Let snake grow when it hits the prey.

snake/snake.py

@@ -3,6 +3,7 @@ from game_object import GameObject
 from snake_segment import SnakeSegment
 from snake_state_machine import SnakeStateMachine
 from wall import Wall
+from prey import Prey
 
 
 class Snake(GameObject):
@@ -14,6 +15,7 @@ class Snake(GameObject):
         
         self.__state_machine = SnakeStateMachine()
         self.__is_dead = False
+        self.__shall_grow = False
 
     
     def __collides_with_wall(self, obj: GameObject):
@@ -24,10 +26,16 @@ class Snake(GameObject):
         return isinstance(obj, Snake) and self.get_bounding_boxes()[0].collidelist(obj.get_bounding_boxes()[1:]) > -1
 
 
+    def __collides_with_prey(self, obj: GameObject):
+        return isinstance(obj, Prey) and self.get_bounding_boxes()[0].colliderect(obj.get_bounding_boxes()[0])
+
+
     def __update_on_collision(self, game_objs: list[GameObject]) -> None:
         for obj in game_objs:
             if self.__collides_with_wall(obj) or self.__collides_with_self(obj):
                 self.__is_dead = True
+            elif self.__collides_with_prey(obj):
+                self.__shall_grow = True
 
 
     def draw(self, surface: pygame.Surface) -> None:
@@ -35,6 +43,8 @@ class Snake(GameObject):
             segment.draw(surface)
 
     def update(self, user_input: int, game_objs: list[GameObject]) -> None:
+        self.__shall_grow = False
+
         if not self.__is_dead:
             self.__update_on_collision(game_objs)
 
@@ -43,7 +53,10 @@ class Snake(GameObject):
                 new_head = self.__state_machine.get_state().get_next_head(self.__segments[0])
                 
                 self.__segments.insert(0, new_head)
+                
+                if not self.__shall_grow:
                     self.__segments.pop()
     
+
     def get_bounding_boxes(self) -> list[pygame.rect.Rect]:
         return [seg.get_bounding_boxes()[0] for seg in self.__segments]