//矩形边界（圆角、描边）
Shader "JC/UI/RectBorder"
{
    Properties
    {
        [PerRendererData] _MainTex("Sprite Texture", 2D) = "white" {}
        _Color("Tint", Color) = (1,1,1,1)
 
        _StencilComp("Stencil Comparison", Float) = 8
        _Stencil("Stencil ID", Float) = 0
        _StencilOp("Stencil Operation", Float) = 0
        _StencilWriteMask("Stencil Write Mask", Float) = 255
        _StencilReadMask("Stencil Read Mask", Float) = 255
 
        _ColorMask("Color Mask", Float) = 15
 
        [Toggle(UNITY_UI_ALPHACLIP)] _UseUIAlphaClip("Use Alpha Clip", Float) = 0
 
        _NodeWidth("Node Width", Float) = 100
        _NodeHeight("Node Height", Float) = 100
        _BorderRadius("Border Radius", Float) = 20
        _BorderRadiusSwitch("Border Radius Switch", Int) = 15
        _BorderWidth("Border Width", Float) = 2
        _BorderColor("Border Color", Color) = (0,0,0,1)
    }
 
    SubShader
    {
        Tags
        {
            "Queue" = "Transparent"
            "IgnoreProjector" = "True"
            "RenderType" = "Transparent"
            "PreviewType" = "Plane"
            "CanUseSpriteAtlas" = "True"
        }
 
        Stencil
        {
            Ref[_Stencil]
            Comp[_StencilComp]
            Pass[_StencilOp]
            ReadMask[_StencilReadMask]
            WriteMask[_StencilWriteMask]
        }
 
        Cull Off
        Lighting Off
        ZWrite Off
        ZTest[unity_GUIZTestMode]
        Blend SrcAlpha OneMinusSrcAlpha
        ColorMask[_ColorMask]
 
        Pass
        {
            CGPROGRAM
#pragma vertex vert
#pragma fragment frag
 
#include "UnityCG.cginc"
#include "UnityUI.cginc"
 
#pragma multi_compile __ UNITY_UI_ALPHACLIP
 
            struct appdata_t
            {
float4 vertex   :
                POSITION;
float4 color    :
                COLOR;
float2 texcoord :
                TEXCOORD0;
            };
 
            struct v2f
            {
float4 vertex   :
                SV_POSITION;
fixed4 color :
                COLOR;
half2 texcoord  :
                TEXCOORD0;
float4 worldPosition :
                TEXCOORD1;
            };
 
            fixed4 _Color;
            fixed4 _TextureSampleAdd;
            float4 _ClipRect;
 
            float _NodeWidth;
            float _NodeHeight;
            float _BorderRadius;
            int _BorderRadiusSwitch;
            float _BorderWidth;
            fixed4 _BorderColor;
 
            float4 _MainTex_TexelSize;
 
            v2f vert(appdata_t IN)
            {
                v2f OUT;
                OUT.worldPosition = IN.vertex;
                OUT.vertex = UnityObjectToClipPos(OUT.worldPosition);
 
                OUT.texcoord = IN.texcoord;
 
#ifdef UNITY_HALF_TEXEL_OFFSET
                OUT.vertex.xy += (_ScreenParams.zw - 1.0)*float2(-1,1);
#endif
 
                OUT.color = IN.color * _Color;
                return OUT;
            }
 
            sampler2D _MainTex;
 
            fixed4 frag(v2f IN) : SV_Target
            {
                half4 color = (tex2D(_MainTex, IN.texcoord) + _TextureSampleAdd) * IN.color;
 
                color.a *= UnityGet2DClipping(IN.worldPosition.xy, _ClipRect);
 
#ifdef UNITY_UI_ALPHACLIP
                clip(color.a - 0.001);
#endif

                // float w = _MainTex_TexelSize.z;
                // float h = _MainTex_TexelSize.w;
                float w = _NodeWidth;
                float h = _NodeHeight;
                float r = _BorderRadius;

                float x = IN.texcoord.x * w;
                float y = IN.texcoord.y * h;
                float bw = _BorderWidth;

                bool switch_lt = (_BorderRadiusSwitch & 1) == 1; //左上角是否要圆角处理
                bool switch_rt = (_BorderRadiusSwitch & 2) == 2; //右上角是否要圆角处理
                bool switch_rb = (_BorderRadiusSwitch & 4) == 4; //右下角是否要圆角处理
                bool switch_lb = (_BorderRadiusSwitch & 8) == 8; //左下角是否要圆角处理
                
                //左下角
                if (switch_lb && x < r && y < r)
                {
                    if ((x - r) * (x - r) + (y - r) * (y - r) > (r - bw) * (r - bw))
                    {
                        if ((x - r) * (x - r) + (y - r) * (y - r) > r * r)
                            color.a = 0;
                        else 
                            color.rgba = _BorderColor.rgba;
                    }
                }
 
                //左上角
                else if (switch_lt && x < r && y > (h - r))
                {   
                    if ((x - r) * (x - r) + (y - (h - r)) * (y - (h - r)) > (r - bw) * (r - bw))
                    {
                        if ((x - r) * (x - r) + (y - (h - r)) * (y - (h - r)) > r * r)
                            color.a = 0;
                        else 
                            color.rgba = _BorderColor.rgba;
                    }
                }
 
                //右下角
                else if (switch_rb && x > (w - r) && y < r)
                {
                    if ((x - (w - r)) * (x - (w - r)) + (y - r) * (y - r) > (r - bw) * (r - bw))
                    {
                        if ((x - (w - r)) * (x - (w - r)) + (y - r) * (y - r) > r * r)
                            color.a = 0;
                        else
                            color.rgba = _BorderColor.rgba;
                    }
                }
 
                //右上角
                else if (switch_rt && x > (w - r) && y > (h - r))
                {
                    if ((x - (w - r)) * (x - (w - r)) + (y - (h - r)) * (y - (h - r)) > (r - bw) * (r - bw))
                    {
                        if ((x - (w - r)) * (x - (w - r)) + (y - (h - r)) * (y - (h - r)) > r * r)
                            color.a = 0;
                        else
                            color.rgba = _BorderColor.rgba;
                    }
                    
                }

                //边界上色
                else if (bw > 0 && x < bw || x > w - bw || y < bw || y > h - bw) color.rgba = _BorderColor.rgba;
 
                return color;
            }
            ENDCG
        }
    }
}