How to render outline differently

Hi, I amtrying to achieve an outline effect similiar to what I found here http://blogs.aerys.in/jeanmarc-lerou...s-cel-shading/. I'm interested only in the first part, the one with drawing the outline. So far I've managed to write this

 CGPROGRAM
  
     #pragma vertex vert
  
     #pragma fragment frag
  
     #include "UnityCG.cginc"
  
    
  
     struct appdata {
  
         float4 vertex : POSITION;
  
         float4 color : COLOR;
  
         float3 normal : NORMAL;
  
     };
  
  
  
     struct v2f {
  
         float4 pos : SV_POSITION;
  
         float3 color : COLOR0;
  
         float isEdge;
  
     };
  
  
  
     v2f vert (appdata v)
  
     {
  
         v2f o;
  
        
  
         float eyeToVertex = normalize(v.vertex - _WorldSpaceCameraPos);
  
         o.isEdge = dot(v.normal, eyeToVertex) < -0.05 ? 1 : 0;
  
         o.pos = mul (UNITY_MATRIX_MVP, v.vertex);
  
  
  
         return o;
  
     }
  
  
  
     half4 frag (v2f i) : COLOR
  
     {
  
         return half4 (lerp(float3(0,0,0), float3(1,1,1), i.isEdge), 1);
  
     }
  
 ENDCG

but It didn't get me where I wanted. I'm having a bit of trouble with this part , more specifically how can I replicate it in shaderlab Code:

 multiply4x4(
         add(vertexPosition, float4(delta, 0)),
         localToScreenMatrix
     );

I already have an outline effect inspired by the unity's toon shader, but now I need to change the way I draw the outline in order to meet some new requirements. Any ideeas? Thanks