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Versions: 6
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Stored size: 1.68 KB
Contents
#
# 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.
#
load_libraries :control_panel
attr_reader :gravity, :panel
def setup
size 640, 340
fill 0
# Control panel for changing gravity
control_panel do |c|
c.slider :gravity, 0..30, 6
@panel = c
end
@mass = 2.0
@s1 = Spring2d.new(width/2, height/2, @mass, gravity)
@s2 = Spring2d.new(width/2, height/2, @mass, gravity)
end
def draw
panel.set_visible(true) if self.visible
background 204
@s1.update(mouse_x, mouse_y, gravity)
display(@s1, mouse_x, mouse_y)
@s2.update(@s1.x, @s1.y, gravity)
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
class Spring2d
include Processing::Proxy
attr_reader :x, :y, :gravity
def initialize(xpos, ypos, mass, gravity)
@x = xpos # The x-coordinate
@y = ypos # The y-coordinate
@gravity = gravity
@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, gravity)
force_x = (target_x - self.x) * @stiffness
ax = force_x / @mass
@vx = @damping * (@vx + ax)
@x += @vx
@gravity = gravity
force_y = (target_y - self.y) * @stiffness
force_y += gravity
ay = force_y / @mass
@vy = @damping * (@vy + ay)
@y += @vy
end
def diameter
@radius * 2
end
end
Version data entries
6 entries across 6 versions & 1 rubygems