Unity3D 检测鼠标位置的Sprite像素颜色

思路

1. 获取鼠标所在屏幕坐标(Vector2)
2. 通过相机ScreenToWorldPoint(Vector3)转为世界坐标 (注意Vector3的z是距离相机的距离，相机需要正交)
3. 通过SpriteRenderer访问边界Bounds
4. 通过Bounds.Contain检测世界坐标是否在SpriteBounds内
5. 通过比例计算来确定在Sprite内的UV坐标，并根据像素长宽确定像素坐标

float pixelX = (worldPositiopn.x - bounds.min.x) / bounds.size.x * bgSprite.texture.width;
float pixelY = (worldPositiopn.y - bounds.min.y) / bounds.size.y * bgSprite.texture.height;

部分编辑器依赖于OdinInspector，不用可以把红线都删了

实现的效果类似这样，根据边界贴图检测鼠标画线位置是否在范围内

using Sirenix.OdinInspector;
using System.Collections;
using System.Collections.Generic;
using Unity.VisualScripting;
using UnityEngine;namespace Yueh0607.ClothOperations
{public class CutBehaviour : MonoBehaviour{[ShowIf("IsRuntime")][ReadOnly][SerializeField]Sprite bgSprite, lineStyleSprite, edgeSprite;[ShowIf("IsRuntime")][ReadOnly][SerializeField]SpriteRenderer bgRenderer, lineStyleRenderer;[SerializeField] Color edgeColor = Color.black;bool initialized = false;#if UNITY_EDITORbool IsRuntime() => Application.isPlaying;
#endif/// <summary>/// 初始化裁剪行为/// </summary>/// <param name="bgSprite">背景精灵图</param>/// <param name="lineStyleSprite">裁剪线样式精灵图</param>/// <param name="edgeSprite">边界范围精灵图(RBGA 0-1 使用(0,0,0,1)表示裁剪线范围)</param>public void Initialize(Sprite bgSprite, Sprite lineStyleSprite, Sprite edgeSprite){this.bgSprite = bgSprite;this.edgeSprite = edgeSprite;this.lineStyleSprite = lineStyleSprite;bool sizeMatch = (lineStyleSprite.texture.width == bgSprite.texture.width && edgeSprite.texture.width == bgSprite.texture.width)&& (lineStyleSprite.texture.height == bgSprite.texture.height && edgeSprite.texture.height == bgSprite.texture.height);bool rectMatch = (lineStyleSprite.rect == bgSprite.rect && edgeSprite.rect == bgSprite.rect);if (!sizeMatch) throw new System.Exception("贴图尺寸不合规");if (!rectMatch) throw new System.Exception("精灵尺寸不合规");DynamicInitialize();initialized = true;}/// <summary>/// 动态内容的初始化/// </summary>private void DynamicInitialize(){GameObject bg = new GameObject("CutBackgroundImage");bg.transform.SetParent(transform);bg.transform.position = Vector3.zero;bgRenderer = bg.AddComponent<SpriteRenderer>();bgRenderer.sprite = bgSprite;GameObject lineStyle = new GameObject("LineStyle");lineStyle.transform.SetParent(transform);lineStyle.transform.position = Vector3.zero;lineStyleRenderer = lineStyle.AddComponent<SpriteRenderer>();lineStyleRenderer.sprite = lineStyleSprite;}/// <summary>/// 检查裁剪行为初始化/// </summary>/// <exception cref="System.Exception"></exception>[System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]private void ExceptionCheck(){if (!initialized) throw new System.Exception("未初始化裁剪行为!");}/// <summary>/// 将世界坐标转换到像素坐标/// </summary>/// <param name="worldPositiopn"></param>/// <param name="pixelPosition"></param>/// <returns></returns>public bool TransPoint(Vector2 worldPositiopn, out Vector2Int pixelPosition){ExceptionCheck();Bounds bounds= bgRenderer.bounds;if (bounds.Contains(worldPositiopn)){//get pixelX and pixelYfloat pixelX = (worldPositiopn.x - bounds.min.x) / bounds.size.x * bgSprite.texture.width;float pixelY = (worldPositiopn.y - bounds.min.y) / bounds.size.y * bgSprite.texture.height;//float pixelX = (worldPositiopn.x - bounds.) / bgSprite.rect.width * bgSprite.texture.width;//float pixelY = (worldPositiopn.y - bgSprite.rect.y) / bgSprite.rect.height * bgSprite.texture.height;pixelPosition = new Vector2Int(Mathf.RoundToInt(pixelX), Mathf.RoundToInt(pixelY));return true;}pixelPosition = Vector2Int.zero;return false;}/// <summary>/// 判断某个世界坐标是否在裁剪线范围内/// </summary>/// <param name="worldPosition">Sprite所在的坐标系坐标</param>/// <returns></returns>public bool IsInEdgeRange(Vector2 worldPosition){ExceptionCheck();bool result = TransPoint(worldPosition, out Vector2Int pixelPosition);if (!result) return false;Color color = edgeSprite.texture.GetPixel(pixelPosition.x, pixelPosition.y);if (color == edgeColor) return true;return false;}}
}