12 static void _trap(int line)
15 printf("Trapped from line %d, use debugger to get backtrace\n",
22 #define trap() _trap(__LINE__)
24 static int quadtree_compare_coord(const struct vector *a,
25 const struct vector *b)
41 static int quadtree_compare(const struct quadtree *a, const struct quadtree *b)
43 return quadtree_compare_coord(&a->pos, &b->pos);
46 static void validate_subtree(const struct quadtree *node)
53 printf("Attempted to validate a null pointer\n");
58 for (i = 0; i < 4; i++) {
62 if (node->child[i]->parent != node) {
63 printf("%s:%d Fatal! Tree inconsistency detected at "
64 "child %d %p in node %p, incorrent parent %p\n",
65 __func__, __LINE__, i, node->child[i], node,
66 node->child[i]->parent);
72 if (node->child[i] == node->parent) {
73 printf("%s:%d Fatal! Tree loop detected "
74 "at child %d in node %p\n",
75 __func__, __LINE__, i, node);
81 dir = quadtree_compare(node, node->child[i]);
84 printf("%s:%d Fatal! Spatial inconsistency detected "
85 "at child %d in node %p\n"
86 "parent: (%f %f), child (%f %f), "
88 __func__, __LINE__, i, node,
89 node->pos.x, node->pos.y,
90 node->child[i]->pos.x, node->child[i]->pos.y,
96 children += node->child[i]->children + 1;
98 validate_subtree(node->child[i]);
101 if (node->depth < 0) {
102 printf("%s:%d Tree statistics inconsistency detected! "
103 "Negative depth: %ld\n",
104 __func__, __LINE__, node->depth);
107 if (node->children != children) {
108 printf("%s:%d Tree statistics inconsistency detected! "
109 "child count mismatch. Expected %ld, got %ld\n",
110 __func__, __LINE__, children, node->children);
115 for (i = 0; i < 4 && node->children; i++) {
119 if (node->depth == node->child[i]->depth + 1)
122 if (node->child[i]->depth > node->depth) {
123 printf("%s:%d Tree statistics inconsistency detected! "
124 "child depth mismatch %ld > %ld\n",
125 __func__, __LINE__, node->child[i]->depth,
131 printf("%s:%d Tree statistics inconsistency detected! "
132 "child depth mismatch.",
139 static void validate_tree(const struct quadtree *node)
147 return validate_subtree(node);
149 for (i = 0; i < 4; i++)
150 if (node->parent->child[i] == node)
154 printf("%s:%d Tree inconsistency detected! "
155 "Wrong parent %p for node %p\n",
156 __func__, __LINE__, node->parent, node);
161 validate_tree(node->parent);
164 void _quadtree_validate_tree(const struct quadtree *node)
169 static struct quadtree *_quadtree_add(struct quadtree *parent,
170 struct quadtree *new)
174 ret = quadtree_compare(parent, new);
176 if (ret < 0 || ret >= 4) {
177 printf("Invalid comparison result of %d\n", ret);
181 if (parent->child[ret])
182 return _quadtree_add(parent->child[ret], new);
184 parent->child[ret] = new;
185 new->parent = parent;
186 for (i = 0; i < 4; i++)
193 * quadtree_add - add a node to a quadtree
194 * @parent: parent node
195 * @new: the new node to be added
197 * Add a node to a quadtree. The tree is kept in order, the new node
198 * is placed in the end of appropriate branch.
