Using Custom Nodes in UE4 - Tips & Links

[teessider]

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@kjetilh: hi, anyone here who has used custom expressions in ue4 material editor? I wonder if there is a list of available engine parameters and properties somewhere. For example I need to access depth and postprocessinput0 inside a custom expression. And functions for converting between spaces and such things.
I’ve used a rendertarget for now for the textures but less than ideal to do that when those buffers are available.

@snake5: can’t they be hooked up as inputs?

@teessider: they can be hooked up as inputs (still restricted to their respective material domains unless you make engine changes)…The parameters available to a shader differ depending on the type (Landscape vs Opaque eg.). To see what a node actually outputs to hlsl, you can plug it in the emissive input and open the HLSL code window, copy the code to a text editor and search for something like Local0 or CalcPixelMaterialInput.
In terms of available parameters - you can start with MaterialTemplate.ush in /Engine/Shaders/Private . In general looking through the /Engine/Shaders/Private is good

there is also this: https://api.unrealengine.com/INT/API/Runtime/Engine/FViewUniformShaderParameters/index.html but that is from C++ POV and they might have different names in the shader files.

@kjetilh: ah, great info! Appreciate it. Good tip with the hlsl window. I forgot that was there
that should really solve the issue. Super!

@teessider: no problem Yeah they don’t make the HLSL code window obvious and I have been doing more custom node stuff recently so I have been discovering more stuff I can do with it
Cool links about using the Custom Node:
https://www.youtube.com/watch?v=HaUAfgrZjlU <---- Cool livestream from Epic about using the Custom node (from Ryan Brucks)
https://shaderbits.com/blog <-- Ryan Brucks’s Blog contains more awesome stuff
http://blog.kiteandlightning.la/ue4-hlsl-shader-development-guide-notes-tips/ <— A Collection of various links which go into more stuff about using Custom Nodes

YouTube Video: Custom Material Node: How to use and create Metaballs | Live Training | Unreal Engine

Kite & Lightning: Blog: UE4 HLSL & Shader Development Guide, Notes, & Tips - Kite & Lightning: Blog

@kjetilh: excellent, will dive into those

[Theodox]

Perhaps the biggest tip of all:

Do all your work in a real text editor, then paste it into the custom node

Otherwise you’ll end up murdering people.

[bob.w]

Do all your work in a real text editor, then paste it into the custom node

There aren’t enough likes on this forum to truly express how much I agree with this.

[Bhmbob]

Since in a custom node you can’t exactly (easily) input other custom nodes, I found defining your functions in a Struct is something I found pretty useful

So something like:

struct ExampleStruct
{
    float ExampleFunc(float input)
    {
        return input;
    }
}

ExampleStruct f;

return f.ExampleFunc(0);

I found this is the next best thing to just adding though a .USF, and haven’t really seen this documented anywhere

I’ve got a better example here that shows an actual use case, this can all hypothetically just be pasted into the custom node:
https://github.com/BhMbOb/Code/blob/master/Shaders/shd_volumeRaymarch_default.hlsl