LIBGDX RayCast：如何停止射线？（如何return只是世界上想要的夹具）

Question

你能帮我理解一下吗，

光线投射撞墙时如何停止？

假设:

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

我有这个水平：

___________________________


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

在这种情况下，如何才能阻止敌人向我射击？

我怎样才能停止 "to see what there is after the wall fixture" 的光线投射？

现在我只得到它们：

     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);

所以是分数可以达到这个目的？如果可以，怎么做？

非常感谢！

Answer 1

通过这种方法，它可以满足我的需要：

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;
}

所以当我打印类型时：

System.out.println(this.rayCastStatus);

结果将是停止光线投射，当它撞到墙上时。

好吧，不是真的要停下来，换句话说，只是为了得到我需要的结果，在这种情况下，当墙先出现时，不是打印播放器。

来自文档，关于 return:

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);
}

LIBGDX RayCast：如何停止射线？（如何return只是世界上想要的夹具）

LIBGDX RayCast: how do i stop the ray? (How to return just the wanted fixture in the world)

java

libgdx

raycasting

LIBGDX RayCast：如何停止射线？ （如何return只是世界上想要的夹具）

LIBGDX RayCast: how do i stop the ray? (How to return just the wanted fixture in the world)

java

libgdx

raycasting

LIBGDX RayCast：如何停止射线？（如何return只是世界上想要的夹具）