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-rw-r--r--libdimension/bvst.c388
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diff --git a/libdimension/bvst.c b/libdimension/bvst.c
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--- a/libdimension/bvst.c
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-/*************************************************************************
- * Copyright (C) 2010 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>
-
-/* Return an empty tree */
-dmnsn_bvst *
-dmnsn_new_bvst()
-{
- dmnsn_bvst *tree = dmnsn_malloc(sizeof(dmnsn_bvst));
- tree->root = NULL;
- return tree;
-}
-
-static dmnsn_bvst_node *
-dmnsn_new_bvst_node()
-{
- dmnsn_bvst_node *node = dmnsn_malloc(sizeof(dmnsn_bvst_node));
- return node;
-}
-
-/* Recursively copy the nodes of a BVST */
-static dmnsn_bvst_node *
-dmnsn_bvst_copy_recursive(dmnsn_bvst_node *root)
-{
- dmnsn_bvst_node *node = dmnsn_new_bvst_node();
- *node = *root;
- if (node->contains) {
- node->contains = dmnsn_bvst_copy_recursive(node->contains);
- node->contains->parent = node;
- }
- if (node->container) {
- node->container = dmnsn_bvst_copy_recursive(node->container);
- node->container->parent = node;
- }
- return node;
-}
-
-/* Copy a BVST */
-dmnsn_bvst *
-dmnsn_copy_bvst(dmnsn_bvst *tree)
-{
- dmnsn_bvst *copy = dmnsn_new_bvst();
- if (tree->root)
- copy->root = dmnsn_bvst_copy_recursive(tree->root);
- else
- copy->root = NULL;
- return copy;
-}
-
-static void
-dmnsn_delete_bvst_node(dmnsn_bvst_node *node)
-{
- free(node);
-}
-
-/* Recursively free a BVST */
-static void
-dmnsn_delete_bvst_recursive(dmnsn_bvst_node *node)
-{
- if (node) {
- dmnsn_delete_bvst_recursive(node->contains);
- dmnsn_delete_bvst_recursive(node->container);
- dmnsn_delete_bvst_node(node);
- }
-}
-
-/* Free a BVST */
-void
-dmnsn_delete_bvst(dmnsn_bvst *tree)
-{
- if (tree) {
- dmnsn_delete_bvst_recursive(tree->root);
- free(tree);
- }
-}
-
-/* Expand node to contain the bounding box from min to max */
-static void dmnsn_bvst_node_swallow(dmnsn_bvst_node *node,
- dmnsn_bounding_box box);
-
-/* Insert an object into the tree */
-void
-dmnsn_bvst_insert(dmnsn_bvst *tree, dmnsn_object *object)
-{
- dmnsn_object_precompute(object);
-
- dmnsn_bvst_node *node = dmnsn_new_bvst_node(), *parent = tree->root;
-
- node->contains = NULL;
- node->container = NULL;
- node->parent = NULL;
- node->object = object;
- node->bounding_box = object->bounding_box;
-
- /* Now insert the node */
-
- while (parent) {
- if (dmnsn_bounding_box_contains(parent->bounding_box,
- node->bounding_box.min)
- && dmnsn_bounding_box_contains(parent->bounding_box,
- node->bounding_box.max))
- {
- /* parent fully contains node */
- if (parent->contains) {
- parent = parent->contains;
- } else {
- /* We found our parent; insert node into the tree */
- parent->contains = node;
- node->parent = parent;
- break;
- }
- } else {
- /* Expand node's bounding box to fully contain parent's if it doesn't
- already */
- dmnsn_bvst_node_swallow(node, parent->bounding_box);
- /* node now fully contains parent */
- if (parent->container) {
- parent = parent->container;
- } else {
- /* We found our parent; insert node into the tree */
- parent->container = node;
- node->parent = parent;
- break;
- }
- }
- }
-
- dmnsn_bvst_splay(tree, node);
-}
-
-/* Expand node to contain the bounding box from min to max */
-static void
-dmnsn_bvst_node_swallow(dmnsn_bvst_node *node, dmnsn_bounding_box box)
-{
- node->bounding_box.min = dmnsn_vector_min(node->bounding_box.min, box.min);
- node->bounding_box.max = dmnsn_vector_max(node->bounding_box.max, box.max);
-}
-
-/* Tree rotations */
-static void dmnsn_bvst_rotate(dmnsn_bvst_node *node);
-
-/* Splay a node: move it to the root via tree rotations */
-void
-dmnsn_bvst_splay(dmnsn_bvst *tree, dmnsn_bvst_node *node)
-{
- while (node->parent) {
- if (!node->parent->parent) {
- /* Zig step - we are a child of the root node */
- dmnsn_bvst_rotate(node);
- break;
- } 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_bvst_rotate(node->parent);
- dmnsn_bvst_rotate(node);
- } else {
- /* Zig-zag step - we are a child on a different side than our parent is */
