#version 440

layout(location=0) in vec3 coord3d;
layout(location=1) in vec3 v_normal;
layout(location=2) in vec3 v_color;
layout(location=3) in vec2 v_texmap;

out vec3 reflectDir;
out float reflectFactor;

out vec3 refractDir_R;
out vec3 refractDir_G;
out vec3 refractDir_B;

uniform vec3 RefractionIndex;
uniform mat4 ModelMatrix;
uniform mat4 mvp;
uniform bool DrawSkyBox;

uniform vec3 WorldCamPos;

void main(void)
{		

//For drawing a mesh with reflected skybox
	if (DrawSkyBox == true)	
		reflectDir = coord3d;
	else
	{
		vec3 P = (ModelMatrix * vec4(coord3d, 1)).xyz;
		vec3 N = normalize(ModelMatrix * vec4(v_normal, 1)).xyz;
		vec3 V = normalize(WorldCamPos - coord3d);

		float R0 = pow(1 - 1.5,2) / pow(1 + 1.5, 2);
		reflectFactor = R0 + (1 - R0) * pow(1 - dot(V, N), 5);

		reflectDir = reflect(-V, N);
		refractDir_R = refract(-V, N, RefractionIndex.r);
		refractDir_G = refract(-V, N, RefractionIndex.g);
		refractDir_B = refract(-V, N, RefractionIndex.b);
	}

	gl_Position = mvp * vec4(coord3d, 1.0f);
}