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Versions: 9
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Contents
require 'ruby-processing'
#
# Ported from http://processing.org/learning/topics/chain.html
#
# One mass is attached to the mouse position and the other is attached the position of the other mass.
# The gravity in the environment pulls down on both.
#
class Chain < Processing::App
attr_reader :gravity
load_library :control_panel
def setup
smooth
fill 0
# Inputs: spring1, spring2, mass, gravity
@gravity = 6.0
@mass = 2.0
@s1 = Spring2d.new(width/2, height/2, @mass)
@s2 = Spring2d.new(width/2, height/2, @mass)
# Control panel for changing gravity
control_panel do |c|
c.slider :gravity, 0..30
end
end
def draw
background 204
@s1.update(mouse_x, mouse_y)
display(@s1, mouse_x, mouse_y)
@s2.update(@s1.x, @s1.y)
display(@s2, @s1.x, @s1.y)
end
def display(spring, nx, ny)
no_stroke
ellipse(spring.x, spring.y, spring.diameter, spring.diameter)
stroke 255
line(spring.x, spring.y, nx, ny)
end
end
class Spring2d
attr_reader :x, :y
def initialize(xpos, ypos, mass)
@x = xpos # The x-coordinate
@y = ypos # The y-coordinate
@mass = mass
@vx, @vy = 0, 0 # The x- and y-axis velocities
@radius = 20
@stiffness = 0.2
@damping = 0.7
end
def update(target_x, target_y)
force_x = (target_x - self.x) * @stiffness
ax = force_x / @mass
@vx = @damping * (@vx + ax)
@x += @vx
force_y = (target_y - self.y) * @stiffness
force_y += $app.gravity
ay = force_y / @mass
@vy = @damping * (@vy + ay)
@y += @vy
end
def diameter
@radius * 2
end
end
Chain.new(:width => 200, :height => 200, :title => "Chain", :full_screen => false)
Version data entries
9 entries across 9 versions & 1 rubygems