add on_screen_change project script event & fix UIDocument::rebuildIndices & move menu background to project script

src/frontend/UiDocument.cpp

@@ -14,11 +14,13 @@ UiDocument::UiDocument(
     const std::shared_ptr<gui::UINode>& root,
     scriptenv env
 ) : id(std::move(id)), script(script), root(root), env(std::move(env)) {
-    gui::UINode::getIndices(root, map);
+    rebuildIndices();
 }
 
 void UiDocument::rebuildIndices() {
+    map.clear();
     gui::UINode::getIndices(root, map);
+    map["root"] = root;
 }
 
 const UINodesMap& UiDocument::getMap() const {

src/frontend/screens/LevelScreen.cpp

@@ -97,7 +97,6 @@ LevelScreen::LevelScreen(
     animator->addAnimations(assets.getAnimations());
 
     loadDecorations();
-    initializeContent();
 }
 
 LevelScreen::~LevelScreen() {
@@ -112,6 +111,10 @@ LevelScreen::~LevelScreen() {
     engine.getPaths().setCurrentWorldFolder("");
 }
 
+void LevelScreen::onOpen() {
+    initializeContent();
+}
+
 void LevelScreen::initializeContent() {
     auto& content = controller->getLevel()->content;
     for (auto& entry : content.getPacks()) {

src/frontend/screens/LevelScreen.hpp

@@ -53,8 +53,13 @@ public:
     );
     ~LevelScreen();
 
+    void onOpen() override;
     void update(float delta) override;
     void draw(float delta) override;
 
     void onEngineShutdown() override;
+
+    const char* getName() const override {
+        return "level";
+    }
 };

src/frontend/screens/MenuScreen.cpp

@@ -13,12 +13,6 @@
 #include "engine/Engine.hpp"
 
 MenuScreen::MenuScreen(Engine& engine) : Screen(engine) {
-    engine.getContentControl().resetContent();
-    
-    auto menu = engine.getGUI().getMenu();
-    menu->reset();
-    menu->setPage("main");
-
     uicamera =
         std::make_unique<Camera>(glm::vec3(), engine.getWindow().getSize().y);
     uicamera->perspective = false;
@@ -29,33 +23,17 @@ MenuScreen::MenuScreen(Engine& engine) : Screen(engine) {
 
 MenuScreen::~MenuScreen() = default;
 
+void MenuScreen::onOpen() {
+    engine.getContentControl().resetContent();
+    
+    auto menu = engine.getGUI().getMenu();
+    menu->reset();
+}
+
 void MenuScreen::update(float delta) {
 }
 
 void MenuScreen::draw(float delta) {
-    auto assets = engine.getAssets();
-
     display::clear();
     display::setBgColor(glm::vec3(0.2f));
-
-    const auto& size = engine.getWindow().getSize();
-    uint width = size.x;
-    uint height = size.y;
-
-    uicamera->setFov(height);
-    uicamera->setAspectRatio(width / static_cast<float>(height));
-    auto uishader = assets->get<Shader>("ui");
-    uishader->use();
-    uishader->uniformMatrix("u_projview", uicamera->getProjView());
-
-    auto bg = assets->get<Texture>("gui/menubg");
-    batch->begin();
-    batch->texture(bg);
-    batch->rect(
-        0, 0, 
-        width, height, 0, 0, 0, 
-        UVRegion(0, 0, width / bg->getWidth(), height / bg->getHeight()), 
-        false, false, glm::vec4(1.0f)
-    );
-    batch->flush();
 }

src/frontend/screens/MenuScreen.hpp

@@ -13,6 +13,12 @@ public:
     MenuScreen(Engine& engine);
     ~MenuScreen();
 
+    void onOpen() override;
+
     void update(float delta) override;
     void draw(float delta) override;
+
+    const char* getName() const override {
+        return "menu";
+    }
 };

src/frontend/screens/Screen.hpp

@@ -13,7 +13,9 @@ protected:
 public:
     Screen(Engine& engine);
     virtual ~Screen();
+    virtual void onOpen() = 0;
     virtual void update(float delta) = 0;
     virtual void draw(float delta) = 0;
     virtual void onEngineShutdown() {};
+    virtual const char* getName() const = 0;
 };