diff -r 362b7659dc76 -r c5dde81b6fb2 test/sandbox.c
--- a/test/sandbox.c	Wed Nov 08 23:17:07 2023 +0100
+++ b/test/sandbox.c	Wed Nov 15 22:51:40 2023 +0100
@@ -26,6 +26,7 @@
  */
 
 #include <ascension/ascension.h>
+#include <cx/printf.h>
 
 static bool show_message_box_on_error(SDL_Window* window) {
     if (asc_has_error()) {
@@ -50,13 +51,34 @@
 
     AscWindow *window = asc_window_initialize(0, &settings);
     asc_shader_initialize_predefined();
+
+    AscTextNode fps_counter = {0};
+    unsigned last_fps = 0;
+
     while (asc_loop_next()) {
         // quit application on any error
         if (show_message_box_on_error(window->window)) break;
 
 
+        // fps counter
+        if (asc_context.elapsed_millis > 0) {
+            unsigned fps = 1000u / asc_context.elapsed_millis;
+            if (fps != last_fps) {
+                last_fps = fps;
+                asc_set_font(asc_font(ASC_FONT_REGULAR, 24));
+                asc_ink_rgb(255, 0, 0);
+                cxmutstr fpstext = cx_asprintf("%u FPS", fps);
+                asc_text_draw(&fps_counter, (asc_vec2i) {50, 50}, fpstext);
+                cx_strfree(&fpstext);
+            } else {
+                asc_text_redraw(&fps_counter);
+            }
+        }
     }
 
+    // TODO: maybe nodes should also be "garbage collected"
+    asc_text_destroy(&fps_counter);
+
     asc_context_destroy();
     return 0;
 }