Eric's Allolib playground

This is a fork of Allolib Playground for my personal projects in CMPSC 190D S24 at UCSB.

Project 0: me and my boids

Iteration 1 Video here: https://youtu.be/h7SJa4J97Pc Iteration 2 video here: https://youtu.be/6n1AKxUpc6w

The complex flocking and wandering behavior of "boids" comes from relatively simple rules. Here I attempt to use this chaotic behavior to make procedural music based on the size of "groups" formed by the boids as time goes on. This is mainly me messing around with Allolib and struggling to understand how it works, rather than studying actual music synthesis.

Currently it just sounds awful. I'll probably return to this later; it might have potential...

Project 1: playable cello

Demo 1: https://youtu.be/pSX_qqyAOzY (Only has the A string and sounds like a bee.)

Demo 2: https://youtu.be/BhyFifdUczQ (Has all four strings and sounds like it's an underwater brass instrument.)

Demo 3: https://youtu.be/U3ju84UVjfY (sounds slightly less underwater)

Playable cello! I show off vibrato with frequency modulation and also crude physical modeling of a cello's bowed string (work in progress (I dont think I will ever finish))

Brief breakdown of the sound setup for a cello string:

• The signal for each string is a saw-tooth oscillator with the frequency set at its base level (i.e. A2 will be at 440 Hz).
• Add slight reverb to make it sound more resonant and realistic.
• Add low-frequency (5 Hz) vibrato that modulates the signal's frequency in order to mimic a musician's vibrato.
• The bow dictates the ADSR envelope of the sound: pushing the bow down (by clicking the mouse) or changing the direction of the bow will start the attack on the string and raising the bow (letting go of the mouse), stopping movement, or leaving the string will trigger the release.
• The faster the velocity of the bow, the louder the sound.
• Add a low-pass and a high-pass filter that I pretty much just played around with until everything sounded okay-ish. These affected the brightness and harshness of the sound.
• Pushing keys on the keyboard would also modulate the frequency in half steps above the base frequency of the string. For example, the A-string would have the keys 12345678 to represent A#, B, C, C#, D...; The D-string used qwertyui for D#, E, F, F#, G, G#... etc. We do this by multiplying the base frequency by $2^{-i/12}$ where i is the "index" of the key (no keys being pressed would represent an index of zero).
• Since it is a 2D environment, the strings needed to be set up in this staggered manner so that it is possible for me to play individual strings, double-stops, and chords while not playing physically impossible things such as playing all four strings at once or double-stopping the A and C string. This introduced even more levels of difficulty while playing! Maybe these other placements could lead to cool possibilities though.

Setup

Get all dependencies and tools required by allolib. See the readme file for allolib.

Run the init.sh script to get the allolib and al_ext libraries or execute in a bash shell:

git submodule update --recursive --init

Building and running applications

The allolib playground provides basic facilties for building and debugging single file applications. On a bash shell on Windows, Linux and OS X do:

./run.sh path/to/file.cpp

This will build allolib, and create an executable for the file.cpp called 'file' inside the '''path/to/bin''' directory. It will then run the application.

Allolib API documentation

You can find the allolib API doxygen documentation at: https://allosphere-research-group.github.io/allolib-doc/