#ifdef GL_ES
// Set default precision to medium
precision mediump int;
precision mediump float;
#endif

uniform mat3 n_matrix;
uniform sampler2D texture;

uniform struct Light {
	vec3 position;
	vec3 intensities;
} light;

uniform bool b_transparent;
uniform bool b_light;

varying vec2 v_surfaceUV;
varying vec3 v_surfacePosition;
varying vec3 v_surfaceNormal;

void main()
{
	// variables
	vec3 diffuse;

	// get fragment color from texture
	vec4 surfaceColor = vec4(texture2D(texture, v_surfaceUV));

	// if not transparent, ignore alpha value and set it to 1
	if(!b_transparent)
		surfaceColor.a = 1.0f;

	if(b_light)
	{
		// calculate normals in worldspace
		vec3 normalWorld = normalize(n_matrix * v_surfaceNormal);

		//get the surface - light vector (cause this is a point light)
		vec3 surfaceToLight = normalize(light.position - v_surfacePosition);

		// calculate the brightness depending on the angle
		float diffuseCoefficient = max(0.0, dot(normalWorld, surfaceToLight));

		// result diffuse color
		diffuse = diffuseCoefficient * surfaceColor.rgb * light.intensities;
	}
	else
	{
		diffuse = surfaceColor.rgb;
	}

	// put all together
	gl_FragColor = vec4(diffuse, surfaceColor.a);
}