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Native Library Management for C# using vcpkg (and other things)

Let me start with a bit of a narrative first:

Around a year ago, I released a C#/.NET Core library called Bassoon. I was looking for a cross platform (Windows, OS X, and Linux) audio` playback library for C#, but I couldn’t find one that was suitable. So I did what any normal software developer would do: make your own. Instead of going full C# with it, I opted to take some off the shelf C libraries and use P/Invoke to chat with them. It uses libsndfile for decoding audio formats (sans MP3, but that might change soon). And PortAudio for making speakers make noise.

If you look at the repo’s README’s Developing section, you might notice that I’m not telling anyone one to do a sudo apt install libsndfile libportaudio (or some other package manager command for another OS). I’m not the biggest fan of baked dev environments. They can be a pain to reproduce for others. I like to have my dependencies per project instead of being installed system wide if I can help it.

The only downside is that you need to then create some (semi-) automated way for others to set up a dev environment for the project. E.g. all that “Download package from here then tar xzf, cd ..., ./configure, make, make install” nonsense. At first, I tried to make a simple bash script, but that got kinda ugly pretty quickly. I’m not the best shell programmer nor am I too fond of the syntax. There was a consideration for Python too, but I assumed that it could get a bit long and verbose.

I found out about CMake’s ExternalProject_Add feature and set off to make one surely disgusting CMakeLists.txt file. After a lot of pain and anguish, I got it to work cross platform and generate all of the native DLLs that I desired. Some things that stick out in my mind are:

  • having to also run the autogen.sh in some cases
  • needing to rename DLLs on Windows
  • finding the correct ./configure options to use on OS X

These all reduced the elegance/simplicity. But hey, it works!... Until about a month ago…

While it was still good on Linux to set up a clean build environment. After some updates on OS X, it stopped building. Same for Windows/MSYS2 as well. This has happened before for me with MSYS2 updates (on other projects) and I waslooking for an alternative solution.


C++ specific package managers are a tad bit of a new thing. I remember hearing about Conan and vcpkg when they first dropped. After doing a little research, I opted to use the Microsoft made option. While it was yet another piece of software to install, it seemed quite straightforward and easy to set up. PortAudio and libsndfile was in the repo as well. After testing it could build those libraries for all three platforms (which it did), I was sold on using it instead. There were a few caveats, but well worth it for my situation:

  1. Dynamic libraries were automatically built on Windows, but I needed to specify 64 bit. It was building 32 bit by default
  2. For Linux and OS X, static libraries are built by default. If you want the dynamic ones all you have to do is something called overlaying tripplets
  3. The generated file names of the DLLs were not always what I needed them to be. For example, in my C# code I have[DllImport(“sndfile”)] to make a P/Invoked function. On Windows, the DLL name must be sndfile.dll, Mac OS is libsndfile.dylib, finally Linux is libsndfile.so. On Windows I get libsndfile-1.dll built by default. Linux nets me libsndfile-shared.so. For these a simple file renaming works. OS X is a bit of a different story:

You see, every operating system has their own personality quirks. The Apple one is no exception. When I tried renaming libsndfile-shared.dylib to libsndfile.dylib, dotnet run crashed saying it couldn’t find the library. I know that I had all of the path & file locations correct, as the previous CMake built libraries worked. I was kinda of stumped...

After setting DYLD_PRINT_LIBRARIES=1 and trying another run I got a little hint. libsndfile.dylib was being loaded and then unloaded almost as soon as it was called:

dyld: loaded: /Users/ben/Desktop/Bassoon/third_party/lib//libsndfile.dylib
dyld: unloaded: /Users/ben/Desktop/Bassoon/third_party/lib//libsndfile.dylib

It also should be loading up libogg.dylib, libFLAC.dylib, libvorbis.dylib, etc. but that wasn’t happening. Looking at the vcpkg generated libs, running otool -L (OS X’s version of ldd), I got the reason why things weren’t the way I expected:

$ otool -L *
libFLAC.dylib:
    @rpath/libFLAC.dylib (compatibility version 0.0.0, current version 0.0.0)
    @rpath/libogg.0.dylib (compatibility version 0.0.0, current version 0.8.4)
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1252.250.1)
libogg.dylib:
    @rpath/libogg.0.dylib (compatibility version 0.0.0, current version 0.8.4)
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1252.250.1)
libsndfile.dylib:
    @rpath/libsndfile-shared.1.dylib (compatibility version 1.0.0, current version 1.0.29)
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1252.250.1)
    @rpath/libogg.0.dylib (compatibility version 0.0.0, current version 0.8.4)
    @rpath/libvorbisfile.3.3.7.dylib (compatibility version 3.3.7, current version 0.0.0)
    @rpath/libvorbis.0.4.8.dylib (compatibility version 0.4.8, current version 0.0.0)
    @rpath/libvorbisenc.2.0.11.dylib (compatibility version 2.0.11, current version 0.0.0)
    @rpath/libFLAC.dylib (compatibility version 0.0.0, current version 0.0.0)
libvorbis.dylib:
    @rpath/libvorbis.0.4.8.dylib (compatibility version 0.4.8, current version 0.0.0)
    @rpath/libogg.0.dylib (compatibility version 0.0.0, current version 0.8.4)
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1252.250.1)
libvorbisenc.dylib:
    @rpath/libvorbisenc.2.0.11.dylib (compatibility version 2.0.11, current version 0.0.0)
    @rpath/libogg.0.dylib (compatibility version 0.0.0, current version 0.8.4)
    @rpath/libvorbis.0.4.8.dylib (compatibility version 0.4.8, current version 0.0.0)
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1252.250.1)
libvorbisfile.dylib:
    @rpath/libvorbisfile.3.3.7.dylib (compatibility version 3.3.7, current version 0.0.0)
    @rpath/libogg.0.dylib (compatibility version 0.0.0, current version 0.8.4)
    @rpath/libvorbis.0.4.8.dylib (compatibility version 0.4.8, current version 0.0.0)
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1252.250.1)

