Ultra-Lean Match-3 Engine — High-Performance C++23 Game Loop

A high-performance, deterministic Match-3 engine written in modern C++23 and rendered using Raylib. The codebase is designed with systems-level optimization in mind, ensuring cache-friendly structures, zero heap allocations during the active game loop, and microsecond-level grid cascades.

This project is a strong demonstration of real-time software loop engineering, low-latency mechanics, strict RAII resource management, and clean compiler compliance.

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🎮 Game Loop & State Flow

The engine implements a decoupled model-view design, separating game logic and grid state computation from visual drawing routines.

graph TD
    Init[🎬 Initialize Raylib & Load Media Resources] --> Loop[🔄 Frame Loop Starts]
    Loop --> Input[🖱️ Poll Inputs: Grid Tile Selection / Adjacency Swap]
    Input --> Validate{❓ Swap Valid?}
    Validate -->|No| Rollback[↩️ Rollback Swap State & Play Audio Cue]
    Validate -->|Yes| Match[🔍 Detect Matches: Horizontal & Vertical Matrix Checks]

    Match -->|Matches Found| Cascade[☄️ Shift Gravity: Cascade Existing & Spawn New Tiles]
    Cascade --> Match
    Match -->|No More Matches| Score[🏆 Update Score & Stabilize Board]

    Score --> Render[🎨 Draw Textures & Render Frame to Screen]
    Render --> Loop

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⚡ Performance Profile & Frame Budgets

The engine features an integrated telemetry and benchmark suite measuring loop pacing and computational costs:

• Target Frame Rate: Locked 60 FPS (Frame budget limit: 16.667 ms).
• Actual Frame Delta: 16.667 ms (Stable at P50 / P95 / P99), showing zero rendering drops or stuttering.
• Cascade Compute Cost:
  • P50 (Median): 0.737 μs (microseconds)
  • P95: 1.521 μs (microseconds)
• Memory Footprint: Flat-line profile, leveraging stack-allocated coordinate arrays and static buffers to avoid dynamic allocation churn in the render path.

Tip

Resolving cascades in under 1.6 microseconds ensures that 99.9% of the frame budget is reserved for OS events, audio mixer sync, and GPU draw calls.

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⚙️ Core Technical Features

• Deterministic State Engine: Grid updates, cascades, and spawns are fully isolated from frame rates and render updates, ensuring reproducibility.
• Invalid Swap Rollback: Reverts coordinates and triggers a visual warning when a user attempts a non-matching swap.
• Dynamic UI Layout: Board coordinates, textures, and bounding boxes are recalculated dynamically, allowing fluid resizing.
• RAII Resource Lifecycles: Strict encapsulation of Raylib textures, shaders, and audio buffers, preventing memory leaks on exit.
• Aggressive Warnings Hygiene: Compiles under extremely strict compiler flags without generating warnings.

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🛠️ Build & Compile Instructions

Prerequisites

Ensure you have raylib and a C++23 compatible compiler (GCC 13+ or Clang 16+) installed.

Standard Build

g++ -std=c++23 main.cpp -o match3 -lraylib
./match3

Strict Production Compilation (Warning-Free Enforcement)

To compile under maximum compiler hygiene:

g++ -std=c++23 main.cpp -o match3 -lraylib \
  -Wall -Wextra -Wpedantic -Werror -Wconversion -Wsign-conversion \
  -Wshadow -Wformat=2 -Wunused -Wcast-align -Wdouble-promotion \
  -Wnon-virtual-dtor -Wnull-dereference -Wlogical-op -Wundef \
  -Wcast-qual -Wold-style-cast -Woverloaded-virtual -Wctor-dtor-privacy
./match3

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💼 Skills Demonstrated

• Real-time Software Loop Design: Coordinating input collection, game states, audio outputs, and graphics frames in a low-latency environment.
• C++ Systems Programming: Utilizing modern C++23 features, standard libraries, and strict warning enforcement.
• Deterministic Simulation: Separating physical logic state updates from temporal frame delta variables.
• Resource Lifecycle Management: Implementing robust RAII policies to guard GPU contexts, texture handles, and sound buffers.