/// <summary>
/// Creates a new bitset for entity, sets the bitset for no components, and pushes it onto the free entities stack.
/// This method should be called in a loop over all entities and should include the initialization of a new component
/// at the index of the entity in that component array.
/// </summary>
/// <param name="entity">Entity to initialize.</param>
protected virtual void Initialize(uint entity)
{
EntityMasks[entity] = new BitSet();
EntityMasks[entity].SetBit(ComponentType.NoComponents);
_freeEntities.Push((uint)entity);
}
/// <summary>
/// Determines whether all of the bits in this instance are also set in the given bitset.
/// </summary>
/// <param name="other">The bitset to check.</param>
/// <returns><c>true</c> if all of the bits in this instance are set in <paramref name="other"/>; otherwise, <c>false</c>.</returns>
public bool IsSubsetOf(BitSet other)
{
if (other == null)
throw new ArgumentNullException("other");
var otherBits = other.bits;
int count = Math.Min(bits.Length, otherBits.Length);
for (int i = 0; i < count; i++)
{
uint bit = bits[i];
if ((bit & otherBits[i]) != bit)
return false;
}
// handle extra bits on our side that might just be all zero
int extra = bits.Length - count;
for (int i = count; i < extra; i++)
{
if (bits[i] != 0)
return false;
}
return true;
}