Added pause functionality

examples/asteroids/main.py

@@ -3,6 +3,7 @@
 import operator
 
 from pygame.math import Vector2
+from pgzero.builtins import pause, is_paused
 
 from space import create_star_scape
 from actors import Player, Asteroid
@@ -139,9 +140,11 @@ def on_key_down(key):
             game.player.turn += 1
         if key == keys.RIGHT:
             game.player.turn -= 1
-        if key == keys.SPACE and not game.player.frozen:
+        if key == keys.SPACE and not game.player.frozen and not is_paused():
             sounds.fire.play()
             game.bullets.append(game.player.fire())
+        if key == keys.RETURN:
+            pause()
     elif game.stage is GameStage.game_over:
         if key == keys.BACKSPACE:
             game.initials = game.initials[:-1]

pgzero/builtins.py

@@ -11,4 +11,4 @@
 
 from .constants import mouse, keys, keymods
 
-from .game import exit
+from .game import exit, pause, is_paused

pgzero/game.py

@@ -13,7 +13,14 @@
 
 screen = None
 DISPLAY_FLAGS = 0
+paused = False
 
+def pause():
+    global paused
+    paused = not paused
+
+def is_paused():
+    return paused
 
 def exit():
     """Wait for up to a second for all sounds to play out
@@ -243,7 +250,7 @@ def mainloop(self):
 
         pgzclock = pgzero.clock.clock
 
-        self.need_redraw = True
+        self.need_redraw = not paused
         while True:
             # TODO: Use asyncio.sleep() for frame delay if accurate enough
             yield from asyncio.sleep(0)
@@ -261,9 +268,9 @@ def mainloop(self):
                     self.keyboard._release(event.key)
                 self.dispatch_event(event)
 
-            pgzclock.tick(dt)
 
-            if update:
+            if update and not paused:
+                pgzclock.tick(dt)
                 update(dt)
 
             screen_change = self.reinit_screen()