noise.aseprite-extension

This plugin is meant to enhance aseprite with various pseudo-random noise generation methods and a few extra effects (e.g., anti-aliasing).

Acknowledgements

The initial foothold for this package was enabled by shemake's excellent makeNoise script. In particular, the later-mentioned dot noise method. I had never written an aseprite extension before this one, so this gave me a good idea of how to approach the scripting. Said script can be found at the shemake site (https://shemake.dev/tech/viewing/Aseprite_makeNoise).

Most methods were translations / modifications of existing source code from Wikipedia and elsewhere. You can find most attributions inlined in the code itself.

The dynamic library source code uses some Lua helper methods inspired by / borrowed directly from the Aseprite source code at ${ASEPRITE_SOURCE_LOCATION}/src/app/script/luacpp.cpp. Given that this is a plugin for the respective software, I hope this is alright.

Noise Method Support

1. "Dot" noise. I don't know an official name, but this refers simply to painting dots on the canvas with a certain chance per pixel with a color picked randomly from a selection or a premade brush.
2. Perlin noise. The quintessential pseudo-random noise function.
   • +Animation.
   • +Tiling.
   • +Octaves/Layering.
3. Voronoi noise.
   • +Animation.
4. Worley noise.
   • +Animation.
   • +Tiling.

See examples for more applications of these functions. More examples coming soon.

Extras

1. Gaussian Blur.
2. SMAA * (Subpixel Morphological Anti-Aliasing).
   • Useful for removing any jagged edges seen in the above noise methods, or generally for anti-aliasing pixel art.

* all methods with a * next to them require the dynamic library to function properly.

Usage

The plugin dialog can be invoked by going to Edit > Generate > Generate Noise. From there the method of noise can be selected, and custom method settings can be selected by clicking the Method Options button to open a separate options menu.

Animation

All methods except dot noise currently support some form of animation.¹

For tiling to work properly many method parameters require that lengths (e.g., movement for Worley animation) be factors of one another. Future updates will hopefully make it clearer which parameters rely on each other with tiling selected.

Installation

This plugin is tested on aseprite v1.3-rc6-x64, and relies on fairly recent aseprite updates to scripting. It does not work with the stable v1.2.40 release on Steam. See this issue for more info and how to easily upgrade Aseprite to the beta release on Steam.

# clone the repository and load any of its dependencies
git clone https://github.com/Cartier1288/noise.aseprite-extension noise
cd noise
git pull
git submodule update --init --recursive
# build the dynamic library extension (this part can be skipped if you don't want it)
mkdir build
cd build
cmake \
    -DCMAKE_BUILD_TYPE=Release \
    -DEXCLUDE_TESTS=1 \
    ..
make install
cd ..
# build the package itself -- zip it into a file called noise.aseprite-extension
./package.sh

If your system has .aseprite-extension extensions registered to aseprite, you should just be able to open the file that running package.sh created and have it automatically add the extension for you.

Otherwise, open the generated noise.aseprite-extension package from within aseprite by going to Edit > Preferences > Extensions, clicking on Add Extension and navigating to the package file and selecting it.

Dynamic Linking Problems

This GitHub comment from dacap himself seems to suggest that dynamic libraries are not supported in plugins. My experience is that my purchased Windows installation allows for the dynamic library to be loaded without issue.

However, having compiled aseprite on Arch Linux I found that I was receiving an error when trying to link the library. This was easily fixed by adding the following lines to ${ASEPRITE_SOURCE_LOCATION}/third_party/CMakeLists.txt:204 (under lua linking):

target_compile_definitions(lua PUBLIC LUA_USE_DLOPEN)
target_compile_definitions(lauxlib PUBLIC LUA_USE_DLOPEN)
target_compile_definitions(lualib PUBLIC LUA_USE_DLOPEN)

and then compiling again.

Technically, this package can be used without the dynamic library extension. Worley noise will be violently slow and lack animation, but it does avoid the extra steps of having to compile it.

I haven't tried using the purchased installer for Debian, so I cannot vouch for whether it will work automatically like it did for Windows.

Dynamic Linking Warnings

As far as I am aware, the reason behind dynamic libraries not being innately supported by Lua is two-fold:

1. they are not directly supported by the C standard, and
2. they pose a security risk.

To address the latter: Lua provides an isolated programming environment that can at least somewhat be curated by the program that it is embedded in. Enabling dynamic libraries throws this out of the window head-first. It means that any program at all with a compatible Lua interface can be linked and run, which can then access the internet, delete files, etc.

You can see the source code for this package and verify for yourself whether it does any of this (it does not). But for this reason, care should be taken when enabling dynamic linking if you are unfamiliar with other extensions and their source code.

Interestingly, I found that the Lua package.loadlib function gave a warning about loading libraries even when I did not have LUA_USE_DLOPEN set. Since this function requires a direct link to the library file, I opted to use require which also happened to give no such warnings. It was my expectation that require would wrap loadlib when loading a dynamic library, so I was surprised to see that. Just know that as far as I am aware you will not be given a warning about loading the library when using the plugin.

Disclaimer

This is a new extension. There are definitely as of yet undetermined bugs. All of the primary functionality gets tested often, but it's probably best to make a backup of files / layers before using it.

Footnotes

1. This is only true if you have dynamic libraries enabled and installed in the package folder. The current implementation of Worley noise for Lua is very slow so it only uses 2D generation, making animation impossible for the pure Lua plugin as of now. ↩