Common technologies of unity

1.3D Pickup Technology
The ray is 3D A point in the world emits in one direction without end . stay unity3d Once our rays collide with other colliders , The rays stop emitting .
In the process of game making, we can judge whether the rays collide , And we can judge who the ray collided with . It has a wide range of applications , For example, it is used to judge whether the target is hit in the shooting game
ray(origin:vector,direction:vector3)
ray.origin Indicates the starting point of the ray
Ray.direction: Indicates the direction of the ray
Case a ： Emit a ray from the origin

void Update(){
Ray ray=new Ray(Vector3.zero,transform.position);
RaycastHit hit;
Physics.Raycast(ray,out hit,100);
debug.DrawLine(ray.origin,hit.point);
}

 Case 2: click the left mouse button to clone the game object 
if(Input.GetMouseButtonDown(0)){
    
  Ray ray=Camera.main.ScreenPointToRay(Input.mousePosition);
  RaycastHit hit;
  if(Physics.Raycast(ray,out hit)){
    
  Instantiate(cube,hit.point,Quaternion.identity);
  }

}
 Wireless length ：Mathf.Infinity
 Find the layer with the specified name 
1<<LayerMask.NameToLayer("cube");
( among << Sinister 1 Open for indication , Not binary, move one bit to the left ;0 Indicates that there is no such layer)`
 Two , Character controller 
Unity3D It encapsulates a very useful component to realize the development of first person perspective and third person perspective Games , We call it the character controller component , Almost no need to write a line of code to complete all operations -CharacterController( Character controller ). So it's also U3D A class in , It can control the movement of objects .
CharacterController Components ：
   Property panel ：Slope Limit  The maximum angle that the character can climb , If you want to climb higher than the angle set by the current box , Can't climb up , You must set a larger value in this box to 
  step offset; The height of the highest step , If the step height in the game is less than the value in this box , Characters can go up the steps in the game 
  Skin Width: The width of the skin that the two colliders can penetrate each other 
  min move distance: Move the minimum step distance 
  center The size relative to the center point of the object 
  height: Height of capsule 
  Radius: Radius of capsule 
   The character components of the game object .SimpleMve(new Vector(0,0,0)) Plane movement , With its own Collider and gravity 
   The character components of the game object .Move() No gravity , With impactor 
   Collision monitoring 
    void  OnControllerColliderHit(ControllerColliderHit hit){
    }