using UnityEngine;
using UnityEngine.UI;

[RequireComponent(typeof(Image))]
public class RoundedRectImage : MonoBehaviour
{
    public float cornerRadius = 10f;

    private Image image;

    void Start()
    {
        image = GetComponent<Image>();
        UpdateMesh();
    }

    void UpdateMesh()
    {
        Rect rect = image.rectTransform.rect;
        Vector2 size = rect.size;
        Vector2 center = rect.center;

        UIVertex[] vertices = new UIVertex[4];
        Vector2[] uv = new Vector2[4];
        Vector2[] positions = new Vector2[4];

        positions[0] = new Vector2(-size.x / 2f, -size.y / 2f);
        positions[1] = new Vector2(size.x / 2f, -size.y / 2f);
        positions[2] = new Vector2(size.x / 2f, size.y / 2f);
        positions[3] = new Vector2(-size.x / 2f, size.y / 2f);

        uv[0] = new Vector2(0f, 0f);
        uv[1] = new Vector2(1f, 0f);
        uv[2] = new Vector2(1f, 1f);
        uv[3] = new Vector2(0f, 1f);

        for (int i = 0; i < 4; i++)
        {
            vertices[i] = UIVertex.simpleVert;
            vertices[i].position = positions[i];
            vertices[i].uv0 = uv[i];
        }

        // 处理圆角
        float halfRadius = cornerRadius / 2f;
        vertices[0].position += new Vector3(halfRadius, halfRadius, 0f);
        vertices[1].position += new Vector3(-halfRadius, halfRadius, 0f);
        vertices[2].position += new Vector3(-halfRadius, -halfRadius, 0f);
        vertices[3].position += new Vector3(halfRadius, -halfRadius, 0f);

        int[] triangles = new int[6] { 0, 1, 2, 2, 3, 0 };

        Mesh mesh = new Mesh();
        mesh.vertices = System.Array.ConvertAll(vertices, v => (Vector3)v.position);
        mesh.uv = uv;
        mesh.triangles = triangles;

        image.canvasRenderer.SetMesh(mesh);
    }
}