How to declare function in material custom node?

Development Rendering
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1

I want to store some codes in a function that update some of my variable that can be called from main function,i turned on shaderdeveloopment in coonfiguration but it didnt give much information
float3 tex;
float rh=1;
float prh;
float th;
float pth;
float ri=0;
float hs;
float ph;
float uvd;

void update(float ho)
{prh=rh;
pth=th;
rh-=ho;
UV-={ho*Tanx,ho*Tany};
uvd=ho/Tan;
return;}

for(int i=0;i<MaxSteps;i++)
{tex=Texture.SampleLevel(TextureSampler,UV,0);
th=tex[HeightChannel];
if(rh<=th){ri=(th-rh)/(prh-pth+th-rh);UV+=uvd*ri;break;}
if(rh<tex[ProbeDepthChannel])
{if(hs=StepSize*Tan<rh){update(hs);continue;}
 update(rh);break;}
ph=rh-tex[ProbeDepthChannel];
if(hs=tex[ProbeRadius]*Tan<ph){update(hs);continue;}
if(ph/Tan>StepSize){update(ph);continue;}
if(hs=StepSize*Tan<rh){update(hs);continue;}
update(rh);break;}

float4 ouput={UV,ri,rh};
return ouput;

119091-提问+-+ue4+answerhubl.png

2

You cannot declare a function in a custom node, yet you can do so with ease in UE4 shader files, located in Engine/Shaders.

Make your own USF file with your functions, and include it to Common.USF

Then you can call it from custom node.

1 Like
3

That sounds too hard for me,I just inlined the function manually,also my function is to update variable inside my custom node,can this do that?thanks for the information.

1 Like
4

Sorry for necroposting, but…
Yes! You actually can declare multiple functions in a Custom Material Node!
I stumbled on this a few months ago looking for the same information.

struct Functions
{
  float3 OrangeBright(float3 c)
  {
      return c * float3(1, .7, 0);
  }
  float3 Out()
  {
    return OrangeBright(InColor);
  }
};
Functions f;
return f.Out();

I found the info here, for which I am eternally grateful:

8 Likes
5

Thank you! This is much cleaner. I love it.

1 Like
6

For anyone that’s having trouble with this in 5.1, saying that the inner functions don’t have access to variables. You can pass in the variables like this:

struct Functions
{
  float3 OrangeBright(float3 c)
  {
      return c * float3(1, .7, 0);
  }
  float3 Out(float3 InColor)
  {
    return OrangeBright(InColor);
  }
};
Functions f;
return f.Out(InColor);
5 Likes
8

nice! thank you