From 7f6d69e986ae9d77b6e7f8e5572f1bdc210a0ad7 Mon Sep 17 00:00:00 2001
From: David Thompson <dthompson@member.fsf.org>
Date: Mon, 2 Sep 2013 09:08:20 -0400
Subject: Add a *running* flag to the game loop.

---
 2d/game-loop.scm | 35 ++++++++++++++++++++++-------------
 2d/game.scm      | 25 +++++++++++++++----------
 2 files changed, 37 insertions(+), 23 deletions(-)

(limited to '2d')

diff --git a/2d/game-loop.scm b/2d/game-loop.scm
index ab81b5a..8dcc65c 100644
--- a/2d/game-loop.scm
+++ b/2d/game-loop.scm
@@ -42,8 +42,9 @@
             on-mouse-motion-hook
             on-mouse-button-down-hook
             on-mouse-button-up-hook
+            current-fps
             run-game-loop
-            current-fps))
+            quit-game-loop!))
 
 ;;;
 ;;; Constants
@@ -57,6 +58,7 @@
 ;;;
 
 (define *fps* 0)
+(define *running* #f)
 
 ;;;
 ;;; Hooks
@@ -200,23 +202,30 @@ INPUT, OUTPUT, and ERROR ports."
 
 (define (game-loop last-time next-time accumulator)
   "Runs input, render, and update hooks."
-  (handle-events)
-  (let* ((time (SDL:get-ticks))
-         (dt (- time last-time))
-         (accumulator (+ accumulator dt))
-         (remainder (update accumulator)))
-    (run-repl)
-    (render)
-    (accumulate-fps! dt)
-    (SDL:delay (time-left (SDL:get-ticks) next-time))
-    (game-loop time
-               (+ next-time tick-interval)
-               remainder)))
+  (when *running*
+    (handle-events)
+    (let* ((time (SDL:get-ticks))
+           (dt (- time last-time))
+           (accumulator (+ accumulator dt))
+           (remainder (update accumulator)))
+      (run-repl)
+      (render)
+      (accumulate-fps! dt)
+      (SDL:delay (time-left (SDL:get-ticks) next-time))
+      (game-loop time
+                 (+ next-time tick-interval)
+                 remainder))))
 
 (define (run-game-loop)
   "Spawns a REPL server and starts the main game loop."
+  (set! *running* #t)
   (spawn-server)
   ;;(lock-mutex game-loop-mutex)
   (agenda-schedule show-fps)
   (let ((time (SDL:get-ticks)))
     (game-loop time (+ time tick-interval) 0)))
+
+(define (quit-game-loop!)
+  "Tell the game loop to finish up the current frame and then
+terminate."
+  (set! *running* #f))
diff --git a/2d/game.scm b/2d/game.scm
index e20638c..cb043ec 100644
--- a/2d/game.scm
+++ b/2d/game.scm
@@ -25,16 +25,11 @@
   #:use-module (srfi srfi-9)
   #:use-module (2d game-loop)
   #:use-module (2d window)
-  #:use-module (2d vector2)
-  #:export (<game>
-            make-game
-            define-game
-            game?
-            game-title
-            game-resolution
-            game-fullscreen?
-            game-first-scene
-            run-game))
+  #:use-module (2d vector2))
+
+;;;
+;;; Games
+;;;
 
 (define-record-type <game>
   (%make-game title resolution fullscreen first-scene)
@@ -64,3 +59,13 @@ value."
                (game-fullscreen? game))
   (run-game-loop)
   (close-window))
+
+(export <game>
+        make-game
+        define-game
+        game?
+        game-title
+        game-resolution
+        game-fullscreen?
+        game-first-scene
+        run-game)
-- 
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