Snowflakes on the ice help!

1

Even if I want to rotate the snow flake it will only rotate once. Can someone help with this?


# For this level we need to a line fractal for the ground and a hexagonal snowflake made up of 6 line fractals. Check the guide for an image of the desired output.

def degreesToRadians(degrees):
    # All vector operations require working in radians rather than degrees.
    return Math.PI / 180 * degrees
    
# This function creates a line fractal.  Read through it so you understand the recursive concept.
def line(start, end):
    # First we need to get the full vector and its magnitude to determine if we are below our minimum threshold.
    full = Vector.subtract(end, start)
    distance = full.magnitude()
    if distance < 4:
        # If under our threshold distance, then we will simply draw a line along the vector and be done (the return tells us to exit the function).
        hero.toggleFlowers(False)
        hero.moveXY(start.x, start.y)
        hero.toggleFlowers(True)
        hero.moveXY(end.x, end.y)
        return
        
    # Otherwise we will create our fractal by getting a vector of half magnitude.
    half = Vector.divide(full, 2)
    
    # We will be creating 4 line fractals (start -> A, A -> B, B -> A, and A -> end) and so we need to calculate the intermediate positions A and B.
    A = Vector.add(half, start)
    
    # To get B, we need to rotate the vector half 90 degrees and multiply by 2/3 (so it is 1/3 of the original magnitude), then add this to A.
    rotate = Vector.rotate(half, degreesToRadians(90))
    rotate = Vector.multiply(rotate, 2 / 3)
    B = Vector.add(rotate, A)

    # Now just draw the 4 lines using the line functions.
    line(start, A)
    line(A, B)
    line(B, A)
    line(A, end)


def flake(start, end):
    # To create a hexagonal flake we need to create 6 line fractals rotated by 60 degrees each time.
    side = Vector.subtract(end, start)
    a = start
    b = end
    for i in range(6):
        line(a, b)
        # To get the next edge, we need to rotate the side 60 degrees.
        rotation = Vector.rotate(side, degreesToRadians(60))
        # Now need to reset a and b with the beginning and end points for the new side.
        a = b
        b = Vector.add(rotation, b)
whiteXs = [Vector(12, 10), Vector(60, 10)]
redXs = [Vector(64, 52), Vector(52, 52)]

# You need to actually call the functions with a start and end vector for each.
line(Vector(12, 10),Vector(60, 10))
# Be sure to use actual Vector objects–simple objects will not work.
flake(redXs[0],redXs[1])
# Refresh often to avoid a memory leak and crash (working on it)
2

I tried your program, it is very close to working.

In your flake() function you make a vector called side.

side = Vector.subtract(end, start)

Then the first time through your for loop you take side and rotate it by 60 degrees to make a new vector called rotate.

rotation = Vector.rotate(side, degreesToRadians(60))

Then the second time through your for loop you take that same old side vector and rotate in by 60 degrees again, so your new rotate vector is pointing in the same direction as your old rotate vector.

(and so on each time through the for loop)

That is why all of the rotated sides are pointing in the same direction.

So, instead of rotating that first side by 60 degrees each time, you want to rotate your most recent rotation by an additional 60 degrees.

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3

Can you change this code to a proper one please?

def flake(start, end):
    # To create a hexagonal flake we need to create 6 line fractals rotated by 60 degrees each time.
    side = Vector.subtract(end, start)
    a = start
    b = end
    for i in range(6):
        line(a, b)
        side = Vector.subtract(end, start)
        
        # To get the next edge, we need to rotate the side 60 degrees.
        rotation = Vector.rotate(side, degreesToRadians(60))
        # Now need to reset a and b with the beginning and end points for the new side.
        a = b
        b = Vector.add(rotation, b)
4

What you have is still rotating the first side each time. I would undo that last change

When you finish the loop set side to your most recent side (you are calling it “rotation”)

1 Like