ascension: src/scene.c@4ccf4703999e

     1 /*

     2  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.

     3  * Copyright 2023 Mike Becker. All rights reserved.

     4  *

     5  * Redistribution and use in source and binary forms, with or without

     6  * modification, are permitted provided that the following conditions are met:

     7  *

     8  *   1. Redistributions of source code must retain the above copyright

     9  *      notice, this list of conditions and the following disclaimer.

    10  *

    11  *   2. Redistributions in binary form must reproduce the above copyright

    12  *      notice, this list of conditions and the following disclaimer in the

    13  *      documentation and/or other materials provided with the distribution.

    14  *

    15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

    16  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

    17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

    18  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE

    19  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

    20  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

    21  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

    22  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

    23  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

    24  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

    25  * POSSIBILITY OF SUCH DAMAGE.

    26  */

    28 #include "ascension/scene.h"

    29 #include "ascension/error.h"

    31 #include <assert.h>

    33 void asc_scene_init(AscScene *scene) {

    34     if (scene->root != NULL) {

    35         asc_error("Scene is already initialized.");

    36         return;

    37     }

    38     scene->root = asc_scene_node_create(NULL);

    39 }

    41 void asc_scene_destroy(AscScene *scene) {

    42     asc_scene_node_free(scene->root);

    43 }

    45 AscSceneNode *asc_scene_node_create(AscSceneNode *parent) {

    46     // TODO: check if this can remain a calloc or if it's too expensive

    47     AscSceneNode *node = calloc(1, sizeof(AscSceneNode));

    48     assert(node != NULL);

    49     asc_scene_node_link(node, parent);

    50     return node;

    51 }

    53 void asc_scene_node_free(AscSceneNode *node) {

    54     if (node == NULL) return;

    56     // free the children recursively

    57     while (node->children != NULL) {

    58         asc_scene_node_free(node->children);

    59     }

    61     // remove this node from its parent

    62     asc_scene_node_unlink(node);

    64     // free the node

    65     free(node);

    66 }

    68 void asc_scene_node_link(

    69         AscSceneNode *node,

    70         AscSceneNode *parent

    71 ) {

    72     if (node->parent == parent) return;

    73     if (node->parent != NULL || parent == NULL) asc_scene_node_unlink(node);

    74     if (parent != NULL) {

    75         if (parent->children == NULL) {

    76             parent->children = node;

    77         } else {

    78             parent->children->prev = node;

    79             node->next = parent->children;

    80         }

    81         node->parent = parent;

    82     }

    83 }

    85 void asc_scene_node_unlink(AscSceneNode *node) {

    86     if (node->parent == NULL) return;

    87     AscSceneNode *left = node->prev;

    88     AscSceneNode *right = node->next;

    89     assert(left == NULL || node->parent->children != node);

    90     if (left != NULL) {

    91         left->next = right;

    92     } else {

    93         node->parent->children = right;

    94     }

    95     if (right != NULL) right->prev = left;

    96     node->parent = node->prev = node->next = NULL;

    97 }

Mercurial > hg > ascension / file revision