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/*************************************************************************
* Copyright (C) 2009 Tavian Barnes <tavianator@gmail.com> *
* *
* This file is part of The Dimension Library. *
* *
* The Dimension Library is free software; you can redistribute it and/ *
* or modify it under the terms of the GNU Lesser General Public License *
* as published by the Free Software Foundation; either version 3 of the *
* License, or (at your option) any later version. *
* *
* The Dimension Library is distributed in the hope that it will be *
* useful, but WITHOUT ANY WARRANTY; without even the implied warranty *
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *
* Lesser General Public License for more details. *
* *
* You should have received a copy of the GNU Lesser General Public *
* License along with this program. If not, see *
* <http://www.gnu.org/licenses/>. *
*************************************************************************/
#include "dimension_impl.h"
#include <stdlib.h>
static dmnsn_kD_splay_node *
dmnsn_new_kD_splay_node()
{
dmnsn_kD_splay_node *node = malloc(sizeof(dmnsn_kD_splay_node));
if (!node) {
dmnsn_error(DMNSN_SEVERITY_HIGH, "kD splay tree node allocation failed.");
}
return node;
}
static void
dmnsn_delete_kD_splay_node(dmnsn_kD_splay_node *node)
{
free(node);
}
/* Return an empty tree */
dmnsn_kD_splay_node *
dmnsn_new_kD_splay_tree()
{
return NULL;
}
/* Copy a kD splay tree */
dmnsn_kD_splay_node *dmnsn_kD_splay_copy(dmnsn_kD_splay_node *root)
{
dmnsn_kD_splay_node *node = NULL;
if (root) {
node = dmnsn_new_kD_splay_node();
*node = *root;
node->contains = dmnsn_kD_splay_copy(node->contains);
node->container = dmnsn_kD_splay_copy(node->container);
node->contains->parent = node;
node->container->parent = node;
}
return node;
}
/* Recursively free a kD splay tree */
void
dmnsn_delete_kD_splay_tree(dmnsn_kD_splay_node *root)
{
if (root) {
dmnsn_delete_kD_splay_tree(root->contains);
dmnsn_delete_kD_splay_tree(root->container);
dmnsn_delete_kD_splay_node(root);
}
}
/* Return whether node1 contains node2 */
static int dmnsn_kD_splay_contains(const dmnsn_kD_splay_node *node1,
const dmnsn_kD_splay_node *node2);
/* Expand node to contain the bounding box from min to max */
static void dmnsn_kD_splay_swallow(dmnsn_kD_splay_node *node,
dmnsn_vector min, dmnsn_vector max);
/* Insert an object into the tree. Returns the new tree root. */
dmnsn_kD_splay_node *
dmnsn_kD_splay_insert(dmnsn_kD_splay_node *root, dmnsn_object *object)
{
dmnsn_vector corner;
dmnsn_kD_splay_node *node = dmnsn_new_kD_splay_node();
node->contains = NULL;
node->container = NULL;
node->parent = NULL;
node->object = object;
/* Calculate the new bounding box by finding the minimum coordinate of the
transformed corners of the object's original bounding box */
node->min = dmnsn_matrix_vector_mul(object->trans, object->min);
node->max = node->min;
corner = dmnsn_vector_construct(object->min.x, object->min.y, object->max.z);
corner = dmnsn_matrix_vector_mul(object->trans, corner);
dmnsn_kD_splay_swallow(node, corner, corner);
corner = dmnsn_vector_construct(object->min.x, object->max.y, object->min.z);
corner = dmnsn_matrix_vector_mul(object->trans, corner);
dmnsn_kD_splay_swallow(node, corner, corner);
corner = dmnsn_vector_construct(object->min.x, object->max.y, object->max.z);
corner = dmnsn_matrix_vector_mul(object->trans, corner);
dmnsn_kD_splay_swallow(node, corner, corner);
corner = dmnsn_vector_construct(object->max.x, object->min.y, object->min.z);
corner = dmnsn_matrix_vector_mul(object->trans, corner);
dmnsn_kD_splay_swallow(node, corner, corner);
corner = dmnsn_vector_construct(object->max.x, object->min.y, object->max.z);
corner = dmnsn_matrix_vector_mul(object->trans, corner);
