public override bool Collide(CircleMask mask, float dx = 0, float dy = 0)
{
Rectangle range = mask.Bounds;
range.Offset((int)(-AbsoluteLeft - dx), (int)(-AbsoluteTop - dy));
int xStart = (int)(range.X / CellWidth);
int yStart = (int)(range.Y / CellHeight);
int xEnd = (int)((range.X + range.Width - 1) / CellWidth);
int yEnd = (int)((range.Y + range.Height - 1) / CellHeight);
Rectangle box = new Rectangle(0, 0, (int)CellWidth, (int)CellHeight);
Vector2 shiftedPosition;
for(int x = xStart; x <= xEnd; ++x)
for (int y = yStart; y <= yEnd; ++y)
{
if (this[x, y])
{
box.X = (int)(x * CellWidth + AbsoluteLeft + dx);
box.Y = (int)(y * CellHeight + AbsoluteTop + dy);
shiftedPosition = box.Closest(mask.AbsolutePosition);
if (shiftedPosition.LengthSquared(mask.AbsolutePosition) <= (mask.Radius * mask.Radius))
return true;
}
}
return false;
}