Shader "chicai/HotDistort2"
{
    Properties
    {
        _DistortTex ("DistortTex", 2D) = "white" {}
        _Distort ("Distort",Range(0,1)) = 0
        _DistortUVSpeedX("DistortUVSpeedX",float) = 0
        _DistortUVSpeedY("DistortUVSpeedY",float) = 0
    }
    SubShader
    {
        Tags { "Queue"="Transparent" }

        GrabPass{"_GrabTex"}

        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            #include "UnityCG.cginc"

            struct appdata
            {
                float4 vertex:POSITION;
                fixed2 uv:TEXCOORD0;
            };

            struct v2f
            {
                float2 uv : TEXCOORD0;
                float4 pos : SV_POSITION;
                float4 screenPos :TEXCOORD1;
            };

            sampler2D _DistortTex;
            float4 _DistortTex_ST;
            sampler2D _GrabTex;
            fixed _Distort;
            float _DistortUVSpeedX,_DistortUVSpeedY;

            v2f vert (appdata v)
            {
                v2f o;
                o.pos = UnityObjectToClipPos(v.vertex);
                o.screenPos = ComputeScreenPos(o.pos);//转换到[0到w]，当uv用需要除以w分量
                o.uv = TRANSFORM_TEX(v.uv, _DistortTex) + float2(_DistortUVSpeedX, _DistortUVSpeedY) * _Time.y;
                return o;
            }

            fixed4 frag (v2f i) : SV_Target
            {
                fixed4 distortCol = tex2D(_DistortTex, i.uv);
                fixed2 uv = lerp(i.screenPos.xy / i.screenPos.w, distortCol, _Distort);
                fixed4 col = tex2D(_GrabTex, uv);
                return col;
            }
            ENDCG
        }
    }
}

Shader "chicai/HotDistort3"
{
    Properties
    {
        _DistortTex ("DistortTex", 2D) = "white" {}
        _Distort ("Distort",Range(0,1)) = 0
        _DistortUVSpeedX("DistortUVSpeedX",float) = 0
        _DistortUVSpeedY("DistortUVSpeedY",float) = 0
    }
    SubShader
    {
        Tags { "Queue"="Transparent" }

        GrabPass{"_GrabTex"}

        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            #include "UnityCG.cginc"

            struct appdata
            {
                float4 vertex:POSITION;
                fixed2 uv:TEXCOORD0;
            };

            struct v2f
            {
                float2 uv : TEXCOORD0;
                float4 pos : SV_POSITION;
            };

            sampler2D _DistortTex;
            float4 _DistortTex_ST;
            sampler2D _GrabTex;
            fixed _Distort;
            float _DistortUVSpeedX,_DistortUVSpeedY;

            v2f vert (appdata v)
            {
                v2f o;
                o.pos = UnityObjectToClipPos(v.vertex);//裁剪空间下的
                o.uv = TRANSFORM_TEX(v.uv, _DistortTex) + float2(_DistortUVSpeedX, _DistortUVSpeedY) * _Time.y;
                return o;
            }

            fixed4 frag (v2f i) : SV_Target
            {
                //i.pos 屏幕的像素坐标 硬件转换
                float2 uv = i.pos.xy/_ScreenParams.xy;
                fixed4 distortCol = tex2D(_DistortTex, i.uv);
                uv = lerp(uv, distortCol, _Distort);
                fixed4 col = tex2D(_GrabTex, uv);
                return col;
            }
            ENDCG
        }
    }
}