code: def glsl_type(self):
          
          if self.dtype is None:
              return None
          dtshape = self.dtype[0].shape
          n = dtshape[0] if dtshape else 1
          if n > 1:
              dtype = 'vec%d' % n
          else:
              dtype = 'float' if 'f' in self.dtype[0].base.kind else 'int'
          return 'attribute', dtype
docs: GLSL declaration strings required for a variable to hold this data.