From this, I was able to identify two problems:

  1. The “id” of a dylib didn’t match it’s filename. E.g. libvorbis.dylib’s id was set to libvorbisfile.3.3.7.dylib
  2. The dylibs were looking for non-existent dylibs. E.g. libvorbisenc.dylib was looking for libogg.0.dylib.

As to why this wasn’t happening with the previously CMake build native libs, it’s because they were configured/compiled with --disable-rpath. With vcpkg, I wasn’t able to set this when building libsndfile. The OS X toolkit does have a utility to fix the rpaths; install_name_tool:

  1. install_name_tool -id "@rpath/<dylib_file>" <dylib_file> is used to set the id we want
  2. install_name_tool -change "@rpath/<bad_dylib_path>" "@rpath/<good_dylib_path>" <dylib_file> can fix an incorrect rpath

Since I wanted the setup process to be fire and forget I still needed to write a script to automate all of this. At first I considered bash again, but then I thought “I don’t want to force someone to install the entire MSYS2 ecosystem for Windows. What else can I use?...” Python came to mind. Any developer is bound to have Python on their machine. I know that’s what I tried to avoid in the first place, but looking at the built in libraries for Python 3.x (.e.g shutil, subproccess, pathlib, etc) it was a better choice IMO. I also like the syntax more; I’ll always trade simple and easy to understand code any day over something that’s complex and shorter. For an example, here is how I have the dylibs for OS X fixed up:

To run this 3rd party dependency setup script, all you need to do is set an environment variable telling it where vcpkg is installed and then it will take care of the rest!


Now that all of the native library dependencies have been automated away, the next challenge was packaging them for NuGet. Before, I told my users to “clone the repo and run the CMake setup command yourself”. That wasn’t good for many reasons. A big one being that no one could easily make their own program using Bassoon and easily distribute it. I know that I needed to also have the native libs also put inside the NuGet package, but what to do…

If you search for “nuget packaging native libraries” into Goggle you get a slew of results telling you what to do; all of it can seem overwhelming from a quick glance. “Do I use dotnet pack or nuget pack? Do I need to make a separate .nuspec file? But wait, dotnet pack does that for me already… What is a .targets file? What is a .props file? How many of those do I need? What is this whole native/libs/* tree structure? Oh man, all that XML looks complicated and scary. I have no idea what I’m reading.” Throwing in cross platform native libraries adds a whole other level of trouble too. Most tutorials are only written for Windows and for use within Visual Studio. Not my situation, which was all three major platforms. Even peeking into other cross platform projects (e.g. SkiaSharp) to see how they did it, makes it look even more confusing. Too many configuration files to make sense of.

Then I found NativeLibraryManager. It has a much more simpler method to solve this problem: embed your native libraries inside of your generated .NET DLL and extract them at runtime. I don’t want to copy what it says in it’s README, so go read that. But I’ll summarize that I only had to add one line for each native library to the .csproj (for embedding). Then for extracting at runtime, a little bit of code. For people who want to use PortAudioSharp or libsndfileSharp directly, they only need to call the function LoadNativeLibrary() before doing anything else. And as for the nature of Bassoon’s initialization, they don’t have to do anything!

I cannot thank @olegtarasov enough for creating this. I’m a programmer. I like to write code; not configuration and settings files.

At the time of writing, libsndfileSharp package is partially broken for OS X due to a bug in NativeLibraryManager. But a ticket has been filed explaining what’s wrong and most likely what needs to be fixed. It should be good soon :P

If anyone wants to help out with Basson (e.g. adding multi-channel support) or the lower level libraries (adding more bindings to libsndfile and PortAudio), I do all of the development over on GitLab.





I’d like to mention that I’m a little less employed than I would like to be; I need a job. My strongest skills are in C/C++, C#/.NET, Python, Qt, OpenGL, Computer Graphics, game technologies, and low level hardware optimizations. I currently live in the Boston area, so I’m looking for something around there. Or a company that lets me work remotely is fine too. I’m also open to part time, contract, and contract-to-hire situations. If you send me an email about your open positions, I’ll respond with a full resume and portfolio if I’m interested.

Please; I’m the sole provider for a cat who’s love is motivated by food. Kibble ain’t free.


Tags: C#, Projects

Views on Godot (3.1)
Godot Logo

If you want to go ahead and skip to the game I made, it's over here.

About 4+ years ago I heard about a new(-ish) game engine called Godot. I thought that it was kinda neat to have another open source one around, but I didn't think too much of it. In the past few years I'd hear about it again from time to time (e.g. when it gained C# support, making it a Unity contender). I was kind of interested in making something with it, but at the time I had no ideas.

Recently, I thought "It has sure been a while since I worked on a personal (technical) project. Not to mention a video game. I'm kinda itching to try out that there Godot thingy...". So about two-ish months ago, I decided to build something with this engine. Thinking about what could be small, short, but good enough to get my feet wet, I settled on reimplementing my Linux Game Jam 2017 entry Pucker Up.

