class_docstr: **Bases:** :class:`GLGraphicsItem <pyqtgraph.opengl.GLGraphicsItem.GLGraphicsItem>`
  
  Displays a 3D triangle mesh. 
code: def shader(self):
      shader = self.opts["shader"]
      if isinstance(shader, shaders.ShaderProgram):
          return shader
      else:
          return shaders.getShaderProgram(shader)
  
file_path: pyqtgraph/pyqtgraph/opengl/items/GLMeshItem.py
imports: from OpenGL.GL import *
  import numpy
  from ...Qt import QtGui
  from ..None import shaders
  from ..GLGraphicsItem import GLGraphicsItem
  from ..MeshData import MeshData
label_desc: Use image node_id 3 for calling the GLMeshItem obj's underlying member method code with example usage: obj.shader() and returns: shader, shaders