Timing Module Update

- Implement a new timing module
- Utilize the new timing module in glium platform implementation for frame limiting and fixed engine updates timing.

core/src/engine.rs

@@ -7,7 +7,8 @@ pub trait EngineTrait {
     type PlatformCtx: Clone;
     fn new() -> Self;
     fn initialize(&mut self, platform_context: Self::PlatformCtx);
-    fn update(&mut self, platform_context: Self::PlatformCtx);
+    fn frame_update(&mut self, platform_context: Self::PlatformCtx);
+    fn fixed_update(&mut self, platform_context: Self::PlatformCtx);
     fn handle_event(&mut self, platform_context: Self::PlatformCtx);
     fn current_scene_mut(&mut self) -> &mut Scene;
     fn get_debug_ui_buffer(&self) -> Rc<RefCell<DebugUIBuffer>>;

core/src/lib.rs

@@ -1,4 +1,6 @@
 pub mod engine;
 pub mod scene;
 pub mod debug_ui;
+pub mod time;
+
 pub use debug_ui::*;

core/src/time.rs

@@ -0,0 +1,144 @@
+use std::thread;
+use std::time::{Duration, Instant};
+
+#[derive(Clone, Debug)]
+pub struct Config {
+    pub target_frame_hz: Option<f64>,
+    pub target_update_hz: f64,
+    pub max_updates_per_frame: u32,
+    pub max_accumulated_steps: u32,
+    pub sleep_tolerance: Duration,
+}
+
+impl Default for Config {
+    fn default() -> Self {
+        Self {
+            target_frame_hz: Some(144.0),
+            target_update_hz: 60.0,
+            max_updates_per_frame: 5,
+            max_accumulated_steps: 8,
+            sleep_tolerance: Duration::from_micros(500),
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct Time {
+    cfg: Config,
+    last_instant: Instant,
+    next_frame_due: Instant,
+    frame_interval: Option<Duration>,
+    fixed_dt: Duration,
+
+    // tracking
+    frame_dt: Duration,
+    accumulator: Duration,
+
+    // counters
+    pub frame_count: u64,
+    pub update_count: u64,
+}
+
+pub struct TickPlan {
+    /// How many fixed updates to run this frame
+    pub updates: u32,
+    /// Interpolation factor for rendering between previous/next sim states
+    pub alpha: f32,
+    /// Measured last frame delta (seconds)
+    pub frame_dt: f32,
+    /// Fixed timestep (seconds)
+    pub fixed_dt: f32,
+}
+
+impl Time {
+    pub fn new(cfg: Config) -> Self {
+        let now = Instant::now();
+        let frame_interval = cfg.target_frame_hz.map(|hz| Duration::from_secs_f64(1.0 / hz));
+        let fixed_dt = Duration::from_secs_f64(1.0 / cfg.target_update_hz);
+        Self {
+            cfg,
+            last_instant: now,
+            next_frame_due: now,
+            frame_interval,
+            fixed_dt,
+            frame_dt: Duration::ZERO,
+            accumulator: Duration::ZERO,
+            frame_count: 0,
+            update_count: 0,
+        }
+    }
+
+    pub fn reconfigure(&mut self, cfg: Config) {
+        self.cfg = cfg.clone();
+        self.frame_interval = cfg.target_frame_hz.map(|hz| Duration::from_secs_f64(1.0 / hz));
+        self.fixed_dt = Duration::from_secs_f64(1.0 / cfg.target_update_hz);
+    }
+
+    pub fn begin_frame_blocking(&mut self) -> TickPlan {
+        // 1) If there's a frame cap, block until next frame deadline
+        if let Some(interval) = self.frame_interval {
+            let mut now = Instant::now();
+            if now < self.next_frame_due {
+                // Sleep most of the remainder, then spin the last tiny bit for precision
+                let total_remaining = self.next_frame_due - now;
+                if total_remaining > self.cfg.sleep_tolerance {
+                    let sleep_for = total_remaining - self.cfg.sleep_tolerance;
+                    thread::sleep(sleep_for);
+                }
+                // Short spin-wait for precision
+                while Instant::now() < self.next_frame_due {
+                    std::hint::spin_loop();
+                }
+                now = self.next_frame_due;
+            }
+            self.next_frame_due = self.next_frame_due + interval;
+            // In case we fell far behind (e.g., debugger pause), resync.
+            if self.next_frame_due < now {
+                self.next_frame_due = now + interval;
+            }
+        }
+
+        // 2) Measure frame dt
+        let now = Instant::now();
+        self.frame_dt = now.saturating_duration_since(self.last_instant);
+        self.last_instant = now;
+        self.frame_count += 1;
+
+        // 3) Accumulate for fixed updates
+        self.accumulator += self.frame_dt;
+
+        // Clamp accumulator to avoid doing a huge number of updates after a stall
+        let max_accumulated = self.fixed_dt * self.cfg.max_accumulated_steps;
+        if self.accumulator > max_accumulated {
+            self.accumulator = max_accumulated;
+        }
+
+        // 4) Determine how many updates to run this frame
+        let mut updates = 0u32;
+        while self.accumulator >= self.fixed_dt && updates < self.cfg.max_updates_per_frame {
+            self.accumulator -= self.fixed_dt;
+            updates += 1;
+            self.update_count += 1;
+        }
+
+        // 5) Compute interpolation factor for rendering (0..1)
+        let alpha = if self.fixed_dt.is_zero() {
+            1.0
+        } else {
+            (self.accumulator.as_secs_f32() / self.fixed_dt.as_secs_f32()).clamp(0.0, 1.0)
+        };
+
+        TickPlan {
+            updates,
+            alpha,
+            frame_dt: self.frame_dt.as_secs_f32(),
+            fixed_dt: self.fixed_dt.as_secs_f32(),
+        }
+    }
+
+    pub fn frame_dt_seconds(&self) -> f32 { self.frame_dt.as_secs_f32() }
+    pub fn fixed_dt_seconds(&self) -> f32 { self.fixed_dt.as_secs_f32() }
+    pub fn alpha(&self) -> f32 {
+        if self.fixed_dt.is_zero() { 1.0 } else { (self.accumulator.as_secs_f32() / self.fixed_dt.as_secs_f32()).clamp(0.0, 1.0) }
+    }
+}

