Gazebo loading custom texture

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How to load custom texture through launch file? I created new directories space in path ~/models.

Dir tree:

-models
--media
---materials
----scripts
-----gazebo.material
----textures
-----texture_01.jpg

World file:

  <material>
    <script>
      <uri>file://media/materials/scripts/gazebo.material</uri>
      <name>Gazebo/Texture_01</name>
    </script>
  </material>

Launch file:

  <include file="$(find test_package)/launch/empty_world.launch">
    <arg name="verbose" value="true"/>
    <arg name="world_name" value="$(find test_package)/worlds/test.world"/>
  </include>

Where and how to pass environments variable in my without changing empty_world.launch?

<env name="GAZEBO_MODEL_PATH" value="$(find test_package)/models"/>
<env name="GAZEBO_RESOURCE_PATH" value="$(find test_package)/media/materials"/>

Putting them in my launch file doesn't work. Typing export GAZEBO_MODEL_PATH=$GAZEBO_MODEL_PATH:~/models/ and export GAZEBO_RESOURCE_PATH=$GAZEBO_RESOURCE_PATH:~/models/media/materials/ also doesn't work. My objects stays white without any texture.