zbullet

zbullet v0.3.0 - Zig bindings for Bullet Physics SDK

Overview

Bullet Physics SDK 3.25 (C++) ---> cbullet v0.2 (C) ---> zbullet (Zig)

cbullet is C API for Bullet Physics SDK which is being developed as a part of zig-gamedev project (source code).

zbullet is built on top of cbullet and provides Zig friendly bindings.

Features

Some cbullet features:

• Most collision shapes
• Rigid bodies
• Most constraint types
• Tries to minimize number of memory allocations
  • Multiple rigid bodies and motion states can be created with one memory allocation
  • New physics objects can re-use existing memory
• Lots of error checks in debug builds

For an example code please see:

• bullet physics test (wgpu)
• intro 6 (Windows-only)
• virtual physics lab (Windows-only, uses cbullet directly)
• zbullet tests

Getting started

Copy zbullet and zmath to a subdirectory of your project and add the following to your build.zig.zon .dependencies:

    .zbullet = .{ .path = "local/path/to/zbullet" },
    .zmath = .{ .path = "local/path/to/zmath" }, // required for tests

Then in your build.zig add:

pub fn build(b: *std.Build) void {
    const exe = b.addExecutable(.{ ... });

    const zbullet = b.dependency("zbullet", .{});
    exe.root_module.addImport("zbullet", zbullet.module("root"));
    exe.linkLibrary(zbullet.artifact("cbullet"));
}

Now in your code you may import and use zbullet:

const zbt = @import("zbullet");

pub fn main() !void {
    ...
    zbt.init(allocator);
    defer zbt.deinit();

    const world = zbt.initWorld();
    defer world.deinit();

    // Create unit cube shape.
    const box_shape = zbt.initBoxShape(&.{ 0.5, 0.5, 0.5 });
    defer box_shape.deinit();

    // Create rigid body that will use above shape.
    const initial_transform = [_]f32{
        1.0, 0.0, 0.0, // orientation
        0.0, 1.0, 0.0,
        0.0, 0.0, 1.0,
        2.0, 2.0, 2.0, // translation
    };
    const box_body = zbt.initBody(
        1.0, // mass (0.0 for static objects)
        &initial_transform,
        box_shape.asShape(),
    );
    defer body.deinit();

    // Add body to the physics world.
    world.addBody(box_body);
    defer world.removeBody(box_body);

    while (...) {
        ...
        // Perform a simulation step.
        _ = world.stepSimulation(time_step, .{});
        ...
    }
}