Flow Master — Interactive Logic Gate Learning Game

The Problem

Learning digital logic gates is traditionally done through static diagrams and truth tables. This approach lacks interactivity and fails to convey the dynamic nature of logic circuits. Students struggle to visualize how signals propagate through gates in real-time.

Technical Approach

Built a browser-based game engine that simulates digital logic in real-time:

1. Simulation Engine

• Double-buffered state management prevents race conditions
• Event-driven propagation for accurate signal timing
• Cycle-accurate simulation matching real hardware behavior
• Collision detection for wire placement validation

2. Progressive Learning System

The game introduces concepts incrementally:

1. Basic Gates: AND, OR, NOT gates with simple objectives
2. Complex Gates: XOR, NAND, NOR with multi-gate puzzles
3. Combinational Logic: Adders, multiplexers, comparators
4. Sequential Circuits: Flip-flops, registers, state machines

3. Automated Verification

Each level includes test cases that automatically verify correctness:

// Test all input combinations
for (let inputs of testVectors) {
  circuit.setInputs(inputs);
  circuit.simulate();
  if (circuit.getOutputs() !== expectedOutputs[inputs]) {
    return { passed: false, failedCase: inputs };
  }
}
return { passed: true };

4. Canvas-Based Rendering

• Hardware-accelerated HTML5 Canvas for smooth 60fps rendering
• Custom wire routing algorithm for clean circuit layouts
• Color-coded signals (red = HIGH, blue = LOW) for visual clarity

Features

✅ 15+ Interactive Levels with increasing complexity ✅ 7 Logic Gate Types (AND, OR, NOT, XOR, NAND, NOR, XNOR) ✅ Real-time Simulation with instant visual feedback ✅ Automated Testing validates solutions against test cases ✅ Hint System provides guidance without giving away solutions ✅ Progress Tracking saves completed levels locally ✅ Responsive Design works on desktop and tablet

Technical Challenges

Double Buffering

Initial implementation had race conditions where gate outputs would update mid-cycle, causing incorrect results. Solution: maintain current and next state buffers, only swapping after all gates compute:

class Circuit {
  simulate() {
    // Compute next state without modifying current
    for (let gate of this.gates) {
      gate.computeNext(this.currentState);
    }

    // Atomic swap after all computations complete
    this.currentState = this.nextState.clone();
  }
}

Wire Routing

Needed an algorithm to draw clean wire paths between gates. Implemented A* pathfinding with Manhattan distance heuristic, avoiding overlapping components.

Performance Optimization

Canvas redraws were causing lag on complex circuits. Added dirty region tracking to only redraw changed areas, improving performance by 5x.

What’s Next?

Currently implementing:

• Multiplayer puzzle challenges
• Custom level editor
• Achievement system
• Mobile touch controls
• Tutorial videos for advanced concepts

Try It Yourself

Play the game: Flow Master Live Demo

View the code: GitHub Repository