Sim Time & Future

Understanding Multisynq’s time system is crucial for building applications with animations, timers, and time-dependent behaviors. Unlike real-world time, Multisynq uses simulation time to ensure perfect synchronization across all users.

Simulation Time vs Real Time

Synchronized, deterministic time used by models

Source: Multisynq reflector heartbeat ticks
Synchronization: Identical across all users
Deterministic: Same time, same results
Access: this.now() in models

class GameModel extends Multisynq.Model {
    init() {
        console.log("Session started at:", this.now()); // Simulation time
        this.tick();
    }
    
    tick() {
        const currentTime = this.now();
        console.log("Simulation time:", currentTime);
        
        // All users see identical time values
        this.future(1000).tick(); // Schedule next tick
    }
}

Simulation time only advances when heartbeat ticks are received from the reflector.

Synchronized, deterministic time used by models

Source: Multisynq reflector heartbeat ticks
Synchronization: Identical across all users
Deterministic: Same time, same results
Access: this.now() in models

class GameModel extends Multisynq.Model {
    init() {
        console.log("Session started at:", this.now()); // Simulation time
        this.tick();
    }
    
    tick() {
        const currentTime = this.now();
        console.log("Simulation time:", currentTime);
        
        // All users see identical time values
        this.future(1000).tick(); // Schedule next tick
    }
}

Simulation time only advances when heartbeat ticks are received from the reflector.

Local system time used by views

Source: Local device system clock
Synchronization: Different on each device
Variable: Can drift between devices
Access: Date.now() in views

class GameView extends Multisynq.View {
    init() {
        console.log("View created at:", Date.now()); // Real time
        this.updateDisplay();
    }
    
    updateDisplay() {
        const realTime = Date.now();
        const simTime = this.model.now();
        
        console.log("Real time:", realTime);
        console.log("Sim time:", simTime);
        
        // Views can use future() with real time
        this.future(16).updateDisplay(); // ~60fps
    }
}

Never use Date.now() in models - it breaks synchronization!

Core Time Concepts

📐 Simulation Time

Time since session began

Measured in milliseconds
Starts at 0 when session begins
Identical for all users
Only advances with reflector heartbeats

// All users get the same value
const time = this.now(); // e.g., 45723 ms

💓 Heartbeat Ticks

Synchronization mechanism

Sent by reflector to all users
Advances simulation time
Ensures synchronized execution
Typically ~60-120Hz

// Multiple calls return same value
console.log(this.now()); // 1000
console.log(this.now()); // 1000 (same!)
console.log(this.now()); // 1000 (until next tick)

The `future()` Method

future() is Multisynq’s scheduling mechanism for time-based behaviors.

Schedule a method to run in the future

this.future(delay).methodName(args);

delay: Milliseconds to wait (can be fractional)
methodName: Method to call when delay expires
args: Optional arguments to pass

class AnimationModel extends Multisynq.Model {
    init() {
        this.x = 0;
        this.startAnimation();
    }
    
    startAnimation() {
        this.x += 1;
        
        // Schedule next frame in 16.67ms (~60fps)
        this.future(1000/60).startAnimation();
    }
    
    explode() {
        // Destroy after 2 seconds
        this.future(2000).destroy();
    }
}

Schedule a method to run in the future

this.future(delay).methodName(args);

delay: Milliseconds to wait (can be fractional)
methodName: Method to call when delay expires
args: Optional arguments to pass

class AnimationModel extends Multisynq.Model {
    init() {
        this.x = 0;
        this.startAnimation();
    }
    
    startAnimation() {
        this.x += 1;
        
        // Schedule next frame in 16.67ms (~60fps)
        this.future(1000/60).startAnimation();
    }
    
    explode() {
        // Destroy after 2 seconds
        this.future(2000).destroy();
    }
}

Models can have multiple future calls active

class GameEntity extends Multisynq.Model {
    init() {
        this.health = 100;
        this.position = { x: 0, y: 0 };
        
