loudixvmuniu/Assets/_Scripts/Framework/Utilities/BorderRadius.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Sprites;
using UnityEngine.UI;

#if UNITY_EDITOR
using UnityEditor;
using UnityEditor.UI;
#endif

/*
 * @author 渡鸦
 * @description 自定义顶点数据实现圆角矩形
 * @公众号文档 https://mp.weixin.qq.com/s/FUO4xDmWmllryt2x7kVqig
 */

#if UNITY_EDITOR
[CustomEditor(typeof(BorderRadius), true)]
public class BorderRadiusEditor : ImageEditor
{
    SerializedProperty _sprite;
    SerializedProperty _cornerRadius;
    SerializedProperty _cornerSegments;

    protected override void OnEnable()
    {
        base.OnEnable();

        this._sprite = this.serializedObject.FindProperty("m_Sprite");
        this._cornerRadius = this.serializedObject.FindProperty("cornerRadius");
        this._cornerSegments = this.serializedObject.FindProperty("cornerSegments");
    }

    public override void OnInspectorGUI()
    {
        this.serializedObject.Update();

        this.SpriteGUI();
        this.AppearanceControlsGUI();
        this.RaycastControlsGUI();
        bool showNativeSize = this._sprite.objectReferenceValue != null;
        this.m_ShowNativeSize.target = showNativeSize;
        this.MaskableControlsGUI();
        this.NativeSizeButtonGUI();
        EditorGUILayout.PropertyField(this._cornerRadius);
        EditorGUILayout.PropertyField(this._cornerSegments);
        EditorGUILayout.PropertyField(this.serializedObject.FindProperty("leftTop"));
        EditorGUILayout.PropertyField(this.serializedObject.FindProperty("rightTop"));
        EditorGUILayout.PropertyField(this.serializedObject.FindProperty("leftBottom"));
        EditorGUILayout.PropertyField(this.serializedObject.FindProperty("rightBottom"));
        this.serializedObject.ApplyModifiedProperties();
    }
}
#endif

public class BorderRadius : Image
{
    public float cornerRadius = 8;

    // 每个角最大的三角形数
    [Range(1, 22)] public int cornerSegments = 8;

    public bool leftTop = true;
    public bool rightTop = true;
    public bool leftBottom = true;
    public bool rightBottom = true;

    protected override void OnPopulateMesh(VertexHelper vh)
    {
        Rect rect = this.rectTransform.rect;
        float left = rect.xMin;
        float right = rect.xMax;
        float top = rect.yMax;
        float bottom = rect.yMin;

        Vector4 outerUV = this.overrideSprite != null ? DataUtility.GetOuterUV(this.overrideSprite) : Vector4.zero;
        var color32 = color;
        float r = this.cornerRadius;

        // 计算uv中对应的半径值坐标轴的半径
        float uvRadiusX = r / (right - left) * (outerUV.z - outerUV.x);
        float uvRadiusY = r / (top - bottom) * (outerUV.w - outerUV.y);

        vh.Clear();

        // 从左往右
        // 0 1 2 3
        vh.AddVert(new Vector3(left, top), color32, new Vector2(outerUV.x, outerUV.w));
        vh.AddVert(new Vector3(left, top - r), color32, new Vector2(outerUV.x, outerUV.w - uvRadiusY));
        vh.AddVert(new Vector3(left, bottom + r), color32, new Vector2(outerUV.x, outerUV.y + uvRadiusY));
        vh.AddVert(new Vector3(left, bottom), color32, new Vector2(outerUV.x, outerUV.y));

        // 4 5 6 7
        vh.AddVert(new Vector3(left + r, top), color32, new Vector2(outerUV.x + uvRadiusX, outerUV.w));
        vh.AddVert(new Vector3(left + r, top - r), color32,
            new Vector2(outerUV.x + uvRadiusX, outerUV.w - uvRadiusY));
        vh.AddVert(new Vector3(left + r, bottom + r), color32,
            new Vector2(outerUV.x + uvRadiusX, outerUV.y + uvRadiusY));
        vh.AddVert(new Vector3(left + r, bottom), color32, new Vector2(outerUV.x + uvRadiusX, outerUV.y));

