New feature with start button

src/freegames/snake.py

@@ -3,40 +3,98 @@
 Exercises
 
 1. How do you make the snake faster or slower?
-2. How can you make the snake go around the edges?
-3. How would you move the food?
-4. Change the snake to respond to mouse clicks.
+2. How do you make the snake change color?
+3. How do you make the snake respond to the mouse?
+4. How would you improve the snake's intelligence?
+
 """
 
 from random import randrange
-from turtle import *
-
+from turtle import (
+    Screen,
+    Turtle,
+    addshape,
+    clear,
+    hideturtle,
+    listen,
+    ontimer,
+    onkey,
+    setup,
+    tracer,
+    update,
+    done,
+)
 from freegames import square, vector
 
+# --- Constants & Game State ---
 food = vector(0, 0)
 snake = [vector(10, 0)]
 aim = vector(0, -10)
 
+# NEW: State to manage game flow ('start', 'playing', 'over')
+state = {'current': 'start'}
+# NEW: Writer turtle for displaying messages
+writer = Turtle(visible=False)
+
+# --- Game Functions ---
 
 def change(x, y):
     """Change snake direction."""
+    if state['current'] != 'playing':
+        return
     aim.x = x
     aim.y = y
 
-
 def inside(head):
     """Return True if head inside boundaries."""
-    return -200 < head.x < 190 and -200 < head.y < 190
-
+    return -200 <= head.x <= 190 and -200 <= head.y <= 190
+
+def display_message(message):
+    """Display a message in the center of the screen."""
+    writer.clear()
+    writer.penup()
+    writer.goto(0, 0)
+    writer.color('white')
+    writer.write(message, align="center", font=("Arial", 16, "normal"))
+
+def reset_game():
+    """Reset all game variables to their initial state."""
+    global food, snake, aim
+    food = vector(0, 0)
+    snake = [vector(10, 0)]
+    aim = vector(0, -10)
+    state['current'] = 'start'
+
+def start_game():
+    """Start the game loop."""
+    if state['current'] == 'start':
+        state['current'] = 'playing'
+        writer.clear()
+        move()
+
+def restart_game():
+    """Clear the screen and restart the game."""
+    if state['current'] == 'over':
+        reset_game()
+        clear()  # Turtle's clear screen function
+        setup_game()  # Re-initialize the game setup
+        display_message("Press SPACE to start")
 
 def move():
-    """Move snake forward one segment."""
+    """Move snake one segment."""
+    # NEW: Only move if in 'playing' state
+    if state['current'] != 'playing':
+        return
+
     head = snake[-1].copy()
     head.move(aim)
 
+    # NEW: Check for game over
     if not inside(head) or head in snake:
         square(head.x, head.y, 9, 'red')
         update()
+        state['current'] = 'over'
+        display_message("Game Over! Press 'R' to Restart")
         return
 
     snake.append(head)
@@ -55,16 +113,26 @@ def move():
 
     square(food.x, food.y, 9, 'green')
     update()
-    ontimer(move, 100)
-
-
-setup(420, 420, 370, 0)
-hideturtle()
-tracer(False)
-listen()
-onkey(lambda: change(10, 0), 'Right')
-onkey(lambda: change(-10, 0), 'Left')
-onkey(lambda: change(0, 10), 'Up')
-onkey(lambda: change(0, -10), 'Down')
-move()
+
+    # NEW: Continue game loop only if 'playing'
+    if state['current'] == 'playing':
+        ontimer(move, 100)
+
+def setup_game():
+    """Set up the game window, controls, and initial state."""
+    setup(420, 420, 370, 0)
+    hideturtle()
+    tracer(False)
+    listen()
+    onkey(lambda: change(10, 0), 'Right')
+    onkey(lambda: change(-10, 0), 'Left')
+    onkey(lambda: change(0, 10), 'Up')
+    onkey(lambda: change(0, -10), 'Down')
+    # NEW: Bind Start and Restart keys
+    onkey(start_game, 'space')
+    onkey(restart_game, 'r')
+
+# --- Main Game Execution ---
+setup_game()
+display_message("Press SPACE to start")
 done()