Shader "Custom/Character"
{
    Properties
    {
        _Color ("Color", Color) = (1,1,1,1)
        [PerRendererData]_MainTex ("Sprite Texture", 2D) = "white" {}
        _Flash ("Flash", Range(0,1)) = 0.5
        _FlashColor ("FlashColor", Color) = (1,1,1,1)
        _Alpha ("_Alpha", Range(0,1)) = 1
        _PaletteTex ("PaletteTex", 2D) = "white" {}
        _ReplaceTex ("ReplaceTex", 2D) = "white" {}
        [IntRange]_ReplaceType ("ReplaceType", Range(0,15)) = 0
        _Direction ("Direction", Vector) = (0, 1, 0, 0)
        _Intensity ("Intensity", Range(0.0, 1.0)) = 0
        _UV ("UV", Vector) = (0, 0, 0, 0)//uv中心xy，uv边界
        _FadingTex ("FadingTex", 2D) = "white" {}
        _FadingColor ("FadingColor", Color) = (1,1,1,1)
        _FadingWidth ("FadingWidth", Range(0,1)) = 0
    }
    SubShader
    {
        Tags
        {
            "Queue" = "Geometry"
        }
        Cull Off
        ZWrite On

        CGPROGRAM
        #pragma surface surf Lambert addshadow fullforwardshadows
        #pragma target 3.0

        sampler2D _MainTex;
        sampler2D _PaletteTex;
        sampler2D _ReplaceTex;
        sampler2D _FadingTex;
        fixed4 _Color;
        fixed _Flash;
        fixed4 _FlashColor;
        fixed _Alpha;
        fixed _ReplaceType;
        fixed4 _Direction;
        fixed _Intensity;
        fixed4 _UV;
        fixed4 _FadingColor;
        fixed _FadingWidth;

        struct Input
        {
            float2 uv_MainTex;
        };

        void surf(Input IN, inout SurfaceOutput o)
        {
            fixed2 uv = IN.uv_MainTex;
            //形变
            if (length(_Direction) > 0 && _Intensity > 0)
            {
                fixed2 dir_center = IN.uv_MainTex - _UV.xy;
                fixed2 dir = normalize(_Direction.xy);
                fixed2 dir1 = dir.xy * _Intensity;
                fixed2 dir2 = cross(fixed3(0, 0, 1), fixed3(dir, 0)).xy * _Intensity;
                fixed2 offset1 = -dot(dir1, dir_center) * dir1;
                fixed2 offset2 = dot(dir2, dir_center) * dir2;
                uv = IN.uv_MainTex + offset1 + offset2;
            }
            //如果采样超出sprite范围 丢弃
            fixed4 bound = fixed4(_UV.x - _UV.z, _UV.x + _UV.z, _UV.y - _UV.w, _UV.y + _UV.w);
            if (uv.x < bound.x || uv.x > bound.y || uv.y < bound.z || uv.y > bound.w)
            {
                discard;
            }
            //采样
            fixed4 c = tex2D(_MainTex, uv);

            //颜色替换
            fixed4 paletteColor = tex2D(_PaletteTex, c.br);
            fixed4 replaceColor = tex2D(_ReplaceTex, fixed2(paletteColor.r, 1 - 0.01 - _ReplaceType * 0.0625));
            if (any(replaceColor.rgb == fixed3(0, 0, 0)))
            {
                replaceColor = tex2D(_ReplaceTex, fixed2(paletteColor.r, 1 - 0.01));
            }
            fixed3 rgb = replaceColor.rgb;

            //闪光
            if (_Flash > 0)
            {
                rgb = rgb * (_Flash + 1) * _FlashColor;
            }

            //消融
            fixed2 nioseUV = fixed2((bound.x + uv.x) / (bound.y - bound.x), (bound.z + uv.y) / (bound.w - bound.z));
            fixed4 noise = tex2D(_FadingTex, nioseUV * 40);
            if (_Alpha < noise.r - _FadingWidth)
            {
                discard;
            }
            if (_Alpha < noise.r)
            {
                o.Albedo = _FadingColor;
                o.Emission = _FadingColor;
            }
            else
            {
                o.Albedo = rgb * _Color;
            }

            o.Alpha = c.a;
            clip(o.Alpha - 0.5);
        }
        ENDCG
    }
    FallBack "Diffuse"
}