Image-based Lighting (IBL) of PBR Materials [Shaders Monthly #11]

In Episode #11 of Shaders Monthly, we talk about image-based lighting of the Cook-Torrance microfacet BRDF. This will allow us to implement image-based lighting for basic PBR materials in GLSL. For real-time performance, we follow closely the Siggraph 2013 tutorial "Real Shading in Unreal Engine 4" by Brian Karis: https://cdn2.unrealengine.com/Resourc... In the practical part, we implement three shaders in GLSL: 1) PrefilterSpecular GSN Composer: https://www.gsn-lib.org/index.html#pr... C++: https://www.mathematik.uni-marburg.de... Java: https://www.mathematik.uni-marburg.de... 2) BRDF Integration Map GSN Composer: https://www.gsn-lib.org/index.html#pr... C++: https://www.mathematik.uni-marburg.de... Java: https://www.mathematik.uni-marburg.de... 3) IBLSpecular GSN Composer: https://www.gsn-lib.org/index.html#pr... C++: https://www.mathematik.uni-marburg.de... Java: https://www.mathematik.uni-marburg.de... Documentation for the shader plugin node of the GSN Composer: https://gsn-lib.org/docs/nodes/Shader... Additional lecture slides: https://www.uni-marburg.de/en/fb12/re... 00:00 Introduction and Refreshers 04:16 Image-based Lighting 07:37 Importance Sampling of the GGX Normal Distribution Function 15:01 Image-based Lighting (Ground Truth Solution) 22:00 Split Sum Approximation 27:17 PrefilterSpecular (Shader 1) 34:44 BRDF Integration Map (Shader 2) 39:33 IBLSpecular (Shader 3) Source for all HDR environment maps that are used in this video: https://polyhaven.com/hdris