{
    output : "vec2",
    input  : {
        scale  : [ "vec2",   [ 1, 1 ],     "scale" ],
    }
}
<source>        
    // Hard-coded while in development
    vec3 position = fragPositionOc;

    // Convert to spherical coordinates.  Note in this definition
    // theta runs along the z axis and phi is in the xy plane.
    float r = length(position);
    float phi = atan(position.y, position.x);
    float theta = acos(position.z / r);

    // Normalize to [0-1) range
    vec2 uv = vec2(1.0, 1.0);
    uv.x = (phi + PI) / (2.0 * PI);
    uv.y = theta / PI;
    return scale * uv;
</source>