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A fast JavaScript implementation of the boid's algorithm obeying coherence, alignment, and separation
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danielmuthama/Boids-algorithm
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A lightweight JavaScript implementation ofboids. Its "API" is a little limited,but it's reasonably performant - my MacBook ran the demo with 1,000 boids at60 frames per second.
I used an earlier, hastier version for the flocks ingrow.
For use withbrowserify:
npm install boids
varboids=require('boids'),raf=require('raf')varflock=boids({boids:50,// The amount of boids to usespeedLimit:0,// Max steps to take per tickaccelerationLimit:1,// Max acceleration per tickseparationDistance:60,// Radius at which boids avoid othersalignmentDistance:180,// Radius at which boids align with otherschoesionDistance:180,// Radius at which boids approach othersseparationForce:0.15,// Speed to avoid atalignmentForce:0.25,// Speed to align with other boidschoesionForce:0.1,// Speed to move towards other boidsattractors:[]})raf(window).on('data',function(){ctx.fillStyle='black'ctx.fillRect(0,0,canvas.width,canvas.height)ctx.fillStyle='white'ctx.save()ctx.translate(-canvas.width/2,-canvas.height/2)flock.tick()flock.boids.forEach(function(boid){ctx.fillRect(boid[0],boid[1],1,1)})ctx.restore()})
flock = boids([options])
flock.tick()
Moves the boid simulation forward one tick - if you're running an animation,you should be calling this on each frame.
flock.boids
All of your boids are stored as an array of arrays, with eacharray containing the following variables for a single boid:
[xPosition,yPosition,xSpeed,ySpeed,xAcceleration,yAcceleration]
Because the flock is just an array, it should be entirely safe for youto add and remove elements without any unintended side effects, provided allof the arrays are at least 6 elements long and contain numerical values. Forexample, you can add a new boid moving at a random speed to the origin like so:
flock.boids.push([0,0,Math.random()*10-5,Math.random()*10-5,0,0])
flock.attractors
You can use attractors to control the flow of the boids - essentially,providing them with goals and obstacles. Each attractor contains:
[xPosition,yPosition,radius,force]
Note that you can use a negative value forforce to repel boids instead ofattracting them. Again, it should be safe to modify, add and remove thesearrays without any surprises.
Runningbenchmark.js yielded the following results in Node:
50 boids: 34013 ticks/sec100 boids: 10000 ticks/sec150 boids: 4537 ticks/sec200 boids: 2583 ticks/sec250 boids: 1653 ticks/sec300 boids: 1159 ticks/sec350 boids: 835 ticks/sec400 boids: 654 ticks/sec450 boids: 518 ticks/sec500 boids: 419 ticks/sec550 boids: 347 ticks/sec600 boids: 292 ticks/sec650 boids: 249 ticks/sec700 boids: 215 ticks/sec750 boids: 187 ticks/sec800 boids: 160 ticks/sec850 boids: 130 ticks/sec900 boids: 119 ticks/sec950 boids: 107 ticks/sec1000 boids: 95 ticks/secI'm very much open to pull requests that can help improve performance :)
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A fast JavaScript implementation of the boid's algorithm obeying coherence, alignment, and separation
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