Getting Started

• Follow the steps on the Getting started page of the rust3ds org on Github to setup your dev environment.
• Run git submodule update --init to include the citro3d-rs submodule required to build the 3DS app
• Inside the app folder, run rustup override set nightly to tell Cargo to use Rust nightly when compiling that project
• Use cargo 3ds build --release or cargo 3ds run --address <3dslink address> --release inside app to test the 3DS app (or alternatively run the examples in the citro3d-rs/citro3d repo/folder) (be sure to use release mode, as debug will be very slow to deserialise and load the model data at startup, resulting in a black screen for a long time before it actually renders)

After building, the output files will be in target/armv6k-nintendo-3ds/release. app.3dsx can be run directly in an emulator like Citra.

Repository structure

• app - The main 3DS app I'm working on
  • app/assets - Place any assets like images to be used as textures or gltf/glb files to be used as models, these will be preprocessed and placed in the romfs folder and bundled in the resulting .3dsx file.
• core3d - A crate for handling much of the 3D data and processing in the 3DS app
• preprocessor - A crate for preprocessing assets like gltf/glb or image files and uses core3d to structure and serialize the data so it can be easily imported and used in the main 3DS app
• citro3d-rs - My fork of the Rust wrapper for the 3DS GPU driver. This is included as a submodule so it can be kept in a separate repo but still easily have the 3DS project refer to a local and easily-modifiable copy of the crate

Exporting from Blender and including assets

The app can currently import and render an animated model exported from Blender in the GLTF format.

The Blender model must have a maximum of 18 bones, as that is the limit I've set in the shader (physical limit of the GPU with the current implementation is ~20 bones).

When exporting a model as gltf/glb, change Skinning -> Bone Influence to 3, and make sure to enable Mesh -> Apply Modifiers if you have any modifiers that haven't already been applied to the model, such as Decimate. Animations and Textures should be included in the export, I left the Materials settings as Export and Automatic, and Animation enabled and with default settings.

Any assets including the output gltf/glb file from Blender, any png/jpg files to be used as textures, or other resources, can be placed inside the app/assets folder, where they will be preprocessed and moved to the app/romfs folder which gets bundled inside the resulting .3dsx file. These can read in using the std::fs module as long as the ctru::romfs has been initialised, and any file paths are prepended with romfs:/.

Other

Feel free to have a look at 3DS programming experience.pdf to see a little presentation I made for my friends about part of my experience with getting all this set up.