TurtleGraphics Python: Bouncing turtle off the walls?

Question

So, I am trying to make a realistic bouncing function, where the turtle hits a wall and bounces off at the corresponding angle. My code looks like this:

def boun         


        

Answer 1

Gday,

Your problem seems to be that you are using the same trigonometry to calculate the right and left walls, as you are the top and bottom. A piece of paper and a pencil should suffice to calculate the required deflections.

def inbounds(limit, value):
    'returns boolean answer to question "is turtle position within my axis limits"'
    return -limit < value * 2 < limit

def bounce(num_steps, step_size, initial_heading):
    '''given the number of steps, the size of the steps 
        and an initial heading in degrees, plot the resultant course
        on a turtle window, taking into account elastic collisions 
        with window borders.
    '''

    turtle.reset()
    height = turtle.window_height()
    width = turtle.window_width()
    turtle.left(initial_heading)

    for step in xrange(num_steps):
        turtle.forward(step_size)
        x, y = turtle.position()

        if not inbounds(height, y):
            turtle.setheading(-turtle.heading())

        if not inbounds(width, x):
            turtle.setheading(180 - turtle.heading())

I've used the setheading function and a helper function (inbounds) to further declare the intent of the code here. Providing some kind of doc-string is also good practice in any code that you write (provided the message it states is accurate!!)

Your mileage may vary on the use of xrange, Python 3.0+ renames it to simply range.