Chapter 5, color calculations

@carlos

One of the nice things about creating your own shaders is that, as long as you’re not attempting physically based lighting, you can define what looks right to you, and I would encourage everyone to play around with the calculations in the shader. I don’t always use the same strict values, and as you suggest, yours is probably a nicer result here :clap: :slight_smile:

The Phong shader is not a physically realistic one, and neither is your result. One of the properties of a physically realistic renderer is energy conservation, which means that the energy emitted cannot be greater than the energy received. (see Adopting a physically based shading model | Sébastien Lagarde)

If you are going for physically realistic (PBR), then I would recommend the seminal book which is now available free online: Physically Based Rendering by Matt Pharr, Wenzel Jakob, and Greg Humphreys: http://www.pbr-book.org. Also the more approachable PBR guide from Allegorithmic: The PBR Guide - Part 1 on Substance 3D Tutorials

Your suggestion of the first argument error, I hope to update in the next version of the book. I made a diagram of the cone direction: Chapter 5, cone direction - #2 by caroline. As long as the math is correct, it isn’t an error, but, as you say, could be clearer.

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