Outline shader with curves and transparency

Question

I'm trying to create an outline shader, who has an edited outline. At the moment it looks like this.

Shader "test/SimpleOutline" {

 Properties {
  _MainTex ("Texture", 2D) = "white" {}
  _OutlineColor ("Outline Color", Color) = (0,0,0,1)
  _Outline ("Outline Width", Range (.002, 1.1)) = .005
}



 SubShader {
      Tags { "Queue"="Transparent" }
      ZWrite off
      CGPROGRAM
          #pragma surface surf Lambert vertex:vert
          struct Input {
          float3 viewDir;
          float2 uv_MainTex;
      };
      float _Outline;
      float4 _OutlineColor;
      void vert (inout appdata_full v) {

          v.vertex.xyz += v.normal * _Outline;

      }
      sampler2D _MainTex;

      void surf (Input IN, inout SurfaceOutput o) 
      {
        o.Emission = float4(0, 1, 0,0);
      }
  ENDCG

  ZWrite on

  CGPROGRAM
      #pragma surface surf Lambert
      struct Input {
          float2 uv_MainTex;
      };

      sampler2D _MainTex;
      void surf (Input IN, inout SurfaceOutput o) {
          o.Albedo = tex2D (_MainTex, IN.uv_MainTex).rgb;
      }
  ENDCG

} 
Fallback "Diffuse"

}

I want it like this.

It should be at a distance from the actual object Transparent so you can see the background. Completely circle each object and be arched. Like this horn?

Does anyone have a suggestion on how best to implement this?

Answer 1

Hm, interesting question.
1. How to outline effect in distance from object?
I suggest stencil
Pass1: draw your mesh with no stencil
Pass2: draw mesh with MaskColor 0 with stencil writing some value
Pass3: draw outline mesh in solid color with stencil enabled with bigger "scale" than previous pass

somth like that.

2. Curving image. Feels like it should be done with techniques like in this video
   https://www.youtube.com/watch?v=xH5uUfeB2Go try to apply it in Pass3.

P.S. I'm gonna try this effect myself in next couple of days if I would have time.