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This code is terribly outdated.

There are "official" (and more importantly, auto-generated) Rust bindings now. Head over to sokol-rust to check them out.

sokol-rs

This repository contains source code of the following Rust library crates:

  • sokol (README) - Rust bindings to the sokol header-only, cross-platform libraries.
  • sokol-imgui (README) - Rust bindings to the sokol_imgui and sokol_gfx_imgui utility libraries.
  • sokol-sys (README) - system crate to compile native dependencies shared by other crates.

To complement the crates above:

  • sokol-stb - a library for easy access to a subset of the stb libraries.
  • sokol-samples - a number of examples ported from sokol-samples.

How to build

The current version compiles (and has been tested) with stable Rust (v1.34.1) on Windows (both MSVC and GNU toolchains), MacOS and Linux.

> git clone --recursive https://github.com/code-disaster/sokol-rs
> cd sokol-rs
> cargo build

The sokol-samples folder contains some examples ported from sokol-samples/sapp.

> cargo run --bin clear-sapp

About the implementation

The SApp program loop

In the C version of sokol_app, when compiled with SOKOL_NO_ENTRY, you call sapp_run(), passing callback function pointers for setup, frame updates, and cleanup.

In the Rust version, you call sokol::app::sapp_run(). This hands over control to the C library, which then will operate as usual. The C callbacks are implemented by sokol-rs. They are forwarded to your application via the SApp trait. User applications implement this trait to power the application loop.

Check the clear-sapp sample for a minimal implementation.

API style and implementation details

I tried to stay as close as possible to the source, while adjusting to the Rust naming conventions, as well as making the public API more convenient in places a direct port would be too cumbersome.

  • Function names stay the same. No change here.
  • Function signatures are identical most of the time. In some rare cases, I moved parameters out of structs and pass them as additional function parameters.
  • Type names are renamed, e.g. sapp_desc -> SAppDesc.
  • Some identifiers, like "type", had to be renamed because they clash with reserved keywords in Rust.
  • Element names in enums are shortened and changed to CamelCase, e.g. sapp_event_type::SAPP_EVENTTYPE_RESIZED becomes SAppEventType::Resized. On the plus side, they are all totally type-safe now.
  • I tried to stay true to the C99-style struct initializers - check the samples to see what it looks like. Since Rust forces you to initialize all struct members, most of them enable #[derive(Default)] so that you are still able to only set the options you are interested in - everything else can be initialized to sokol's default values with ..Default::default().
  • Arrays in structs, which are all fixed-sized in sokol, are initialized using Vec<T> in public declarations. This is because they can be set conveniently with vec![], so you don't have to keep an eye on the array size, and/or spatter Default::default() all over the place. (I tried to be clever and use macro magic to make this part even more convenient while not paying the Vec<> allocation overhead, but I'm not nearly clever enough with Rust... yet.)

In the Rust library, the app, gfx and audio modules are not as separable as their C counterparts. Essentially, sokol-rs assumes that you use them in conjunction.

  • sg_setup() uses app functions to configure the render backend.
  • If saudio_setup() is told to use callbacks, the function callback is part of the SApp trait (and, as a matter of fact, managed by the app module in most parts).

Status

The following libraries are implemented:

header Rust module status notes
sokol_app.h sokol::app done
sokol_args.h n/a n/a low priority: there are many cmdline parsers for Rust already
sokol_audio.h sokol::audio done callback API via trait in sokol::app
sokol_gfx.h sokol::gfx mostly done trace hooks are enabled (and consumed by the sokol_gfx_imgui implementation in the sokol-imgui crate)

missing: separate resource management, render contexts, user-provided buffers

not implemented: sg_query_*_info() functions
sokol_time.h sokol::time done

Additionally, some utility libraries are available:

header Rust module status notes
sokol_gfx_imgui.h sokol_imgui::gfx partially
done		 sg_imgui_t is wrapped opaquely instead of replicated in Rust

missing: sg_imgui_draw_*_content and sg_imgui_draw_*_window functions
sokol_gl.h n/a n/a no plans yet
sokol_imgui.h sokol_imgui::imgui done

Remarks

  • gfx is configured to use the "native" render API on each platform:
    • Windows (MSVC): Direct3D 11
    • Windows (not MSVC, tested with x86_64-pc-windows-gnu): OpenGL 3.3
    • MacOS: Metal
    • Linux: OpenGL 3.3
  • x86_64-pc-windows-gnu uses GL33 because sokol_gfx fails to compile for Direct3D 11 with gcc on MinGW64. I didn't invest much time to figure out why.