rect_tree_intersects_tree()

int rect_tree_intersects_tree	(	const RECT_NODE *	n1,
		const RECT_NODE *	n2
	)

Definition at line 79 of file lwtree.c.

References FP_GT, rect_node::left_node, LW_FALSE, lw_segment_intersects(), LW_TRUE, LWDEBUG, LWDEBUGF, rect_node::p1, rect_node::p2, rect_node_is_leaf(), rect_tree_intersects_tree(), rect_node::right_node, rect_node::xmax, rect_node::xmin, rect_node::ymax, and rect_node::ymin.

Referenced by rect_tree_intersects_tree(), and test_rect_tree_intersects_tree().

{
        LWDEBUGF(4,"n1 (%.9g %.9g,%.9g %.9g) vs n2 (%.9g %.9g,%.9g %.9g)",n1->xmin,n1->ymin,n1->xmax,n1->ymax,n2->xmin,n2->ymin,n2->xmax,n2->ymax);
        /* There can only be an edge intersection if the rectangles overlap */
        if ( ! ( FP_GT(n1->xmin, n2->xmax) || FP_GT(n2->xmin, n1->xmax) || FP_GT(n1->ymin, n2->ymax) || FP_GT(n2->ymin, n1->ymax) ) )
        {
                LWDEBUG(4," interaction found");
                /* We can only test for a true intersection if the nodes are both leaf nodes */
                if ( rect_node_is_leaf(n1) && rect_node_is_leaf(n2) )
                {
                        LWDEBUG(4,"  leaf node test");
                        /* Check for true intersection */
                        if ( lw_segment_intersects(n1->p1, n1->p2, n2->p1, n2->p2) )
                                return LW_TRUE;
                        else
                                return LW_FALSE;
                }
                else
                {
                        LWDEBUG(4,"  internal node found, recursing");
                        /* Recurse to children */
                        if ( rect_node_is_leaf(n1) )
                        {
                                if ( rect_tree_intersects_tree(n2->left_node, n1) || rect_tree_intersects_tree(n2->right_node, n1) )
                                        return LW_TRUE;
                                else
                                        return LW_FALSE;
                        }
                        else
                        {
                                if ( rect_tree_intersects_tree(n1->left_node, n2) || rect_tree_intersects_tree(n1->right_node, n2) )
                                        return LW_TRUE;
                                else
                                        return LW_FALSE;
                        }
                }
        }
        else
        {
                LWDEBUG(4," no interaction found");
                return LW_FALSE;
        }
}

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