fixed4 frag(v2f i) :SV_Target{

    float time = floor(_Time.y*_Speed);//_Time.y 表示自场景加载到当前经过的时间
    float row=floor(time/_HorizonAmount);//行索引
    float column = time - _HorizonAmount * row;//列索引

    float2 uv;
    uv.x =i.uv.x + column;//加在uv上
    uv.y =i.uv.y - row;//因为纹理列坐标 上大下小 所以是减法 变小
    uv.x /= _HorizonAmount;//映射到 局部的小片段纹理中的坐标 
    uv.y /= _VerticleAmount;
    fixed4 c=tex2D(_MainTex,uv);
    c.rgb *= _Color.rgb;
    return c;

}

v2f vert (appdata v)
     {
         v2f o;
         o.pos = UnityObjectToClipPos(v.vertex);
         o.uv.xy = TRANSFORM_TEX(v.uv, _FarTex)+frac(float2(_Time.y * _FarMoveSpeed,0.0));
         o.uv.zw = TRANSFORM_TEX(v.uv, _NearTex)+frac(float2(_Time.y*_NearMoveSpeed,0.0));
         //对采样坐标进行偏移

         return o;
     }

v2f vert (appdata v)
            {
                v2f o;
                float4 offset;
                offset.yzw = float3(0.0,0.0,0.0);
                offset.x = sin(_Frequency * _Time.y + v.vertex.x * _InvWaveLength + v.vertex.y * _InvWaveLength + v.vertex.z * _InvWaveLength) * _Magnet;
                
                o.vertex = UnityObjectToClipPos(v.vertex+offset);
                o.uv = TRANSFORM_TEX(v.uv, _MainTex);
                o.uv += float2(0.0, _Time.y * _Speed);
                return o;
            }

float3 centerOffs = v.vertex.xyz - center;
                float3 localPos = center + rightDir * centerOffs.x + upDir * centerOffs.y + normalDir * centerOffs.z;

bump = normalize(half3(dot(i.TtoW0.xyz,bump),dot(i.TtoW1.xyz,bump),dot(i.TtoW2.xyz,bump)));
fixed3 reflectDir = reflect(-worldViewDir, bump);
fixed4 texColor = tex2D(_MainTex,i.uv.xy);
fixed3 reflColor = texCUBE(_Cubemap,reflectDir).rgb * texColor.rgb;

fixed3 bump = UnpackNormal(tex2D(_BumpTex, i.uv.zw));
float2 offset = bump.xy * _Disortion * _RefractionTex_TexelSize.xy;
i.scrPos.xy = i.scrPos.xy + offset.xy;
fixed3 refrColor = tex2D(_RefractionTex,i.scrPos.xy / i.scrPos.w).rgb;

Shader "chp10/GlassRefractionShader"
{
	Properties
	{
		_MainTex("Texture", 2D) = "white" {}
		_BumpTex("Normal map",2D) = "while"{}
		_Cubemap("Environment Cubemap",Cube) = "_Skybox"{}

		_Disortion("Disortion",Range(0,100)) = 10
		_RefractionAmount("RefractionAmount",Range(0,1)) = 0.5
	}
		SubShader
		{
			Tags {"Queue" = "Transparent" "RenderType" = "Opaque" }

			GrabPass{"_RefractionTex"}

			Pass
			{
				CGPROGRAM
				#pragma vertex vert
				#pragma fragment frag

				#include "UnityCG.cginc"

				sampler2D _MainTex;
				float4 _MainTex_ST;
				sampler2D _BumpTex;
				float4 _BumpTex_ST;
				samplerCUBE _Cubemap;

				float _Disortion;
				fixed _RefractionAmount;

				sampler2D _RefractionTex;
				float4 _RefractionTex_TexelSize;

				struct a2v {
					float4 vertex : POSITION;
					float3 normal : NORMAL;
					float4 tangent : TANGENT;
					float2 texcoord: TEXCOORD0;
				};

				struct v2f {
					float4 pos : SV_POSITION;
					float4 scrPos : TEXCOORD0;
					float4 uv : TEXCOORD1;
					float4 TtoW0 : TEXCOORD2;
					float4 TtoW1 : TEXCOORD3;
					float4 TtoW2 : TEXCOORD4;
				};


			v2f vert(a2v v)
			{
				v2f o;
				o.pos = UnityObjectToClipPos(v.vertex);
				o.scrPos = ComputeGrabScreenPos(o.pos);
				o.uv.xy = TRANSFORM_TEX(v.texcoord, _MainTex);
				o.uv.zw = TRANSFORM_TEX(v.texcoord, _BumpTex);

				float3 worldPos = mul(unity_ObjectToWorld, v.vertex).xyz;
				fixed3 worldNormal = UnityObjectToWorldNormal(v.normal);
				fixed3 worldTangent = UnityObjectToWorldDir(v.tangent.xyz);
				fixed3 worldBinormal = cross(worldNormal,worldTangent) * v.tangent.w;

				o.TtoW0 = float4(worldTangent.x,worldBinormal.x,worldNormal.x,worldPos.x);
				o.TtoW1 = float4(worldTangent.y, worldBinormal.y, worldNormal.y, worldPos.y);
				o.TtoW2 = float4(worldTangent.z, worldBinormal.z, worldNormal.z, worldPos.z);
				return o;
			}

			fixed4 frag(v2f i) : SV_Target
			{
				float3 worldPos = float3(i.TtoW0.w,i.TtoW1.w,i.TtoW2.w);
				fixed3 worldViewDir = normalize(UnityWorldSpaceViewDir(worldPos));

				fixed3 bump = UnpackNormal(tex2D(_BumpTex, i.uv.zw));
				float2 offset = bump.xy * _Disortion * _RefractionTex_TexelSize.xy;
				i.scrPos.xy = i.scrPos.xy + offset.xy;


				//折射:从grabmap读
				fixed3 refrColor = tex2D(_RefractionTex,i.scrPos.xy / i.scrPos.w).rgb;

				//反射:从cubemap读
				bump = normalize(half3(dot(i.TtoW0.xyz,bump),dot(i.TtoW1.xyz,bump),dot(i.TtoW2.xyz,bump)));
				fixed3 reflectDir = reflect(-worldViewDir, bump);
				fixed4 texColor = tex2D(_MainTex,i.uv.xy);
				fixed3 reflColor = texCUBE(_Cubemap,reflectDir).rgb * texColor.rgb;
				//混合
				fixed3 finalColor = reflColor * (1 - _RefractionAmount) + refrColor * _RefractionAmount;
				return fixed4(finalColor, 1);
			}
			ENDCG
		}
		}
}