Lemme take a brief aside to tell you about Pucker Up. As stated before, it was for a jam. My first Jam in fact. At that time, I was a bit more into tinkering with the Nim language. I kinda wanted to be a bit more HARDCORE™ with my approach in the jam. Luckily the only restriction was "Make a game that runs on Linux". No theme whatsoever; quite nice. We had 72 hours to finish and submit it. Then it would be live streamed by the jam creator.

I originally planned out a much more complex game (i.e. what was a tower defence). Then being HARDCORE™ I set out to grab some GLFW bindings, write my own game engine/framework, graphics/shaders, physics, etc. At the end of the first day, I realized how much of a difficult decision that I had made. All I got done were the initial windowing and input management, being able to draw flat coloured debug circles, and circle intersection algorithms; it was absolutely piddly. Realizing the pickle I had put myself into, I reevaluated what I could do with the toolkit I had made from scratch. I threw out my 99% of my original idea. Thinking instead about some sort of arcade-like game. The result was a sort of Pong with the goal in the center, where you had to keep the puck out of it. The QWOP control scheme happened by accident (I swear). Turned out it was kind of fun.

After the Jam was over, leveraging Nim's compile to JS feature, I was actually able to make a web browser playable version of the game in a short amount of time. I didn't have to force users to download a sketchy executable which was nice. That took me about two weeks since I needed to also add some extra Nim to JS/HTML5 bindings and work out a few kinks and bug or two. But it actually was quite simple. (Speaking about Nim, it also has some Godot bindings too.)

I've been looking at that JS/HTML5 version of Pucker Up for the two-ish years, discovered some bugs here and there, I thought it would be best to give it a little refresh. So instead of trying to wracking my brain to think up a new game, I settled on renewing something old I had.

Back to Godot-land. What I would say that originally drew me to the engine is it seemed like a nice professional project that was very liberal with it's licensing and it is openly developed. Linux being a first class citizen for the project is very sweet too. I tried out the Unreal engine on Linux and wasn't too happy with it. I've also had some serious issues with playing Unity made games on Linux.

I'm a person who has probably made more game engines than games. I don't know why this has been the case for me, but it just has. Maybe it's that feeling of being closer to what's going on in the whole program, or rather knowing 100% how something was made. Looking at the source for Godot (and the docs, which has A+ tutorials), I appreciate how easy and hackable this engine is. And to boot, the community is quite friendly.

Godot's built in source editor

I originally wanted to make my game in C#, as I prefer the more structured languages. I soon found out that it was a no-go for me. My desire is to target the Web as my main platform. As of writing this blog post, C# only has desktop support. Therefore, I would have to use Godot's built in language GDScript. I wasn't too adversed to trying it out. It had a very Pythonic feel to it. This also helps too if I want to bring Pucker Up to any Android or iOS platform. It definitely feels a little odd a times. In the sense that I feel that I'm writing Python code, but some of the APIs are completely different. I also miss the safety of explicitly typed languages. They offer some more preflight checks. Godot has some (Python is even worse), yet I am not completely satisfied. In the future, if I make a serious Desktop game, I'm going to use C#. But for jams and any non-Desktop platforms, I'll reluctantly use GDScript. I really don't like writing JavaScript though I want to target the web, so I'm willing to make this small compromise.

Javascript Makes Me and Milhouse want to cry

The tutorial section of the Docs are quite good, but the API docs don't feel like they are fully here right now. For example if you look at much of Microsoft's C# docs, many methods usually have an accompanying example with them. This isn't always the case with Godot. For instance, to spruce up Pucker Up, I wanted to add some directional sound. Doing some googling I was led to the docs for AudioEffectPanner. Looking through, it's super sparse, and doesn't have a simple example of how it can be used. Not nice.

The main draw of using any engine is "Look at all the stuff we provide for you." When I started make games, it mostly was only a set of APIs. Tooling was something you had to do on your own. Godot provides a pretty nice editor (UI, level, animation, etc...), but it does take some learning.

I'm also a pretty big fan of Animation (go look through some of my other posts to see). The builtin framework for Animation that Godot provides I think is nice, but the editor isn't the most intuitive. I've used programs such as Flash (R.I.P.), Moho, Clip Studio Paint, and even Unity. They were always pretty easy to get started with. In Godot, I had some trouble figuring out how to key properties. I didn't know what kind of interpolation I was initially using. And the curves editor was difficult when it came to zooming it's viewport(.e.g I needed to work on a value in the range of [0.0, 1.0], it was a bit of a struggle). One of the other things that drove me nuts: If you didn't reset the playback head to `0` before running your game, the animation would start where the head was left in the editor. I can see how this is handy for Animations that are longer (.e.g 5+ seconds). Though if you notice in video games, many actions/effects are on the quick side (e.g. 1/4 of a second). When you're doing this, you tend to what to see the whole thing. I will admit that my digital animation experience it a bit lacking (I think I've spend more hours with a pencil and paper than with a Wacom tablet), but some stuff didn't feel that natural. I also ran into a bug: when tabbing through options to adjust properties, sometimes the editor would freeze. Not fun.

Godot's Animation editor

Godot also has a minimal UI framework is built in. Adding custom skinning can be quite the hassle though. A CSS like way to skin the UI would be wonderful (which is that the Qt and Gtk frameworks already do). This might be a time sink for the engine (and would add much extra complexity) for what is only a minor feature. I can dream though...

