separate global tick from draw so on tick any node can request a redraw

PanoPainter/GameViewController.m

@@ -427,8 +427,11 @@ std::set<UITouch*> ignored_touch;
 - (void)glkView:(GLKView *)view drawInRect:(CGRect)rect
 {
     static auto time = std::chrono::steady_clock::now();
+    static double elapsed = 0;
     auto now = std::chrono::steady_clock::now();
     auto dt = std::chrono::duration<float>(now - time);
+    time = now;
+    elapsed += dt.count();
 
     std::deque<std::packaged_task<void()>> working_list;
     if (!tasklist.empty())
@@ -436,6 +439,8 @@ std::set<UITouch*> ignored_touch;
         std::lock_guard<std::mutex> lock(task_mutex);
         working_list = std::move(tasklist);
     }
+    
+    App::I.tick(dt.count());
 
     [self async_lock];
     if (!(App::I.redraw || App::I.animate || !working_list.empty()))
@@ -451,10 +456,10 @@ std::set<UITouch*> ignored_touch;
         working_list.pop_front();
     }
     App::I.clear();
-    App::I.update(dt.count());
+    App::I.update(elapsed);
     [self.context presentRenderbuffer:GL_FRAMEBUFFER];
     [self async_unlock];
-    time = now;
+    elapsed = 0;
 }
 
 @end