engine/src/engine.rs

@@ -44,7 +44,7 @@ impl EngineTrait for Engine {
     }
 
     /// Update the engine
-    fn update(&mut self, platform_context: PlatformContext) {
+    fn frame_update(&mut self, platform_context: PlatformContext) {
         self.debug_ui_buffer.borrow_mut().reset_buffer();
         let mut ctx = SystemContext {
             scene: self.scene_manager.current_mut(),
@@ -53,7 +53,19 @@ impl EngineTrait for Engine {
         };
 
         for system in self.system_manager.systems.values_mut() {
-            system.update(&mut ctx);
+            system.frame_update(&mut ctx);
+        }
+    }
+
+    fn fixed_update(&mut self, platform_context: PlatformContext) {
+        let mut ctx = SystemContext {
+            scene: self.scene_manager.current_mut(),
+            platform_context,
+            debug_ui_buffer: self.debug_ui_buffer.clone(),
+        };
+
+        for system in self.system_manager.systems.values_mut() {
+            system.fixed_update(&mut ctx);
         }
     }
 

engine/src/system.rs

@@ -19,7 +19,8 @@ pub trait System {
     /// Spawn the first entities of the world.
     fn load_world(&mut self, _ctx: &mut SystemContext) {}
     fn handle_event(&mut self, _ctx: &mut SystemContext) {}
-    fn update(&mut self, _ctx: &mut SystemContext) {}
+    fn fixed_update(&mut self, _ctx: &mut SystemContext) {}
+    fn frame_update(&mut self, _ctx: &mut SystemContext) {}
 }
 
 pub struct SystemManager {

game/src/main.rs

@@ -1,3 +1,4 @@
+use std::fmt::format;
 use glam::{Quat, Vec3};
 use raidillon_engine::{Engine, system::System};
 use raidillon_engine::system::SystemContext;
@@ -34,8 +35,8 @@ impl System for UpdateAspectRatioSystem {
 
 #[derive(Default)]
 struct RenderingTestSystem;
+
 impl System for RenderingTestSystem {
-    fn initialize(&mut self) {}
     fn load_world(&mut self, ctx: &mut SystemContext) {
         ctx.scene.world.spawn((Camera {
             eye:    Vec3::new(0.0, 0.0, 2.0),
@@ -61,9 +62,19 @@ impl System for RenderingTestSystem {
         ));
     }
 
-    fn update(&mut self, ctx: &mut SystemContext) {
-        ctx.debug_ui_buffer.borrow_mut().text("Hello World!".to_owned());
+    fn frame_update(&mut self, ctx: &mut SystemContext) {
+        let mut dbg_ui = ctx.debug_ui_buffer.borrow_mut();
+        dbg_ui.text("Hello World!".to_owned());
+        dbg_ui.text(format!("Frame Delta: {}", ctx.platform_context.time_ctx.frame_dt));
+        dbg_ui.text(format!("Fixed Delta: {}", ctx.platform_context.time_ctx.fixed_dt));
     }
+
+    fn fixed_update(&mut self, ctx: &mut SystemContext) {
+        ctx.scene.world.query_mut::<(&mut Transform, &ModelHandle)>().into_iter().for_each(|(_, (t, _))| {
+            t.rotation *= Quat::from_rotation_y(10.0 * ctx.platform_context.time_ctx.fixed_dt);
+        });
+    }
+
 }
 
