et al.	Monte Carlo Techniques for Direct Lighting Calculations
Metropolis Light Transport	1997.Vaech.MLT	Eric Veach & Leonidas Guibas	Metropolis Light Transport

工程配置

• 安装 vcpkg 及依赖库
• VSCode 配置

Ray Casting - Arthur Appel, 1968

• Resolve visibility & depth
• Lambertian shading
• Sharp shadow

Recursive Ray Tracing - Turner Whitted, 1980

• Blinn–Phong shading
• Reflection
• Refraction

Distributed Ray Tracing - Robert Cook et al., 1984

• Soft shadow
• Depth of field
• Glossy reflection
• Motion blur

Path Tracing - James Kajiya, 1986

• Monte Carlo Direct lighting
• Indirect lighting with Russian Roulette termination
• Next Event Estimation

Analytic Direct Lighting - Arvo 1995

Multiple Importance Sampling - Eric Veach et al., 1995

• TODO
• Phong Importance Sampling
• Distant Environment Lighting
• Importance Sampling GGX

My Ray Tracing Kit

• Cross platform: MacOS, Windows 10
• Multi-threaded rendering

RTKit1

• Scene object instancing
• Triangle mesh with BVH

RTKit2

• Towards Physically-based Rendering
• Embree for intersection