3DS homebrew sdk written entirely in zig.

zig fetch --save git+https://github.com/GasInfinity/zitrus

Then add this to your build.zig:

const zitrus = @import("zitrus");

const zitrus_dep = b.dependency("zitrus", .{});

// zitrus contains code useful for tooling outside of a 3DS environment.
const zitrus_mod = zitrus_dep.module("zitrus");

const exe = b.addExecutable(.{
    .name = "panic.elf",
    .root_module = b.createModule(.{
        .root_source_file = b.path("src/main.zig"),
        .target = b.resolveTargetQuery(zitrus.target.arm11.horizon.query), // zig 0.16.0 will add 'arm-3ds' and this will be deprecated!
        .optimize = optimize,
        .single_threaded = true, // XXX: Currently needed for page_allocator.
        .imports = &.{
            .{ .name = "zitrus", .module = zitrus_mod },
        },
    }),
});

// 3DSX's are PIE's
exe.pie = true;

// Needed for any binary which targets the 3DS
exe.setLinkerScript(zitrus_dep.path(zitrus.target.arm11.horizon.linker_script));

// You can skip installing the elf but it is recommended to keep it for debugging purposes
b.installArtifact(exe);

const smdh: zitrus.MakeSmdh = .init(zitrus_dep, .{
    .settings = b.path("path-to-smdh-settings.zon"), // look at any demo for a quick sample.
    .icon = b.path("path-to-icon.png/jpg/..."), // supported formats depends on zigimg image decoding.
});

// See `MakeRomFs` if you need something patchable unlike `@embedFile`.
// WARNING: Won't be properly cached as there's an issue upstream.

// This step will convert your executable to 3dsx (the defacto homebrew executable format) to execute it in an emulator or real 3DS
const final_3dsx: zitrus.Make3dsx = .init(zitrus_dep, .{ .exe = exe, .smdh = smdh });
final_3dsx.install(b, .default);

In your root file, you must also add this, as there's no way to implicitly tell zig to evaluate/import it automagically:

pub const panic = zitrus.horizon.panic;

comptime {
    _ = zitrus;
}

Currently there are multiple examples in the demo/ directory. To build them, you must have zig 0.15.1 in your path and run zig build.

• mango contains samples of how to use the mango graphics api.

• panic is a simple example that panics when opened to test panics and traces.

• info is a simple app that currently shows the console region and model (will be updated to show more info over time).

• bitmap is a port of the bitmap example in libctru's 3ds-examples.

• flappy is a simple fully functional flappy bird clone written entirely with software blitting.

• gpu is a playground for mango, bleeding edge features are tested there. Not really an example per-se.

⚠️ Feature regressed temporarily due to dependency or upstream (usually when zig updates this can happen)

⛔ Blocked due to upstream. Impossible to do until something gets fixed or added, usually listed in #1

🟢 Fully implemented 🟡 Partially implemented 🔴 Implementation not started/missing critical things

🔋 High priority 🪫 Low priority

• 🟡 Mango
• 🟡 Horizon

• 🟡 Horizon
• 🟡 Mango

• 🟢 Smdh (tools/Smdh): Make / Dump
• 🟢 3dsx (tools/3dsx): Make / Dump
• 🟢 Zpsh (tools/Pica): Make. Specific to zitrus, ZitrusPicaSHader. Used in mango
• 🟡 Firm (tools/Firm): Info
• 🟡 Ncch (tools/Ncch): Dump (/ Info)
  • 🟡 ExeFS (tools/ExeFs): Info / Dump
  • 🟢 RomFS (tools/RomFs): Make / List / Dump
• 🟡 LZrev (tools/LzRev): Decompression

• 🔴⛔ threadlocal variables.
• 🟡⛔🔋 Panic / error reporting and tracing.
• 🟡⛔🔋 Application Test runner.

• 🟢 srv:
• 🟢 err:f
• 🟡 APT:S/A/U
• 🟡 hid:SPRV/USER
• 🟢 ir:rst
• 🟡 fs:USER/LDR
• 🟡 cfg:u/s/i
• 🟢 gsp::Gpu
• 🟡🪫 gsp::Lcd
• 🟡 ns:s
• 🟢 ns:p/c
• 🟡 csnd:SND
• 🟡🪫 pm:app
• 🟢 pm:dbg
• 🟡 soc:U
• 🟡 ps:ps
• 🟡 pxi:ps9
• 🟡 Loader
• 🔴 All other services not listed here

• 🟢 error
• 🟡 swkbd
• 🔴 All other applets not listed here.

• 🟢 Horizon
• 🔴 Interface (for freestanding usage)

• 🟢 Presentation engine: 240x400, 240x400x2, 240x800 + 240x320. Double or Triple buffered in Mailbox or Fifo.
• 🟡 Queues
  • 🟡 Fill (clear and fill operations)
  • 🟡 Transfer (copy and blit operations)
  • 🟢 Submit (CommandBuffer submission)
  • 🟢 Present (see PresentationEngine)
• 🟢 Semaphores
• 🟢 DeviceMemory
• 🟢 Buffers
• 🟢 Sampler
• 🟢 Images / ImageViews
• 🟢 CommandPools
• 🟡 Pipelines
  • 🟢 Lighting
  • 🔴 Shadows
  • 🔴 Geometry shaders
  • 🔴 Fog
  • 🔴 Gas
• 🟡 CommandBuffers
  • 🔴 Shadow Rendering
  • 🔴 Gas Rendering
  • 🟡 Image Sampling
    • 🔴 Shadow textures
    • 🔴 Cubemaps

• 🟢 CSND
• 🟢 PXI
• 🟢 LGY
• 🟢 HID
• 🟡 DSP
• 🟡 PICA200: Missing typing of some documented registers, mostly done.

I wanted to learn arm and always wanted to develop 3DS homebrew, also I searched and I haven't found any kind of zig package that doesn't use libctru, so I just started reading a lot and doing things. Furthermore, using only zig has a lot of advantages:

• Really simplified and easy development. You don't need complex toolchains, you just need the zig executable, that's it! (However, obviously it is recommended that you use devkitPRO's tools as I'm sure you'll need them. You want to use gdb, don't you?)
• Safety in Debug and ReleaseSafe modes. Zitrus currently uses the ErrDisp port to report panics and returned errors. The only missing thing is reporting return traces with debugging symbols (Currently only addresses are logged)
• Really useful and simple build-system (as you've seen the example build.zig is really small and makefiles are really arcane)

• 3dbrew is seriously the best resource if you need info about the 3DS hardware/software.
• gbatek is the second best resource for low level info about the 3DS hardware.
• @devkitPro for the tooling, a starting point/reference for this project and reference for unknown/undocumented/unspecified things (e.g: libctru and how tf jumping to home menu worked).
• @azahar-emu/azahar for providing an emulator to quickly test changes and the initial iterations.
• @LumaTeam/Luma3DS for literally saving my life when trying to debug things in my 2DS.