Work on demos

1 files changed, 12 insertions, 0 deletions

diff --git a/engine.scm b/engine.scm
index 0318616..38ebfed 100644
--- a/engine.scm
+++ b/engine.scm
@@ -99,6 +99,17 @@
          (create (state-hook state #:create)))
     (when create (create game))))
 
+;; Set renderer draw color for SDL_RenderClear (called every frame before clear).
+(define (renderer-set-clear-color! renderer scene)
+  (let ((bg (and scene (scene-background scene))))
+    (if (and (list? bg) (>= (length bg) 3))
+        (let ((r (list-ref bg 0))
+              (g (list-ref bg 1))
+              (b (list-ref bg 2))
+              (a (if (>= (length bg) 4) (list-ref bg 3) 255)))
+          (set! (sdl2:render-draw-color renderer) (sdl2:make-color r g b a)))
+        (set! (sdl2:render-draw-color renderer) (sdl2:make-color 0 0 0 255)))))
+
 ;; ── game-run! ──────────────────────────────────────────────────────────────
 ;; Main event loop and lifecycle orchestration
 
@@ -167,6 +178,7 @@
                                       target
                                       (game-width game)
                                       (game-height game)))))))
+            (renderer-set-clear-color! (game-renderer game) (game-scene game))
             (sdl2:render-clear! (game-renderer game))
             (when (game-scene game)
               (render-scene! (game-renderer game) (game-scene game)))