game: Add game started hook.

* sly/game.scm (game-start-hook, game-started?): New variables.
  (run-game-loop): Run game-start-hook before loop starts.

1 files changed, 16 insertions, 2 deletions

diff --git a/sly/game.scm b/sly/game.scm
index 6e82b78..615f934 100644
--- a/sly/game.scm
+++ b/sly/game.scm
@@ -36,18 +36,31 @@
   #:use-module (sly math vector)
   #:use-module (sly window)
   #:use-module (sly render)
-  #:export (draw-hook
+  #:export (game-start-hook
+            draw-hook
             after-game-loop-error-hook
+            game-started?
+
             run-game-loop
             stop-game-loop))
 
+
 ;;;
-;;; Game Loop
+;;; Hooks and initializers
 ;;;
 
+(define game-start-hook (make-hook))
 (define draw-hook (make-hook 2))
 (define after-game-loop-error-hook (make-hook))
 
+(define-signal game-started?
+  (hook->signal game-start-hook #f (lambda () #t)))
+
+
+;;;
+;;; Game Loop
+;;;
+
 (define (interval rate)
   (floor (/ 1000 rate)))
 
@@ -159,6 +172,7 @@ milliseconds of the last iteration of the game loop."
          (lambda (signum)
            (stop-game-loop)))
        ;; Let's play!
+       (run-hook game-start-hook)
        (game-loop (sdl-ticks) 0))
      (lambda (cont callback)
        (when (procedure? callback)