        // Multiple timing systems
        this.updatePosition();    // 60fps movement
        this.checkCollisions();   // 20fps collision detection
        this.regenerateHealth();  // Every 5 seconds
    }
    
    updatePosition() {
        // High-frequency position updates
        this.position.x += this.velocity.x;
        this.position.y += this.velocity.y;
        
        this.future(1000/60).updatePosition();
    }
    
    checkCollisions() {
        // Lower-frequency collision detection
        this.detectCollisionsWithOtherEntities();
        
        this.future(1000/20).checkCollisions();
    }
    
    regenerateHealth() {
        // Periodic health regeneration
        if (this.health < 100) {
            this.health = Math.min(100, this.health + 1);
        }
        
        this.future(5000).regenerateHealth();
    }
}

Precise timing with decimal values

class PreciseTimer extends Multisynq.Model {
    init() {
        this.frame = 0;
        
        // Exact frame rates
        this.render60fps();   // 16.666... ms
        this.render30fps();   // 33.333... ms
        this.physics120fps(); // 8.333... ms
    }
    
    render60fps() {
        this.frame++;
        this.future(1000/60).render60fps(); // 16.67ms
    }
    
    render30fps() {
        this.updateSlowSystems();
        this.future(1000/30).render30fps(); // 33.33ms
    }
    
    physics120fps() {
        this.updatePhysics();
        this.future(1000/120).physics120fps(); // 8.33ms
    }
}

Common Patterns

🎮 Game Loop

Classic game update pattern

class GameModel extends Multisynq.Model {
    init() {
        this.gameState = "playing";
        this.entities = new Map();
        this.lastUpdate = this.now();
        
        // Start the main game loop
        this.gameLoop();
    }
    
    gameLoop() {
        const currentTime = this.now();
        const deltaTime = currentTime - this.lastUpdate;
        
        // Update all game systems
        this.updatePhysics(deltaTime);
        this.updateAI(deltaTime);
        this.updateAnimations(deltaTime);
        this.checkWinConditions();
        
        this.lastUpdate = currentTime;
        
        // Schedule next frame (60fps)
        this.future(1000/60).gameLoop();
    }
    
    updatePhysics(dt) {
        for (const entity of this.entities.values()) {
            entity.update(dt);
        }
    }
    
    updateAI(dt) {
        // AI logic runs at game loop frequency
    }
    
    updateAnimations(dt) {
        // Smooth animation updates
    }
}

⏰ Timer System

Countdown timers and delayed actions

class TimerModel extends Multisynq.Model {
    init() {
        this.timers = new Map();
        this.nextTimerId = 1;
    }
    
    createTimer(duration, callback, repeat = false) {
        const timerId = this.nextTimerId++;
        const timer = {
            id: timerId,
            duration,
            callback,
            repeat,
            startTime: this.now()
        };
        
        this.timers.set(timerId, timer);
        this.scheduleTimer(timer);
        
        return timerId;
    }
    
    scheduleTimer(timer) {
        this.future(timer.duration)[timer.callback]();
        
        if (timer.repeat) {
            // Reschedule for repeated timers
            this.future(timer.duration).rescheduleTimer(timer.id);
        }
    }
    
    rescheduleTimer(timerId) {
        const timer = this.timers.get(timerId);
        if (timer && timer.repeat) {
            this.scheduleTimer(timer);
        }
    }
    
    cancelTimer(timerId) {
        this.timers.delete(timerId);
        // Note: Cannot cancel already scheduled future calls
    }
    
    // Example usage
    startGame() {
        // Game ends in 5 minutes
        this.createTimer(5 * 60 * 1000, "endGame", false);
        
        // Spawn enemies every 10 seconds
        this.createTimer(10000, "spawnEnemy", true);
    }
    
    endGame() {
        this.gameState = "finished";
        this.publish("game", "ended", { time: this.now() });
    }
    
    spawnEnemy() {
        const enemy = Enemy.create();
        this.entities.set(enemy.id, enemy);
    }
}

