From 0c3a700aa94a0256c5e5b1a14819f10b3d3e869b Mon Sep 17 00:00:00 2001
From: Gene Pasquet <dev@etenil.net>
Date: Wed, 8 Apr 2026 00:38:55 +0100
Subject: Support scling

---
 engine.scm | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

(limited to 'engine.scm')

diff --git a/engine.scm b/engine.scm
index 38ebfed..d88a94b 100644
--- a/engine.scm
+++ b/engine.scm
@@ -18,6 +18,7 @@
 
 (defstruct game
   title width height
+  scale          ;; positive integer: whole-game pixel scaling factor
   window renderer
   input          ;; input-state record
   input-config   ;; input-config record
@@ -41,14 +42,18 @@
 (define (make-game #!key
     (title "Downstroke Game")
     (width 640) (height 480)
+    (scale 1)
     (frame-delay 16)
     (input-config *default-input-config*)
     (preload #f) (create #f) (update #f) (render #f)
     (debug? #f))
+  (unless (and (integer? scale) (positive? scale))
+    (error "make-game: scale must be a positive integer" scale))
   (make-game*
     title:        title
     width:        width
     height:       height
+    scale:        scale
     window:       #f
     renderer:     #f
     scene:        #f
@@ -128,12 +133,18 @@
         (sdl2:game-controller-open! i))
       (init-controllers (+ i 1))))
 
-  ;; 2. Create window + renderer
-  (game-window-set! game
-    (sdl2:create-window! (game-title game) 'centered 'centered
-                         (game-width game) (game-height game) '()))
-  (game-renderer-set! game
-    (sdl2:create-renderer! (game-window game) -1 '(accelerated)))
+  ;; 2. Create window + renderer (window size = logical size × scale)
+  (let ((scale (game-scale game)))
+    (game-window-set! game
+      (sdl2:create-window! (game-title game) 'centered 'centered
+                           (* (game-width game) scale)
+                           (* (game-height game) scale) '()))
+    (game-renderer-set! game
+      (sdl2:create-renderer! (game-window game) -1 '(accelerated)))
+    (when (> scale 1)
+      (sdl2:render-logical-size-set!
+        (game-renderer game)
+        (list (game-width game) (game-height game)))))
 
   ;; 3. preload: hook — user loads assets here
   (when (game-preload-hook game)
-- 
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