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Contents
#
# Acceleration with Vectors
# by Daniel Shiffman.
#
# Demonstration of the basics of motion with vector.
# A 'Mover' object stores location, velocity, and acceleration as vectors
# The motion is controlled by affecting the acceleration (in this case towards the mouse)
#
# For more examples of simulating motion and physics with vectors, see
# Simulate/ForcesWithVectors, Simulate/GravitationalAttraction3D
# See library/vecmath for Vec2D examples
#
# A Mover object
attr_reader :mover
def setup
size(640,360)
@mover = Mover.new(width, height)
end
def draw
background(0)
# Update the location
mover.update
# Display the Mover
mover.display
end
#
# Acceleration with Vectors
# by Daniel Shiffman.
#
# Demonstration of the basics of motion with vector.
# A 'Mover' object stores location, velocity, and acceleration as vectors
# The motion is controlled by affecting the acceleration (in this case towards the mouse)
#
class Mover
# The Mover tracks location, velocity, and acceleration
attr_reader :location, :velocity, :acceleration,
# The Mover's maximum speed
:topspeed
def initialize(width, height)
# Start in the center
@location = PVector.new(width / 2, height / 2)
@velocity = PVector.new(0,0)
@topspeed = 5
end
def update
# Compute a vector that points from location to mouse
mouse = PVector.new(mouse_x, mouse_y)
@acceleration = PVector.sub(mouse, location)
# Set magnitude of acceleration
acceleration.set_mag(0.2)
# Velocity changes according to acceleration
velocity.add(acceleration)
# Limit the velocity by topspeed
velocity.limit(topspeed)
# Location changes by velocity
location.add(velocity)
end
def display
stroke(255)
stroke_weight(2)
fill(127)
ellipse(location.x, location.y, 48, 48)
end
end
Version data entries
6 entries across 6 versions & 1 rubygems