Vector3.ProjectOnPlane

参数

返回值

Vector3 vector 在平面上的正交投影。

描述

将向量投影到平面。

对于由 planeNormal 描述的给定平面和给定向量 vector，Vector3.ProjectOnPlane 生成一个新的向量，该向量正交于 planeNormal 且平行于平面。注意：planeNormal 不需要被标准化。


''红线代表 vector，黄线代表 planeNormal，蓝线代表 vector 在平面上的投影。''

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 the projection on the plane as a blue line.
        Gizmos.color = Color.blue;
        Gizmos.DrawLine(Vector3.zero, response);
        Gizmos.DrawSphere(response, 0.05f);

        // Show the vector perpendicular to the plane in yellow
        Gizmos.color = Color.yellow;
        Gizmos.DrawLine(vector, response);

        // Now show the input position.
        Gizmos.color = Color.red;
        Gizmos.DrawSphere(vector, 0.05f);
        Gizmos.DrawLine(Vector3.zero, vector);
    }
}