# Objective
- Make the reusable PBR shading functionality a little more reusable
- Add constructor functions for `StandardMaterial` and `PbrInput` structs to populate them with default values
- Document unclear `PbrInput` members
- Demonstrate how to reuse the bevy PBR shading functionality
- The final important piece from #3969 as the initial shot at making the PBR shader code reusable in custom materials
## Solution
- Add back and rework the 'old' `array_texture` example from pre-0.6.
- Create a custom shader material
- Use a single array texture binding and sampler for the material bind group
- Use a shader that calls `pbr()` from the `bevy_pbr::pbr_functions` import
- Spawn a row of cubes using the custom material
- In the shader, select the array texture layer to sample by using the world position x coordinate modulo the number of array texture layers
<img width="1392" alt="Screenshot 2022-06-23 at 12 28 05" src="https://user-images.githubusercontent.com/302146/175278593-2296f519-f577-4ece-81c0-d842283784a1.png">
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
