code: def on_draw(self, event):
      # Draw the same scene as as in hello_quad.py, but draw it to the FBO
      with self._fbo:
          gloo.set_clear_color((0.0, 0.0, 0.5, 1))
          gloo.clear(color=True, depth=True)
          gloo.set_viewport(0, 0, *self.physical_size)
          self._program1.draw("triangle_strip")
  
      # Now draw result to a full-screen quad
      # Init
      gloo.set_clear_color("white")
      gloo.clear(color=True, depth=True)
      self._program2.draw("triangle_strip")
  
file_path: vispy/examples/gloo/hello_fbo.py
imports: from vispy import gloo
  from vispy import app
  import numpy
label_desc: Use image node_id 3 for calling the Canvas obj's underlying member method code with example usage: obj.on_draw(event) without return types