triplanar texturing with Unity HDRP - unity3d

Question

I wrote a surface shader in Unity with the default render pipeline to use Triplanar texturing on a mesh with no UVs, this worked fine, with the following code:
Shader "Custom/TerrainShader"
{
// These properties can be modified from the material inspector.
Properties{
_MainTex("Ground Texture", 2D) = "white" {}
_WallTex("Wall Texture", 2D) = "white" {}
_TexScale("Texture Scale", Float) = 1
}
// You can have multiple subshaders with different levels of complexity. Unity will pick the first one
// that works on whatever machine is running the game.
SubShader{
Tags { "RenderType" = "Opaque" } // None of our terrain is going to be transparent so Opaque it is.
LOD 200 // We only need diffuse for now so 200 is fine. (higher includes bumped, specular, etc)
CGPROGRAM
#pragma surface surf Standard fullforwardshadows // Use Unity's standard lighting model
#pragma target 3.0 // Lower target = fewer features but more compatibility.
// Declare our variables (above properties must be declared here)
sampler2D _MainTex;
sampler2D _WallTex;
float _TexScale;
// Say what information we want from our geometry.
struct Input {
float3 worldPos;
float3 worldNormal;
};
// This function is run for every pixel on screen.
void surf(Input IN, inout SurfaceOutputStandard o) {
float3 scaledWorldPos = IN.worldPos / _TexScale; // Get a the world position modified by scale.
float3 pWeight = abs(IN.worldNormal); // Get the current normal, using abs function to ignore negative numbers.
pWeight /= pWeight.x + pWeight.y + pWeight.z; // Ensure pWeight isn't greater than 1.
// Get the texture projection on each axes and "weight" it by multiplying it by the pWeight.
float3 xP = tex2D(_WallTex, scaledWorldPos.yz) * pWeight.x;
float3 yP = tex2D(_MainTex, scaledWorldPos.xz) * pWeight.y;
float3 zP = tex2D(_WallTex, scaledWorldPos.xy) * pWeight.z;
// Return the sum of all of the projections.
o.Albedo = xP + yP + zP;
}
ENDCG
}
FallBack "Diffuse"
}
However, when switching to the new RP (HD or LW) the material using it becomes pink. I know it's because Unity no longer supports surface shaders, so my question is, how do you achieve triplanar texturing with the new RP?

Answer 1

There is support for triplanar texturing through the shader graph. Just hit space inside the graph editor and search for "triplanar" and it will show up.
HDRP shaders use deferred rendering, so its shaders look fundamentally different. If you want to learn, i suggest you create a basic shader in the shader graph and then right click on the master node and select "copy shader". Then, you can paste the shader code into a text editor and try to reverse engineer it. The SRP GitHub is also a good reference:
https://github.com/Unity-Technologies/Graphics/tree/master/com.unity.render-pipelines.high-definition/Runtime/ShaderLibrary
https://github.com/Unity-Technologies/Graphics/tree/master/com.unity.render-pipelines.high-definition/Runtime/RenderPipeline/ShaderPass
For LWRP, there is this template shader which i've found quite useful:
https://gist.github.com/phi-lira/225cd7c5e8545be602dca4eb5ed111ba