After about two-ish months of work, I had a more sophisticated version of Pucker Up ready. I had some extra animations, more sound variation, smoother movement, improved score reporting; I could go on for a while. Without Godot, these would have taken much longer. There was one last hurdle to overcome: Exporting to HTML5. I was hoping for this to be a few clicks and done, but it wasn't quite that easy. Retrieving the HTML5 export was simple enough. IIRC, there was a one-click download button. Export prep was a breeze too. The issue arose when I then went to run the game in my browser. When I loaded up the game.html file in my browser, the scaling and placement of my assets were not where I expected them to be. Even across browsers (and different machines) it all appeared vastly different. I got some of my other friends to help me test this out. I did file a ticket on the Godot issue tracker about my problem. I also asked the Godot Reddit community for their experiences with targeting HTML5. From there, someone was able to suggest I tinker with the "Stretch" settings for the project. Voila! It gave me the result that I wanted and order was fully restored. This was quite the frustrating experience and I think it could be remedied by mentioning these "Stretch" settings in the "Exporting for the Web" doc page.

I've also noticed that the performance of Pucker Up is much smoother in Chrome(ium) than in Firefox. That isn't good. The later browser has some semi-choppy movement of the puck (and high speeds), and the sound effects (such as the bounces) weren't playing at the exact moment that they should. They were off by a few milliseconds. While this doesn't grandly impact the game (as it's still playable), I don't like having to add a "Plays slightly better on Chrome based browsers." footnote to my game page.

All in all, it may seem that I'm be a little extra critical of Godot here, but in earnest it's been a very pleasant experience (re)making Pucker Up with it. With were it stands right now, things can only get better with the framework as time goes on. I'm looking forward to the next game jam I'll enter because I'm sure enough to use this tool. Or maybe I go on with a more grand idea. Godot only knows. :P

You can find the Godot version of Pucker Up over here. Please enjoy.


Tags: Video Games, Projects

Status Update 8
So it's been quite a bit since I last did an update. A few months short of two years to be exact. I've been fairly busy with work and some other long term personal projects. But in the meantime, I did get to release a much smaller one; Basson, a cross platform audio playback engine for C#/.NET Core:
https://gitlab.com/define-private-public/Bassoon

I created this since I wanted to be able to do audio playback in C# on Linux, Windows, and OS X. While there were some packages available on NuGet, they were not preferable to me, so I took the time to make my own. It's hobbled together using P/Invoke bindings to `libsndfile` and PortAudio. At the moment it does not support MP3 decoding (though that is planned), which is one of the main drawbacks. And you also need to build the native dependencies yourself, but a CMake file is provided to handle that. In the future, I hope to also add some more features such as audio recording and some minor effects. So far I am happy with it.

Tags: C#, Status Update, Projects

Random Art in Nim

A Random Art Example

 

Edit (Jan 30th, 2017): I written an article on how Random Art works.  You can read it here.

Have you ever heard of Random Art before?  If you don't know what it is, the short and skinny is that it's a program that will generate some really stunning images using a randomly generated math equation.  That's what the image above was made with.  The original program was written by Andrej Bauer.  The Random Art website uses an OCaml program that been compiled to JavaScript.  Unfortunately the source for that is not publicly posted (which is a shame because it makes some of the best pictures), but a simple Python implement is available.  Going off from that, I decided it port it over to Nim and add support for rending with OpenGL (and make a few other changes I see fit).

Well... actually I ported that to C++ (& Qt) first about a year ago, then I did another port over to C# four months later.  The C# one was a little more interesting because it was a distributed rendering system leveraging cloud services and RabbitMQ; I ended up using it on a film I was working on.  Pretty cool.  Those... I don't really feel comfortable sharing the source to right now.  But I'll give you a Nim implementation instead.  : P

You can find the application over here on GitLab (or GitHub if you prefer it).  To compile the thing, your going to need GLFW installed as well.  It can run into two modes: CPU bounding rendering and GPU (via OpenGL).  There is a lot more info the in the Readme, but here is the usage message:

 

Usage:
  ./random_art [input] [options..]

  input : a path to an equation file, or provide `stdin` to read input
          from standard input

  Options:
  -r, --renderer : cpu | opengl
                   render on the CPU or with a GPU (using OpenGL)
  -s, --size     : <width>x<height>
                   the dimension of the render, must be a positive int
  -b, --bounds   : <xMin>,<xMax>,<yMin>,<yMax>
                   the bounds to use to render, must be a float
  -o, --output   : <filename>.png
                   the file to save the render as, must end with .png

 

If you run the application without providing an equation, it will think up one for you.  Writing your own equations has this Scheme-like syntax.  It's pretty easy to understand, but also to parse.  The equation below makes the image to the right.

A Simple Random Art Example

 

(mul
  (var y)
  (mod
    (sum
      (var x)
      (var y)
    )
    (const 1 0.7 -0.1 0.95)
  )
)

 

I plan on working on this some more down the road.  You can already see some of my changes showing up (e.g. an alpha value).  I'll keep you guys posted.  Once again, the code is available here (GitHub mirror).


Tags: Computer Graphics, Nim, Art, Procedural Generation, Projects

Blit, A Retrospective On My Largest Project Ever

Before I begin, you can find the source for Blit over here.

I want to talk a little bit about a project I worked on every day from July 2014 till the end of August 2015. You may have seen a few entries about it back on earlier posts; that project was something I called “Blit.” If you’re wondering what Blit was, it was my attempt at trying to make an Animation focused art program. It was pretty ambitious for someone like me at the time.

