This program simulates how fish behave in large groups, run from predators, avoid obstacles, avoid borders, and more.
Note: If you have access to Visual Studio, and would prefer that version, it can be found here: https://github.com/Zachhi/FlockingBoids-VS
(Quality much worse here due to gif-conversion)
Watch the video here (above is only a 10 second gif): https://www.youtube.com/watch?v=G17Cqs6FFl0&t=18s
A major part of this program was to make it look as clean as possible. I focused on having it look professionally done, and I put a lot of thought into the design of the simulation itself. There have been plenty of flocking boid programs done, and I wanted mine to pop out and look better than any others. This simulation is worth a look at, so go ahead and scroll to the Demo section to watch the youtube video.
The base idea comes from Craig Reynolds, who developed a model for flocking in 1986. More can be read here: https://www.red3d.com/cwr/boids/
Flocking Boids considers 3 rules: Seperation, Cohesion, and Allignment
- Seperation defines the way boids avoid each other and avoid contact with each other.
- Cohesion refers to how the boids group together. They will attempt to move to the average center of mass of the boids around them.
- Allignment defines the way boids allign, as they will steer towards the average heading of the boids around them.
The union of these three simple rules gives you incredible flocking behavior. The three rules are each multiplied by a certain coefficient, and changing these coefficients will signifigantly change their behavior.
This is the very simple, very base idea that doesn't do the simulation justice. Scroll down to the demo section and watch the youtube video in order to see the simulation in all its detail
Flocking Types
There are 3 different flocking types provided. The first can be thought of the normal flocking type. Boids stay an average distance apart with an average sight range to each other. In the second type, boids stay very close together, and don't have as much as sight range. This flocking type is very visually pleasing, and looks best when there is no predator chasing them. The third one is my favorite and would probably be considered the most realistic. Boids are much farther apart with a much farther sight range. This leads to bigger groups. This type works best when there are a lot of boids on screen, and it looks the coolest when a predator is on screen. When a predator chases boids that are in flocking type 3, it leads to the most visually pleasing results of the program.
Boid Types
- Blue Boid: Has normal movement and rotation speed. Lets the predator get an average distance near them. Then they speed up at an average pace and head away, and slow down once the predator is an average distance away.
- Dark Blue boids: A little faster in both movement and rotation. Lets the predator get a little closer to them than the average. Then they speed up at a slower pace and head away, and slow down once the predator is less than the average distance away. These are the easiest to catch for the predator.
- Pink Boids: Even faster in both movement and rotation. Lets the predator get really close, much closer than any others. Than they speed up much faster than any other, and they don't slow down until they are really far from the predator. These are the most scattery fish, and the hardest to catch for the predator.
- Yellow boids: Fastest in both movement and rotation. Doesn't let the predator get close at all. They run away at a much higher distance than any other boid. They start running before the predator can even detect them. However, when they are being chased, they don't speed up at all.
- White Boids: Slowest in both movement and rotation. However, they are not deteced by predators. They still run away when a predator get's close though.
Other
- Toggling every rule except cohesion off, and then repeatedly clicking "X" leads to cool effects
- Clicking "H" shows the boid's headings. This is where they wish to go according to the 3 rules+predators+borders+repulsions
- Repulsions are fun to mess with. It is a stand still obstacle boids wil avoid. Clicking "O" creaes a circle of them. It is interesting to do this, add a bunch of boids inside, then spawn a predator inside.
- Changing the game speed can be really satisfying. Right before a predator goes in for the kill, start turning it down. Then you can see in slo-mo the boid's running away.
- Mess with it. There are many variants you can do, such as
- Spawning 50 predators and one prey (I reccomend a pink boid for this)
- Spawning 500 boids of different types and seeing how they flock. Add a predator in and watch the chaos. Turn off borders for a less chaotic screen.
- See how boids interact with repulsions in their way. I made it so boids will "wiggle" their way out of them.
- Seeing how one predator will chase one prey
- Seeing how boids behave when different rules are toggled on or off
- Looking at a boids heading while running from a predator or while flocking is very satisfying
- Spawning multiple repulsion circles of different sizes, and adding boids inside of these
- And whatever else you wish
Eventually, my plan is to make this into a screensaver people can download and use.
Animations were drawn myself, The "Clair De Lune" and "Comptine d'un autre été - Amélie" music tracks were performed myself.
- Top Right: Shows the three rules and which are toggled, the FPS, and the game speed
- Bottom Right: Shows the current boid you are spwaning
- Bottom Left: Shows the current counts of the boids on screen
- Top Left: Shows the rules
- LShift: See all the controls (will show in top left)
- Left click: Spawn the current boid type (either a prey or predator)
- Space: Spawn 20 of the current boid types in random locations
- X: Spawn 2 of the current boid types facing each other on opposite sides of screen
- Left/Right Arrow Keys: Next/Previous boid type
- P: Change current boid type to predator and back
- Right Click: Create/delete repulsion
- O: Spawn a circle of repulsions
- I: Change the type of repulsion circle that will spawn
- 1: Toggle rule 1 (Separation)
- 2: Toggle rule 2 (Cohesion)
- 3: Toggle rule 3 (Allignment)
- LTab: cycle to a new flocking behavior
- B: Toggle borders on and off
- H: Toggle boid headings on and off
- C: Clear everything from the screen
- V: Clear current object type from the screen
- R: Clear all repulsions from the screen
- Up/Down Arrow Keys: Increase/decrease game speed (slow-mo or fast-mo)
- N: Cycle to next song
- LCtrl: Hide GUI
- Esc: Exit program
- Windows or Linux
- SFML (Simple and Fast Multi-Media Library) 2.5.1 or later. However, I have set everything up already for your convenience. You will not be required to download/link any libraries. The downside is that the download is ~30 MB more.
- GCC 7.3.0 MinGW (32 bit) or later. If you want to use 64 bit version of GCC, download the SFML GCC 64-bit version from https://www.sfml-dev.org/download/sfml/2.5.1/ then simply replace the
includeandlibfiles insfmlFileswith theincludeandlibraryfiles you just downloaded. Then delete and replace the current .dlls with the .dll files in thebinfolder you just downloaded. - GNU Make
If you want to use Visual Studio, which would not require the use of a makefile (if you dont have GNU Make set up), scroll to the top to find the link
Windows or Linux:
- Download the source code from here, or copy the repository into your enviroment
- Open your terminal
- run the command
maketo build project - Now run the executable by running the command
runorrun.exeto start the program - If it does not work right away for you, there is two things you have to check:
- Go to your default compiler path or
C_Cpp.default.compilerpathand make the path is set toC:/MinGW/bin/g++.exeor wherever your MinGW is located - Go to your default include path or
C_Cpp.default.includepathand make sure the path is set to["${workspaceFolder}**/"] - Run
makeandrunagain and the program should execute
- Go to your default compiler path or
Zachary Chi [email protected]
This project is licensed under the MIT License - see the LICENSE.md file for details