SpriteShader备注——UV旋转扭曲动画效果

效果： UV旋转扭曲动画效果.gif

//////////////////////////////////////////////
/// 2DxFX v3 - by VETASOFT 2018 //
//////////////////////////////////////////////


//////////////////////////////////////////////

Shader "2DxFX_Extra_Shaders/Animated_Twist"
{
    Properties
    {
        //贴图
        [PerRendererData] _MainTex("Sprite Texture", 2D) = "white" {}
        //扭曲
        AnimatedTwistUV_AnimatedTwistUV_Bend_1("AnimatedTwistUV_AnimatedTwistUV_Bend_1", Range(-1, 1)) = 0.354
        //偏移_X
        AnimatedTwistUV_AnimatedTwistUV_PosX_1("AnimatedTwistUV_AnimatedTwistUV_PosX_1", Range(-1, 2)) = 0.5
        //偏移_Y
        AnimatedTwistUV_AnimatedTwistUV_PosY_1("AnimatedTwistUV_AnimatedTwistUV_PosY_1", Range(-1, 2)) = 0.5
        //旋转半径
        AnimatedTwistUV_AnimatedTwistUV_Radius_1("AnimatedTwistUV_AnimatedTwistUV_Radius_1", Range(0, 1)) = 0.5
        //速度
        AnimatedTwistUV_AnimatedTwistUV_Speed_1("AnimatedTwistUV_AnimatedTwistUV_Speed_1", Range(-10, 10)) = 2.679
        //插值
        _LerpUV_Fade_1("_LerpUV_Fade_1", Range(0, 1)) = 1
        //褪色
        _SpriteFade("SpriteFade", Range(0, 1)) = 1.0

        // required for UI.Mask
        [HideInInspector]_StencilComp("Stencil Comparison", Float) = 8
        [HideInInspector]_Stencil("Stencil ID", Float) = 0
        [HideInInspector]_StencilOp("Stencil Operation", Float) = 0
        [HideInInspector]_StencilWriteMask("Stencil Write Mask", Float) = 255
        [HideInInspector]_StencilReadMask("Stencil Read Mask", Float) = 255
        [HideInInspector]_ColorMask("Color Mask", Float) = 15

    }

    SubShader
    {
        //渲染队列 = 透明通道            忽略投影                渲染类别                     预览类型 = 面板       可以使用精灵图集吗
        Tags {"Queue" = "Transparent" "IgnoreProjector" = "true" "RenderType" = "Transparent" "PreviewType"="Plane" "CanUseSpriteAtlas"="True" }
        //深度缓存      透明度混合       背面渲染剔除
        ZWrite Off Blend SrcAlpha OneMinusSrcAlpha Cull Off

        // required for UI.Mask
        Stencil
        {
        Ref [_Stencil]
        Comp [_StencilComp]
        Pass [_StencilOp]
        ReadMask [_StencilReadMask]
        WriteMask [_StencilWriteMask]
        }

        Pass
        {

            CGPROGRAM
            //声明顶点着色器代码块
            #pragma vertex vert
            //声明片元着色器代码块
            #pragma fragment frag
            //使用低精度渲染
            #pragma fragmentoption ARB_precision_hint_fastest
            #include "UnityCG.cginc"

            //顶点着色器输入结构体
            struct appdata_t{
            float4 vertex   : POSITION;//位置信息
            float4 color    : COLOR;//颜色信息
            float2 texcoord : TEXCOORD0;//纹理坐标集
            };

            //片元着色器输入结构体
            struct v2f
            {
            float2 texcoord  : TEXCOORD0;//纹理坐标集
            float4 vertex   : SV_POSITION;//屏幕坐标信息
            float4 color    : COLOR;//颜色信息
            };

            //对应开始声明的材质属性
            sampler2D _MainTex;
            float _SpriteFade;
            float AnimatedTwistUV_AnimatedTwistUV_Bend_1;
            float AnimatedTwistUV_AnimatedTwistUV_PosX_1;
            float AnimatedTwistUV_AnimatedTwistUV_PosY_1;
            float AnimatedTwistUV_AnimatedTwistUV_Radius_1;
            float AnimatedTwistUV_AnimatedTwistUV_Speed_1;
            float _LerpUV_Fade_1;

            //顶点着色器代码块
            v2f vert(appdata_t IN)
            {
                v2f OUT;
                OUT.vertex = UnityObjectToClipPos(IN.vertex);//将顶点从模型空间转到裁剪空间
                OUT.texcoord = IN.texcoord;//纹理坐标集
                OUT.color = IN.color;//颜色信息
                return OUT;
            }

            //UV扭曲动画                uv          扭曲  偏移量X            Y       旋转半径     旋转速度
            float2 AnimatedTwistUV(float2 uv, float value, float posx, float posy, float radius, float speed)
            {
                //中心点
                float2 center = float2(posx, posy);
                //获取UV顶点到中心的向量
                float2 tc = uv - center;
                //根据向量获取长度
                float dist = length(tc);
                //如果长度小于旋转半径，范围内旋转
                if (dist < radius)
                {   
                    //百分比  越靠近中心点，扭曲度越大
                    float percent = (radius - dist) / radius;
                    //中心推移量
                    float theta = percent * percent * 16.0 * sin(value);

                    //正弦、余弦，用中心推移量乘以时间乘以速度，得到旋转动画
                    float s = sin(theta + _Time.y * speed);
                    float c = cos(theta + _Time.y * speed);

                    //？？？？没看懂
                    tc = float2(dot(tc, float2(c, -s)), dot(tc, float2(s, c)));
                }
                //归位
                tc += center;
                return tc;
            }

            //片元着色器代码块
            float4 frag (v2f i) : COLOR
            {
                //UV扭曲动画
                float2 AnimatedTwistUV_1 = AnimatedTwistUV(i.texcoord,AnimatedTwistUV_AnimatedTwistUV_Bend_1,AnimatedTwistUV_AnimatedTwistUV_PosX_1,AnimatedTwistUV_AnimatedTwistUV_PosY_1,AnimatedTwistUV_AnimatedTwistUV_Radius_1,AnimatedTwistUV_AnimatedTwistUV_Speed_1);
                //插值，，可以控制UV在处理后与处理前标量
                i.texcoord = lerp(i.texcoord,AnimatedTwistUV_1,_LerpUV_Fade_1);
                //纹理采样
                float4 _MainTex_1 = tex2D(_MainTex,i.texcoord);
                //声明最终结果
                float4 FinalResult = _MainTex_1;
                FinalResult.rgb *= i.color.rgb;
                //褪色处理
                FinalResult.a = FinalResult.a * _SpriteFade * i.color.a;
                return FinalResult;
            }

            ENDCG
        }
    }
    Fallback "Sprites/Default"
}