shader_type spatial;
render_mode unshaded, cull_disabled, blend_mix;

uniform float mist_level = 0.0;
uniform vec4 mist_color : hint_color = vec4( 1.0, 0.0, 1.0, 1.0 );
uniform float mist_height = 0.0;
uniform float mist_distance = 25.0;

varying mat4 CAMERA;

void vertex() 
{
    POSITION = vec4(VERTEX, 1.0);
    CAMERA = CAMERA_MATRIX;
}

void fragment()
{
    float depth = texture(DEPTH_TEXTURE, SCREEN_UV).x;
    vec3 ndc = vec3(SCREEN_UV, depth) * 2.0 - 1.0;

    vec4 view = INV_PROJECTION_MATRIX * vec4(ndc, 1.0);
    view.xyz /= view.w;
    float linear_depth = -view.z;
    
    vec4 world = CAMERA * INV_PROJECTION_MATRIX * vec4(ndc, 1.0);
    vec3 world_position = world.xyz / world.w;
    
    if ( linear_depth*mist_level <= mist_distance )
    {
        ALBEDO = vec3( 1.0, 0.0, 1.0 ) * mist_level;
        ALPHA = (linear_depth*mist_level)/mist_distance;
    }
    else
    {
        ALBEDO = vec3( 1.0, 0.0, 1.0 );
        ALPHA = 1.0;
    }
//    if ( world_position.y > 0.2 && world_position.y >= mist_height )
//    {
//        ALPHA *= mist_height/world_position.y;
//    }
}