"Unity 3D" Learning note 40: Ray

Ray

Ray, the analogy of understanding is the bullets in the game. is a line in the 3D world in which a point is fired in one direction without an end. In the course of the launch, once it collides with other objects, it stops firing.

The principle of Ray

When creating a ray, you first need to know the coordinates of the beginning and end of the ray in the 3D world.

Using unityengine;using System.collections;public class Script_06_08:monobehaviour {void Update () {//create ray, emitted from 0 to object Ray Ray = new Ray (Vector3.zero, transform.position);//Calculate the start and end point of the Ray Raycasthit hit; Physics.raycast (Ray, out hit, 100);//Use the Debug method to draw this line (the debug method records the presence in the scene view) Debug.drawline (Ray.origin, Hit.point);}}

After execution:

In the above code, the Debug.drawline () method is only visible in the scene view. It is a false idea to draw the Rays in the game, using the GL graphics library or the Linerenderer method.

Collision Monitoring

A ray can be used to infer collisions with other objects in the game, such as the camera's position as the origin, and a ray emitted to the mouse moving point. It's like hitting a bull's-eye and inferring if it's hit.

Using unityengine;using System.collections;public class Script_06_09:monobehaviour {//Bullseye map Public Texture texture;// Hint Information private string info;void Update () {//create Ray Ray Ray = Camera.main.ScreenPointToRay from camera position to mouse position  ( Input.mouseposition); Raycasthit hit;//Infers if the ray is hitting the game object if (Physics.raycast (Ray, out)) {info = "Hitting the bull's Eye";} Else{info = "Missed Bull's Eye";}} void Ongui () {//calculate the coordinates of a quasi-heart map rect rect = new Rect (input.mouseposition.x-(Texture.width >>1), Screen.height-input.mou SEPOSITION.Y-(texture.height >> 1), texture.width,texture.height);//Draw quasi-heart map gui.drawtexture (rect,texture);// Enter the target information Guilayout.label (info + ", hit the coordinates:" +input.mouseposition);}}

After execution:

The code above uses the Camera.main.ScreenPointToRay method to wear a ray emitted by the camera to the current position of the mouse, and then uses Physics.raycast to infer whether the ray intersects a game, the intersection returns TRUE, and No returns FALSE.

"Unity 3D" Learning note 40: Ray