 

Blit's Main Window

 

There were two main reasons why I started to work on it:

  1. Back when I was an undergraduate, I was part of a student group were we had to do these things called “major projects,” each year if we wanted to retain membership. They usually are of a technical nature (programming & engineering). This is where my initial drive came from
  2. I’ve never worked on a “large,” or “longterm,” project before. Everything else I’ve done up till that point were small things like class assignments, course projects, or tasks for my internships. I had friends who had worked on their own projects for two or three years straight and made some really cool stuff. I really wanted to be able to tell others (mainly prospective employers) “Yeah, I’ve been working on this thing for over year. Want to take a look?” Other than just “having something,” I also wanted to learn how to manage a larger and lengthier project.

The “major project,” was something that was pretty easy to fulfill. But for the second I did something kind of stupid, but worked well for me. I told myself “Alright, I’m going to work on a project that will have a 365 day long GitHub streak.” In reality, git streaks are a silly thing to track progress. I was working on Blit in a private repo, so the outside world would not see my streak at all. I feel bad for the people who have the need to maintain one. For me it was a reminder to build on Blit each day. It worked.

Whether it be programming, logging issues, source code cleanup, design & planing, writing documentation, etc., I had to minimum goal of one meaningful commit per day. Normally I would spend an hour on Blit per day (more on the weekends). I would keep at it until the kitchen timer to my side beeped. Somehow that little thing was able to keep me focused for a straight hour.

 

So What Is (or Was) Blit?

I’ve always been someone who’s liked art and programming. Especially combining the two. One of my favorite genres is pixel art, or sprites as they are also known. I’ve dabbled in making a few other art programs before, but nothing like this.

Originally Blit supposed to be only a sprite animation tool that had a modern look and feel, but my ideas for it grew greater (*sigh* feature creep). There are many other sprinting tools out there like GrafX2, Aseprite, (and other 2D animation programs like TVPaint). I’m not saying that it’s wrong that they make their own GUI toolkit, but it feels kind of odd. I really wanted to bring these types of programs out of the days of the Amiga. After doing some initial research, I settled on using Qt. Here are my reasons:

  1. It’s cross platform. I work on a Linux system, but I want my Windows and OS X friends to be able to use what I make
  2. It’s a C++ library; my native tongue. But there exists bindings to other languages, such as Python
  3. There’s a lot more to Qt than just widgets. It really is a fully featured desktop application framework
  4. It has a massive community around it and it’s very well documented. So if I ever ran into trouble I’d be able to find some help

Before I move any further, you might be wondering where the name “Blit.” came from. Since it had a focus on 2D graphics, the name came from the “Bit blit,” algorithm. I used to do a lot of programming with libSDL, so the function SDL_BlitSurface() has been burned into my brain.  I thought it would be a cute name too.

I also wanted to keep more of a “traditional animation,” approach to Blit. Instead of drawing on images there were “Cels.” Layers were called “Planes.” Instead of a Dope Sheets I had “Exposure Sheets.” I didn’t call it “onion skinning,” but “turning on the Light Table.”

 

Starting Out

As mentioned before, I was focused on sprite animation (originally). I wanted to keep things as easy as possible. While I did consider using Qt’s native C++ libraries, I decided on making the program in Python with PyQt. Scripting languages are typically much faster to write code for. I felt as if I would be able to get more done in less time. I didn’t think that there would be too many computationally intensive procedures to worry about. In the event that I needed some performance boost, I could always write a C/C++ extension for Python.

After choosing my tools, the first thing I did was draft some design documents. These included a user interface mockup and an initial file format structure. I started to log tickets on the GitHub issue tracker. I had an miniature road map to start from. Within a month and a half, I was able to load up one of my files into Blit, do a little simple Cel & Frame editing, and then save it. You couldn’t do too much with it, but I thought it was a good starting point.

 

Blit's Python Version

 

During my initial research of Qt, I discovered something called the “Graphics View Framework.” There were a lot of widgets that I had to custom make such as the Timeline or the Canvas; it made my life much easier. It really is one of the nice features of Qt. If you’re making a heavily graphical application you should take a look into it.

Despite being able to get a basic animation loaded, edited and played back, I was starting to run into some issues with the development language: Python. I had issues with things like circular imports and nested imports (python files imported from many directories deep). I don’t want to go into the details of how they were affecting me and the project, but all I can say is that they were driving me up the wall. So I devised a solution: Switch to C++.

Now, switching development languages is not always something that’s advised. But at the point where I was, it was feasible to do and would possibly have a better impact on my project. Nested imports are a non-issue in C++ and the circular imports are fixed with simple include guards. On top of that, I wouldn’t have to use PyQt’s bindings anymore and Python would not be a performance bottleneck since it would be gone. Working at my usual hour a day pace, it took somewhere between two and three weeks to port everything I had to C++. I wasn’t happy about losing that time to work on new features, but I think it was a better choice in the end.

I didn’t entirely ditch Python & PyQt. If I needed to prototype a widget, I would use those tools. It helped to realize ideas pretty quickly, then later I would integrate it into the C++ source.

 

Feature Creep, “Future Planning,” and Broadening Horizons

In the first couple of months that I was working on Blit, more ideas started to pour into my head of what it could or should be able to do. We all know what this is; Feature Creep. Whenever I though of a cool new thing I wanted to add, I usually weighed the cost of adding it in within my current milestone, the next, or burring it in the issue tracker. This is where I developed the “Future Planning,” tag. If something popped into my head, almost 95% of the time I would not mark it under any milestone and put it under that tag. It was a good way for me to tell myself “Alright, I think this would be a good thing, but I need to focus on other stuff right now.” This worked actually pretty well for me. At all times, the most populous tag in my issue tracker was the “Future Planning,” one.

