WebGL Beginner's Guide - Chapter 3

Phong Shading + Phong Lighting

Light Color (Light Diffuse Term):			Sphere Color (Material Diffuse Term):
Light Ambient Term:	0.03		Material Ambient Term:	1.0
Light Specular Term:	1.0		Material Specular Term:	1.0
X:	0		Shininess:	230
Y:	-1.0		Background Color (gl.clearColor):
Z:	-1.0

This model has three terms:

• Ia: ambient term
• Id: diffuse term
• Is: specular term

Unlike the Goraud interpolation that calculates a final color per-vertex, the Phong interpolation calculates a final color per-pixel.

If you explore the source code for the Vertex Shader and the Fragment Shader you will see that the heavy processing occurs this time in the fragment shader

For the sake of simplicity we have omitted the Light Specular property