Shader chunk to add to the head of a fragment shader to be able to use Phong shading.

var color: vec3f = vec3(1.0);
let specularColor: vec3f = vec3(1.0);
let specularStrength: f32 = 1.0;
let shininess: f32 = 32.0;
color = getPhong(normal, worldPosition, color, viewDirection, specularColor, specularStrength, shininess);