v2f vert (appdata_full v)
            {
                v2f o;

                o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);

                // get direction to camera in object space
                float3 facing = normalize(mul((float3x3)unity_WorldToObject, _WorldSpaceCameraPos) - v.vertex);
                // v.normal contains the direction
                float3 up = v.normal;
                // cross product gets the perpendicular
                float3 right = normalize(cross(facing, up));


                float3 lineBillboardOffset = mul((float3x3)UNITY_MATRIX_MVP, right);
                //v.texcoord.x contains if its left or right
                lineBillboardOffset.xy *= v.texcoord.x;
                //set the line thickness
                lineBillboardOffset.xy *= _LineThickness;

                //Add the offset
                o.vertex.xy += lineBillboardOffset;

                return o;
            }