LIBGDX RayCast：我如何阻止射線？ （如何在世界上只返回想要的夾具）

Question

能否請你幫我瞭解，

我如何阻止光線投射，當它撞上了一堵牆？

假設：

$==player, #==wall, %==Enemy, RayCast == ------. 

，我有這個水平：

___________________________ 


     # 
     # 
% -----#---$--- 
___________________________ 

我怎樣才能阻止敵人在這種情況下，在我拍攝？

我該如何停止光線廣播以「看看牆面夾具後有什麼」？

現在我只想找到他們兩個：

 RayCastCallback callback= new RayCastCallback() { 
     @Override 
     public float reportRayFixture(Fixture fixture, Vector2 point, Vector2 normal, float fraction) { 

      if (fixture.getFilterData().categoryBits == Application.PLAYER){ 
       return fraction; 
      } 


      if (fixture.getFilterData().categoryBits == Application.ENEMY){ 
       return fraction; 
      } 

      return 0; 
     } 
    }; 


    world.rayCast(callback, p1, p2); 

所以這是可以實現的幾分之幾？如果是這樣，怎麼樣？

非常感謝！

Answer 1

這種方法，它的作品，我需要：

private static final int NOTHING = 0; 
private static final int WALL = 1; 
private static final int PLAYER = 2; 
private int type = NOTHING; 
private Vector2 position; 

@Override 
public float reportRayFixture(Fixture fixture, Vector2 point, Vector2 normal, float fraction) { 

    if (fixture.getFilterData().categoryBits == Application.WALL){ 
     type = WALL; 
    } 
    if (fixture.getFilterData().categoryBits == Application.PLAYER){ 
     type = PLAYER; 
    } 

    return fraction; 
} 

所以當我打印類型：

System.out.println(this.rayCastStatus); 

結果將是停止光線投射，當它撞上了一堵牆。換句話說，就是爲了得到我需要的結果，在這種情況下，當牆壁到達時，不需要打印播放器。

從文檔，關於退換貨：

public interface RayCastCallback { 
/** Called for each fixture found in the query. You control how  the ray cast proceeds by returning a float: return -1: ignore 
* this fixture and continue return 0: terminate the ray cast return fraction: clip the ray to this point return 1: don't clip 
* the ray and continue. 
* 
* The {@link Vector2} instances passed to the callback will be reused for future calls so make a copy of them! 
* 
* @param fixture the fixture hit by the ray 
* @param point the point of initial intersection 
* @param normal the normal vector at the point of intersection 
* @return -1 to filter, 0 to terminate, fraction to clip the ray for closest hit, 1 to continue **/ 
public float reportRayFixture (Fixture fixture, Vector2 point, Vector2 normal, float fraction); 
}