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

var color: vec4f = vec3(1.0);
let specularColor: vec3f = vec3(1.0);
let specularIntensity: f32 = 1.0;
let shininess: f32 = 30.0;

color = getPhong(normal, worldPosition, color, viewDirection, specularIntensity, specularColor, shininess);