koffi

Introduction

koffi is a fast and easy-to-use FFI module for Node.js, with support for complex data types such as structs.

The following platforms are supported at the moment:

• Windows x86 (cdecl, stdcall)
• Windows x86_64
• Linux x86
• Linux x86_64
• Linux AArch64

This is still in development, more platforms and more tests will come in the near future.

Installation

Windows

First, make sure the following dependencies are met:

• The "Desktop development with C++" workload from Visual Studio 2022 or 2019 or the "C++ build tools" workload from the Build Tools, with the default optional components.
• CMake meta build system
• Node 16 LTS, but a newer version should work too

Once this is done, run this command from the project root:

npm install

Other platforms (Linux, macOS, etc.)

Make sure the following dependencies are met:

• gcc and g++ >= 8.3 or newer
• GNU Make 3.81 or newer
• CMake meta build system

Once these dependencies are met, simply run the follow command:

npm install

How to use

This section assumes you know how to build C shared libraries.

This examples illustrates how to use koffi with a Raylib shared library:

const koffi = require('koffi/build/Release/koffi.node');

const Color = koffi.struct('Color', {
    r: 'uchar',
    g: 'uchar',
    b: 'uchar',
    a: 'uchar'
});

const Image = koffi.struct('Image', {
    data: koffi.pointer('void'),
    width: 'int',
    height: 'int',
    mipmaps: 'int',
    format: 'int'
});

const GlyphInfo = koffi.struct('GlyphInfo', {
    value: 'int',
    offsetX: 'int',
    offsetY: 'int',
    advanceX: 'int',
    image: Image
});

const Vector2 = koffi.struct('Vector2', {
    x: 'float',
    y: 'float'
});

const Rectangle = koffi.struct('Rectangle', {
    x: 'float',
    y: 'float',
    width: 'float',
    height: 'float'
});

const Texture = koffi.struct('Texture', {
    id: 'uint',
    width: 'int',
    height: 'int',
    mipmaps: 'int',
    format: 'int'
});

const Font = koffi.struct('Font', {
    baseSize: 'int',
    glyphCount: 'int',
    glyphPadding: 'int',
    texture: Texture,
    recs: koffi.pointer(Rectangle),
    glyphs: koffi.pointer(GlyphInfo)
});

// Fix the path to Raylib DLL
let raylib = koffi.load('Raylib.dll', {
    InitWindow: ['void', ['int', 'int', 'string']],
    SetTargetFPS: ['void', ['int']],
    GetScreenWidth: ['int', []],
    GetScreenHeight: ['int', []],
    ClearBackground: ['void', [Color]],
    BeginDrawing: ['void', []],
    EndDrawing: ['void', []],
    WindowShouldClose: ['bool', []],
    GetFontDefault: [Font, []],
    MeasureTextEx: [Vector2, [Font, 'string', 'float', 'float']],
    DrawTextEx: ['void', [Font, 'string', Vector2, 'float', 'float', Color]]
});

raylib.InitWindow(800, 600, 'Test Raylib');
raylib.SetTargetFPS(60);

let angle = 0;

while (!raylib.WindowShouldClose()) {
    raylib.BeginDrawing();
    raylib.ClearBackground({ r: 0, g: 0, b: 0, a: 255 }); // black

    let win_width = raylib.GetScreenWidth();
    let win_height = raylib.GetScreenHeight();

    let text = 'Hello World!';
    let text_width = raylib.MeasureTextEx(raylib.GetFontDefault(), text, 32, 1).x;

    let color = {
        r: 127.5 + 127.5 * Math.sin(angle),
        g: 127.5 + 127.5 * Math.sin(angle + Math.PI / 2),
        b: 127.5 + 127.5 * Math.sin(angle + Math.PI),
        a: 255
    };
    let pos = {
        x: (win_width / 2 - text_width / 2) + 120 * Math.cos(angle - Math.PI / 2),
        y: (win_height / 2 - 16) + 120 * Math.sin(angle - Math.PI / 2)
    };

    raylib.DrawTextEx(raylib.GetFontDefault(), text, pos, 32, 1, color);

    raylib.EndDrawing();

    angle += Math.PI / 180;
}