Unity (C/C++ Scripting)

Language: C

Game Development

Unity was developed by Unity Technologies in 2005 to provide an accessible yet powerful game engine. For high-performance needs, developers use C/C++ plugins to interact with Unity, enabling optimized physics, graphics, AI, or platform-specific integrations.

Unity is a cross-platform game engine that allows developers to create 2D, 3D, VR, and AR games. While Unity primarily uses C#, low-level plugins and performance-critical components can be developed using C or C++ for integration via Unity's Native Plugin Interface.

Installation

unity: Download and install Unity Hub from https://unity.com/

plugin_dev: Install C/C++ development tools (Visual Studio, Xcode, or gcc/clang) for creating native plugins

Usage

Unity allows you to write C# scripts for game logic, while C/C++ can be used for native plugins that are called from Unity scripts. These plugins provide performance-critical functions, access to platform APIs, or custom rendering/physics systems.

Creating a simple C plugin

// myplugin.c
#include <stdio.h>

extern "C" void HelloPlugin() {
    printf("Hello from C plugin!\n");
}

Defines a simple C function that prints a message. The `extern "C"` is needed to avoid name mangling for C++ compilers.

Calling C plugin from Unity C#

using System.Runtime.InteropServices;
using UnityEngine;

public class PluginTest : MonoBehaviour {
    [DllImport("myplugin")]
    private static extern void HelloPlugin();

    void Start() {
        HelloPlugin();
    }
}

Shows how to import and call a C function from Unity using DllImport in a C# script.

Passing data to C plugin

// myplugin.c
extern "C" void AddNumbers(int a, int b, int* result) {
    *result = a + b;
}

Demonstrates passing values and pointers between Unity C# and a C plugin.

Using C++ for complex logic

// myplugin.cpp
#include <cmath>
extern "C" float ComputeDistance(float x1, float y1, float x2, float y2) {
    return sqrtf((x2 - x1)*(x2 - x1) + (y2 - y1)*(y2 - y1));
}

Shows a C++ plugin function performing calculations callable from Unity.

Integration with Unity physics

// Native physics calculations in C/C++ can be exposed as plugin functions
// Then invoked from Unity scripts for performance-critical tasks.

Use C/C++ for heavy physics, AI, or rendering tasks that require native speed.

Error Handling

DllNotFoundException: Ensure the plugin binary is in the correct folder (Assets/Plugins) and named correctly for the platform.

EntryPointNotFoundException: Check the function names in the C/C++ plugin and match them in DllImport attributes.

Segmentation fault / Access violation: Ensure proper memory management and pointer usage in C/C++ code. Avoid invalid dereferencing.

Best Practices

Use C/C++ plugins only for performance-critical code.

Keep plugin APIs simple and well-documented for Unity integration.

Manage memory carefully to prevent leaks or crashes.

Ensure platform-specific binaries are compiled for all target platforms (Windows, Mac, iOS, Android).

Use Unity Profiler to identify areas where native plugins provide real performance gains.

Official Docs Github