anchor.diff:  const int MAX_POINT_LIGHTS = 5;
   const int MAX_SPOT_LIGHTS = 5;
   
  +in vec2 outTexCoord;
   in vec3 vNorm;
   in vec3 vPos;
   
  
positive.code: struct Material
  {
      vec3 color;
      float reflectance;
  };
  
  uniform vec3 ambientLight;
  uniform float specularPower;
  uniform Material material;
  
negative.code: {
      return calcLightColour(light.colour, light.intensity, position, normalize(-light.direction), normal);
  }
  vec4 calcBaseColour(Material material, vec2 text_coord)
  {
      vec4 baseColour;
      if ( material.hasTexture == 1 )
      {
          baseColour = texture(texture_sampler, text_coord);
      }
      else
      {
          baseColour = vec4(material.colour, 1);
      }
      return baseColour;
  }
  
  void main()
  {
      vec4 baseColour = calcBaseColour(material, outTexCoord);
  
      vec4 totalLight = vec4(ambientLight, 1.0);
      totalLight += calcDirectionalLight(directionalLight, vPos, vNorm);
  
  