#version 450

uniform sampler2D tex;
uniform samplerCube dstex;

uniform vec4 diffuse;
// uniform vec4 specular;
// uniform float shininess;

uniform float fog_density;
const vec3 sky_color = vec3(0.35, 0.5, 0.65);

varying vec3 pos;
// varying vec3 normal;
// varying vec3 ldir;
varying vec2 tex_coord;
varying vec3 world_normal;

out vec4 color;

void main()
{
	vec4 itexel = textureCube(dstex, normalize(world_normal));
	// vec3 p = normalize(pos);
	// vec3 n = normalize(normal);
	// vec3 l = normalize(ldir);

	// vec3 r = normalize(-reflect(l, n));
	// vec3 vdir = normalize(-p);

	// float cdiff = max(dot(l, n), 0.0);
	// float cspec = pow(max(dot(r, vdir), 0.0), shininess);

	vec4 texel = texture2D(tex, tex_coord);
	// vec3 object_color = diffuse.xyz * cdiff * texel.xyz + specular.xyz * cspec;
	vec3 object_color = diffuse.xyz * texel.xyz * itexel.xyz;
	float dist = -pos.z;
	float fog = clamp(exp(-fog_density * dist), 0.0, 1.0);

	color.xyz = mix(sky_color, object_color, fog);
	color.w = 1.0;
}