        // 8 9 10 11
        vh.AddVert(new Vector3(right - r, top), color32, new Vector2(outerUV.z - uvRadiusX, outerUV.w));
        vh.AddVert(new Vector3(right - r, top - r), color32,
            new Vector2(outerUV.z - uvRadiusX, outerUV.w - uvRadiusY));
        vh.AddVert(new Vector3(right - r, bottom + r), color32,
            new Vector2(outerUV.z - uvRadiusX, outerUV.y + uvRadiusY));
        vh.AddVert(new Vector3(right - r, bottom), color32, new Vector2(outerUV.z - uvRadiusX, outerUV.y));

        // 12 13 14 15
        vh.AddVert(new Vector3(right, top), color32, new Vector2(outerUV.z, outerUV.w));
        vh.AddVert(new Vector3(right, top - r), color32, new Vector2(outerUV.z, outerUV.w - uvRadiusY));
        vh.AddVert(new Vector3(right, bottom + r), color32, new Vector2(outerUV.z, outerUV.y + uvRadiusY));
        vh.AddVert(new Vector3(right, bottom), color32, new Vector2(outerUV.z, outerUV.y));

        // 左边矩形
        vh.AddTriangle(2, 5, 1);
        vh.AddTriangle(2, 5, 6);
        // 中间矩形
        vh.AddTriangle(7, 8, 4);
        vh.AddTriangle(7, 8, 11);
        // 右边矩形
        vh.AddTriangle(10, 13, 9);
        vh.AddTriangle(10, 13, 14);

        List<Vector2> positionList = new List<Vector2>();
        List<Vector2> uvList = new List<Vector2>();
        List<int> vertexList = new List<int>();

        // 右上角圆心
        positionList.Add(new Vector2(right - r, top - r));
        uvList.Add(new Vector2(outerUV.z - uvRadiusX, outerUV.w - uvRadiusY));
        vertexList.Add(9);

        // 左上角圆心
        positionList.Add(new Vector2(left + r, top - r));
        uvList.Add(new Vector2(outerUV.x + uvRadiusX, outerUV.w - uvRadiusY));
        vertexList.Add(5);

        // 左下角圆心
        positionList.Add(new Vector2(left + r, bottom + r));
        uvList.Add(new Vector2(outerUV.x + uvRadiusX, outerUV.y + uvRadiusY));
        vertexList.Add(6);

        // 右下角圆心
        positionList.Add(new Vector2(right - r, bottom + r));
        uvList.Add(new Vector2(outerUV.z - uvRadiusX, outerUV.y + uvRadiusY));
        vertexList.Add(10);

        // 每个三角形角度
        float degreeDelta = Mathf.PI / 2 / this.cornerSegments;

        // 当前角度
        float degree = 0;
        for (int i = 0; i < vertexList.Count; i++)
        {
            int currVertCount = vh.currentVertCount;
            for (int j = 0; j <= this.cornerSegments; j++)
            {
                float cos = Mathf.Cos(degree);
                float sin = Mathf.Sin(degree);
                Vector3 position = new Vector3(positionList[i].x + cos * r, positionList[i].y + sin * r);
                Vector3 uv0 = new Vector2(uvList[i].x + cos * uvRadiusX,
                    uvList[i].y + sin * uvRadiusY);
                vh.AddVert(position, color32, uv0);
                degree += degreeDelta;
            }

            degree -= degreeDelta;

            if (i == 0 && !this.rightTop)
            {
                vh.AddTriangle(vertexList[i], 8, 12);
                vh.AddTriangle(vertexList[i], 12, 13);
                continue;
            }

            if (i == 1 && !this.leftTop)
            {
                vh.AddTriangle(vertexList[i], 0, 4);
                vh.AddTriangle(vertexList[i], 0, 1);
                continue;
            }

            if (i == 2 && !this.leftBottom)
            {
                vh.AddTriangle(vertexList[i], 3, 2);
                vh.AddTriangle(vertexList[i], 3, 7);
                continue;
            }

            if (i == 3 && !this.rightBottom)
            {
                vh.AddTriangle(vertexList[i], 15, 14);
                vh.AddTriangle(vertexList[i], 15, 11);
                continue;
            }

            for (int j = 0; j <= this.cornerSegments - 1; j++)
            {
                vh.AddTriangle(vertexList[i], currVertCount + j + 1, currVertCount + j);
            }
        }
    }
}