src/scene_node.c

/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 * Copyright 2023 Mike Becker. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   1. Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *
 *   2. Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "ascension/scene_node.h"
#include "ascension/context.h"

#include <cx/tree.h>
#include <cx/linked_list.h>

static CxTreeIterator asc_scene_node_iterator(
        AscSceneNode *node,
        bool visit_on_exit
) {
    return cx_tree_iterator(
            node, visit_on_exit,
            offsetof(AscSceneNode, children),
            offsetof(AscSceneNode, next)
    );
}

AscSceneNode *asc_scene_node_empty(void) {
    AscSceneNode *node = calloc(1, sizeof(AscSceneNode));
    node->render_group = ASC_RENDER_GROUP_NONE;
    node->scale.x = node->scale.y = node->scale.z = 1;
    asc_transform_identity(node->transform);
    asc_transform_identity(node->world_transform);
    return node;
}

static void asc_scene_node_destroy(AscSceneNode *node) {
    cxListFree(node->behaviors);
    if (node->destroy_func != NULL) {
        node->destroy_func(node);
    }
    free(node->name);
}

void asc_scene_node_free(AscSceneNode *node) {
    if (node == NULL) return;

    // remove this node from its parent
    asc_scene_node_unlink(node);

    // free the entire subtree
    CxTreeIterator iter = asc_scene_node_iterator(node, true);
    cx_foreach(AscSceneNode*, child, iter) {
        if (!iter.exiting) continue;
        asc_scene_node_destroy(child);
        free(child);
    }
}

void asc_scene_node_link(AscSceneNode * restrict parent, AscSceneNode * restrict node) {
    cx_tree_link(
            parent, node,
            offsetof(AscSceneNode, parent),
            offsetof(AscSceneNode, children),
            offsetof(AscSceneNode, last_child),
            offsetof(AscSceneNode, prev),
            offsetof(AscSceneNode, next)
    );
    asc_node_update_transform(node);
}

void asc_scene_node_unlink(AscSceneNode *node) {
    cx_tree_unlink(
            node,
            offsetof(AscSceneNode, parent),
            offsetof(AscSceneNode, children),
            offsetof(AscSceneNode, last_child),
            offsetof(AscSceneNode, prev),
            offsetof(AscSceneNode, next)
    );
    asc_node_update_transform(node);
}

// TODO: rename in asc_node_add_behavior or just asc_add_behavior()
void asc_scene_add_behavior(
        AscSceneNode *node,
        asc_scene_node_update_func behavior
) {
    if (node->behaviors == NULL) {
        node->behaviors = cxLinkedListCreateSimple(CX_STORE_POINTERS);
    }
    // TODO: create AscBehavior struct with more stuff than just a fptr
    cxListAdd(node->behaviors, behavior);
}

void asc_scene_remove_behavior(
        AscSceneNode *node,
        asc_scene_node_update_func behavior
) {
    if (node->behaviors != NULL) {
        cxListFindRemove(node->behaviors, behavior);
    }
}

void asc_node_update(AscSceneNode *node) {
    asc_set_flag(node->flags, ASC_SCENE_NODE_UPDATE_GRAPHICS);
}

void asc_node_update_transform(AscSceneNode *node) {
    // fast skip if node is already marked
    if (asc_test_flag(node->flags, ASC_SCENE_NODE_UPDATE_TRANSFORM)) {
        return;
    }

    CxTreeIterator iter = asc_scene_node_iterator(node, false);
    cx_foreach(AscSceneNode*, n, iter) {
        if (asc_test_flag(n->flags, ASC_SCENE_NODE_UPDATE_TRANSFORM)) {
            cxTreeIteratorContinue(iter);
        }
        asc_set_flag(n->flags, ASC_SCENE_NODE_UPDATE_TRANSFORM);
    }
}