I’ve got a curved world shader and I want to add an outline to my objects.

I’m able to do a curved world and outline separately, but when I combine the two by adding a second pass to the curved shader, the problem is that the outline doesn’t curve along with the objects.

Here’s the shader code for this:

Shader "Custom/Curved Shader"
{
    Properties
    {
        _Color ("Main Color", Color) = (1,1,1,1)
        _MainTex ("Base (RGB)", 2D) = "white" {}
 
        _OutlineColor ("Outline Color", Color) = (0, 0, 0, 1)
        _OutlineThickness ("Outline Thickness", Range(0,1)) = 0.1
    }
 
    SubShader
    {
        Tags { "RenderType"="Opaque" }
        LOD 150
 
        CGPROGRAM
 
        #pragma surface surf Lambert vertex:vert addshadow
 
        #include "UnityCG.cginc"
        #include "CurvedWorldCore.cginc"
 
        sampler2D _MainTex;
     
        struct Input
        {
            float2 uv_MainTex;
        };
 
        fixed4 _Color;
   
        void surf (Input IN, inout SurfaceOutput o)
        {
            fixed4 c = tex2D(_MainTex, IN.uv_MainTex) * _Color;
            o.Albedo = c.rgb;
            o.Alpha = c.a;
        }
 
        ENDCG
 
        Pass{
            Cull Front
 
            CGPROGRAM
 
            #include "UnityCG.cginc"
            #include "CurvedWorldCore.cginc"
 
            #pragma vertex vert
            #pragma fragment frag
 
            fixed4 _OutlineColor;
            float _OutlineThickness;
 
            struct appdata{
                float4 vertex : POSITION;
                float4 normal : NORMAL;
            };
 
            struct v2f{
                float4 position : SV_POSITION;
            };
 
            v2f vert(appdata v){
                v2f o;
                o.position = UnityObjectToClipPos(v.vertex + normalize(v.normal) * _OutlineThickness);
                return o;
            }
 
            fixed4 frag(v2f i) : SV_TARGET{
                return _OutlineColor;
            }
 
            ENDCG
        }
    }
    FallBack "Mobile/VertexLit"
}

CurvedWorldCore.cginc

float3 _Curvature;
float _Distance;
 
void vert(inout appdata_full v)
{              
    float4 vPos = mul( unity_ObjectToWorld, v.vertex);
 
    float dist = 0;
    dist = distance(vPos.z , _WorldSpaceCameraPos.z) - _Distance;
    if( dist < 0)    {    dist = 0;    }      
   
    float addY = dist * dist;
   
    vPos.y -= addY * _Curvature.y;
 
    dist = vPos.x - _WorldSpaceCameraPos.x;
    float addHY = dist * dist;
    vPos.y -= addHY* _Curvature.x ;
   
    // for corner
    vPos.x += addY * _Curvature.z;
 
    vPos = mul ( unity_WorldToObject, vPos);
    v.vertex = vPos;
}

CurvedWorld.cs

public class CurvedWorld : MonoBehaviour {
 
    public Vector3 Curvature = new Vector3(0, 0.5f, 0);
    public float Distance = 0;
 
    [Space]
    public float CurvatureScaleUnit = 1000f;
   
    int CurvatureID;
    int DistanceID;
 
    private void OnEnable()
    {
        CurvatureID = Shader.PropertyToID("_Curvature");
        DistanceID = Shader.PropertyToID("_Distance");
    }
 
    void Update()
    {
        Vector3 curvature = CurvatureScaleUnit == 0 ? Curvature : Curvature / CurvatureScaleUnit;
 
        Shader.SetGlobalVector(CurvatureID, curvature);
        Shader.SetGlobalFloat(DistanceID, Distance);
    }
}

Another method I tried is by using this asset Quick Outline to create the outline via script rather than through a shader, but I get the same issue where the outline doesn’t curve.

I’m stuck as to how to fix this so I’d be grateful for some help with this issue.