Class: HotCocoa::Graphics::Particle

Inherits:
Object
  • Object
show all
Defined in:
lib/hotcocoa/graphics/elements/particle.rb

Overview

wandering particle with brownian motion

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(x, y, velocity_x = 0.0, velocity_y = 2.0) ⇒ Particle

initialize particle origin x,y coordinates (relative to the center)



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# File 'lib/hotcocoa/graphics/elements/particle.rb', line 23

def initialize (x, y, velocity_x=0.0, velocity_y=2.0)
  @age = 0
  @acceleration = 0.5

  @x = x
  @y = y

  @previous_x = 0
  @previous_y = 0

  # initialize velocity
  @velocity_x=velocity_x
  @velocity_y=velocity_y

  # append the point to the array
  @points = [NSPoint.new(@x, @y)]
  @stroke = Color.white
end

Instance Attribute Details

#acceleration ⇒ Object

Returns the value of attribute acceleration.



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# File 'lib/hotcocoa/graphics/elements/particle.rb', line 20

def acceleration
  @acceleration
end

#points ⇒ Object

Returns the value of attribute points.



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# File 'lib/hotcocoa/graphics/elements/particle.rb', line 20

def points
  @points
end

#stroke ⇒ Object

Returns the value of attribute stroke.



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# File 'lib/hotcocoa/graphics/elements/particle.rb', line 20

def stroke
  @stroke
end

#velocity_x ⇒ Object

Returns the value of attribute velocity_x.



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# File 'lib/hotcocoa/graphics/elements/particle.rb', line 20

def velocity_x
  @velocity_x
end

#velocity_y ⇒ Object

Returns the value of attribute velocity_y.



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# File 'lib/hotcocoa/graphics/elements/particle.rb', line 20

def velocity_y
  @velocity_y
end

#x ⇒ Object

Returns the value of attribute x.



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# File 'lib/hotcocoa/graphics/elements/particle.rb', line 20

def x
  @x
end

#y ⇒ Object

Returns the value of attribute y.



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# File 'lib/hotcocoa/graphics/elements/particle.rb', line 20

def y
  @y
end

Instance Method Details

#draw(canvas) ⇒ Object 



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# File 'lib/hotcocoa/graphics/elements/particle.rb', line 67

def draw(canvas)
  canvas.nofill
  canvas.lines(@points)
end

#move ⇒ Object

move to a new position using brownian motion



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# File 'lib/hotcocoa/graphics/elements/particle.rb', line 43

def move
  # save old x,y position
  @previous_x=@x
  @previous_y=@y

  # move particle by velocity_x,velocity_y
  @x += @velocity_x
  @y += @velocity_y

  # randomly increase/decrease direction
  @velocity_x += random(-1.0, 1.0) * @acceleration
  @velocity_y += random(-1.0, 1.0) * @acceleration

  # draw a line from the old position to the new
  #CANVAS.line(@previous_x,@previous_y,@x,@y);
  @points.push(NSPoint.new(@x, @y))

  # grow old
  @age += 1
  if @age>200
    # die and be reborn
  end
end