 

A Pen & Eraser Tool

 

Around 100 days into the project, I felt like I had a good direction that I was going in. I was nearing the end of my (second) internship and I would be left with nearly two months before classes would begin again. With all of this free time, I set myself the goal of “Be able to draw a bouncing ball animation and export it as a Spritesheet,” before Christmas hit. I achieved that.

 

100 day long streak

 

A Bouncing Ball (spritesheet)

 

By this time you could move Cels around on the Frames, move the Frames on the Timeline, and adjust their hold values. I think I focused more on the staging of objects rather than editing them. To work on this shortcoming, I decided to start work on a Tool interface. I had the idea that editing tools should be plugins and people should be able to write their own; a very common idea in art applications. Instead of only “put pixel,” and “erase pixel,” I added line/shape drawing, filling, and was working on a soft brush tool.

 

Fun issues with debugging the Color Palette Widget

 

When I got back to school I fulfilled that first goal of passing it as a “major project,” in my student group. It was well received for what it was at the time, a very simple pixel art animation tool. Though, I started to think more beyond simple spriting. Not only do I consider myself a fan of Animation, but someone who really enjoys making it. I started to ponder “What if Blit could be used for all sorts of 2D animation, not just pixel art?”

 

200 day long streak

 

I didn’t think it would be too hard to add a camera hookup to the program (something that I’ve done with Qt before), so Blit could be turned into an application to do pencil tests, capture paper drawn animation, or even stop motion. My rule became “If it’s Bitmap based, Blit should be able to do something with it.” I also thought that there wasn’t a good free (both as in beer and speech) software solution to 2D computer animation. TVPaint, Dragonframe, and FlipBook were used a lot in the animation department. I can understand the expensive cost of them for professionals and that it’s niche software, but it really sucks for students who want to learn how to animate, but already were paying a small fortune for their college tuition.

To make Blit more generic, it had to undergo something I called dubbed “The Grand Refactoring.” The whole animation module was like this: an Animation owns an XSheet, which owns a list of Frames, where each Frame owns a list of Cels. No reuse. This was good to get started with, but pretty bad since in the real world animation is reused all of the damn time. So I devised up this system instead:

 

The new and improved Animation module

 

As it would force me to fix up almost every single thing in the program that touched the Animation module (including the file format), I set this to be its own “half milestone.” It took about a month and a half to complete. It really sucked not being to add any new features for that time; only endless refactoring. At the end of that, all the logic was in the code to be able stage the same Cel across multiple Frames, or instance a Frame multiple times in the Timeline. Though, because I was focused on fixing things up, I didn’t add in an interface where the user could actually reuse Cels and Frames. If they wanted to, they would have to edit the sequence.xml file. So it was there, it worked, but wasn’t usable by the layman.

While taking classes and juggling other (smaller) projects it sometimes became difficult to make meaningful contributions to Blit. I tried to stick to my “one hour a day rule,” but that became hard. Also, refactoring isn’t fun. You don’t get to see new features, you’re restructuring stuff that already exist. You might also break things and then have to spend time fixing them. It’s hard to stay motivated when nothing is new or exciting.

My brain was fried after writing code for my class assignments. I found that (better) documenting the source code, reviewing issue tracker tickets, and revisiting design documents wasn’t too hard. If I recall correctly there was a two week stint were that was all that I did.

 

GitHub Streaking...
I cut that one really close.  I swear it was a meaningful commit.

 

Despite all these speed bumps, I got to do something really cool with Blit at the end of the year. If you’ve read some of my older blog posts, you may have seen this thing I made called MEGA_MATRIX. For those of you who don’t know what it was, it is a 24x24 LED Dot Matrix display. I actually developed it in tandem with Blit during the early days of the application. Anyways, at the end of the year my college hosts what is essentially a campus wide show and tell day. I thought it would be neat If I could let people doodle animations in Blit, then upload them onto MEGA_MATRIX. Turns out it was. I made a special fork of Blit called “The MEGA_MATRIX Edition,” where I only let users draw in two colors (red and black), preview their animations, and then upload them to an Arduino to drive the display. One of my friends said it was his favorite thing at the festival because “[I] practically made a hardware implementation of Mario Paint.

 

The MEGA_MATRIX Edition

 

 

Altered Scope, One Full Year, and the End of Development

At the beginning of 2015’s summer, I was off to my next internship. During the day I would write C# code for a rendering infrastructure. After work I would exercise, watch some TV, play a few video games, but also work on Blit, for well, at least an hour a day.

 

301 day long streak.

 

After “The Grand Refactoring,” and the MEGA_MATRIX Edition I was able to get a few more features out of the way. Changing the Canvas’ backdrop color, pixel grid, selective playback, a color picker tool and more. One of my favorite additions was onion skinning (I called it the Light Table). Thanks to the newly redesigned Animation module, it actually made it pretty easy to implement.

Then sometime in mid July I hit my second goal; hold onto a GitHub streak for one year straight.

 

The full year streak
I thought it was going to be 365 days long, turns out 366 is what fills up all of the blocks.

