| 27 | |
| 28 | |
| 29 | def drawBranch(x, y, direction, branchLength): |
| 30 | # if the branch is too small, just quit |
| 31 | if branchLength < 5: |
| 32 | return |
| 33 | |
| 34 | # Draw the branch: |
| 35 | branchThickness = max(branchLength / 7.0, 1) + random.randint(-1, 1) |
| 36 | turtle.pensize(branchThickness) |
| 37 | for i in range(4): |
| 38 | turtle.forward(branchLength / 4.0 + random.randint(-10, 10)) |
| 39 | turtle.left(random.randint(-8, 8)) |
| 40 | |
| 41 | if random.randint(0, 5) == 0: |
| 42 | tinyBranchAngle = random.randint(-LEFT_ANGLE, RIGHT_ANGLE) |
| 43 | turtle.right(tinyBranchAngle) |
| 44 | drawBranch(turtle.xcor(), turtle.ycor(), turtle.heading(), branchLength / 2) |
| 45 | turtle.left(tinyBranchAngle) |
| 46 | turtle.pensize(branchThickness) |
| 47 | |
| 48 | if random.randint(0, 5) == 0: |
| 49 | branchLength = branchLength * 0.9 |
| 50 | |
| 51 | # Draw the two recursive branches: |
| 52 | if random.randint(0, 9) != 0: |
| 53 | turtle.left(LEFT_ANGLE) |
| 54 | drawBranch(turtle.xcor(), turtle.ycor(), turtle.heading(), branchLength - LEFT_DECREASE) |
| 55 | turtle.right(LEFT_ANGLE) |
| 56 | |
| 57 | if random.randint(0, 9) != 0: |
| 58 | turtle.right(RIGHT_ANGLE) |
| 59 | drawBranch(turtle.xcor(), turtle.ycor(), turtle.heading(), branchLength - RIGHT_DECREASE) |
| 60 | turtle.left(RIGHT_ANGLE) |
| 61 | |
| 62 | # Return back to the starting point: |
| 63 | turtle.penup() |
| 64 | turtle.goto(x, y) |
| 65 | turtle.setheading(direction) |
| 66 | turtle.pendown() |
| 67 | |
| 68 | def drawTree(x, y, direction, seed): |
| 69 | global LEFT_ANGLE, RIGHT_ANGLE, LEFT_DECREASE, RIGHT_DECREASE |