#version 450

#define SHADING_UNIFORMS 1

layout(binding = 0) uniform sampler2D tex;
layout(binding = 1) uniform samplerCube dstex;

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

/* varyings */
layout(location = 4) in vec3 pos;
layout(location = 5) in vec2 tex_coord;
layout(location = 6) in vec3 world_normal; 

layout(location = 0) out vec4 color;

const vec3 sky_color = vec3(0.35, 0.5, 0.65);

void main()
{
	vec4 itexel = texture(dstex, normalize(world_normal));
	vec4 texel = texture(tex, tex_coord);
	vec3 object_color = s.diffuse.xyz * texel.xyz * itexel.xyz;
	float dist = -pos.z;
	float fog = clamp(exp(-s.fog_density * dist), 0.0, 1.0);

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