 

The code for Blit was starting to get really huge at this point. I still was able to manage it myself, but it started to become a bit of a chore too. I also spent a lot more time refactoring and fixing existing code rather than working on new features. I feel like I lost a little of my drive then. As my two initial goals were achieved I could have stopped here. But for some reason, I didn’t want to. I kept on pushing.

My internship came to an end, I had a week at home, and then I was off to another internship. All of the previous places were I interned let me work on outside projects if I wanted to. As long as it wasn’t during work time, with work equipment, or a competing product I was free to do what I want. This time around, my employer asked me to stop working on outside projects all together.

 

3001 commits

 

While I felt that work on Blit was starting to go stale I still didn’t feel to happy about having to quit development. I could have worked on it in secret, but that didn’t feel right to me. So, right before leaving for the first day of work I made an early morning final commit to the Blit repo. It was kind of poetic that my ending streak was exactly 400 days long.

 

400 day long streak

 

In the month that followed, I was bummed that I wasn’t able to add an interface for the reusable Cels/Frames, the Brush and Resize tools were still unfinished, no work on multiple planes was ever done (Cel layering existed though), but worst of all, I feel that it sucked when trying to make sprites; the original goal of Blit. I still had ideas popping into my head. Such as using FFmpeg to export animations as animated GIFs. All I could do is just scribble them down on some note paper and file it away for when I was done with my current internship.

So four months down the road I was done with my final practicum. Did I start back working on Blit? No. The previous month was pretty turbulent for me, as well as the next couple. It was my last semester at college and I was more focused on graduating. I still had ideas coming into my head for Blit, but they would go into the issue tracker instead of the code. I felt that I was way too out of it to startup work back on Blit. I also realized how much of a behemoth the source had become. Thus I decided to put it on hiatus indefinitely.

 

Final Lookback and the Future

Almost everything I’ve done is a learning project for me. Some of I learnt very little from, others a lot. Working on Blit taught me so much more about Qt than I ever wanted to know. Hell, in the process of developing Blit I spotted a minor bug in Qt and was able to submit a(n) (accepted) patch to the project. That was one of the more rewarding moments, as I’ve never contributed to a major open source project before.

But the main thing I gained from Blit was learning how to manage/handle/organize a larger project. I was never involved with issue tracking, documentation, and design so much before. As stupid of an idea it was to maintain a year long GitHub streak, it somehow worked for me. It was fun to show off the streak to my friends, it was really there for me to motive myself.

While building Blit, one the things I always wanted to do was work on it with other people. Though, I kept it in a private repo I always had the intention of releasing the source code when I was done with some of the core features. While many of my friends thought it was interesting, I couldn’t find anyone else who wanted to work on it. I always made sure to keep good documentation of the design and source code for this reason. I really wish I had others to help me with this, not only so that I could have had Blit in a much further state, but also so I could learn how to collaborate with others better too.

It’s now been a year since I last touched Blit. At the beginning of this past Summer there was a monkey on my back to figure out “the future of Blit.” I know I wanted to release the source for it, but I’m not sure where I want to go with it. In the past year Dwango released OpenToonz and Krita has added some animation tools. Both of these have much better drawing capabilities. It’s hard to compete.

I have a small desire to restart work on Blit. For example, adding a camera connection to shoot paper drawn animation or working on some FFmpeg exporting. But I have other priorities right now. If I had to do it again, I would want to write Blit in C# instead of C++. I’ve grown to love C# a lot in the past year and development in it is much easier than C++, and performance is still pretty good. I really hope that QtSharp can get off of the ground sometime soon.

If you want to check out the source for Blit, you can find it over here: gitlab.com/define-private-public/blit. If you want to see some of my fabulous source documention, it’s at: https://blit.gitlab.io/SourceDocs/. And if in the slightest chance that you’re interested in working on Blit, please contact me.

To end with, here are some stats:

  • 97 source code files
  • 8,175 lines of code (95% C++)
  • 400 days of contributions
  • 364 issues tracked
  • 3,151 commits
  • 91,528 additions, 65,617 deletions
  • An unknown amount of users
  • and 1 developer (me)

 

The Bouncing Ball

 


Tags: Computer Graphics, Art, Arduino, Projects, C/C++, PCBs, Blit, Animation, MEGA_MATRIX

C# Networking Tutorials

I've been hard at work to make sure that the new "Tutorials," section works well and functions the way I intended it to. Nearly every day I've been finding and fixing a new bug. Anyways, to kick it off, I will be running a series of tutorials around C#'s Networking API (the System.Net namespace). You can find it over here.

There isn't much there now, but expect more soon!


Tags: C#, Tutorials, Projects

One Year of Blit

Back around mid to late July in 2014 I set out to create Blit. One year on now (as of last Wednesday), I've made a lot of progress from practically nothing. Thinking back I ask myself “why did I want to make Blit?”

I've made many other projects before. Some of them successes whereas others were really failures (cough buzz cough). Those projects had something in common. They were short, small, and contained. When I look back on all of the stuff that I've made, I noticed that there was nothing that I could call a “grand,” or “large,” project. I wanted something that I could call a major project that I built. More importantly I wanted to know how to manage a larger project; something I've never done before.

So I set a goal for myself: “Make something large. Something that you can never really call 'complete,' but work on it for an entire year.” That's what I did. I had nothing more than a silly GitHub streak to motivate me. It now says “371 days.” There were a few days where all I did was just update a TODO file, add some extra documentation, or ones that I didn't want to work on it at all (but I did anyways).

