Demo 26 - Force field rim effect and texture

Shader "Custom/Shield" {
    Properties {
        _MainTex ("Texture", 2D ) = "white" {}
        _Color ("Color", Color) = (1, 1, 1, 1)
        _RimEffect ("Rim effect", Range(0, 1)) = 0
    }
    SubShader {
        Pass {
            Tags { "Queue"="Transparent" "RenderType"="Transparent" }
            Blend One One
            Cull Off
            ZWrite Off

            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            #include "UnityCG.cginc"

            struct v2f {
                float4 pos : SV_POSITION;
                float3 normal : NORMAL;
                float2 uv : TEXCOORD0;
                float3 viewDir : TEXCOORD1;
            };

            sampler2D _MainTex;
            float4 _MainTex_ST;

            v2f vert(appdata_full v) {
                v2f o;
                o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
                o.normal = normalize(mul((float3x3)_Object2World, v.normal.xyz));
                o.viewDir = normalize(_WorldSpaceCameraPos - mul((float3x3)_Object2World, v.vertex.xyz));
                o.uv = TRANSFORM_TEX(v.texcoord.xy, _MainTex);
                return o;
            }

            fixed4 _Color;
            fixed _RimEffect;

            fixed4 frag(v2f i) : COLOR {
                float t = tex2D(_MainTex, i.uv);
                float val = 1 - abs(dot(i.viewDir, i.normal)) * _RimEffect;
                return _Color * _Color.a * val * val * t;
            }

            ENDCG
        }
    }
    FallBack "Diffuse"
}