#version 330 core
out vec4 FragColor;

in vec3 FragPos;
in vec3 Normal;

uniform vec3 objectColor;
uniform vec3 lightColor;
uniform vec3 lightDir; /* Normalised direction vector for the light source. */

void main() {
  /* Ambient lighting (cheap, constant base light) */
  float ambientStrength = 0.3;
  vec3 ambient = ambientStrength * lightColor;

  /* Diffuse lighting (depends on angle of the surface) */
  vec3 norm = normalize(Normal);
  float diff = max(dot(norm, normalize(-lightDir)), 0.0);
  vec3 diffuse = diff * lightColor;

  vec3 result = (ambient + diffuse) * objectColor;
  FragColor = vec4(result, 1.0);
}