Blit still isn't really what I originally imaged it to be. Some sort of 2D Animation solution for pixel art and larger things (and hopefully pencil testing too). And I'm still not sure 100% what I want out of it. I consider what I've done so far to be nothing more than a prototype for a future vision.

I've met my goal of “work on something for a year,” but I plan to still chug along with it until I feel that I'm done. It's been fun so far.

Here are some stats:

  • 371 days of continuous development (avg. one hour per day, more on the weekends)
  • 75,868 additions / 47,902 deletions
  • 7,846 lines of code (core application, mostly C++ w/ Qt)
  • 2,887 commits
  • 352 tickets
  • 247 closed
  • 105 open
  • 43 more issues until the next one
  • 12 (active) branches
  • 1 (and a 1/2) milestones completed
  • 1 contributor (me)

This is what my network looks like.

Cheers.


Tags: Computer Graphics, Projects, Blit, Animation

Status Update 5

I was planning on doing another post after Imagine RIT, but I've been pretty busy. I was able to display off MEGA_MATRIX there along with a small fork of Blit where you can create animations then upload them to the device. It's was pretty popular with the kids. I'll be posting some of the creations soon enough.

Speaking of Blit I have been still working on it daily since the first release back in February. The big thing that I had to do was refactor the underlying monolithic Animation module into a more flexible and reusable system.

Some small stats:

  • 3.5 months
  • +1,100 lines of code (exactly)
  • 655 commits
  • 51 tickets (felt like 151)

I've also done a few other things like add a shape tool, line tool, fill tool (you know, the basics), and a few icons. There are many other features that I want to add too like exporting to GIF and video files. I think I'll be able to get them done for P-2.

Pendulum is coming...


Tags: Computer Graphics, Status Update, Projects, Blit, Animation, MEGA_MATRIX

Status Update 4

It's been a while since my last update. In that time, I've been working on a few projects here in there. As for MEGA_MATRIX, I've added support for the Arduino MEGA and have been able to do a few proof of concept stuff for the Raspberry Pi. The Pi version right now can get a whopping 20K FPS in the native C version! The Pi version isn't too functional right now, but expect soon enough. Link to source on GitHub.

Since the end of the summer, I've been working on my own Animation tool. It's not much right now, but you can find Linux and OS X binaries right over here. Here's the first thing I was able to make with it, a bouncing ball:

Bouncing Ball


Tags: Computer Graphics, Status Update, Projects, Blit, Animation, MEGA_MATRIX

MEGA_MATRIX

After tinkering with Arduinos for more two and a half years, I still find it a lot of fun just to turn LEDs on and off. What's more fun than that? Turning on and off a bunch of LEDs. When I first got my starter kit I ordered an 8x8 LED matrix along with it. I have whatsoever no formal training in electronics, so it took me a while to figure out how to use that thing. Using the magic of Charlieplexing I was able to get a small, very tiny image lit. Not satisfied with having an extra 64 LEDs at my disposal, I wanted to go bigger; I needed a 3x3 of 8x8's, a 24x24, I wanted 576 LEDs to blink on and off at my whim. There were a few challenges along the way.

The Arduino UNO R3 doesn't have enough I/O pins for this by itself (I'd need a good 48). The simple solution to this was use use some 74HC595 shift registers. By daisy-chaining two sets of three (one to act as the row controller and the other for the column), I could get away with only using six pins. Though it's possible that I could have used less. The final product uses ten pins on the Arduino (to have better control of the MR and OE pins on the shift register).

I originally planned to lay this all out on a protoboard, but as you can see from the below picture, it started to get really frustrating and confusing. I always wanted to learn how to make PCBs, so I though this would be a good opportunity to do so. I got myself a copy of KiCad, read a few tutorials, then went to work. I was actually surprised how easy it was to use this software. I did have some frustrations. Like that it's kind of half broken on Linux/GNU. It's only really usable under Windows or Wine (though there are still some quirks).

After receiving the print of the schematic, I found out that the footprints for the 788BS matrix were off, and the through holes where not wide enough. This wasn't a fun discovery. The next day, I spent a good two hours re-routing everything. I also added a CSH logo to the edge cuts. While I was waiting for the fixed boards to arrive I started to write the software to control the monstrous matrix. To my surprise, the circuit actually worked (this is on the bad board), and all I had to do was put globs of solder onto the pads and bend the pins on the 8x8 matrix. I also found out that it was a bit better to use a 200 Ohm resistor instead of 1K.

 

When using Arduino functions “digitalWrite(),” and “digitalRead(),” they may work okay for an 8x8 matrix, but I found out that on a 24x24, it doesn't work that well. I was getting around 75-ish frames per second. While I could have gotten away with showing a still image, it wasn't the easiest thing on the eyes. After doing some reading it seemed like writing some AVR C might be the remedy. One of the great things about the Arduino platform is that you can mix in AVR C code. After using C code to drive the matrix, I was getting around 625 frames per second. All of these measurements were made using timers and mathematics.

Now since I could display one image, the next logical step was to display a moving image. It only took another few hours of work to make this a possibility. The Arduino is always listening for data on its serial line. Once it has read in a full 72 bytes, it will display up a new picture. I also drafted a small pseudo scripting language where you can specify files to act as frames, assign them a delay, put them in a certain sequence, then have it loop.

If you want to check out the code for the project, you can find the repo right here: https://github.com/define-private-public/MEGA_MATRIX

And if you want a board, just send me a message. I've got a few to spare.


Tags: Arduino, Projects, PCBs, MEGA_MATRIX

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