Phong Specular

Learn core lighting terms (diffuse/specular/rim) on a simple sphere.

Overview

• Compute lighting terms and shade a shape.

Learning Objectives

• Understand the math behind the lighting term

Prerequisites

• lambert-sphere

Key Concepts

• Diffuse lighting uses max(dot(n, l), 0.0).

float diff = max(dot(n, lightDir), 0.0);

• Specular highlights use pow (Phong/Blinn-Phong).

float spec = pow(max(dot(r, v), 0.0), shininess);

How To Implement (Step-by-step)

• Get normal n and a normalized light direction.
• Compute diffuse term with dot(n, l).
• Optionally compute specular with pow.
• Combine terms and output.

Self-check

• Does it compile without errors?
• Does the output match the goal?
• Are key values kept in [0,1]?

Common Mistakes

• Clamp t into [0,1] when needed.