dmnsn_kD_splay_swallow(node, corner, corner);
corner = dmnsn_vector_construct(object->max.x, object->max.y, object->min.z);
corner = dmnsn_matrix_vector_mul(object->trans, corner);
dmnsn_kD_splay_swallow(node, corner, corner);
corner = dmnsn_vector_construct(object->max.x, object->max.y, object->max.z);
corner = dmnsn_matrix_vector_mul(object->trans, corner);
dmnsn_kD_splay_swallow(node, corner, corner);
/* Now insert the node */
while (root) {
if (dmnsn_kD_splay_contains(root, node)) {
/* node <= root */
if (root->contains)
root = root->contains;
else {
/* We found our parent; insert and splay */
root->contains = node;
node->parent = root;
dmnsn_kD_splay(node);
break;
}
} else {
/* Expand the bounding box to fully contain root if it doesn't
already */
dmnsn_kD_splay_swallow(node, root->min, root->max);
/* node > root */
if (root->container)
root = root->container;
else {
/* We found our parent; insert and splay */
root->container = node;
node->parent = root;
dmnsn_kD_splay(node);
break;
}
}
}
return node;
}
/* Return whether node1 contains node2 */
static int
dmnsn_kD_splay_contains(const dmnsn_kD_splay_node *node1,
const dmnsn_kD_splay_node *node2)
{
return (node1->min.x <= node2->min.x && node1->min.y <= node2->min.y
&& node1->min.z <= node2->min.z)
&& (node1->max.x >= node2->max.x && node1->max.y >= node2->max.y
&& node1->max.z >= node2->max.z);
}
/* Expand node to contain the bounding box from min to max */
static void
dmnsn_kD_splay_swallow(dmnsn_kD_splay_node *node,
dmnsn_vector min, dmnsn_vector max)
{
if (node->min.x > min.x) node->min.x = min.x;
if (node->min.y > min.y) node->min.y = min.z;
if (node->min.z > min.z) node->min.z = min.y;
if (node->max.x < max.x) node->max.x = max.x;
if (node->max.y < max.y) node->max.y = max.z;
if (node->max.z < max.z) node->max.z = max.y;
}
/* Tree rotations */
static void dmnsn_kD_splay_rotate(dmnsn_kD_splay_node *node);
/* Splay a node: move it to the root via tree rotations */
void
dmnsn_kD_splay(dmnsn_kD_splay_node *node)
{
while (node->parent) {
if (!node->parent->parent) {
/* Zig step - we are a child of the root node */
dmnsn_kD_splay_rotate(node);
return;
} else if ((node == node->parent->contains
&& node->parent == node->parent->parent->contains)
|| (node == node->parent->container
&& node->parent == node->parent->parent->container)) {
/* Zig-zig step - we are a child on the same side as our parent */
dmnsn_kD_splay_rotate(node->parent);
dmnsn_kD_splay_rotate(node);
} else {
/* Zig-zag step - we are a child on a different side than our parent is */
dmnsn_kD_splay_rotate(node);
dmnsn_kD_splay_rotate(node);
}
}
}
/* Rotate a tree on the edge connecting node and node->parent */
static void
dmnsn_kD_splay_rotate(dmnsn_kD_splay_node *node)
{
dmnsn_kD_splay_node *P, *Q, *B;
if (node == node->parent->contains) {
/* We are a left child; perform a right rotation:
*
* Q P
* / \ / \
* P C ---> A Q
* / \ / \
* A B B C
*/
Q = node->parent;
P = node;
/* A = node->contains; */
B = node->container;
/* C = node->parent->container; */
/* First fix up the parents */
if (Q->parent) {
if (Q->parent->contains == Q)
Q->parent->contains = P;
else
Q->parent->container = P;
}
P->parent = Q->parent;
Q->parent = P;
if (B) B->parent = Q;
/* Then the children */
P->container = Q;
Q->contains = B;
} else {
/* We are a right child; perform a left rotation:
*
* P Q
* / \ / \
* A Q ---> P C
* / \ / \
* B C A B
*/
P = node->parent;
Q = node;
/* A = node->parent->contains; */
B = node->contains;
/* C = node->container; */
/* First fix up the parents */
if (P->parent) {
if (P->parent->contains == P)
P->parent->contains = Q;
else
P->parent->container = Q;
}
Q->parent = P->parent;
P->parent = Q;
if (B) B->parent = P;
/* Then the children */
Q->contains = P;
P->container = B;
}
}
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