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Unable to sample custom texture inside custom expression


I am unable to sample textures inside a "Custom" node. I get an error saying cannot implicitly convert 'Texture2D' to 'sampler2D'. I have attached a screenshot of my setup below.

My custom expression code:

 float4 myTexture = tex2D(In, Texcoord);
 return myTexture;

alt text

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asked May 30 '14 at 05:45 PM in Bug Reports

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3 answers: sort voted first

Hello HypnoticShark,

Unfortunately, You can't sample a texture from within a custom expression. This is a known limitation that we currently do not support. But, I have raised awareness about this issue and expect it to be fixed in a future release.


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answered Jun 02 '14 at 07:38 PM

avatar image HypnoticShark Jun 02 '14 at 09:12 PM

I see. Well I guess this documentation page needs to be updated in that case. https://docs.unrealengine.com/latest/INT/Engine/Rendering/Materials/ExpressionReference/Custom/index.html


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I found a temporary solution as explained here : https://forums.unrealengine.com/showthread.php?405-HLSL-code-Texture2D-to-sampler2D

when analysing hlsl code, It seems that the CustomTexture node generate a Texture2D, but Custom node wait a sampler2D as argument function...

I would request a fix for custom node (and/or custom texture) and a real window to edit code instead of a single line text box.


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answered Jun 05 '14 at 09:09 PM

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avatar image HypnoticShark Jun 05 '14 at 09:29 PM

Thats awesome! thanks fredakilla and yes I agree with the real window to edit code thing.

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It is officially supported since about 4.7:


(if your texture pin is named Tex)

References: http://oliverm-h.blogspot.sk/2014/12/ue4-quick-tip-sampling-textures-in.html https://answers.unrealengine.com/questions/455514/undeclared-identifier-texsampler.html

However it did not work for me, I had to use this:

  Tex.SampleLevel(TexSampler, UV, 0);

References: http://shaderbits.com/blog/uv-dilation

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answered May 03 '18 at 09:37 PM

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