- dmnsn_bvst_rotate(node);
- dmnsn_bvst_rotate(node);
- }
- }
- tree->root = node;
-}
-
-/* Rotate a tree on the edge connecting node and node->parent */
-static void
-dmnsn_bvst_rotate(dmnsn_bvst_node *node)
-{
- dmnsn_bvst_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;
- }
-}
-
-typedef struct {
- dmnsn_bvst_node *node;
- bool intersected;
- dmnsn_intersection intersection;
-} dmnsn_bvst_search_result;
-
-static dmnsn_bvst_search_result
-dmnsn_bvst_search_recursive(dmnsn_bvst_node *node, dmnsn_line ray, double t);
-
-bool
-dmnsn_bvst_search(dmnsn_bvst *tree, dmnsn_line ray,
- dmnsn_intersection *intersection)
-{
- dmnsn_bvst_search_result result
- = dmnsn_bvst_search_recursive(tree->root, ray, -1.0);
-
- if (result.intersected) {
- dmnsn_bvst_splay(tree, result.node);
- *intersection = result.intersection;
- }
-
- return result.intersected;
-}
-
-static bool dmnsn_ray_box_intersection(dmnsn_line ray, dmnsn_bounding_box box,
- double t);
-
-static dmnsn_bvst_search_result
-dmnsn_bvst_search_recursive(dmnsn_bvst_node *node, dmnsn_line ray, double t)
-{
- dmnsn_bvst_search_result result_temp, result = {
- .node = NULL,
- .intersected = false
- };
-
- if (!node)
- return result;
-
- /* Go down the right subtree first because the closest object is more likely
- to lie in the larger bounding boxes */
- result_temp = dmnsn_bvst_search_recursive(node->container, ray, t);
- if (result_temp.node && (t < 0.0 || result_temp.intersection.t < t)) {
- result = result_temp;
- t = result.intersection.t;
- }
-
- if (dmnsn_bounding_box_contains(node->bounding_box, ray.x0)
- || dmnsn_ray_box_intersection(ray, node->bounding_box, t))
- {
- if (dmnsn_bounding_box_contains(node->object->bounding_box, ray.x0)
- || dmnsn_ray_box_intersection(ray, node->object->bounding_box, t))
- {
- result_temp.intersected =
- (*node->object->intersection_fn)(node->object, ray,
- &result_temp.intersection);
-
- if (result_temp.intersected
- && (t < 0.0 || result_temp.intersection.t < t)) {
- result.node = node;
- result.intersected = true;
- result.intersection = result_temp.intersection;
- t = result.intersection.t;
- }
- }
-
- /* Go down the left subtree */
- result_temp = dmnsn_bvst_search_recursive(node->contains, ray, t);
- if (result_temp.node && (t < 0.0 || result_temp.intersection.t < t)) {
- result = result_temp;
- }
- }
-
- return result;
-}
-
-static bool
-dmnsn_ray_box_intersection(dmnsn_line line, dmnsn_bounding_box box, double t)
-{
- double t_temp;
- dmnsn_vector p;
-
- if (line.n.x != 0.0) {
- /* x == box.min.x */
- t_temp = (box.min.x - line.x0.x)/line.n.x;
- p = dmnsn_line_point(line, t_temp);
- if (p.y >= box.min.y && p.y <= box.max.y
- && p.z >= box.min.z && p.z <= box.max.z
- && t_temp >= 0.0 && (t < 0.0 || t_temp < t))
- return true;
-
- /* x == box.max.x */
- t_temp = (box.max.x - line.x0.x)/line.n.x;
- p = dmnsn_line_point(line, t_temp);
- if (p.y >= box.min.y && p.y <= box.max.y
- && p.z >= box.min.z && p.z <= box.max.z
- && t_temp >= 0.0 && (t < 0.0 || t_temp < t))
- return true;
- }
-
- if (line.n.y != 0.0) {
- /* y == box.min.y */
- t_temp = (box.min.y - line.x0.y)/line.n.y;
- p = dmnsn_line_point(line, t_temp);
- if (p.x >= box.min.x && p.x <= box.max.x
- && p.z >= box.min.z && p.z <= box.max.z
- && t_temp >= 0.0 && (t < 0.0 || t_temp < t))
- return true;
-
- /* y == box.max.y */
- t_temp = (box.max.y - line.x0.y)/line.n.y;
- p = dmnsn_line_point(line, t_temp);
- if (p.x >= box.min.x && p.x <= box.max.x
- && p.z >= box.min.z && p.z <= box.max.z
- && t_temp >= 0.0 && (t < 0.0 || t_temp < t))
- return true;
- }
-
- if (line.n.z != 0.0) {
- /* z == box.min.z */
- t_temp = (box.min.z - line.x0.z)/line.n.z;
- p = dmnsn_line_point(line, t_temp);
- if (p.x >= box.min.x && p.x <= box.max.x
- && p.y >= box.min.y && p.y <= box.max.y
- && t_temp >= 0.0 && (t < 0.0 || t_temp < t))
- return true;
-
- /* z == box.max.z */
- t_temp = (box.max.z - line.x0.z)/line.n.z;
- p = dmnsn_line_point(line, t_temp);
- if (p.x >= box.min.x && p.x <= box.max.x
- && p.y >= box.min.y && p.y <= box.max.y
- && t_temp >= 0.0 && (t < 0.0 || t_temp < t))
- return true;
- }
-
- return false;
-}
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