🏃 Animation System

Smooth object animations

class AnimatedObject extends Multisynq.Model {
    init() {
        this.position = { x: 0, y: 0 };
        this.target = { x: 100, y: 100 };
        this.animationDuration = 2000; // 2 seconds
        this.animationStart = null;
        
        this.startAnimation();
    }
    
    startAnimation() {
        this.animationStart = this.now();
        this.animate();
    }
    
    animate() {
        const elapsed = this.now() - this.animationStart;
        const progress = Math.min(elapsed / this.animationDuration, 1);
        
        // Smooth easing function
        const easedProgress = this.easeInOutCubic(progress);
        
        // Interpolate position
        this.position.x = this.lerp(0, this.target.x, easedProgress);
        this.position.y = this.lerp(0, this.target.y, easedProgress);
        
        // Notify views of position change
        this.publish("animation", "position", {
            id: this.id,
            position: this.position,
            progress: progress
        });
        
        if (progress < 1) {
            // Continue animation next frame
            this.future(1000/60).animate();
        } else {
            // Animation complete
            this.onAnimationComplete();
        }
    }
    
    easeInOutCubic(t) {
        return t < 0.5 
            ? 4 * t * t * t 
            : 1 - Math.pow(-2 * t + 2, 3) / 2;
    }
    
    lerp(start, end, progress) {
        return start + (end - start) * progress;
    }
    
    onAnimationComplete() {
        this.publish("animation", "complete", { id: this.id });
    }
}

Views and Time

Views use real time, not simulation time!

Views can use future() with real time

class GameView extends Multisynq.View {
    init() {
        this.canvas = document.getElementById('canvas');
        this.lastFrame = Date.now();
        
        // Start render loop using real time
        this.renderLoop();
    }
    
    renderLoop() {
        const now = Date.now();
        const deltaTime = now - this.lastFrame;
        
        // Render current frame
        this.render(deltaTime);
        
        this.lastFrame = now;
        
        // Schedule next frame (~60fps)
        this.future(16).renderLoop();
    }
    
    render(deltaTime) {
        // Use simulation time for game state
        const gameTime = this.model.now();
        
        // Use real time for smooth interpolation
        this.drawGameObjects(gameTime, deltaTime);
    }
}

Views can use future() with real time

class GameView extends Multisynq.View {
    init() {
        this.canvas = document.getElementById('canvas');
        this.lastFrame = Date.now();
        
        // Start render loop using real time
        this.renderLoop();
    }
    
    renderLoop() {
        const now = Date.now();
        const deltaTime = now - this.lastFrame;
        
        // Render current frame
        this.render(deltaTime);
        
        this.lastFrame = now;
        
        // Schedule next frame (~60fps)
        this.future(16).renderLoop();
    }
    
    render(deltaTime) {
        // Use simulation time for game state
        const gameTime = this.model.now();
        
        // Use real time for smooth interpolation
        this.drawGameObjects(gameTime, deltaTime);
    }
}

Coordinate between sim time and real time

class SmoothView extends Multisynq.View {
    init() {
        this.interpolatedPositions = new Map();
        this.renderLoop();
        
        // Listen to model updates
        this.subscribe("object", "moved", this.onObjectMoved);
    }
    
    onObjectMoved(data) {
        // Store position with simulation time
        const interpolation = {
            startPos: this.interpolatedPositions.get(data.id) || data.position,
            endPos: data.position,
            startTime: Date.now(),
            simTime: this.model.now()
        };
        
        this.interpolatedPositions.set(data.id, interpolation);
    }
    
    renderLoop() {
        const realTime = Date.now();
        
        // Smooth interpolation between model updates
        for (const [id, interp] of this.interpolatedPositions) {
            const elapsed = realTime - interp.startTime;
            const progress = Math.min(elapsed / 100, 1); // 100ms interpolation
            
            const smoothPos = {
                x: this.lerp(interp.startPos.x, interp.endPos.x, progress),
                y: this.lerp(interp.startPos.y, interp.endPos.y, progress)
            };
            
            this.drawObject(id, smoothPos);
        }
        
        this.future(16).renderLoop(); // ~60fps
    }
}

Timing Best Practices

⚡ Performance

Optimize timing frequency

// ✅ Good: Different rates for different systems
this.updatePhysics();    // 60fps - needs precision
this.updateAI();         // 10fps - less critical
this.updateNetworking(); // 20fps - moderate

