Class: Ruboid::Boid

Inherits:
Object
  • Object
show all
Defined in:
lib/ruboid/ruboid.rb

Overview

Represents a boid : You can think of it as a fish or a bird

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(position, velocity) ⇒ Boid

the initial parameters of the boid are the responsibility of the calling application



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# File 'lib/ruboid/ruboid.rb', line 143

def initialize(position,velocity)
  @position = position
  @velocity = velocity
end

Instance Attribute Details

#position ⇒ Object

position of the boid



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# File 'lib/ruboid/ruboid.rb', line 138

def position
  @position
end

#velocity ⇒ Object

distance done by the boid by unit of time chosen by the application using the lib



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# File 'lib/ruboid/ruboid.rb', line 140

def velocity
  @velocity
end

Instance Method Details

#alignment(boids) ⇒ Object

Modifies the velocity so the boids have the tendency to go in the same direction : Rule 3 of Conrad Parker’s pseudo code



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# File 'lib/ruboid/ruboid.rb', line 206

def alignment(boids)
  perceived_velocity = Vector.zero(dimension)
  boids.each do |b|
    if b != self
      perceived_velocity.add(b.velocity)
    end
  end
  perceived_velocity.div(boids.length - 1).sub(@velocity)
end

#bound(bound_corner1, bound_corner2, bound_encouragement) ⇒ Object 



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# File 'lib/ruboid/ruboid.rb', line 169

def bound(bound_corner1,bound_corner2,bound_encouragement)
  v = Vector.zero(dimension)
  v.each_index do |i|
    if @position[i] < bound_corner1[i]
      v[i] = bound_encouragement[i]
    elsif @position[i] > bound_corner2[i]
      v[i] = -bound_encouragement[i]
    end
  end
  v
end

#cohesion(boids) ⇒ Object

Moves the boid to the center of mass : Rule 1 of Conrad Parker’s pseudo code



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# File 'lib/ruboid/ruboid.rb', line 182

def cohesion(boids)
  perceived_center = Vector.zero(dimension)
  boids.each do |b|
    if b != self
      perceived_center.add(b.position)
    end
  end
  perceived_center.div(boids.length - 1).sub(@position)
end

#dimension ⇒ Object 



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# File 'lib/ruboid/ruboid.rb', line 148

def dimension
  @position.dimension
end

#go_to(goal) ⇒ Object 



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# File 'lib/ruboid/ruboid.rb', line 165

def go_to(goal)
  goal.clone.sub(@position)
end

#limit(velocity_limit) ⇒ Object

Limits the velocity of the boid so it doesn’t go supersonic.



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# File 'lib/ruboid/ruboid.rb', line 158

def limit(velocity_limit)
  velocity_norm = @velocity.norm
  if velocity_norm > velocity_limit
    @velocity.mul(velocity_limit / velocity_norm)
  end
end

#move ⇒ Object

Move a boid of one step



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# File 'lib/ruboid/ruboid.rb', line 153

def move
  @position.add(@velocity)
end

#separation(boids, distance) ⇒ Object

Moves the boid away from the other boids which are too close to it : Rule 2 of Conrad Parker’s pseudo code



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# File 'lib/ruboid/ruboid.rb', line 193

def separation(boids,distance)
  c = Vector.zero(dimension)
  boids.each do |b|
    if b != self
      if b.position.distance_to(@position) < distance
        c.add(@position).sub(b.position)
      end
    end
  end
  c
end