This is a great book I have read in past. It primarily focuses on underlying math for interactive graphics but you will notice it will also touch photo-realism

This is a great book I have read in past. It primarily focuses on underlying math for interactive graphics but you will notice it will also touch photo-realism later. Indeed, it describes how raytracing works at chapter 10 "The Lighting Equation: Putting It All Together" and covers wide span of graphics knowledge.