// ❌ Avoid: Everything at maximum rate
this.future(16).updateEverything(); // Wasteful

// ✅ Good: Batch related operations
this.future(100).batchUpdate();

batchUpdate() {
    this.updateMultipleThings();
    this.processAllChanges();
    this.future(100).batchUpdate();
}

🎯 Precision

Use appropriate timing precision

// ✅ Good: Match timing to need
this.future(1000/60).renderFrame();   // 60fps for smooth animation
this.future(1000/20).checkCollisions();// 20fps for game logic
this.future(5000).saveProgress();      // 5s for persistence

// ❌ Avoid: Inappropriate frequencies
this.future(1).highFrequencySpam();    // Too fast
this.future(10000).criticalGameLogic(); // Too slow

Debugging Time Issues

Debug timing problems

class DebugModel extends Multisynq.Model {
    init() {
        this.tickCount = 0;
        this.startTime = this.now();
        
        this.debugTick();
    }
    
    debugTick() {
        this.tickCount++;
        const elapsed = this.now() - this.startTime;
        const averageInterval = elapsed / this.tickCount;
        
        console.log(`Tick ${this.tickCount}:`);
        console.log(`  Sim time: ${this.now()}`);
        console.log(`  Elapsed: ${elapsed}ms`);
        console.log(`  Average interval: ${averageInterval.toFixed(2)}ms`);
        
        this.future(1000).debugTick(); // Every second
    }
}

Debug timing problems

class DebugModel extends Multisynq.Model {
    init() {
        this.tickCount = 0;
        this.startTime = this.now();
        
        this.debugTick();
    }
    
    debugTick() {
        this.tickCount++;
        const elapsed = this.now() - this.startTime;
        const averageInterval = elapsed / this.tickCount;
        
        console.log(`Tick ${this.tickCount}:`);
        console.log(`  Sim time: ${this.now()}`);
        console.log(`  Elapsed: ${elapsed}ms`);
        console.log(`  Average interval: ${averageInterval.toFixed(2)}ms`);
        
        this.future(1000).debugTick(); // Every second
    }
}

Track timing performance

class PerformanceModel extends Multisynq.Model {
    init() {
        this.performanceStats = {
            frameCount: 0,
            totalTime: 0,
            maxFrameTime: 0,
            minFrameTime: Infinity
        };
        
        this.monitorPerformance();
    }
    
    monitorPerformance() {
        const frameStart = this.now();
        
        // Do your frame work here
        this.updateGame();
        
        const frameEnd = this.now();
        const frameTime = frameEnd - frameStart;
        
        // Update statistics
        this.performanceStats.frameCount++;
        this.performanceStats.totalTime += frameTime;
        this.performanceStats.maxFrameTime = Math.max(
            this.performanceStats.maxFrameTime, 
            frameTime
        );
        this.performanceStats.minFrameTime = Math.min(
            this.performanceStats.minFrameTime, 
            frameTime
        );
        
        // Log stats every 60 frames
        if (this.performanceStats.frameCount % 60 === 0) {
            this.logPerformanceStats();
        }
        
        this.future(1000/60).monitorPerformance();
    }
    
    logPerformanceStats() {
        const stats = this.performanceStats;
        const avgFrameTime = stats.totalTime / stats.frameCount;
        
        console.log("Performance Stats:");
        console.log(`  Average frame time: ${avgFrameTime.toFixed(2)}ms`);
        console.log(`  Max frame time: ${stats.maxFrameTime.toFixed(2)}ms`);
        console.log(`  Min frame time: ${stats.minFrameTime.toFixed(2)}ms`);
    }
}

Common Pitfalls

Avoid these timing mistakes:

// ❌ NEVER do this in models
class BadModel extends Multisynq.Model {
    init() {
        this.startTime = Date.now(); // BREAKS SYNCHRONIZATION!
        this.badTick();
    }
    
    badTick() {
        const now = Date.now(); // DIFFERENT ON EACH DEVICE!
        if (now - this.startTime > 5000) {
            this.doSomething(); // Will happen at different times!
        }
        this.future(100).badTick();
    }
}

