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点击鼠标左键在屏幕上绘制线段
准备
VertexHelper 网格绘制工具类向量、叉乘RectTransformUtility.ScreenPointToLocalPointInRectangleSetVerticesDirtyOnPopulateMesh
思路
鼠标按下#xff0c;记录线段起点#xff1b;鼠标持续按下#xff0c;记录鼠标当前帧的…描述
点击鼠标左键在屏幕上绘制线段
准备
VertexHelper 网格绘制工具类向量、叉乘RectTransformUtility.ScreenPointToLocalPointInRectangleSetVerticesDirtyOnPopulateMesh
思路
鼠标按下记录线段起点鼠标持续按下记录鼠标当前帧的移动向量使用叉乘获取垂直与移动向量的单位向量根据设置的宽度获取四个顶点设置顶点脏数据,更新网格
示例
新建脚本继承MaskableGraphic 创建一个Image,移除Image组件添加新建脚本。 脚本内容如下
引入命名空间
using UnityEngine;
using UnityEngine.UI;
using System.Collections.Generic;属性
private ListListUIVertex vertexList new ListListUIVertex();//缓存线段上的网格顶点
private Vector3 lastPoint;//上一帧的点击点
private Vector3 lastLeftPoint;
private Vector3 lastRightPoint;
bool isNewLine;//绘制新的线段
[SerializeField] private float lineWidth 4f;//线段宽度方法 绘制网格
protected override void OnPopulateMesh(VertexHelper vh)//绘制网格
{vh.Clear();for (int i 0; i vertexList.Count; i)vh.AddUIVertexQuad(vertexList[i].ToArray());
}方法 屏幕坐标转为本地坐标
Vector2 ScreenPointToLocalPoint(Vector2 mousePoint)
{var Rect GetComponentRectTransform();Vector2 result Vector2.zero;switch (canvas.renderMode){case RenderMode.ScreenSpaceOverlay:RectTransformUtility.ScreenPointToLocalPointInRectangle(Rect, mousePoint, null, out result);break;case RenderMode.ScreenSpaceCamera:RectTransformUtility.ScreenPointToLocalPointInRectangle(Rect, mousePoint, canvas.worldCamera, out result);break;case RenderMode.WorldSpace:RectTransformUtility.ScreenPointToLocalPointInRectangle(Rect, mousePoint, canvas.worldCamera, out result);break;}return result;
}方法 设置网格顶点
private void Update()
{if (Input.GetMouseButtonDown(0))//按下鼠标坐标表示 绘制新的线段{lastPoint ScreenPointToLocalPoint(Input.mousePosition);//屏幕点转换到当前recttransform上的点isNewLine true;vertexList.Clear();//清除上一次绘制的线段 若要保留 可不清除}else{if (Input.GetMouseButton(0)){Vector3 currentPoint ScreenPointToLocalPoint(Input.mousePosition);Vector3 dir currentPoint - lastPoint;//移动向量if (dir.magnitude 10)//移动量过小 不绘制网格return;Vector3 normal Vector3.Cross(dir.normalized, transform.forward);//移动向量和当前ui的朝向 进行叉乘if (isNewLine){isNewLine false;lastLeftPoint lastPoint normal * lineWidth;//绘制新的线段时 作为左侧起点lastRightPoint lastPoint - normal * lineWidth;}Vector3 leftPoint currentPoint normal * lineWidth;//当前线段的左侧终点Vector3 rightPoint currentPoint - normal * lineWidth;ListUIVertex ver new ListUIVertex();UIVertex uIVertex new UIVertex();//网格顶点列表uIVertex.position lastLeftPoint;uIVertex.color color;ver.Add(uIVertex);UIVertex uIVertex2 new UIVertex();uIVertex2.position lastRightPoint;uIVertex2.color color;ver.Add(uIVertex2);UIVertex uIVertex3 new UIVertex();uIVertex3.position rightPoint;uIVertex3.color color;ver.Add(uIVertex3);UIVertex uIVertex4 new UIVertex();uIVertex4.position leftPoint;uIVertex4.color color;ver.Add(uIVertex4);vertexList.Add(ver);lastLeftPoint leftPoint;//更新起点 当前帧的终点作为下一帧的起点lastRightPoint rightPoint;lastPoint currentPoint;SetVerticesDirty();//设置顶点脏数据 更新网格}}
}