200 * The case of nodes sharing identical coordinates is not taken into
204 struct quadtree *quadtree_add(struct quadtree *parent, struct quadtree *new,
205 struct quadtree_ops *ops)
210 validate_tree(parent);
212 _quadtree_add(parent, new);
215 printf("adding node %p to parent %p\n", new, parent);
219 quadtree_recalculate_parent_stats(new, ops);
226 static double max_by_dir(double a, double b, int direction)
241 static double maxv_by_dir(struct quadtree *a, int direction)
256 static double quadtree_get_max_dimension(struct quadtree *node, int direction)
258 struct quadtree *ch1 = NULL, *ch2 = NULL;
263 ch1 = node->child[0];
264 ch2 = node->child[1];
267 ch1 = node->child[1];
268 ch2 = node->child[3];
271 ch1 = node->child[2];
272 ch2 = node->child[3];
275 ch1 = node->child[0];
276 ch2 = node->child[2];
283 a = quadtree_get_max_dimension(ch1, direction);
284 b = quadtree_get_max_dimension(ch2, direction);
285 return max_by_dir(a, b, direction);
289 a = quadtree_get_max_dimension(ch1, direction);
290 b = maxv_by_dir(ch1, direction);
291 return max_by_dir(a, b, direction);
294 a = quadtree_get_max_dimension(ch2, direction);
295 b = maxv_by_dir(ch2, direction);
296 return max_by_dir(a, b, direction);
299 return maxv_by_dir(node, direction);
303 * Stores the lower right and upper left corner coordinates to the
306 static void quadtree_get_tree_dimensions(struct quadtree *node,
307 struct vector *corner)
309 corner[0].y = quadtree_get_max_dimension(node, 2);
310 corner[0].x = quadtree_get_max_dimension(node, 1);
311 corner[1].y = quadtree_get_max_dimension(node, 0);
312 corner[1].x = quadtree_get_max_dimension(node, 3);
315 printf("\nInitial Search rectangle (%f %f) (%f %f), (%f %f)\n",
316 corner[0].x, corner[0].y,
317 corner[1].x, corner[1].y,
318 node->pos.x, node->pos.y);
322 if ((corner[0].x < corner[1].x) ||
323 (corner[0].y < corner[1].y))
327 static int is_within(struct vector *pos, struct vector *corner)
329 if ((pos->x >= corner[1].x) && (pos->x <= corner[0].x) &&
330 (pos->y >= corner[1].y) && (pos->y <= corner[0].y))
335 static int quadrants_to_search(struct quadtree *node, struct vector *corner)
337 int direction = 0, i;
338 int up = 0, left = 0, right = 0, down = 0;
340 for (i = 0; i < 2; i++) {
341 if (corner[i].x <= node->pos.x)
343 else if (corner[i].x >= node->pos.x)
345 if (corner[i].y <= node->pos.y)
347 else if (corner[i].y >= node->pos.y)
352 direction |= QUADTREE_UPLEFT;
354 direction |= QUADTREE_UPRIGHT;
356 direction |= QUADTREE_DOWNLEFT;
358 direction |= QUADTREE_DOWNRIGHT;
363 static struct quadtree *quadtree_find_nearest(struct quadtree *tree,
365 struct vector *corner)
368 struct quadtree *nearest, *node;
369 double distance = 0, dist;
372 if (!is_within(pos, corner)) {
374 printf("No nearest to be found from (%f %f) (%f %f) "
376 corner[0].x, corner[0].y,
377 corner[1].x, corner[1].y,
384 if (is_within(&tree->pos, corner)) {
385 vector_sub(pos, &tree->pos, &tmp);
386 distance = vector_abs(&tmp);
392 directions = quadrants_to_search(tree, corner);
394 for (i = 0; i < 4; i++) {
399 if (!(directions & (1 << i)))
402 node = quadtree_find_nearest(tree->child[i], pos, corner);
407 vector_sub(pos, &node->pos, &tmp);
408 dist = vector_abs(&tmp);
410 if (!nearest || dist < distance) {
417 if (nearest && !is_within(&nearest->pos, corner)) {
419 printf("Node %p (%f %f) is not within "
420 "search window (%f %f) (%f %f)\n",
421 nearest, nearest->pos.x, nearest->pos.y,
422 corner[0].x, corner[0].y,
423 corner[1].x, corner[1].y);
430 static struct quadtree *quadtree_find_nearest_noparent(struct quadtree *tree,
432 struct vector *corner)
434 struct quadtree *nearest;
436 struct quadtree *node;
437 double dist = 0, dist2;
440 nearest = quadtree_find_nearest(tree, pos, corner);
446 printf("Avoiding parent or NULL node %p\n", nearest);
449 * oops, we don't want to pick the parent node, let's choose
453 for (i = 0; i < 4; i++) {
458 nearest = quadtree_find_nearest(tree->child[i], pos,
464 vector_sub(pos, &nearest->pos, &sub);
465 dist = vector_abs(&sub);
468 node = quadtree_find_nearest(tree->child[i],
