static constexpr bool IsBorder(int idx) {
return
- idx < Width() * Height() ||
- (idx / Width()) % Height() == 0 ||
- (idx / Width()) % Height() == Height() - 1 ||
- (idx / (Width() * Height())) == Depth() - 1;
+ idx < Width() * Height() || // low Z plane
+ idx % Width() == 0 || // low X plane
+ (idx / (Width() * Height())) == Depth() - 1 || // high Z plane
+ idx % Width() == Width() - 1 || // high X plane
+ (idx / Width()) % Height() == 0 || // low Y plane
+ (idx / Width()) % Height() == Height() - 1; // high Y plane
}
// check if block at given index is completely enclosed (and therefore invisible)