ascension: src/scene.c@e7ddb52facd3

add behavior nodes + restructure test program

Also, the test program will now officially be a game of snake.

     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 <cx/tree.h>

    33 #include <assert.h>

    35 #define child_list_off_ \

    36     offsetof(AscSceneNode, children), offsetof(AscSceneNode, next)

    38 void asc_scene_init(AscScene *scene) {

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

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

    41         return;

    42     }

    43     scene->root = asc_scene_node_empty();

    44 }

    46 void asc_scene_destroy(AscScene *scene) {

    47     asc_scene_node_free(scene->root);

    48 }

    50 void asc_scene_add(AscScene *scene, AscSceneNode *node) {

    51     asc_scene_node_link(scene->root, node);

    52     asc_node_update(node);

    53 }

    55 void asc_scene_draw(AscScene const *scene) {

    56     CxTreeIterator iter = cx_tree_iterator(scene->root, false, child_list_off_);

    58     // skip the root node deliberately, we know it's just the container

    59     cxIteratorNext(iter);

    61     // update the children

    62     cx_foreach(AscSceneNode*, node, iter) {

    63         // execute behaviors, first

    64         AscBehaviorNode *behavior = node->behaviors;

    65         while (behavior) {

    66             behavior->func(node);

    67             behavior = behavior->next;

    68         }

    70         // check if geometry needs update

    71         if (node->need_update && node->update_func != NULL) {

    72             node->need_update = false;

    73             asc_transform_copy(node->transform, node->parent->transform);

    74             node->update_func(node);

    75         }

    77         // TODO: don't visit the tree for drawing, visit the render groups

    78         if (node->draw_func != NULL) {

    79             node->draw_func(node);

    80         }

    81     }

    82 }

    84 AscSceneNode *asc_scene_node_empty(void) {

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

    86     assert(node != NULL);

    87     node->free_func = (asc_scene_free_func) free;

    88     asc_transform_identity(node->transform);

    89     return node;

    90 }

    92 void asc_scene_node_free(AscSceneNode *node) {

    93     if (node == NULL) return;

    95     // remove this node from its parent

    96     asc_scene_node_unlink(node);

    98     // free the entire subtree

    99     CxTreeIterator iter = cx_tree_iterator(node, true, child_list_off_);

   100     cx_foreach(AscSceneNode*, child, iter) {

   101         if (!iter.exiting) continue;

   102         if (child->free_func != NULL) {

   103             child->free_func(child);

   104         } else {

   105             free(child);

   106         }

   107     }

   108 }

   110 void asc_scene_node_link(AscSceneNode * restrict parent, AscSceneNode * restrict node) {

   111     cx_tree_link(

   112             parent, node,

   113             offsetof(AscSceneNode, parent),

   114             offsetof(AscSceneNode, children),

   115             offsetof(AscSceneNode, prev),

   116             offsetof(AscSceneNode, next)

   117     );

   118 }

   120 void asc_scene_node_unlink(AscSceneNode *node) {

   121     cx_tree_unlink(

   122             node,

   123             offsetof(AscSceneNode, parent),

   124             offsetof(AscSceneNode, children),

   125             offsetof(AscSceneNode, prev),

   126             offsetof(AscSceneNode, next)

   127     );

   128 }

   130 AscBehaviorNode *asc_scene_add_behavior(AscSceneNode *node, asc_scene_update_func behavior) {

   131     AscBehaviorNode *behavior_node = calloc(1, sizeof(AscBehaviorNode));

   132     behavior_node->func = behavior;

   133     cx_tree_link(

   134             node,

   135             behavior_node,

   136             offsetof(AscBehaviorNode, parent),

   137             offsetof(AscSceneNode, behaviors),

   138             offsetof(AscBehaviorNode, prev),

   139             offsetof(AscBehaviorNode, next)

   140     );

   141     return behavior_node;

   142 }

   144 void asc_scene_remove_behavior(AscBehaviorNode *node) {

   145     cx_tree_unlink(

   146             node,

   147             offsetof(AscBehaviorNode, parent),

   148             offsetof(AscSceneNode, behaviors),

   149             offsetof(AscBehaviorNode, prev),

   150             offsetof(AscBehaviorNode, next)

   151     );

   152 }

Mercurial > hg > ascension / file revision