 fn main() {

glium_platform/src/platform.rs

@@ -1,6 +1,6 @@
 use std::cell::RefCell;
 use std::rc::Rc;
-use raidillon_platform::{Platform, PlatformContext};
+use raidillon_platform::{Platform, PlatformContext, TimeContext};
 use glium::backend::glutin::Display;
 use glium::backend::glutin::SimpleWindowBuilder;
 use glium::glutin::surface::WindowSurface;
@@ -11,6 +11,8 @@ use crate::system::{RenderingContext, RenderingSystemManager};
 use winit::event::{Event, WindowEvent};
 use raidillon_assets::ModelManagerRef;
 use raidillon_core::engine::EngineTrait;
+use raidillon_core::time;
+use raidillon_core::time::Time;
 use crate::render::debug_ui::ImguiBridge;
 use crate::render::BasicMeshRenderingSystem;
 use crate::GliumAssetManager;
@@ -22,6 +24,7 @@ pub struct GliumPlatform<E: EngineTrait<PlatformCtx = PlatformContext>> {
     rendering_system_manager: RenderingSystemManager,
     asset_manager: ModelManagerRef,
     engine: E,
+    time: time::Time,
 }
 
 impl<E: EngineTrait<PlatformCtx = PlatformContext>> Platform<E> for GliumPlatform<E> {
@@ -38,6 +41,9 @@ impl<E: EngineTrait<PlatformCtx = PlatformContext>> Platform<E> for GliumPlatfor
         let asset_manager: ModelManagerRef = Rc::new(RefCell::new(Box::new(GliumAssetManager::new(Box::new(display.clone())))));
         let mut rendering_system_manager = RenderingSystemManager::new();
 
+        let time_cfg = time::Config::default();
+        let time = time::Time::new(time_cfg);
+
         // Install rendering systems
         rendering_system_manager.add::<BasicMeshRenderingSystem>(&display, &window);
         rendering_system_manager.add::<ImguiBridge>(&display, &window);
@@ -49,6 +55,7 @@ impl<E: EngineTrait<PlatformCtx = PlatformContext>> Platform<E> for GliumPlatfor
             rendering_system_manager,
             asset_manager,
             engine,
+            time,
         }
     }
 
@@ -59,6 +66,7 @@ impl<E: EngineTrait<PlatformCtx = PlatformContext>> Platform<E> for GliumPlatfor
             asset_manager: self.asset_manager.clone(),
             frame_width: w as f32,
             frame_height: h as f32,
+            time_ctx: self.construct_time_ctx(),
         };
         self.engine.initialize(ctx.clone());
         let _ = &self.event_loop.run(move |event, el| {
@@ -98,9 +106,22 @@ impl<E: EngineTrait<PlatformCtx = PlatformContext>> Platform<E> for GliumPlatfor
                     _ => {},
                 },
                 Event::AboutToWait => {
+                    let plan = self.time.begin_frame_blocking();
+
                     let mut ctx2 = ctx.clone();
-                    ctx2.current_event = event.clone();
-                    self.engine.update(ctx2);
+                    ctx2.time_ctx = TimeContext {
+                        frame_dt: self.time.frame_dt_seconds(),
+                        fixed_dt: self.time.fixed_dt_seconds(),
+                        alpha: self.time.alpha(),
+                    };
+                    ctx2.current_event = Event::AboutToWait;
+
+                    for _ in 0..plan.updates {
+                        self.engine.fixed_update(ctx2.clone());
+                    }
+
+                    self.engine.frame_update(ctx2.clone());
+
                     self.rendering_system_manager
                         .systems
                         .values_mut()
@@ -112,3 +133,13 @@ impl<E: EngineTrait<PlatformCtx = PlatformContext>> Platform<E> for GliumPlatfor
         });
     }
 }
+
+impl<E: EngineTrait<PlatformCtx = PlatformContext>> GliumPlatform<E> {
+    fn construct_time_ctx(&self) -> TimeContext {
+        TimeContext {
+            frame_dt: self.time.frame_dt_seconds(),
+            fixed_dt: self.time.fixed_dt_seconds(),
+            alpha: self.time.alpha(),
+        }
+    }
+}

platform/src/context.rs

@@ -7,4 +7,12 @@ pub struct PlatformContext {
     pub asset_manager: ModelManagerRef,
     pub frame_width: f32,
     pub frame_height: f32,
+    pub time_ctx: TimeContext,
+}
+
+#[derive(Clone)]
+pub struct TimeContext {
+    pub frame_dt: f32,
+    pub fixed_dt: f32,
+    pub alpha: f32,
 }

platform/src/lib.rs

@@ -5,4 +5,4 @@ pub mod context;
 
 pub use platform::Platform;
 pub use camera::Camera;
-pub use context::PlatformContext;
+pub use context::{PlatformContext, TimeContext};