Add and control snake

Author: Ethan

snek/__init__.py

@@ -6,4 +6,5 @@
 from .sprites import *
 from .ui import *
 from .scenes import *
+from .snek import Snek
 from .client import Client

snek/scenes.py

@@ -78,26 +78,26 @@ def draw(self):
 
 
 class MainScene(Scene):
-    __slots__ = Scene.__slots__ + ("background", "apple")
+    __slots__ = Scene.__slots__ + ("background", "apple", "snek")
 
     def __init__(self, client):
         super().__init__(client)
         self.background = snek.Sprite(pg.image.load("./assets/backgrounds/board.png").convert(), 0, 0)
         self.apple = snek.AppleSprite(pg.image.load("./assets/sprites/apple.png").convert_alpha())
+        self.snek = snek.Snek(pg.image.load("./assets/sprites/snekpart.png").convert_alpha())
 
     def handle_events(self, events):
         for event in events:
             if event.type == pg.KEYDOWN:
-                self.apple.teleport()
-                events.remove(event)
+                self.snek.change_direction(event.key)
         return events
 
     def update(self, delta):
         self.timer += delta
-
-        if self.timer % 1 < 0.002:
-            self.apple.teleport()
+        self.snek.move(delta)
 
     def draw(self):
         # self.wnd.blit(self.background)
         self.wnd.blit(self.apple)
+        for part in self.snek.body:
+            self.wnd.blit(part)

snek/snek.py

@@ -0,0 +1,81 @@
+from collections import deque
+from enum import Enum
+
+import pygame as pg
+
+import snek
+
+
+class Direction(Enum):
+    UP = 0
+    DOWN = 1
+    LEFT = 2
+    RIGHT = 3
+
+
+DIRECTION_MAPPING = {
+    pg.K_UP: (Direction.UP, Direction.DOWN),
+    pg.K_DOWN: (Direction.DOWN, Direction.UP),
+    pg.K_LEFT: (Direction.LEFT, Direction.RIGHT),
+    pg.K_RIGHT: (Direction.RIGHT, Direction.LEFT),
+}
+
+
+class Snek:
+    __slots__ = ("part", "body", "maxlen", "direction", "speed", "movement_delay", "direction_changed")
+
+    def __init__(self, part):
+        self.part = part
+
+        w = self.part.get_width()
+        h = self.part.get_height()
+        x = round((snek.WINDOW_WIDTH / 2) / w) * w
+        y = round((snek.WINDOW_HEIGHT / 2) / h) * h
+
+        self.body = deque(
+            [snek.Sprite(self.part, x, y), snek.Sprite(self.part, x - w, y)]
+        )
+        self.maxlen = 2
+        self.direction = Direction.RIGHT
+        self.speed = 10
+        self.movement_delay = 0.
+        self.direction_changed = False
+
+    @property
+    def movement_interval(self):
+        return 1 / self.speed
+
+    def change_direction(self, key):
+        if not self.direction_changed:
+            for k, (d, o) in DIRECTION_MAPPING.items():
+                if key == k:
+                    if self.direction != o:
+                        self.direction = d
+                        self.direction_changed = True
+                        break
+
+    def shift(self, x, y):
+        self.body.appendleft(snek.Sprite(self.part, x, y))
+        if len(self.body) > self.maxlen:
+            self.body.pop()
+
+    def extend(self):
+        self.maxlen += 1
+        self.speed += 1
+
+    def move(self, delta):
+        if self.movement_delay < self.movement_interval:
+            self.movement_delay += delta
+            return
+
+        head = self.body[0]
+        movement = [
+            (head.x, head.y - head.h),
+            (head.x, head.y + head.h),
+            (head.x - head.w, head.y),
+            (head.x + head.w, head.y)
+        ][self.direction.value]
+
+        self.shift(*movement)
+        self.movement_delay = 0
+        self.direction_changed = False