examples: fix compilation of the graph.v example

examples/hot_reload/graph.v

@@ -12,29 +12,33 @@ const (
 )
 
 struct Context {
+mut:
 	gg &gg.Context
 }
 
 fn main() {
-	gconfig := gg.Cfg {
+	mut context := &Context{
+		gg: 0
+	}
+	context.gg = gg.new_context({
 		width: size
 		height: size
+		font_size: 20
 		use_ortho: true
-			create_window: true
+		user_data: context
 		window_title: 'Graph builder'
-			always_on_top: true
+		create_window: true
+		frame_fn: frame
+		bg_color: gx.white
+		font_path: gg.system_font_path()
+	})
+	context.gg.run()
 }
-	ctx := &Context{ gg: gg.new_context(gconfig) }
-	ctx.gg.window.set_user_ptr( ctx )
-	go update() // update the scene in the background in case the window isn't focused
-	for {
-		if ctx.gg.window.should_close() {
-			break
-		}
-		gg.clear(gx.white)
+
+fn frame(mut ctx Context) {
+	ctx.gg.begin()
 	ctx.draw()
-		ctx.gg.render()
-	}
+	ctx.gg.end()
 }
 
 [live]
@@ -60,10 +64,3 @@ fn (ctx &Context) draw() {
 		ctx.gg.draw_rect(f32(center + x * scale), f32(center + y * scale), 1, 1, gx.red)
 	}
 }
-
-fn update() {
-	for {
-		gg.post_empty_event()
-		time.sleep_ms(16) // 60 fps
-	}
-}