https://github.com/prime31/zig-ecs

https://github.com/prime31/zig-ecs

zig

Last synced: about 2 months ago
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• Host: GitHub
• URL: https://github.com/prime31/zig-ecs
• Owner: prime31
• License: mit
• Created: 2020-06-01T04:23:04.000Z (over 4 years ago)
• Default Branch: master
• Last Pushed: 2024-05-10T16:42:57.000Z (4 months ago)
• Last Synced: 2024-06-11T21:17:48.511Z (3 months ago)
• Topics: zig
• Language: Zig
• Homepage:
• Size: 298 KB
• Stars: 204
• Watchers: 2
• Forks: 35
• Open Issues: 3
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# Zig ECS

Zig ECS is a zig port of the fantasic [Entt](https://github.com/skypjack/entt). Entt is _highly_ templated C++ code which depending on your opinion is either a good thing or satan itself in code form. Zig doesn't have the same concept as C++ templates (thank goodness!) so the templated code was changed over to use Zig's generics and compile time metaprogramming.

## What does a zigified Entt look like?

Below are examples of a View and a Group, the two main ways to work with entities in the ecs along with the scaffolding code.

Declare some structs to work with:

```zig

pub const Velocity = struct { x: f32, y: f32 };

pub const Position = struct { x: f32, y: f32 };

```

Setup the Registry, which holds the entity data and is where we run our queries:

```zig

var reg = ecs.Registry.init(std.testing.allocator);

```

Create a couple entities and add some components to them

```zig

var entity = reg.create();

reg.add(entity, Position{ .x = 0, .y = 0 });

reg.add(entity, Velocity{ .x = 5, .y = 7 });

...

```

Create and iterate a View that matches all entities with a `Velocity` and `Position` component:

```zig

var view = reg.view(.{ Velocity, Position }, .{});

var iter = view.iterator();

while (iter.next()) |entity| {

    const pos = view.getConst(Position, entity); // readonly copy

    var vel = view.get(Velocity, entity); // mutable

}

```

The same example using an owning Group:

```zig

var group = reg.group(.{ Velocity, Position }, .{}, .{});

group.each(each);

fn each(e: struct { vel: *Velocity, pos: *Position }) void {

    e.pos.*.x += e.vel.x;

    e.pos.*.y += e.vel.y;

}

```