TIL: Python Basics Day 23 - Turtle Crossing Game

Turtle Crossing Game

class, inheritance, using turtle graphics.

I struggled with
step2. generating cars
step3. speeding up cars when levelup

1. Why car manager is not inheriting directly from turtle.

-> car manager class itself doesn't need turtle's methods.

-it has create_car(inherited from turtle), move_cars, speed_up(level_up) methods
-speed_up(): screen updates every 0.1 sec, turtle moves a certain distance with goto() or forward(), to move farther in a same time, it should move faster. -> thats how we creates 'speed'. / goto(original coordinate + additional distance), forward(distance) needs
-carmanager class creates one car at a time and add it on to the all_cars list. Use for loop to loop through all the items in the list with move()
-init holds empty list(class's attribute = variable) 'all_cars' as a starting value self.all_cars = []
(Attribute: variable that's associated with an object.)

2. why speed control is different from pong game's ball case.
How to add speed on a ball at Pong game:

new_x = xcor() + additional distance(self.x_move = 10 -> set variable on init)
new_y = ycor() + additional distance
goto(new_x, new_y)

How to add speed on a car at Turtle Crossing game:

    def move_cars(self):
       for car in self.all_cars:
           car.backward(self.car_speed) -> distance

    def speed_up(self):
        self.car_speed += MOVE_INCREMENT

-> Difference btw goto() and forward()

• forward: Move the turtle forward by the specified distance, in the direction the turtle is headed
  -it can be used with setheading(angle) to change the direction.
  (wherever within the radius)
• goto: Move turtle to an absolute position. If the pen is down, draw line. Do not change the turtle’s orientation
  -used to set its first coordinate.(fixed position)

main.py

import time
from turtle import Screen
from player import Player
from car_manager import CarManager
from scoreboard import ScoreBoard

screen = Screen()
screen.setup(width=600, height=600)
screen.tracer(0)

player = Player()
car_manager = CarManager()
scoreboard = ScoreBoard()

screen.listen()
screen.onkey(player.move_up, "Up")

game_is_on = True
while game_is_on:
    time.sleep(0.1)
    screen.update()
    car_manager.create_car()
    car_manager.move_cars()
    
    # Detect player collision with car
    for car in car_manager.all_cars:
        if player.distance(car) <25:
            scoreboard.game_over()
            game_is_on = False
            screen.exitonclick()

	#safely reached to a finish line
    if player.finishline():
        player.go_to_start()
        car_manager.speed_up()
        scoreboard.score_up()

player.py

from turtle import Turtle
STARTING_POSITION = (0, -280)
MOVE_DISTANCE = 10
FINISH_LINE_Y = 280


class Player(Turtle):

    def __init__(self):
        super().__init__()
        self.shape("turtle")
        self.setheading(90)
        self.penup()
        self.goto(STARTING_POSITION)


    def move_up(self):
        new_y = self.ycor() + MOVE_DISTANCE
        self.goto(self.xcor(), new_y)

    def go_to_start(self):
        self.goto(STARTING_POSITION)

    def finishline(self):
        if self.ycor() > FINISH_LINE_Y:
            return True 
        else:
            return False

car_manager.py

from turtle import Turtle
import random

COLORS = ["red", "orange", "yellow", "green", "blue", "purple"]
STARTING_MOVE_DISTANCE = 5
MOVE_INCREMENT = 10

class CarManager:
    def __init__(self):
        self.all_cars = []   #cant' understand
        self.car_speed = STARTING_MOVE_DISTANCE

    def create_car(self):
        random_chance = random.randint(1, 6)  #probability 1 out of 6
        if random_chance == 1:
            new_car = Turtle("square")
            new_car.color(random.choice(COLORS))
            new_car.penup()
            new_car.turtlesize(stretch_wid=1, stretch_len=2)
            random_y = random.randint(-250, 250)
            new_car.goto(300, random_y)
            self.all_cars.append(new_car)  # can't understand

    def move_cars(self):
       for car in self.all_cars:
           car.backward(self.car_speed)

    def speed_up(self):
        self.car_speed += MOVE_INCREMENT

scoreboard.py

from turtle import Turtle
FONT = ("Courier", 24, "normal")
OVER_FONT = ("Courier", 60, "bold")


class ScoreBoard(Turtle):
    def __init__(self):
        super().__init__()
        self.color("black")
        self.penup()
        self.hideturtle()
        self.score = 1
        self.update_scoreboard()

    def update_scoreboard(self):
        self.clear()
        self.goto(0, 260)
        self.write(f"Level: {self.score}", align="center", font=FONT)

    def score_up(self):
        self.score += 1
        self.update_scoreboard()

    def game_over(self):
        self.goto(0, 0)
        self.write("GAME OVER", align="center", font=OVER_FONT)