474 vector_sub(pos, &node->pos, &sub);
475 dist2 = vector_abs(&sub);
487 static void get_middle_point(struct vector *corner, struct vector *middle)
489 middle->x = (corner[0].x + corner[1].x) / (double)2;
490 middle->y = (corner[0].y + corner[1].y) / (double)2;
493 static int quadtree_split_by_node(struct quadtree *node,
494 struct vector *corner, int dir)
496 if (!is_within(&node->pos, corner)) {
498 printf("Not within search rectangle\n");
503 case QUADTREE_UPLEFT:
504 corner[0] = node->pos;
506 case QUADTREE_UPRIGHT:
507 corner[0].y = node->pos.y;
508 corner[1].x = node->pos.x;
510 case QUADTREE_DOWNRIGHT:
511 corner[1] = node->pos;
513 case QUADTREE_DOWNLEFT:
514 corner[0].x = node->pos.x;
515 corner[1].y = node->pos.y;
522 printf("Search rectangle is now (%f %f) (%f %f), (%f %f)\n",
523 corner[0].x, corner[0].y,
524 corner[1].x, corner[1].y,
525 node->pos.x, node->pos.y);
527 if ((corner[0].x < corner[1].x) ||
528 (corner[0].y < corner[1].y))
535 * Quickly detach a node from a tree. Move all child nodes under
538 static int _quadtree_del(struct quadtree *node, struct quadtree *parent)
543 /* Detach from the tree */
545 for (i = 0; i < 4; i++) {
546 if (node->parent->child[i] == node) {
547 node->parent->child[i] = 0;
556 for (i = 0; i < 4; i++) {
561 _quadtree_del(n, parent);
562 _quadtree_add(parent, n);
569 * Move everything under @tree node to @parent node, everything
570 * else except the @tree node itself
572 static int optimally_move_tree(struct quadtree *tree, struct quadtree *parent,
573 struct vector *corner_orig,
574 struct quadtree_ops *ops)
576 struct vector corner[2], mid;
577 struct quadtree *t, *tmp;
580 get_middle_point(corner_orig, &mid);
581 t = quadtree_find_nearest_noparent(tree, &mid, corner_orig);
585 printf("Cannot find nearest node\n");
591 * Now we have the t node which contains the object of the
592 * spatial middle coordinates of the tree.
596 printf("Relocating node %p (%f %f) under parent %p\n", t,
597 t->pos.x, t->pos.y, parent);
598 printf("There are %ld child nodes left\n", tree->children);
601 _quadtree_del(t, tree);
602 quadtree_add(parent, t, ops);
610 * Now split the search rectangle in quadtres and do the same
611 * with all of the quarters.
614 corner[0] = corner_orig[0];
615 corner[1] = corner_orig[1];
616 if (quadtree_split_by_node(t, corner, QUADTREE_UPLEFT))
617 moved += optimally_move_tree(tree, parent, corner, ops);
619 corner[0] = corner_orig[0];
620 corner[1] = corner_orig[1];
621 if (quadtree_split_by_node(t, corner, QUADTREE_UPRIGHT))
622 moved += optimally_move_tree(tree, parent, corner, ops);
624 corner[0] = corner_orig[0];
625 corner[1] = corner_orig[1];
626 if (quadtree_split_by_node(t, corner, QUADTREE_DOWNLEFT))
627 moved += optimally_move_tree(tree, parent, corner, ops);
629 corner[0] = corner_orig[0];
630 corner[1] = corner_orig[1];
631 if (quadtree_split_by_node(t, corner, QUADTREE_DOWNRIGHT))
632 moved += optimally_move_tree(tree, parent, corner, ops);
634 get_middle_point(corner_orig, &mid);
635 tmp = quadtree_find_nearest(tree, &mid, corner_orig);
636 if (tmp && tmp != tree)
641 printf("Now moved %d nodes, %ld left\n", moved, tree->children);
647 * quadtree_del - Detach a node from the tree
649 * Return value: The new root node of the tree. If we are detaching
650 * anything but the root node of the entire tree, the returned root
651 * value will be the original root of the tree.
653 struct quadtree *quadtree_del(struct quadtree *node,
654 struct quadtree_ops *ops)
656 struct quadtree *parent = NULL;
657 struct vector corner[2];
658 int i, children = node->children, moved;
663 printf("Deleting node %p under parent %p\n",
665 printf("Relocating %ld children\n", node->children);
671 * We are deleting the root node. This means we have
672 * to select a new root node and reconstruct the
673 * entire tree under it again.
676 printf("Deleting root node\n");
679 for (i = 0; i < 4; i++) {
683 parent = node->child[i];
684 _quadtree_del(parent, node);
686 quadtree_recalculate_parent_stats(parent, ops);
691 * The node has a parent. Detach the node from it and
692 * relocate the children.
