src/engine/scene.c

   1 /**
   2  * Copyright 2020 Iwo 'Outfrost' Bujkiewicz
   3  *
   4  * This Source Code Form is subject to the terms of the Mozilla Public
   5  * License, v. 2.0. If a copy of the MPL was not distributed with this
   6  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   7  */
   8
   9 #include "scene.h"
  10
  11 #include <stdlib.h>
  12
  13 #include "engine/logger.h"
  14
  15 Scene* currentScene = NULL;
  16
  17
  18
  19 Scene* newScene() {
  20         Scene* scene = malloc(sizeof(Scene));
  21         *scene = (Scene) { .parent = NULL,
  22                            .numChildren = 0u,
  23                            .children = NULL,
  24                            .transform = identity(),
  25                            .solid = NULL };
  26         return scene;
  27 }
  28
  29 void insertChildScene(Scene* scene, Scene* newChild) {
  30         if (!scene || !newChild) {
  31                 return;
  32         }
  33         if (newChild->parent) {
  34                 logError(
  35                         "Cannot insert Scene 0x%p as child of 0x%p, because it is already child of 0x%p",
  36                         newChild,
  37                         scene,
  38                         newChild->parent);
  39                 return;
  40         }
  41
  42         scene->children = realloc(scene->children, ++(scene->numChildren) * sizeof(Scene*));
  43         scene->children[scene->numChildren - 1] = newChild;
  44
  45         newChild->parent = scene;
  46 }
  47
  48 void reparentScene(Scene* scene, Scene* newParent) {
  49         if (!scene) {
  50                 return;
  51         }
  52
  53         if (scene->parent) {
  54                 Scene* parent = scene->parent;
  55                 size_t indexInParent = parent->numChildren;
  56                 for (size_t i = 0; i < parent->numChildren; ++i) {
  57                         if (parent->children[i] == scene) {
  58                                 indexInParent = i;
  59                                 break;
  60                         }
  61                 }
  62                 // This includes the hopefully impossible case where parent->numChildren == 0
  63                 if (indexInParent == parent->numChildren) {
  64                         logError("Scene %p not found in children of parent %p", scene, parent);
  65                 }
  66                 else {
  67                         for (size_t i = indexInParent; i < parent->numChildren - 1; ++i) {
  68                                 parent->children[i] = parent->children[i + 1];
  69                         }
  70                         parent->children = realloc(parent->children, --(parent->numChildren) * sizeof(Scene*));
  71                 }
  72         }
  73
  74         scene->parent = NULL;
  75
  76         insertChildScene(newParent, scene);
  77 }
  78
  79 Transform worldTransform(const Scene* scene) {
  80         if (!scene) {
  81                 logError("Cannot compute world space Transform of null Scene");
  82                 return identity();
  83         }
  84
  85         if (scene->parent) {
  86                 return multiply(scene->transform, worldTransform(scene->parent));
  87         }
  88         else {
  89                 return scene->transform;
  90         }
  91 }
  92