//     影作成シェーダ
//        ver 1.2 2020/09/06
//        by yarunashi@dooon

// xs_begin
// author : 'yarunashi@dooon'
// arg : { id = '0' name = 'pitch' value = '50' range = '-90 90' step = '1'	decimal = '0' }
// arg : { id = '1' name = 'yaw' value = '50' range = '0 360' step = '1' decimal = '0' }
// arg : { id = '2' name = 'onlyshadow' value = '0' range = '0 1' step = '1' decimal = '0' }
// xs_end

float pitch = radians(i_args[0]); 
float yaw = radians(i_args[1]); 
float onlyshadow = i_args[2]; 


float map(vec3 v){
    if (onlyshadow == 0.0 && voxel(v) > 0.0) return voxel(v);

    if (v.z >= 1.0) return 0.0;

    float z = sin(pitch);
    float tmp = cos(pitch);
    float y = tmp * -cos(yaw);
    float x = tmp * sin(yaw);
    vec3 dt = normalize(vec3(x, y, z));

    vec3 lay = vec3(v.x, v.y, 0.0);
    while(true) {
        if (voxel(lay) > 0.0f) return i_color_index;
 
        lay = lay + dt;

        if (lay.z < 0.0f || lay.z > i_volume_size.z) break;
        if (lay.y < 0.0f || lay.y > i_volume_size.y) break;
        if (lay.x < 0.0f || lay.x > i_volume_size.x) break;
    }
    return 0.0;
}