Unity Manual之Physics.Raycast射线投射

1、C# ⇒ public static bool Raycast(Vector3 origin, Vector3 direction, float maxDistance = Mathf.Infinity, int layerMask = DefaultRaycastLayers);

当光线投射与任何碰撞器交叉时为真，否则为假。

在场景中投下可与所有碰撞器碰撞的一条光线。

using UnityEngine;using System.Collections; public class ExampleClass : MonoBehaviour {    void Update() {        Vector3 fwd = transform.TransformDirection(Vector3.forward);        if (Physics.Raycast(transform.position, fwd, 10))            print("There is something in front of the object!");     }}

注意：如果射线从碰撞体的内部或者背面打，Raycast不检测碰撞。如果你用脚本或动画移动碰撞器，需要至少一个在FixedUpdate执行，因为物理库能更新它的数据结构，因此一条射线在它的新位置之前打到碰撞器。

2、C# ⇒ public static bool Raycast(Vector3 origin, Vector3 direction, out RaycastHit hitInfo, float maxDistance = Mathf.Infinity, int layerMask = DefaultRaycastLayers);

using UnityEngine;using System.Collections; public class ExampleClass : MonoBehaviour {    void Update() {        RaycastHit hit;        if (Physics.Raycast(transform.position, -Vector3.up, out hit))            float distanceToGround = hit.distance;     }}

using UnityEngine;using System.Collections; public class ExampleClass : MonoBehaviour {    void Update() {        RaycastHit hit;        if (Physics.Raycast(transform.position, -Vector3.up, out hit, 100.0F))            float distanceToGround = hit.distance;     }}

3、C# ⇒ public static bool Raycast(Ray ray, float maxDistance = Mathf.Infinity, int layerMask = DefaultRaycastLayers);

using UnityEngine;using System.Collections; public class ExampleClass : MonoBehaviour {    void Update() {        Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);        if (Physics.Raycast(ray, 100))            print("Hit something");     }}

4、C# ⇒ public static bool Raycast(Ray ray, out RaycastHit hitInfo, float maxDistance = Mathf.Infinity, int layerMask = DefaultRaycastLayers);

using UnityEngine;using System.Collections; public class ExampleClass : MonoBehaviour {    void Update() {        Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);        RaycastHit hit;        if (Physics.Raycast(ray, out hit, 100))            Debug.DrawLine(ray.origin, hit.point);     }}

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结束。