Contents

#
# Bouncing Ball with Vectors 
# by Daniel Shiffman.  
# PVector was used in the original (instead of Vec2D)
#
# Demonstration of using vectors to control motion of body
# This example is not object-oriented
# See AccelerationWithVectors for an example of how to simulate motion using vectors in an object
#
load_library :vecmath

attr_reader :loc,  # Location of shape
            :velocity,  # Velocity of shape
            :gravity   # Gravity acts at the shape's acceleration

def setup
  size(640,360)
  smooth 4
  @loc = Vec2D.new(100,100)
  @velocity = Vec2D.new(1.5,2.1)
  @gravity = Vec2D.new(0,0.2)

end

def draw
  background(0)
  
  # Add velocity to the location.
  @loc += velocity
  # Add gravity to velocity
  @velocity += gravity
  
  # Bounce off edges
if ((loc.x > width) || (loc.x < 0))
    velocity.x *= -1
  end
if (loc.y > height)
    # We're reducing velocity ever so slightly 
    # when it hits the bottom of the window
    velocity.y *= -0.95 
    loc.y = height
  end

  # Display circle at location vector
  stroke(255)
  stroke_weight(2)
  fill(127)
  ellipse(loc.x,loc.y,48,48)
end

Version data entries

4 entries across 4 versions & 1 rubygems

Version	Path
ruby-processing-2.4.4	samples/processing_app/library/vecmath/bouncing_ball.rb
ruby-processing-2.4.3	samples/processing_app/library/vecmath/bouncing_ball.rb
ruby-processing-2.4.2	samples/processing_app/library/vecmath/bouncing_ball.rb
ruby-processing-2.4.1	samples/processing_app/library/vecmath/bouncing_ball.rb