From 994e6805f2082b07a3415c0b10df6474c5c6a57f Mon Sep 17 00:00:00 2001
From: David Thompson <dthompson2@worcester.edu>
Date: Tue, 7 Jan 2014 21:56:28 -0500
Subject: Make game loop status parameter.

* 2d/game.scm (%state): Replace with game-loop-status.
(game-loop-status): New parameter.
(run-game-loop): Set status to running.
(game-running?, game-paused?, pause-game, resume-game, quit-game): Use
parameter.
---
 2d/game.scm | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/2d/game.scm b/2d/game.scm
index da4e0b8..cd73f8f 100644
--- a/2d/game.scm
+++ b/2d/game.scm
@@ -54,15 +54,15 @@
 ;; * stopped
 ;; * running
 ;; * paused
-(define %state 'stopped)
+(define game-loop-status (make-parameter 'stopped))
 (define ticks-per-second 60)
 (define tick-interval (make-parameter 0))
 (define draw-hook (make-hook))
 
 (define (run-game-loop)
   "Start the game loop."
-  (parameterize ((tick-interval (floor (/ 1000 ticks-per-second))))
-    (set! %state 'running)
+  (parameterize ((game-loop-status 'running)
+                 (tick-interval (floor (/ 1000 ticks-per-second))))
     (resume-game)
     (spawn-server)
     (game-loop (SDL:get-ticks) 0)))
@@ -125,24 +125,24 @@ time in milliseconds that has passed since the last game update."
 ;;;
 
 (define (game-running?)
-  (or (eq? %state 'running)
-      (eq? %state 'paused)))
+  (or (eq? (game-loop-status) 'running)
+      (eq? (game-loop-status) 'paused)))
 
 (define (game-paused?)
-  (eq? %state 'paused))
+  (eq? (game-loop-status) 'paused))
 
 (define (pause-game)
   "Pauses the game loop. Useful when developing."
-  (set! %state 'paused))
+  (game-loop-status 'paused))
 
 (define (resume-game)
   "Resumes the game loop."
   (when (game-paused?)
-    (set! %state 'running)))
+    (game-loop-status 'running)))
 
 (define (quit-game)
   "Finish the current frame and terminate the game loop."
-  (set! %state 'stopped))
+  (game-loop-status 'stopped))
 
 ;;;
 ;;; Event Handling
-- 
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