// ✅ Correct approach
class GoodModel extends Multisynq.Model {
    init() {
        this.startTime = this.now(); // Use simulation time
        this.goodTick();
    }
    
    goodTick() {
        const now = this.now(); // SYNCHRONIZED!
        if (now - this.startTime > 5000) {
            this.doSomething(); // Happens simultaneously!
        }
        this.future(100).goodTick();
    }
}

// ❌ NEVER do this in models
class BadModel extends Multisynq.Model {
    init() {
        this.startTime = Date.now(); // BREAKS SYNCHRONIZATION!
        this.badTick();
    }
    
    badTick() {
        const now = Date.now(); // DIFFERENT ON EACH DEVICE!
        if (now - this.startTime > 5000) {
            this.doSomething(); // Will happen at different times!
        }
        this.future(100).badTick();
    }
}

// ✅ Correct approach
class GoodModel extends Multisynq.Model {
    init() {
        this.startTime = this.now(); // Use simulation time
        this.goodTick();
    }
    
    goodTick() {
        const now = this.now(); // SYNCHRONIZED!
        if (now - this.startTime > 5000) {
            this.doSomething(); // Happens simultaneously!
        }
        this.future(100).goodTick();
    }
}

// ❌ Cannot cancel future calls
class ProblematicModel extends Multisynq.Model {
    startTimer() {
        const futureCall = this.future(5000).doSomething();
        
        // This doesn't work - cannot cancel!
        // clearTimeout(futureCall); // No such method
        // futureCall.cancel();      // No such method
    }
    
    // ✅ Use flags for cancellation
    startTimer() {
        this.timerActive = true;
        this.future(5000).conditionalAction();
    }
    
    conditionalAction() {
        if (this.timerActive) {
            this.doSomething();
        }
    }
    
    cancelTimer() {
        this.timerActive = false; // Prevents execution
    }
}

// ❌ Don't block the main thread
class BlockingModel extends Multisynq.Model {
    tick() {
        // This blocks synchronization!
        for (let i = 0; i < 1000000; i++) {
            this.heavyCalculation(i);
        }
        
        this.future(16).tick();
    }
}

// ✅ Break work into chunks
class NonBlockingModel extends Multisynq.Model {
    init() {
        this.workQueue = [];
        this.processWork();
    }
    
    processWork() {
        // Process only a small chunk each frame
        const startTime = this.now();
        while (this.workQueue.length > 0 && this.now() - startTime < 5) {
            const work = this.workQueue.shift();
            this.processWorkItem(work);
        }
        
        this.future(16).processWork();
    }
}

Next Steps

Events & Pub-Sub

Learn how events work with time-based systems

Writing a Multisynq Model

Master model development with proper timing

View Smoothing

Create smooth animations between model updates

Random

Understand synchronized random number generation

Mastering simulation time and the future() method is essential for creating responsive, synchronized applications. Always use simulation time in models and real time in views to maintain perfect synchronization across all users.

Get Started

Tutorials

Conceptual

Essentials

AI Development

Simulation Time vs Real Time

Core Time Concepts

📐 Simulation Time

💓 Heartbeat Ticks

The `future()` Method

Common Patterns

Views and Time

Timing Best Practices

⚡ Performance

🎯 Precision

Debugging Time Issues

Common Pitfalls

Next Steps

Events & Pub-Sub

Writing a Multisynq Model

View Smoothing

Random

Get Started

Tutorials

Conceptual

Essentials

AI Development

​Simulation Time vs Real Time

​Core Time Concepts

📐 Simulation Time

💓 Heartbeat Ticks

​The future() Method

​Common Patterns

​Views and Time

​Timing Best Practices

⚡ Performance

🎯 Precision

​Debugging Time Issues

​Common Pitfalls

​Next Steps

Events & Pub-Sub

Writing a Multisynq Model

View Smoothing

Random

Simulation Time vs Real Time

Core Time Concepts

The `future()` Method

Common Patterns

Views and Time

Timing Best Practices

Debugging Time Issues

Common Pitfalls

Next Steps