Modifying the Chicken Scheme SDL2 basics demo (https://gitlab.com/chicken-sdl2/chicken-sdl2/blob/25d66ebd4383a9847bd26c9f69dbfc0e54e2a8b4/demos/basics.scm) to use 2D Accelerated Rendering

basics-2d-accelerated.patch

diff --git a/demos/basics.scm b/demos/basics.scm
index 65280b6..a9b16f9 100644
--- a/demos/basics.scm
+++ b/demos/basics.scm
@@ -150,20 +150,31 @@
 (define smiley1 (make-obj (make-smile-surf (make-random-color)) 300 300))
 (define smiley2 (make-obj (make-smile-surf (make-random-color)) 500 300))
 
-
+(define renderer (sdl2:create-renderer! window -1 (list 'accelerated)))
 
 ;;; Draw (or redraw) the entire scene. It would be more efficient to
 ;;; only redraw the parts of the scene that have changed, but since
 ;;; this is just a demo program we don't want to get too complex.
 (define (draw-scene!)
-  (let ((window-surf (sdl2:window-surface window)))
-    ;; Clear the whole screen using a blue background color
-    (sdl2:fill-rect! window-surf #f (sdl2:make-color 0 80 160))
+  ;; Create a new surface the same size as the window
+  (let ((surf (sdl2:make-surface* 800 600 32)))
+    ;; Clear the new surface screen using a blue background color
+    (sdl2:fill-rect! surf #f (sdl2:make-color 0 80 160))
     ;; Draw the smileys
-    (draw-obj! smiley2 window-surf)
-    (draw-obj! smiley1 window-surf)
-    ;; Refresh the screen
-    (sdl2:update-window-surface! window)))
+    (draw-obj! smiley2 surf)
+    (draw-obj! smiley1 surf)
+    ;; Convert the surface to a texture
+    (let ((texture (sdl2:create-texture-from-surface* renderer surf)))
+      ;; TODO: check if the texture creation was successful
+      ;; Free the surface since we're done converting it to a texture
+      (sdl2:free-surface! surf)
+      ;; Clear the screen
+      (sdl2:render-clear! renderer)
+      ;; Copy our texture into the renderer
+      (sdl2:render-copy! renderer texture)
+      (sdl2:render-present! renderer)
+      ;; Destroy the texture after we're done
+      (sdl2:destroy-texture! texture))))