Rectangle Intersection

bool Rect::DoesIntersect( const Rect& other ) const
{
	//see which rectangle is 'bigger' - this is done as the bigger
	//rect can never lie completely inside the smaller

	unsigned int this_area = Width() * Height();
	unsigned int other_area = other.Width() * other.Height();

	const Rect* a;
	const Rect* b;

	if( this_area > other_area )
	{
		a = this;
		b = &other
	}
	else
	{
		a = &other
		b = this;
	}

	//rect 'a' can never lie completely 'inside' rect 'b'

	//check top-left point
	if( b->top >= a->top && b->top <= a->bottom )
		if( b->left >= a->left && b->left <= a->right )
			return true;

	//check top-right point
	if( b->top >= a->top && b->top <= a->bottom )
		if( b->right >= a->left && b->right <= a->right )
			return true;

	//check bottom-left point
	if( b->bottom >= a->top && b->bottom <= a->bottom )
		if( b->left >= a->left && b->left <= a->right )
			return true;

	//check bottom-right point
	if( b->bottom >= a->top && b->bottom <= a->bottom )
		if( b->right >= a->left && b->right <= a->right )
			return true;

	return false;
}