wip: Changes of the week

- Move engine to a different crate
- Add engine trait
- Refactor the rest of the codebase to work with these changes
- Add debug ui buffer, use it to finish imgui support

core/src/engine.rs

@@ -1,59 +1,15 @@
 use std::cell::RefCell;
 use std::rc::Rc;
-use winit::event::Event;
-use crate::SceneManager;
-use crate::system::{SystemContext, SystemManager};
-use raidillon_assets::{ModelManager, ModelManagerRef};
 use crate::context::PlatformContext;
+use crate::DebugUIBuffer;
+use crate::scene::Scene;
 
-pub struct Engine {
-    pub scene_manager: SceneManager,
-    pub system_manager: SystemManager,
-}
-
-impl Engine {
-    pub fn new() -> Self {
-        let scene_manager = SceneManager::new();
-        let system_manager = SystemManager::new();
-        Self {
-            scene_manager,
-            system_manager,
-        }
-    }
-
-    /// Initialize systems, load the world.
-    pub fn initialize(&mut self, platform_context: PlatformContext) {
-        // Engine Loading Stage 1: initialize systems
-        for (system_id, system) in self.system_manager.systems.iter_mut() {
-            system.initialize();
-        }
-
-        let mut ctx = SystemContext {
-            scene: self.scene_manager.current_mut(),
-            platform_context,
-        };
-
-        // Engine Loading Stage 2: load world
-        for (system_id, system) in self.system_manager.systems.iter_mut() {
-            system.load_world(&mut ctx);
-        }
-    }
-
-    /// Update the engine
-    pub fn update(&mut self, platform_context: PlatformContext) {
-        let mut ctx = SystemContext {
-            scene: self.scene_manager.current_mut(),
-            platform_context,
-        };
-
-        for (system_id, system) in self.system_manager.systems.iter_mut() {
-            system.update(&mut ctx);
-        }
-    }
-
-    // pub fn build_system_context(&mut self) -> SystemContext {
-    //     SystemContext {
-    //         scene: self.scene_manager.current_mut(),
-    //     }
-    // }
+pub trait EngineTrait {
+    fn new() -> Self;
+    fn initialize(&mut self, platform_context: PlatformContext);
+    fn update(&mut self, platform_context: PlatformContext);
+    fn current_scene_mut(&mut self) -> &mut Scene;
+    fn get_debug_ui_buffer(&self) -> Rc<RefCell<DebugUIBuffer>>;
+    fn reset_debug_ui_buffer(&mut self);
+    fn scene_and_debug_ui_buffer_mut(&mut self) -> (&mut Scene, Rc<RefCell<DebugUIBuffer>>);
 }