def register_pta(self, name, input_type):
        """ Registers a new input, type should be a glsl type """
        pta = self.glsl_type_to_pta(input_type).empty_array(1)
        self.ptas[name] = pta
        if self.use_ubo:
            self._inputs[self.name + "_UBO." + name] = pta
        else:
            self._inputs[self.name + "." + name] = pta
 Registers a new input, type should be a glsl type 
metadrive/render_pipeline/rpcore/util/shader_input_blocks.py