# What is the define I need to use in the PBR materials shader code to check if mesh.receiveShadows

**URL:** <https://forum.babylonjs.com/t/what-is-the-define-i-need-to-use-in-the-pbr-materials-shader-code-to-check-if-mesh-receiveshadows/20372>\
**Category:** Questions\
**Created:** [April 27, 2021, 7:32pm UTC](https://forum.babylonjs.com/t/what-is-the-define-i-need-to-use-in-the-pbr-materials-shader-code-to-check-if-mesh-receiveshadows/20372 "2021-04-27T19:32:14Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Pryme8](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/pryme8/32/7212_2.png) [@Pryme8](https://forum.babylonjs.com/u/Pryme8)\
**Post date:** [April 27, 2021, 7:32pm UTC](https://forum.babylonjs.com/t/what-is-the-define-i-need-to-use-in-the-pbr-materials-shader-code-to-check-if-mesh-receiveshadows/20372/1 "2021-04-27T19:32:14Z")

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So if I am modifying something in the PBR glsl code how do I do a define check for mesh.receiveShadows?

Something like

```auto
#ifdef SHADOWS
   doSomething
#endif

```

Its not seeming to be the SHADOWS define though.

---

<div class="post-metadata">

**Author:** ![Evgeni\_Popov](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/evgeni_popov/32/4432_2.png) [@Evgeni\_Popov](https://forum.babylonjs.com/u/Evgeni_Popov)\
**Post date:** [April 27, 2021, 9:53pm UTC](https://forum.babylonjs.com/t/what-is-the-define-i-need-to-use-in-the-pbr-materials-shader-code-to-check-if-mesh-receiveshadows/20372/2 "2021-04-27T21:53:46Z")

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It’s `SHADOW0`, `SHADOW1`, etc because we append the light index to `SHADOW` to make the define.