134 lines
4.1 KiB
C#
134 lines
4.1 KiB
C#
using UnityEngine;
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using UnityEngine.UI;
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/// <summary>
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/// 挂载在Canvas上，控制两个背景Image从上往下无限滚动（适配实际屏幕高度间隔）
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/// </summary>
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[RequireComponent(typeof(Canvas))]
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//[ExecuteInEditMode]
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public class BackgroundScroll : MonoBehaviour
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{
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[Header("滚动速度（像素/秒）")]
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public float scrollSpeed = 50f;
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[Header("是否自动获取子物体的两个Image（取消则手动指定）")]
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public bool autoGetImages = true;
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[Header("手动指定的两个背景Image（autoGetImages为false时生效）")]
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public Image bgImage1;
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public Image bgImage2;
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// Image的RectTransform组件
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private RectTransform rt1;
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private RectTransform rt2;
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// Image在屏幕上的实际显示高度（关键：适配Aspect缩放）
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private float actualImageHeight;
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private float rt1ScaleY = 1;
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void Start()
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{
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}
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private void OnEnable()
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{
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// 初始化Image和RectTransform
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InitImages();
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// 计算Image的实际屏幕高度（适配Aspect模式）
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if (rt1 != null)
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{
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actualImageHeight = GetImageActualHeight(rt1);
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rt1ScaleY = rt1.localScale.y;
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// 初始化第二个Image的位置：在第一个Image顶部上方，间隔实际屏幕高度
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rt2.anchoredPosition = new Vector2(0, rt1.anchoredPosition.y + actualImageHeight);
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//Debug.Log($"图片实际屏幕高度：{actualImageHeight}，已初始化第二张图位置");
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}
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else
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{
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Debug.LogError("未找到有效的背景Image，请检查Canvas下的子物体或手动指定Image！");
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}
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}
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void Update()
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{
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if (rt1 == null || rt2 == null) return;
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if (rt1ScaleY != rt1.localScale.y)
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{
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actualImageHeight = GetImageActualHeight(rt1);
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rt2.anchoredPosition = new Vector2(0, rt1.anchoredPosition.y + actualImageHeight);
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rt1ScaleY = rt1.localScale.y;
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}
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// 让两个Image向下滚动（anchoredPosition的y轴减小）
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rt1.anchoredPosition -= new Vector2(0, scrollSpeed * Time.deltaTime);
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rt2.anchoredPosition -= new Vector2(0, scrollSpeed * Time.deltaTime);
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// 检测第一个Image是否完全滚出屏幕下方，重置位置（用实际高度判断）
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if (rt1.anchoredPosition.y <= -actualImageHeight)
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{
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rt1.anchoredPosition = new Vector2(0, rt2.anchoredPosition.y + actualImageHeight);
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}
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// 检测第二个Image是否完全滚出屏幕下方，重置位置（用实际高度判断）
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if (rt2.anchoredPosition.y <= -actualImageHeight)
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{
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rt2.anchoredPosition = new Vector2(0, rt1.anchoredPosition.y + actualImageHeight);
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}
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}
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/// <summary>
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/// 初始化Image组件和RectTransform
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/// </summary>
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private void InitImages()
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{
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if (autoGetImages)
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{
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Image[] images = GetComponentsInChildren<Image>();
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if (images.Length >= 2)
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{
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bgImage1 = images[0];
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bgImage2 = images[1];
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}
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else
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{
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Debug.LogError("Canvas下的Image数量不足2个，请检查！");
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return;
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}
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}
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if (bgImage1 != null) rt1 = bgImage1.GetComponent<RectTransform>();
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if (bgImage2 != null) rt2 = bgImage2.GetComponent<RectTransform>();
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}
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/// <summary>
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/// 计算RectTransform在屏幕上的实际显示高度（适配Aspect缩放）
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/// </summary>
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/// <param name="rt">目标RectTransform</param>
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/// <returns>实际屏幕高度（像素）</returns>
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private float GetImageActualHeight(RectTransform rt)
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{
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// 获取RectTransform的世界空间包围盒
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//Bounds bounds = RectTransformUtility.CalculateRelativeRectTransformBounds(transform, rt);
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// 转换为屏幕空间的高度（考虑Canvas的缩放）
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//float canvasScale = GetComponent<Canvas>().scaleFactor;
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return rt.sizeDelta.y * rt.localScale.y;
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}
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///// <summary>
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///// 编辑器下实时预览（可选）
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///// </summary>
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//private void OnDrawGizmos()
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//{
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// if (Application.isPlaying) return;
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// InitImages();
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// if (rt1 != null)
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// {
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// actualImageHeight = GetImageActualHeight(rt1);
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// if (rt2 != null)
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// {
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// rt2.anchoredPosition = new Vector2(0, actualImageHeight);
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// }
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// }
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//}
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} |