Updated more scene item coponents to state system

src/dawn/scene/components/ui/UICanvas.cpp

@@ -15,39 +15,11 @@ UICanvas * UICanvas::create(Scene *scene) {
   return item->addComponent<UICanvas>();
 }
 
-UICanvas::UICanvas(SceneItem *item) : SceneItemComponent(item) {
-}
-
-void UICanvas::onRenderTargetResize(float_t w, float_t h){
-  auto it = this->children.begin();
-  while(it != this->children.end()) {
-    (*it)->updatePositions();
-    ++it;
-  }
-}
-
-void UICanvas::onSceneUpdate() {
-  if(this->currentMenu != nullptr) {
-    this->currentMenu->onTick();
-  }
-}
-
-void UICanvas::setCamera(Camera *camera) {
-  assertTrue(camera != this->camera);
-  
-  if(this->camera != nullptr) {
-    this->camera->eventRenderTargetResized.removeListener(
-      this, &UICanvas::onRenderTargetResize
-    );
-  }
-
-  this->camera = camera;
-  
-  if(this->camera != nullptr) {
-    this->camera->eventRenderTargetResized.addListener(
-      this, &UICanvas::onRenderTargetResize
-    );
-  }
+UICanvas::UICanvas(SceneItem *item) :
+  SceneItemComponent(item),
+  camera(nullptr),
+  currentMenu(nullptr)
+{
 }
 
 float_t UICanvas::getWidth() {
@@ -64,34 +36,47 @@ float_t UICanvas::getHeight() {
   return this->camera->getRenderTarget()->getHeight();
 }
 
-struct UIMenu * UICanvas::getCurrentMenu() {
-  return this->currentMenu;
-}
-
 void UICanvas::setCurrentMenu(struct UIMenu *menu) {
-  if(this->currentMenu != nullptr) this->currentMenu->onInactive();
-  this->currentMenu = menu;
-  if(menu != nullptr) menu->onActive();
 }
 
 void UICanvas::onStart() {
-  if(this->camera == nullptr) {
-    auto camera = this->getScene()->findComponent<Camera>();
-    this->setCamera(camera);
-  }
+  useEffectWithTeardown([&]{
+    if(this->camera == nullptr) return evtCamResize = [&]{};
+    
+    auto it = this->children.begin();
+    while(it != this->children.end()) {
+      (*it)->updatePositions();
+      ++it;
+    }
 
-  this->getScene()->eventSceneUpdate.addListener(this, &UICanvas::onSceneUpdate);
+    return evtCamResize = useEvent([&](float_t w, float_t h){
+      auto it = this->children.begin();
+      while(it != this->children.end()) {
+        (*it)->updatePositions();
+        ++it;
+      }
+    }, camera->event2RenderTargetResized);
+  }, camera);
+
+  useEffectWithTeardown([&]{
+    if(currentMenu != nullptr) currentMenu->onActive();
+    
+    return [&] {
+      if(currentMenu == nullptr) currentMenu->onInactive();
+    };
+  }, this->currentMenu);
+
+  // Scene Update
+  useEventLegacy([&]{
+    if(this->currentMenu == nullptr) return;
+    this->currentMenu->onTick();
+  }, getScene()->eventSceneUpdate);
+
+  // Find Camera if we need to.
+  if(camera == nullptr) camera = this->getScene()->findComponent<Camera>();
 }
 
 void UICanvas::onDispose() {
-  if(this->camera != nullptr) {
-    this->camera->eventRenderTargetResized.removeListener(
-      this, &UICanvas::onRenderTargetResize
-    );
-  }
-
-  this->getScene()->eventSceneUpdate.removeListener(this, &UICanvas::onSceneUpdate);
-  
   auto it = this->children.begin();
   while(it != this->children.end()) {
     delete *it;