# picoarch - a libretro frontend designed for small screens and low power

picoarch uses libpicofe and SDL to create a small frontend to libretro cores. It's designed for small (320x240 2.0-2.4") screen, low-powered devices like the Trimui Model S (PowKiddy A66).

## Building

The frontend can currently be built for the TrimUI Model S and Linux (useful for testing and debugging).

First, fetch the repo with submodules:

```
git clone --recurse-submodules https://git.crowdedwood.com/picoarch
```

### Linux instructions

To build picoarch itself, you need libSDL 1.2, libpng, and libasound. Different cores may need additional dependencies.

After that, `make` bulids picoarch and all supported cores into this directory.

### TrimUI instructions

To build for TrimUI, you need to set up the [toolchain](https://git.crowdedwood.com/trimui-toolchain/about/) first.

To build generic binaries:

```
make platform=trimui
```

If you want to build for MinUI, you need to install [libmmenu](https://github.com/shauninman/libmmenu) into the toolchain. Then:

```
make platform=trimui MINUI=1
```

`MINUI=1` will change save/config/system paths to match MinUI standards. If you just want to include mmenu, you can run:

```
make platform=trimui MMENU=1
```

### Other build options

To debug:

```
make DEBUG=1
```

To build a specific supported core:

```
make gpsp_libretro.so
```

To clean a core so it will be built again:

```
make clean-gpsp
```

To completely clean the repo (will delete, pull, and patch all core repos from scratch)

```
make force-clean
```

Distribution builds can also be made for gmenunx and MinUI:

```
make platform=trimui dist-gmenu
make platform=trimui MINUI=1 dist-minui
```

These will output a directory structure that can be moved onto the SD card into `pkg/gmenunx` or `pkg/MinUI`.

To build profiles for profile-guided optimization:

```
make PROFILE=GENERATE
```

To apply the generated profiles:

```
make PROFILE=APPLY
```

PGO can lead to major speed improvements with some emulators.

## Notes on cores

In order to make development and testing easier, the Makefile will pull and build supported cores.

A few common changes will need to be made when you add cores, since TrimUI is not a supported libretro platform. picoarch has a `patches/` directory containing needed changes to make cores work well in picoarch. Patches are applied in order after checking out the repository.

Common changes include:

- Adding a `platform=trimui` target to the core Makefile
- Modifying `libretro_core_options.h` to shorten text, add manual line breaks, and change defaults for small screen / low power devices
- Hiding unnecessary core options and forcing different defaults

picoarch also keeps the running core name in a global variable. This can be used for:

- Renaming buttons to match the core's system
- Adding frameskip to make fast-forward faster
- Displaying extra options or hiding unnecessary options

Some features and fixes are also included in `patches` -- it would be best for them to be upstreamed eventually.