=Ruboid Ruboid is a ruby implementation of Craig Reynolds' Boid alogrithm (http://www.red3d.com/cwr/boids/), which realistically simulates the behaviour of a flock of creatures with a small set of simple rules. See Conrad Parker's page at http://www.vergenet.net/~conrad/boids/pseudocode.html for a more detailed explanation of how the simulation is performed. ===Operations ==== Basic operations Currently, the library implements the 3 rules descibed by Reynolds. You could create a Flock and give it a few boids like this: flock = Flock.new 1.upto(10) do |i| flock << Boid.new(Vector.new([rand(300),rand(300)]), Vector.new([rand(10)-5,rand(10)-5])) end Here I created a flock composed of 10 boids with a random starting position and an initial velocity between -5 and 5. The velocity can be understood as the distance the boid moves per time step. To move the flock, you must call the method +update_and_move+ on the flock: 1.upto(100) do |i| flock.update_and_move end The flock has just moved of 100 steps. You should perform some actions (like drawing the flock) between each update. ==== More operations On top of these basic rules, some addition ones have been implemented: - +scatter+: Scatters the flock, not as a reaction to a particular obstacle, but for example, as a reaction to a loud noise. It will break the cohesion. To reverse it, you should use +regroup+. - +go_to+: Gives a goal to reach to the boids. Boids will have a tendency to go in the direction of this goal. Use +forget_goal+ to reverse it. - +bound+: Encourages the boids to stay in a certain area (for example the drawing area). Use +move_freely+ to reverse it. - +rebel+: Adds an element of chance to the movement of boids. Use +calm_down+ to reverse it. ==== Examples I have included 2 examples in the distribution. One is stand-alone, the other necessitates RMagick and draws an animated GIF. ==== Vector class To ease the computations, I have created a Vector class, which can be of any dimension. All the positions and velocities of the boids are in this format. You can create a vector from an array of value like this: v = Vector.new(array) And access it like that : v[0] v.each ... ===Installation To install the latest version, just type : gem install Ruboid ===License Ruboid is released under the MIT license. ===Support Any questions, enhancement proposals, bug notifications or corrections can be sent to mailto:guilhem.vellut+georuby@gmail.com.