dm_control: Import of refs/pull/315/head

PiperOrigin-RevId: 464986102
Change-Id: Ia5a5d56e244e9ab0502bed3f954a5638b405b672

Author: JeanElsner

dm_control/viewer/gui/glfw_gui.py

@@ -283,12 +283,21 @@ def event_loop(self, tick_func):
       tick_func: A callable, function to call every frame.
     """
     while not glfw.window_should_close(self._context.window):
-      pixels = tick_func()
-      with self._context.make_current() as ctx:
-        ctx.call(
-            self._update_gui_on_render_thread, self._context.window, pixels)
-      self._mouse.process_events()
-      self._keyboard.process_events()
+      self.update(tick_func)
+
+  def update(self, render_func):
+    """Updates the window and renders a new image.
+
+    Args:
+      render_func: A callable returning a 3D numpy array of bytes (np.uint8),
+        with dimensions (width, height, 3).
+    """
+    pixels = render_func()
+    with self._context.make_current() as ctx:
+      ctx.call(
+          self._update_gui_on_render_thread, self._context.window, pixels)
+    self._mouse.process_events()
+    self._keyboard.process_events()
 
   def _update_gui_on_render_thread(self, window, pixels):
     self._fullscreen_quad.render(pixels, self.shape)