Shader "UI/RoundedRectangle"
{
    Properties
    {
        _Color("Color", Color) = (1,1,1,1)
        _Radius("Corner Radius", Range(0, 2.5)) = 0.1
    }

        SubShader
    {
        Tags
        {
            "Queue" = "Transparent"
            "RenderType" = "Transparent"
            "PreviewType" = "Plane"
        }

        Blend SrcAlpha OneMinusSrcAlpha
        ZWrite Off
        Cull Off

        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #pragma multi_compile_instancing

            #include "UnityCG.cginc"

            struct appdata
            {
                float4 vertex : POSITION;
                float2 uv : TEXCOORD0;
                UNITY_VERTEX_INPUT_INSTANCE_ID
            };

            struct v2f
            {
                float2 uv : TEXCOORD0;
                float4 vertex : SV_POSITION;
                float2 size : TEXCOORD1; // 传递 UI 组件的宽高
                UNITY_VERTEX_INPUT_INSTANCE_ID
            };

            UNITY_INSTANCING_BUFFER_START(Props)
                UNITY_DEFINE_INSTANCED_PROP(fixed4, _Color)
                UNITY_DEFINE_INSTANCED_PROP(half, _Radius)
            UNITY_INSTANCING_BUFFER_END(Props)

            v2f vert(appdata v)
            {
                v2f o;
                UNITY_SETUP_INSTANCE_ID(v);
                UNITY_TRANSFER_INSTANCE_ID(v, o);

                o.vertex = UnityObjectToClipPos(v.vertex);
                o.uv = v.uv;

                // 计算 UI 组件的实际宽高
                float2 size = float2(
                    length(float3(unity_ObjectToWorld[0].x, unity_ObjectToWorld[1].x, unity_ObjectToWorld[2].x)),
                    length(float3(unity_ObjectToWorld[0].y, unity_ObjectToWorld[1].y, unity_ObjectToWorld[2].y))
                );
                o.size = size; // 传递宽高信息

                return o;
            }

            // 计算 SDF 圆角边界
            float roundedBoxSDF(float2 uv, float2 size, float radius)
            {
                // 归一化 UV 到 [-1,1]，保持正确比例
                uv = (uv - 0.5) * 2.0;
                uv *= size / min(size.x, size.y); // 保持等比例缩放

                // 计算边界
                float2 corner = float2(1.0 - radius, 1.0 - radius);
                float2 d = abs(uv) - corner;
                return length(max(d, 0.0)) + min(max(d.x, d.y), 0.0) - radius;
            }

            fixed4 frag(v2f i) : SV_Target
            {
                UNITY_SETUP_INSTANCE_ID(i);

                float radius = UNITY_ACCESS_INSTANCED_PROP(Props, _Radius) * min(i.size.x, i.size.y) * 0.5;

                // 计算 SDF 圆角
                float sdf = roundedBoxSDF(i.uv, i.size, radius);

                // 抗锯齿处理
                float alpha = 1.0 - smoothstep(0.0, 0.01 * min(i.size.x, i.size.y), sdf);

                fixed4 color = UNITY_ACCESS_INSTANCED_PROP(Props, _Color);
                return fixed4(color.rgb, alpha * color.a);
            }
            ENDCG
        }
    }
}