695 for (i = 0; i < 4; i++) {
696 if (node->parent->child[i] == node) {
697 node->parent->child[i] = 0;
704 parent = node->parent;
707 * The sub branch is now detached from the main
708 * tree. Fix the stats.
710 quadtree_recalculate_parent_stats(node->parent, ops);
713 validate_tree(parent);
718 * Now we are ready to prepare for relocating the nodes under
722 quadtree_get_tree_dimensions(node, corner);
723 moved = optimally_move_tree(node, parent, corner, ops);
726 if (moved != children) {
727 printf("Got %d children but %d were moved\n",
729 printf("nearest children left:\n");
730 for (i = 0 ; i < 4; i++)
732 printf(" node %d %p, (%f %f)\n",
734 node->child[i]->pos.x,
735 node->child[i]->pos.y);
739 printf("Delete done, returning parent %p\n", parent);
744 validate_tree(parent);
745 return quadtree_find_parent(parent);
748 static void check_for_crossed_subnodes(struct quadtree *node,
749 struct vector *limit, struct quadtree_ops *ops)
751 int direction = 0, i;
752 int up = 0, left = 0, right = 0, down = 0;
754 for (i = 0; i < 2; i++) {
755 if (limit[i].x < node->pos.x)
759 if (limit[i].y < node->pos.y)
766 direction |= QUADTREE_UPLEFT;
768 direction |= QUADTREE_UPRIGHT;
770 direction |= QUADTREE_DOWNLEFT;
772 direction |= QUADTREE_DOWNRIGHT;
773 if ((left && right) || (up && down))
774 direction |= QUADTREE_SELF;
776 if ((direction & QUADTREE_UPLEFT) && node->child[0])
777 check_for_crossed_subnodes(node->child[0], limit, ops);
779 if ((direction & QUADTREE_UPRIGHT) && node->child[1])
780 check_for_crossed_subnodes(node->child[0], limit, ops);
782 if ((direction & QUADTREE_DOWNLEFT) && node->child[2])
783 check_for_crossed_subnodes(node->child[0], limit, ops);
785 if ((direction & QUADTREE_DOWNRIGHT) && node->child[3])
786 check_for_crossed_subnodes(node->child[0], limit, ops);
788 if (direction & QUADTREE_SELF) {
789 struct quadtree *parent;
791 parent = quadtree_del(node, ops);
792 quadtree_add(parent, node, ops);
796 struct quadtree *quadtree_move(struct quadtree *node, struct vector new_pos,
797 struct quadtree_ops *ops)
799 struct quadtree *parent, *tree_parent;
802 /* Check if we have crossed any of the parents */
803 parent = node->parent;
805 if (node->pos.x < parent->pos.x && new_pos.x > parent->pos.x)
807 if (node->pos.x > parent->pos.x && new_pos.x < parent->pos.x)
809 if (node->pos.y < parent->pos.y && new_pos.y > parent->pos.y)
811 if (node->pos.y > parent->pos.y && new_pos.y < parent->pos.y)
815 parent = parent->parent;
820 * If the node has crossed the boundaries, remove it
821 * from the tree and add it again to it. It is then
822 * guaranteed to be in the correct position of the
825 tree_parent = quadtree_del(node, ops);
827 quadtree_add(tree_parent, node, ops);
831 /* Move the node into its new location */
836 * Now, search the subtree for any children that are
837 * located in wrong place and move them into correct
838 * place within the tree.
840 struct vector limit[2];
842 limit[0] = node->pos;
844 check_for_crossed_subnodes(node, limit, ops);
847 return quadtree_find_parent(node);
851 static int _walk_tree(struct quadtree *head, const struct quadtree_iterator *it)
853 int direction, count = 0;
855 direction = it->direction(head, (struct quadtree_iterator *)it);
857 if ((direction & QUADTREE_UPLEFT) && head->child[0])
858 count += _walk_tree(head->child[0], it);
860 if ((direction & QUADTREE_UPRIGHT) && head->child[1])
861 count += _walk_tree(head->child[1], it);
863 if ((direction & QUADTREE_DOWNLEFT) && head->child[2])
864 count += _walk_tree(head->child[2], it);
866 if ((direction & QUADTREE_DOWNRIGHT) && head->child[3])
867 count += _walk_tree(head->child[3], it);
869 if ((direction & QUADTREE_SELF) && it->callback) {
870 it->callback(head, (struct quadtree_iterator *)it);
877 int walk_quadtree(const struct quadtree_iterator *it)
879 return _walk_tree(it->head, it);