import msp_interface;
import _sky;

uniform sampler2D distant;

#pragma MSP stage(vertex)
void main()
{
	gl_Position = vec4(vertex.xy, 1.0, 1.0);
	mat4 inv_projection = inverse(projection_matrix);
	out vec4 view_dir = inv_projection*vec4(vertex.xy, -1.0, 1.0);
	view_dir /= view_dir.w;
	view_dir = inverse(eye_world_matrix)*vec4(view_dir.xyz, 0.0);
}

#pragma MSP stage(fragment)
void main()
{
	vec3 nview = normalize(view_dir.xyz);
	float azimuth = atan(nview.y, nview.x);
	frag_color = texture(distant, vec2(azimuth/(2*pi), nview.z*0.5+0.5))*light_color;
}