Unity 2D SpriteRenderer filled Shader实现

最近遇到个需求需要将2D图片SpriteRenderer支持类似UGUI的Image Filled填充功能，搜了下百度居然搜不到(=_=)，然后就自己研究了下Shader，下边直接上代码

目前只支持水平和垂直方向的fill填充，暂时不需要角度填充，所以这里就懒得加了，后面有机会补上角度填充功能

Shader "Sprite/Filled"
{
    Properties
    {
        [PerRendererData] _MainTex ("Sprite Texture", 2D) = "white" {}
        [MaterialToggle] PixelSnap ("Pixel snap", Float) = 0
        [HideInInspector] _RendererColor ("RendererColor", Color) = (1,1,1,1)
        [HideInInspector] _Flip ("Flip", Vector) = (1,1,1,1)
        [PerRendererData] _AlphaTex ("External Alpha", 2D) = "white" {}
        [PerRendererData] _EnableExternalAlpha ("Enable External Alpha", Float) = 0
        _Color ("Tint", Color) = (1,1,1,1)

        [Enum(Horizontal, 0, Vertical, 1)]_FillType ("FillType", Float) = 0
        _FillAmount ("FillAmount", Range(0,1)) = 1
        [Toggle]_FillFlip ("FillFlip", Float) = 0
    }

    SubShader
    {
        Tags
        {
            "Queue"="Transparent"
            "IgnoreProjector"="True"
            "RenderType"="Transparent"
            "PreviewType"="Plane"
            "CanUseSpriteAtlas"="True"
        }
 
        Cull Off
        Lighting Off
        ZWrite Off
        Blend One OneMinusSrcAlpha
 
        Pass
        {
        CGPROGRAM
            #pragma vertex SpriteVert
            // #pragma fragment SpriteFrag
            #pragma fragment Frag
            #pragma target 2.0
            #pragma multi_compile_instancing
            #pragma multi_compile_local _ PIXELSNAP_ON
            #pragma multi_compile _ ETC1_EXTERNAL_ALPHA
            #include "UnitySprites.cginc"
            
            float _FillType;
            fixed _FillAmount;
            fixed _FillFlip;

            fixed4 Frag(v2f IN) : SV_Target
            {
                fixed4 col = SampleSpriteTexture (IN.texcoord) * IN.color;
                //计算fill
                float uvValue = lerp(IN.texcoord.x, IN.texcoord.y, sign(saturate(_FillType)));
                float fValue1 = lerp(uvValue, _FillAmount, sign(saturate(_FillFlip)));
                float fValue2 = lerp(_FillAmount, uvValue, sign(saturate(_FillFlip)));
                col.a *= step(fValue1, fValue2);
                //end
                col.rgb *= col.a;
                return col;
            }
        ENDCG
        }
    }
}

Inspector面板视图

C#调用

    /// 

    /// SetSpriteRendererFill
    /// 
    /// 
    ///  0-1 
    ///  0 or 1 (0:Horizaontal, 1:Vertical) 
    ///  翻转 0 or 1 
    public static void SetSpriteRendererFill(GameObject obj, float fillAmount, float fillType = 0, float fillFlip = 0)
    {
        SpriteRenderer sr = obj.GetComponent();
        if (sr == null) return;

        Material mat = sr.material;
        if (mat == null || mat.name != "SpriteToFilled") return;

        fillType = Mathf.Clamp01(fillType);
        fillAmount = Mathf.Clamp01(fillAmount);
        mat.SetFloat("_FillType", fillType);
        mat.SetFloat("_FillAmount", fillAmount);
        mat.SetFloat("_FillFlip", fillFlip);
    }