import sokol.sapp
 
 fn main() {
-    gg.new_context(
+    mut ctx := gg.new_context(
         bg_color: gx.white
         window_title: 'Cursor'
         frame_fn: frame
         init_fn: init
-    ).run()
+    )
+    ctx.run()
 }
 
 fn init(mut ctx gg.Context) {

     color gx.Color
 }
 
-struct App {
+pub struct App {
 pub:
     args         simargs.ParallelArgs
     request_chan chan &sim.SimRequest

         ft: 0
         ui_mode: cfg.ui_mode
         native_rendering: cfg.native_rendering
-    }
-    if cfg.user_data == unsafe { nil } {
-        ctx.user_data = ctx
+        window: sapp.Desc{
+            init_userdata_cb: gg_init_sokol_window
+            frame_userdata_cb: gg_frame_fn
+            event_userdata_cb: gg_event_fn
+            fail_userdata_cb: gg_fail_fn
+            cleanup_userdata_cb: gg_cleanup_fn
+            window_title: &char(cfg.window_title.str)
+            html5_canvas_name: &char(cfg.window_title.str)
+            width: cfg.width
+            height: cfg.height
+            sample_count: cfg.sample_count
+            high_dpi: true
+            fullscreen: cfg.fullscreen
+            __v_native_render: cfg.native_rendering
+            // drag&drop
+            enable_dragndrop: cfg.enable_dragndrop
+            max_dropped_files: cfg.max_dropped_files
+            max_dropped_file_path_length: cfg.max_dropped_file_path_length
+            swap_interval: cfg.swap_interval
+        }
     }
     ctx.set_bg_color(cfg.bg_color)
     // C.printf('new_context() %p\n', cfg.user_data)
-    window := sapp.Desc{
-        user_data: ctx
-        init_userdata_cb: gg_init_sokol_window
-        frame_userdata_cb: gg_frame_fn
-        event_userdata_cb: gg_event_fn
-        fail_userdata_cb: gg_fail_fn
-        cleanup_userdata_cb: gg_cleanup_fn
-        window_title: &char(cfg.window_title.str)
-        html5_canvas_name: &char(cfg.window_title.str)
-        width: cfg.width
-        height: cfg.height
-        sample_count: cfg.sample_count
-        high_dpi: true
-        fullscreen: cfg.fullscreen
-        __v_native_render: cfg.native_rendering
-        // drag&drop
-        enable_dragndrop: cfg.enable_dragndrop
-        max_dropped_files: cfg.max_dropped_files
-        max_dropped_file_path_length: cfg.max_dropped_file_path_length
-        swap_interval: cfg.swap_interval
-    }
-    ctx.window = window
     return ctx
 }
 
 // run starts the main loop of the context.
-pub fn (ctx &Context) run() {
+pub fn (mut ctx Context) run() {
+    // set context late, in case it changed (e.g., due to embedding)
+    ctx.window = sapp.Desc{
+        ...ctx.window
+        user_data: ctx
+    }
+    if ctx.user_data == unsafe { nil } {
+        ctx.user_data = ctx
+    }
     sapp.run(&ctx.window)
 }
 

     sz.height = g.height
     sz.width = g.width
     g.config = cfg
-    if isnil(cfg.user_data) {
-        g.user_data = g
-    }
     g.window = dom.window()
     document := dom.document
     canvas_elem := document.getElementById(cfg.canvas.str) or {
 }
 
 pub fn (mut ctx Context) run() {
+    // set context late, in case it changed (e.g., due to embedding)
+    if isnil(ctx.user_data) {
+        ctx.user_data = ctx
+    }
+
     gg_animation_frame_fn(mut ctx)
 }