#version 450

layout(binding = 0) uniform sampler2D tex;
layout(binding = 0) uniform samplerCube dstex;

layout(std140, binding = 0) uniform shading_state {
	vec4 diffuse;
	vec4 specular;
	float shininess;
	float fog_density;
} s;

layout(location = 0) in vec3 pos;
layout(location = 1) in vec2 tex_coord;
layout(location = 2) in vec3 world_normal;

// const float fog_density = 0.005;
const vec3 sky_color = vec3(0.35, 0.5, 0.65);

layout(location = 0) out vec4 color;

void main()
{
	/*vec4 itexel = textureCube(dstex, normalize(world_normal)); */
	vec4 itexel = texture(dstex, normalize(world_normal));

/*	vec3 p = normalize(pos); // view space dir
	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);
*/

	float dist = -pos.z;
	float fog = clamp(exp(-s.fog_density * dist), 0.0, 1.0);

	vec4 texel = texture(tex, tex_coord);

	// vec3 object_color = (diffuse.xyz * cdiff * texel.xyz + specular.xyz * cspec) * itexel.xyz;
	vec3 object_color = s.diffuse.xyz * texel.xyz * itexel.xyz;

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