Unity3d LineRenderer画线
LineRenderer线渲染器主要是用于在3D中渲染线段，虽然我们也可以使用GL图像库来渲染线段，但是使用LineRenderer我们可以对线段进行更多的操作，例如:设置颜色，宽度等。在这里要注意LineRenderer渲染出的线段的两个端点是3D世界中的点，即他是属于世界坐标（World Point）中的。
LineRenderer是以组件形成存在的，首先我们新建一个空的Game Object，然后我们选择“Component→Effects→Line Renderer”，即可为其添加LineRenderer组件了。
其实我们也可以通过脚本来为其添加LineRenderer组件：
LineRenderer lineRenderer = gameObject.AddComponent<LineRenderer>();
获取LineRenderer组件：
lineRenderer = GetComponent<LineRenderer>();
【 案例】根据鼠标左击的位置，来持续绘制线段
首先我们在场景中新建一个空的 GameObject，并Reset一下。然后将Script1脚本添加给他。
using UnityEngine;
using System.Collections;
using System.Collections.Generic;
//[RequireComponent(typeof(LineRenderer))]
public class DrawLine : MonoBehaviour
{
private LineRenderer line;
private bool isMousePressed;
private List pointsList;
private Vector3 mousePos;
//private Vector3 m_DownCamPos;
//private Vector3 m_mouseDownStartPos;
//主相机节点下
// Structure for line points
struct myLine
{
public Vector3 StartPoint;
public Vector3 EndPoint;
};
// -----------------------------------
void Awake() {
_Init();
}
private void _Init() {
if (m_init) return;
m_init = true;
// Create line renderer component and set its property
//line = this.GetComponent();
line = gameObject.AddComponent();
line.material = new Material(Shader.Find("Particles/Additive"));
line.SetVertexCount(0);
line.SetWidth(0.1f, 0.1f);
line.SetColors(Color.green, Color.green);
line.useWorldSpace = true;
isMousePressed = false;
pointsList = new List();
line.sortingLayerName = "Ignore Raycast";
line.sortingOrder = 999;
// renderer.material.SetTextureOffset(
//m_mainCam = this.GetComponent();
}
bool m_init = false;
//Camera m_mainCam;
// -----------------------------------
void Update() {
// If mouse button down, remove old line and set its color to green
if (Input.GetMouseButtonDown(1)) {
isMousePressed = true;
line.SetVertexCount(0);
pointsList.RemoveRange(0, pointsList.Count);
line.SetColors(Color.green, Color.green);
//m_DownCamPos = Camera.main.transform.position;
//m_mouseDownStartPos = Camera.main.ScreenToWorldPoint(new Vector3(Input.mousePosition.x, Input.mousePosition.y, Camera.main.nearClipPlane + 1f));
}
else if (Input.GetMouseButtonUp(1)) {
isMousePressed = false;
}
//if (Input.GetMouseButton(0) || Input.GetMouseButton(1) || Input.GetMouseButton(2)) {
// Vector3 crelpos = Camera.main.transform.position;
// for (int i = 0; i < pointsList.Count; i++) {
// line.SetPosition(i, crelpos + pointsList[i]);
// //line.SetPosition(pointsList.Count - 1, (Vector3)pointsList[pointsList.Count - 1]);
// }
//}
// Drawing line when mouse is moving(presses)
if (isMousePressed) {
Vector3 crelpos = Camera.main.transform.position;
//将鼠标点击的屏幕坐标转换为世界坐标，然后存储到position中
mousePos = Camera.main.ScreenToWorldPoint(new Vector3(Input.mousePosition.x, Input.mousePosition.y, Camera.main.nearClipPlane + 1f));
Vector3 offsetpos = mousePos - crelpos;
//Vector3 hitp = Vector3.zero;
//bool ok = GetRayCastZero2DPlanePoint(Camera.main, Camera.main.transform.TransformPoint(0f, 0f, Camera.main.nearClipPlane + 1f).z, out hitp);
//mousePos = hitp;
if (!pointsList.Contains(offsetpos)) {
pointsList.Add(offsetpos);
line.SetVertexCount(pointsList.Count);
for (int i = 0; i < pointsList.Count; i++) {
line.SetPosition(i, crelpos + pointsList[i]);
//line.SetPosition(pointsList.Count - 1, (Vector3)pointsList[pointsList.Count - 1]);
}
if (isLineCollide()) {
isMousePressed = false;
line.SetColors(Color.red, Color.red);
}
}
}
}
// -----------------------------------
// Following method checks is currentLine(line drawn by last two points) collided with line
// -----------------------------------
private bool isLineCollide() {
if (pointsList.Count < 2)
return false;
int TotalLines = pointsList.Count - 1;
myLine[] lines = new myLine[TotalLines];
if (TotalLines > 1) {
for (int i = 0; i < TotalLines; i++) {
lines[i].StartPoint = (Vector3)pointsList[i];
lines[i].EndPoint = (Vector3)pointsList[i + 1];
}
}
for (int i = 0; i < TotalLines - 1; i++) {
myLine currentLine;
currentLine.StartPoint = (Vector3)pointsList[pointsList.Count - 2];
currentLine.EndPoint = (Vector3)pointsList[pointsList.Count - 1];
if (isLinesIntersect(lines[i], currentLine))
return true;
}
return false;
}
// -----------------------------------
// Following method checks whether given two points are same or not
// -----------------------------------
private bool checkPoints(Vector3 pointA, Vector3 pointB) {
return (pointA.x == pointB.x && pointA.y == pointB.y);
}
// -----------------------------------
// Following method checks whether given two line intersect or not
// -----------------------------------
private bool isLinesIntersect(myLine L1, myLine L2) {
if (checkPoints(L1.StartPoint, L2.StartPoint) ||
checkPoints(L1.StartPoint, L2.EndPoint) ||
checkPoints(L1.EndPoint, L2.StartPoint) ||
checkPoints(L1.EndPoint, L2.EndPoint))
return false;
return ((Mathf.Max(L1.StartPoint.x, L1.EndPoint.x) >= Mathf.Min(L2.StartPoint.x, L2.EndPoint.x)) &&
(Mathf.Max(L2.StartPoint.x, L2.EndPoint.x) >= Mathf.Min(L1.StartPoint.x, L1.EndPoint.x)) &&
(Mathf.Max(L1.StartPoint.y, L1.EndPoint.y) >= Mathf.Min(L2.StartPoint.y, L2.EndPoint.y)) &&
(Mathf.Max(L2.StartPoint.y, L2.EndPoint.y) >= Mathf.Min(L1.StartPoint.y, L1.EndPoint.y))
);
}
}