The PBR Guide: A Handbook for Physically Based Rendering;

This book, written by Wes McDermott and cross-checked by experts in the field, outlines the principles of physically based rendering and shading (PBR) and provides practical guidelines for PBR texturing. The first part of the book addresses the principles underlying physically based rendering, starting with a light ray and working up to the definition of key factors for proper PBR. This part is essential to texture artists for understanding how light interacts with objects. The second part offers practical guidelines for PBR texturing, which are based on the foundations established in the first part: redefinition of PBR from an artistic perspective; discussion of the metal/roughness and specular/glossiness workflows, and recommendations for authoring physically accurate texture maps.