# Is needDepthPrePass work for ShaderMaterial too?

**URL:** <https://forum.babylonjs.com/t/is-needdepthprepass-work-for-shadermaterial-too/3527>\
**Category:** Questions\
**Created:** [May 27, 2019, 7:03am UTC](https://forum.babylonjs.com/t/is-needdepthprepass-work-for-shadermaterial-too/3527 "2019-05-27T07:03:21Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![nasimiasl](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/nasimiasl/32/34_2.png) [@nasimiasl](https://forum.babylonjs.com/u/nasimiasl)\
**Post date:** [May 27, 2019, 7:03am UTC](https://forum.babylonjs.com/t/is-needdepthprepass-work-for-shadermaterial-too/3527/1 "2019-05-27T07:03:21Z")

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hey  
i try needDepthPrePass = true;

 ![image](https://us1.discourse-cdn.com/flex024/uploads/babylonjs/original/2X/4/40e7e9d081da684360fcaa299059d2aa4bb2641b.jpeg)

all material is shaderMaterial

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**Author:** ![sebavan](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/sebavan/32/57_2.png) [@sebavan](https://forum.babylonjs.com/u/sebavan)\
**Post date:** [May 27, 2019, 12:20pm UTC](https://forum.babylonjs.com/t/is-needdepthprepass-work-for-shadermaterial-too/3527/2 "2019-05-27T12:20:54Z")

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It should work, can you create a repro in the playground ?

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<div class="post-metadata">

**Author:** ![nasimiasl](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/nasimiasl/32/34_2.png) [@nasimiasl](https://forum.babylonjs.com/u/nasimiasl)\
**Post date:** [May 28, 2019, 2:40pm UTC](https://forum.babylonjs.com/t/is-needdepthprepass-work-for-shadermaterial-too/3527/3 "2019-05-28T14:40:01Z")

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> [@nasimiasl](#):
>
> needDepthPrePass

that not work on standardmaterial too?  
when one mesh inside of the others

> **[Babylon.js Playground](https://www.babylonjs-playground.com/#PJQTXN%233)**
>
> Babylon.js playground is a live editor for Babylon.js WebGL 3D scenes

[https://www.babylonjs-playground.com/#PJQTXN#4](https://www.babylonjs-playground.com/#PJQTXN#4) : with needDepthPrePass = true;  
both is wrong result

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<div class="post-metadata">

**Author:** ![Deltakosh](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/deltakosh/32/26635_2.png) [@Deltakosh](https://forum.babylonjs.com/u/Deltakosh)\
**Post date:** [May 28, 2019, 4:37pm UTC](https://forum.babylonjs.com/t/is-needdepthprepass-work-for-shadermaterial-too/3527/4 "2019-05-28T16:37:53Z")

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I think you may want to use alphaIndex instead:  
[https://www.babylonjs-playground.com/#PJQTXN#7](https://www.babylonjs-playground.com/#PJQTXN#7)

Doc: [Transparency and How Meshes Are Rendered - Babylon.js Documentation](https://doc.babylonjs.com/resources/transparency_and_how_meshes_are_rendered#alpha-index)

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<div class="post-metadata">

**Author:** ![nasimiasl](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/nasimiasl/32/34_2.png) [@nasimiasl](https://forum.babylonjs.com/u/nasimiasl)\
**Post date:** [May 28, 2019, 6:53pm UTC](https://forum.babylonjs.com/t/is-needdepthprepass-work-for-shadermaterial-too/3527/5 "2019-05-28T18:53:34Z")

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thanks

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<div class="post-metadata">

**Author:** ![nasimiasl](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/nasimiasl/32/34_2.png) [@nasimiasl](https://forum.babylonjs.com/u/nasimiasl)\
**Post date:** [May 29, 2019, 6:46am UTC](https://forum.babylonjs.com/t/is-needdepthprepass-work-for-shadermaterial-too/3527/6 "2019-05-29T06:46:59Z")

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[https://www.babylonjs-playground.com/#PJQTXN#8](https://www.babylonjs-playground.com/#PJQTXN#8)

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<div class="post-metadata">

**Author:** ![nasimiasl](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/nasimiasl/32/34_2.png) [@nasimiasl](https://forum.babylonjs.com/u/nasimiasl)\
**Post date:** [May 29, 2019, 6:54am UTC](https://forum.babylonjs.com/t/is-needdepthprepass-work-for-shadermaterial-too/3527/7 "2019-05-29T06:54:36Z")

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