Version: 2021.3

Vector3.ProjectOnPlane

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public static Vector3 ProjectOnPlane (Vector3 vector, Vector3 planeNormal);

参数

planeNormal 从矢量到平面的方向。
vector 平面上方的矢量的位置。

返回

Vector3 平面中的矢量的位置。

描述

将向量投影到由法线定义的平面上(法线与该平面正交)。

Vector3 将给定 vector 的位置存储在 3D 空间中。另一个 Vector3planeNormal 提供,用于定义通过原点从平面到 vector 的方向。Vector3.ProjectOnPlane 使用两个 Vector3 值在 planeNormal 方向生成 vector 的位置,并返回 Vector3 在平面上的位置。


矢量从红色圆圈处开始,在黑色圆圈(代表平面法线)处结束。

以下脚本示例使 Update 生成一个 vector 位置和一个 planeNormal 法线。Vector3.ProjectOnPlane 静态方法可接收参数并返回 Vector3 位置。

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

// Vector3.ProjectOnPlane - example

// Generate a random plane in xy. Show the position of a random // vector and a connection to the plane. The example shows nothing // in the Game view but uses Update(). The script reference example // uses Gizmos to show the positions and axes in the Scene.

public class Example : MonoBehaviour { private Vector3 vector, planeNormal; private Vector3 response; private float radians; private float degrees; private float timer = 12345.0f;

// Generate the values for all the examples. // Change the example every two seconds. void Update() { if (timer > 2.0f) { // Generate a position inside xy space. vector = new Vector3(Random.Range(-1.0f, 1.0f), Random.Range(-1.0f, 1.0f), 0.0f);

// Compute a normal from the plane through the origin. degrees = Random.Range(-45.0f, 45.0f); radians = degrees * Mathf.Deg2Rad; planeNormal = new Vector3(Mathf.Cos(radians), Mathf.Sin(radians), 0.0f);

// Obtain the ProjectOnPlane result. response = Vector3.ProjectOnPlane(vector, planeNormal);

// Reset the timer. timer = 0.0f; } timer += Time.deltaTime; }

// Show a Scene view example. void OnDrawGizmosSelected() { // Left/right and up/down axes. Gizmos.color = Color.white; Gizmos.DrawLine(transform.position - new Vector3(2.25f, 0, 0), transform.position + new Vector3(2.25f, 0, 0)); Gizmos.DrawLine(transform.position - new Vector3(0, 1.75f, 0), transform.position + new Vector3(0, 1.75f, 0));

// Display the plane. Gizmos.color = Color.green; Vector3 angle = new Vector3(-1.75f * Mathf.Sin(radians), 1.75f * Mathf.Cos(radians), 0.0f); Gizmos.DrawLine(transform.position - angle, transform.position + angle);

// Show a connection between vector and response. Gizmos.color = Color.yellow; Gizmos.DrawLine(vector, response);

// Now show the input position. Gizmos.color = Color.red; Gizmos.DrawSphere(vector, 0.05f);

// And finally the resulting position. Gizmos.color = Color.black; Gizmos.DrawSphere(response, 0.05f); } }