Why I can't add Sample Texture 2D multiple to position

[Rachan]

as the name of topic, Why I can’t add a Sample Texture2D multiply with position?

I working on create shader for grass or tree, that can only sway at top of the sprite
so I would multiply it with some gradient texture like this, But I can’t add it to any node

any suggestion?

Thanks!!!

[wwWwwwW1]

Hi, the vertex stage doesn’t support Sample Texture 2D node, which automatically choose a suitable mipmap level for the texture. You should use Sample Texture 2D LOD node and provide a mipmap level (usually 0) instead.

Detailed explanation from another post :

@jvo3dc

It’s not so much that automatic derivatives are not supported in a vertex shader in Unity.

These derivatives are calculated by taking the difference with neighbouring pixels and this is only possible because the GPU will always render at least a 2x2 grid of pixels. In the vertex shader there is no per pixel difference available, since the pixels are yet to be rasterized. So that’s why the ddx and ddy instructions and all instructions that rely on it are not available.

So, it has nothing to do with Unity. It’s also not really unsupported. The whole ddx instruction just makes no sense in a vertex shader. Which in term means that tex2D makes no sense in a vertex shader. This might seem a bit weird at first, but knowing how graphics cards work, it is actually logical that only tex2Dlod is available in vertex shaders.

[Rachan]

@wwWwwwW1

Hi, the vertex stage doesn’t support Sample Texture 2D node, which automatically choose a suitable mipmap level for the texture. You should use Sample Texture 2D LOD node and provide a mipmap level (usually 0) instead.

Detailed explanation from another post :

Whow Thank you very much! I changed to use Preview+Power node instead, I don’t know which one is heavier?
between small gradient Texture and Gradient Logic by Preview.

[Qriva]

@Rachan

I changed to use Preview+Power node instead, I don’t know which one is heavier?

Two days ago someone answered you that preview node is complied away and you got several other advices about shader performence, and I think you are still asking the same thing. Furthermore I am pretty sure this is not the first time it’s the case. I don’t know what is the reason, if you just don’t read what people write, or you don’t understand what they said, or you picked wrong words to describe the problem, but you should stop doing this.