Unity中实现UI翻转

Posted 2022-04-26 Hello Bug.

一：效果演示

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二：使用

FlipType：翻转类型(水平翻转、竖直翻转、水平竖直翻转)

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三：为什么不使用将Scale设置为-1

将Scale的x、y设置为-1也可以实现翻转的效果，但是这样还会影响到子物体以及animation，所以最佳的方法是修改图片的显示，我们可以继承UGUI提供的网格效果基类BaseMeshEffect修改网格顶点去实现翻转效果

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四：代码实现

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

/// <summary>
/// 翻转
/// </summary>
/// 与将Scale设置为-1效果相同
[DisallowMultipleComponent]
[RequireComponent(typeof(RectTransform))]
[AddComponentMenu("LFramework/UI/Effects/Flip")]
public class Flip : BaseMeshEffect

    /// <summary>
    /// 翻转类型
    /// </summary>
    public enum EFlipType
    
        Horizontal,
        Vertical,
        HorizontalAndVertical,
    

    //翻转类型
    [SerializeField]
    EFlipType m_FlipType;
    public EFlipType FlipType
    
        get
        
            return m_FlipType;
        
        set
        
            m_FlipType = value;
            graphic.SetVerticesDirty();
        
    

    //顶点缓存
    List<UIVertex> vertexCache = new List<UIVertex>();

    public override void ModifyMesh(VertexHelper vh)
    
        vh.GetUIVertexStream(vertexCache);
        vh.Clear();

        ApplyFlip(vertexCache, graphic.rectTransform.rect.center);

        vh.AddUIVertexTriangleStream(vertexCache);
        vertexCache.Clear();
    

    void ApplyFlip(List<UIVertex> vertexCache, Vector2 pivot)
    
        int vertexCount = vertexCache.Count;
        for (int i = 0; i < vertexCount; i++)
        
            UIVertex veretx = vertexCache[i];
            if (m_FlipType == EFlipType.HorizontalAndVertical)
            
                veretx.position.x = 2 * pivot.x - veretx.position.x;
                veretx.position.y = 2 * pivot.y - veretx.position.y;
            
            else if (m_FlipType == EFlipType.Horizontal)
            
                veretx.position.x = 2 * pivot.x - veretx.position.x;
            
            else if (m_FlipType == EFlipType.Vertical)
            
                veretx.position.y = 2 * pivot.y - veretx.position.y;
            
            vertexCache[i] = veretx;