zig-glfw/README.md

# mach/glfw - Ziggified GLFW bindings [![CI](https://github.com/hexops/mach-glfw/workflows/CI/badge.svg)](https://github.com/hexops/mach-glfw/actions) <a href="https://hexops.com"><img align="right" alt="Hexops logo" src="https://raw.githubusercontent.com/hexops/media/main/readme.svg"></img></a>

Ziggified GLFW bindings that [Mach engine](https://github.com/hexops/mach) uses, with 100% API coverage, zero-fuss installation, cross compilation, and more.

This repository is a separate copy of the same library in the [main Mach repository](https://github.com/hexops/mach), and is automatically kept in sync, so that anyone can use this library in their own project / engine if they like!

## Zero fuss installation, cross compilation, and more

[Just as with Mach](https://github.com/hexops/mach#zero-fuss-installation--cross-compilation), you get zero fuss installation & cross compilation using these GLFW bindings. **only `zig` and `git` are needed to build from any OS and produce binaries for every OS.** No system dependencies at all.

## 100% API coverage, 130+ tests, etc.

These bindings have 100% API coverage of GLFW v3.3.4. Every function, type, constant, etc. has been wrapped in a ziggified API.

There are 130+ tests, and CI tests on all major platforms as well as cross-compilation between platforms:

[platform support table](https://github.com/hexops/mach#supported-platforms)

## What does a ziggified GLFW API offer?

Why create a ziggified GLFW wrapper, instead of just using `@cImport` and interfacing with GLFW directly? You get:

- Errors as [zig errors](https://ziglang.org/documentation/master/#Errors) instead of via a callback function.
- `true` and `false` instead of `c.GLFW_TRUE` and `c.GLFW_FALSE` constants.
- Generics, so you can just use `window.hint` instead of `glfwWindowHint`, `glfwWindowHintString`, etc.
- **Enums**, always know what value a GLFW function can accept as everything is strictly typed. And use the nice Zig syntax to access enums, like `window.getKey(.escape)` instead of `c.glfwGetKey(window, c.GLFW_KEY_ESCAPE)`
- Slices instead of C pointers and lengths.
- [packed structs](https://ziglang.org/documentation/master/#packed-struct) represent bit masks, so you can use `if (joystick.down and joystick.right)` instead of `if (joystick & c.GLFW_HAT_DOWN and joystick & c.GLFW_HAT_RIGHT)`, etc.
- Methods, e.g. `my_window.hint(...)` instead of `glfwWindowHint(my_window, ...)`

## How do I use OpenGL, Vulkan, WebGPU, etc. with this?

You'll need to bring your own library for this. Some are:

- (Vulkan) https://github.com/Snektron/vulkan-zig (also see https://github.com/Avokadoen/zig_vulkan)
- (OpenGL) https://github.com/ziglibs/zgl

## Examples

A minimal Vulkan example can be found in the [mach-glfw-vulkan-example](https://github.com/hexops/mach-glfw-vulkan-example) repository:

<img width="912" alt="image" src="https://user-images.githubusercontent.com/3173176/139573985-d862f35a-e78e-40c2-bc0c-9c4fb68d6ecd.png">

## Getting started

### Adding dependency (using Git)

In a `libs` subdirectory of the root of your project:

```sh
git clone https://github.com/hexops/mach-glfw
```

Then in your `build.zig` add:

```zig
...
const glfw = @import("libs/mach-glfw/build.zig");

pub fn build(b: *Builder) !void {
    ...
    exe.addPackage(glfw.pkg(b));
    try glfw.link(b, exe, .{});
}
```

<details>
<summary>

### (optional) Adding dependency using Gyro

</summary>

```sh
gyro add --src github hexops/mach-glfw --root src/main.zig --alias glfw
gyro add --build_dep --src github hexops/mach-glfw --root build.zig --alias build-glfw
```

Then in your `build.zig` add:

```zig
...
const pkgs = @import("deps.zig").pkgs;
const glfw = @import("build-glfw");

pub fn build(b: *Builder) !void {
    ...

    exe.addPackage(pkgs.glfw);
    try glfw.link(b, exe, .{});
}
```

**Note: You should use `gyro build` instead of `zig build` to use gyro**

</details>

# Next steps

Now in your code you may import and use GLFW:

```zig
const glfw = @import("glfw");

pub fn main() !void {
    try glfw.init(.{});
    defer glfw.terminate();

    // Create our window
    const window = try glfw.Window.create(640, 480, "Hello, mach-glfw!", null, null, .{});
    defer window.destroy();

    // Wait for the user to close the window.
    while (!window.shouldClose()) {
        try glfw.pollEvents();
    }
}
```

## A warning about error handling

Unless the action you're performing is truly critical to your application continuing further, you should avoid using `try`.

This is because GLFW unfortunately must return errors for _a large portion_ of its functionality on some platforms, but especially for Wayland - so ideally your application is resiliant to such errors and merely e.g. logs failures that are not critical.

Instead of `try window.getPos()` for example, you may use:

```zig
const pos = window.getPos() catch |err| {
    std.log.err("failed to get window position: error={}\n", .{err});
    return;
};
```

Here is a rough list of functionality Wayland does not support:

- `Window.setIcon`
- `Window.setPos`, `Window.getPos`
- `Window.iconify`, `Window.focus`
- `Monitor.setGamma`
- `Monitor.getGammaRamp`, `Monitor.setGammaRamp`

## Join the community

Join the Mach engine community [on Matrix chat](https://matrix.to/#/#hexops:matrix.org) to discuss this project, ask questions, get help, etc.

## Issues

Issues are tracked in the [main Mach repository](https://github.com/hexops/mach/issues?q=is%3Aissue+is%3Aopen+label%3Aglfw).

## Contributing

Contributions are very welcome. Pull requests must be sent to [the main repository](https://github.com/hexops/mach/tree/main/libs/glfw) to avoid some complex merge conflicts we'd get by accepting contributions in both repositories. Once the changes are merged there, they'll get sync'd to this repository automatically.

For now mach/glfw tracks the latest `master` revision of GLFW, as recorded [in this file](https://github.com/hexops/glfw/blob/main/VERSION), as this version has critical undefined behavior fixes required for GLFW to work with Zig. We will switch to stable releases of GLFW once GLFW 3.4 is tagged.