[unity3d] emission (raycast) physical ray (Ray)

1 Preface

        Impactor assembly Collider  This paper introduces the in 2 Collision detection between collision bodies , This paper will introduce the collision detection between physical ray and collision body . Physical rays are composed of Ray Definition , adopt Physics.RayCast / Physics.RayCastAll Emit radiation , return RayCastHit Collision detection information .

         Rays are only used to detect collisions , The game interface cannot be seen , But users can use Debug.DrawRay Draw rays , adopt   Debug.DrawLine Draw line segments , The rays and line segments they draw can only be in Scene Window view , stay Game The window is invisible .

        1） Defining rays

// origin:  The starting point , direction:  Direction 
public Ray(Vector3 origin, Vector3 direction)
//  Screen ray :  Start with the camera position ,  Rays projected to the direction of the mouse position on the near plane 
Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);

        2） Emit radiation

// ray:  Rays to be emitted , hitInfo:  Collision detection information , maxDistance:  The farthest distance from which a ray is emitted ,  Returns whether a collision occurred ,  Only the first collision object is detected 
public static bool Raycast(Ray ray)
public static bool Raycast(Ray ray, out RaycastHit hitInfo)
public static bool Raycast(Ray ray, float maxDistance)
public static bool Raycast(Ray ray, out RaycastHit hitInfo, float maxDistance)
//  Check all collisions within the range of the ray 
public static RaycastHit[] RaycastAll(Ray ray)
public static RaycastHit[] RaycastAll(Ray ray, float maxDistance)

         explain ： The above method is Physics Class static methods ,hitInfo Encapsulates collision information , Contains the collision location point、 Colliding body collider etc. .

        3） Commissioning ray

// start:  Ray starting point , dir:  The direction of the ray , color:  Ray color 
public static void DrawRay(Vector3 start, Vector3 dir)
public static void DrawRay(Vector3 start, Vector3 dir, Color color)
// start:  The starting point of the line segment , end:  End of line segment , color:  Line color 
public static void DrawLine(Vector3 start, Vector3 end)
public static void DrawLine(Vector3 start, Vector3 end, Color color)

        4） Area collision detection

//  Check whether there is a collision body within the scope of the cube 
public static bool CheckBox(Vector3 center, Vector3 halfExtents)
public static bool CheckBox(Vector3 center, Vector3 halfExtents, Quaternion orientation, int layermask)
//  Check whether there is a collision body within the sphere 
public static bool CheckSphere(Vector3 position, float radius)
public static bool CheckSphere(Vector3 position, float radius, int layerMask)
//  Inspect whether there is collision body within the scope of capsule 
public static bool CheckCapsule(Vector3 start, Vector3 end, float radius)
public static bool CheckCapsule(Vector3 start, Vector3 end, float radius, int layermask)

         explain ： The above method is Physics Class static methods .

        5） Project objects

//  Project Cube 
public static bool BoxCast(Vector3 center, Vector3 halfExtents, Vector3 direction)
public static bool BoxCast(Vector3 center, Vector3 halfExtents, Vector3 direction, out RaycastHit hitInfo, Quaternion orientation, float maxDistance, int layerMask)
public static RaycastHit[] BoxCastAll(Vector3 center, Vector3 halfExtents, Vector3 direction)
public static RaycastHit[] BoxCastAll(Vector3 center, Vector3 halfExtents, Vector3 direction, Quaternion orientation, float maxDistance, int layermask)
//  Project a sphere 
public static bool SphereCast(Ray ray, float radius)
public static bool SphereCast(Ray ray, float radius, out RaycastHit hitInfo, float maxDistance, int layerMask)
public static bool SphereCast(Vector3 origin, float radius, Vector3 direction, out RaycastHit hitInfo)
public static bool SphereCast(Vector3 origin, float radius, Vector3 direction, out RaycastHit hitInfo, float maxDistance, int layerMask)
public static RaycastHit[] SphereCastAll(Ray ray, float radius)
public static RaycastHit[] SphereCastAll(Ray ray, float radius, float maxDistance, int layerMask)
public static RaycastHit[] SphereCastAll(Vector3 origin, float radius, Vector3 direction)
public static RaycastHit[] SphereCastAll(Vector3 origin, float radius, Vector3 direction, float maxDistance, int layerMask)
//  Project capsule 
public static bool CapsuleCast(Vector3 point1, Vector3 point2, float radius, Vector3 direction)
public static bool CapsuleCast(Vector3 point1, Vector3 point2, float radius, Vector3 direction, out RaycastHit hitInfo, float maxDistance, int layerMask)
public static RaycastHit[] CapsuleCastAll(Vector3 point1, Vector3 point2, float radius, Vector3 direction)
public static RaycastHit[] CapsuleCastAll(Vector3 point1, Vector3 point2, float radius, Vector3 direction, float maxDistance, int layermask)

         explain ： The above method is Physics Class static methods . 

2 application

        1） The game object

         The object of the game Transform The component parameters are as follows ：

Name	Type	Position	Rotation	Scale	Color
Plane	Plane	(0, 0, 0)	(0, 0, 0)	(2, 2, 2)	#B8B2B2FF
Cube1	Cube	(-3, 0.5, 3)	(0, 0, 0)	(1, 1, 1)	#F91D1DFF
Cube2	Cube	(0, 0.5, 3)	(0, 0, 0)	(1, 1, 1)	#F91D1DFF
Cube3	Cube	(3, 0.5, 3)	(0, 0, 0)	(1, 1, 1)	#F91D1DFF
Cube4	Cube	(-3, 0.5, 0)	(0, 0, 0)	(1, 1, 1)	#F91D1DFF
Cube5	Cube	(0, 0.5, 0)	(0, 0, 0)	(1, 1, 1)	#F91D1DFF
Cube6	Cube	(3, 0.5, 0)	(0, 0, 0)	(1, 1, 1)	#F91D1DFF
Cube7	Cube	(-3, 0.5, -3)	(0, 0, 0)	(1, 1, 1)	#F91D1DFF
Cube8	Cube	(0, 0.5, -3)	(0, 0, 0)	(1, 1, 1)	#F91D1DFF
Cube9	Cube	(3, 0.5, -3)	(0, 0, 0)	(1, 1, 1)	#F91D1DFF
Bullet	Sphere	(0, 0.5, -5)	(0, 0, 0)	(0.3, 0.3, 0.3)	#FDF723FF
BulletCreater	Empty	(0, 0, 0)	(0, 0, 0)	(1, 1, 1)	——

        Add ：Cube1~Cube9 and Bullet Add the Rigidbody Rigid body components , take Bullet Drag to Assets Window Resources/Prefabs Under the table of contents , Generate preset （prefab）, And then delete Hierarchy Under the window  Bullet object .

        2） Script components

        to  BulletCreater Add game objects RayController Script components .

        RayController.cs

using UnityEngine;

public class RayController : MonoBehaviour {
	private GameObject bulletPrefab; //  Shell preset 
	private RaycastHit hit; //  Collision information 

	void Start () {
		bulletPrefab = (GameObject) Resources.Load("Prefabs/Bullet");
		hit = new RaycastHit();
	}

	void Update () {
		if (Input.GetMouseButtonDown(0)) {
			Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
			if (Physics.Raycast(ray, out hit, 100)) {
				// ray.origin = Camera.main.transform.position
				GameObject bullet = Instantiate(bulletPrefab, ray.origin, Quaternion.identity); //  Create shells from presets 
				bullet.GetComponent<Rigidbody>().velocity = ray.direction * 100;
				Destroy(bullet, 3);
			}
		}
	}
}

        3） Running effect