Glass.shader

Shader "Effect/Glass"
{
	Properties
	{
		_Color("Color", Color) = (1,1,1,1)
		_Shift("Shift", float) = 0.3
		_Chroma("Chroma", float) = 0.01
	}
	SubShader
	{
		Tags
		{
			"RenderType"="Transparent"
			"Queue"="Transparent"
		}

		GrabPass { }

		Cull Front

		Pass
		{
			CGPROGRAM
			#pragma vertex vert
			#pragma fragment frag
			
			#include "UnityCG.cginc"

			sampler2D _GrabTexture;
			float _Shift;
			float _Chroma;

			struct appdata
			{
				float4 vertex : POSITION;
				float3 normal : NORMAL;
			};

			struct v2f
			{
				float4 vertex : SV_POSITION;
				float4 localPos : POSITION1;
				float3 normal : NORMAL;
				float3 localNormal : TEXCOORD1;
			};

			v2f vert (appdata v)
			{
				v2f o;
				o.vertex = UnityObjectToClipPos(v.vertex);
				o.localPos = v.vertex;
				o.normal = UnityObjectToWorldNormal(v.normal);
				o.localNormal = v.normal;
				return o;
			}
			
			fixed4 frag (v2f i) : SV_Target
			{
				float3 p = i.localPos.xyz;
				float3 v = -normalize(ObjSpaceViewDir(i.localPos));
				float3 n = i.normal * dot(v, i.normal);
				float3 p1 = p + n * _Shift;
				float3 p2 = p + n * (_Shift + _Chroma);
				float3 p3 = p + n * (_Shift + _Chroma * 2.0);
				float4 wp1 = UnityObjectToClipPos(float4(p1, 1.0));
				float4 wp2 = UnityObjectToClipPos(float4(p2, 1.0));
				float4 wp3 = UnityObjectToClipPos(float4(p3, 1.0));
				float4 sp1 = ComputeGrabScreenPos(wp1);
				float4 sp2 = ComputeGrabScreenPos(wp2);
				float4 sp3 = ComputeGrabScreenPos(wp3);
				fixed4 col1 = tex2Dproj(_GrabTexture, sp1);
				fixed4 col2 = tex2Dproj(_GrabTexture, sp2);
				fixed4 col3 = tex2Dproj(_GrabTexture, sp3);
				fixed4 col;
				col.r = col1.r;
				col.g = col2.g;
				col.b = col3.b;
				// col.r = col1.r * 0.6 + col2.r * 0.3 + col3.r * 0.1;
				// col.g = col1.g * 0.2 + col2.g * 0.6 + col3.g * 0.2;
				// col.b = col1.b * 0.1 + col2.b * 0.3 + col3.b * 0.6;
				col.a = 1.0;
				return col;
			}
			ENDCG
		}

		GrabPass { }

		Cull Back

		Pass
		{
			CGPROGRAM
			#pragma vertex vert
			#pragma fragment frag
			
			#include "UnityCG.cginc"

			sampler2D _GrabTexture;
			float4 _Color;
			float _Shift;
			float _Chroma;

			struct appdata
			{
				float4 vertex : POSITION;
				float3 normal : NORMAL;
				float2 uv : TEXCOORD0;
			};

			struct v2f
			{
				float4 vertex : SV_POSITION;
				float4 localPos : POSITION1;
				float3 normal : NORMAL;
				float3 localNormal : TEXCOORD1;
			};

			v2f vert (appdata v)
			{
				v2f o;
				o.vertex = UnityObjectToClipPos(v.vertex);
				o.localPos = v.vertex;
				o.normal = UnityObjectToWorldNormal(v.normal);
				o.localNormal = v.normal;
				return o;
			}
			
			fixed4 frag (v2f i) : SV_Target
			{
				float3 p = i.localPos.xyz;
				float3 v = -normalize(ObjSpaceViewDir(i.localPos));
				float3 n = i.normal * dot(v, i.normal);
				float3 p1 = p + n * _Shift;
				float3 p2 = p + n * (_Shift + _Chroma);
				float3 p3 = p + n * (_Shift + _Chroma * 2.0);
				float4 wp1 = UnityObjectToClipPos(float4(p1, 1.0));
				float4 wp2 = UnityObjectToClipPos(float4(p2, 1.0));
				float4 wp3 = UnityObjectToClipPos(float4(p3, 1.0));
				float4 sp1 = ComputeGrabScreenPos(wp1);
				float4 sp2 = ComputeGrabScreenPos(wp2);
				float4 sp3 = ComputeGrabScreenPos(wp3);
				fixed4 col1 = tex2Dproj(_GrabTexture, sp1);
				fixed4 col2 = tex2Dproj(_GrabTexture, sp2);
				fixed4 col3 = tex2Dproj(_GrabTexture, sp3);
				fixed4 col;
				col.r = col1.r;
				col.g = col2.g;
				col.b = col3.b;
				col.a = 1.0;
				float d = abs(dot(v, i.localNormal));
				col.rgb *= 1.0 + (0.3 - min(d, 0.3)) * 10.0;
				return col * _Color;
			}
			ENDCG
		}
	}
}