Libgdx 3d 中的光线投射 [英] RayCasting in Libgdx 3d

问题描述

好吧，所以我也已经尝试了很长一段时间了，因为我在 libgdx 中使用 Raycast 根据我正在寻找的位置进行 3D 碰撞检测.但是我画了一个空白，似乎在任何地方都没有任何文档.有人会好心把我送到正确的方向吗?

Alright so I've been trying for quite some time too Raycast in libgdx for 3d collision detection based on where im looking.. But I've drawn a blank and doesn't seem to be any documentation anywhere. Would someone be kind enough to send me in the right direction?

推荐答案

使用 libgdx 实际上很容易实现您想要做的事情.以下是我用来进行射线测试并找到我的射线会击中的最近碰撞对象的内容.假设它位于一个名为 BulletUtil 的类中.

It is actually really easy with libgdx to achieve what you are trying to do. The following is what I'm using to do a ray test and find the closest collision object that my ray would hit. Let's assume it is located in a class called BulletUtil.

private static final Vector3 rayFrom = new Vector3();
private static final Vector3 rayTo = new Vector3();
private static final ClosestRayResultCallback callback = new ClosestRayResultCallback(rayFrom, rayTo);

public static btCollisionObject rayTest(btCollisionWorld collisionWorld, Ray ray) {
    rayFrom.set(ray.origin);
    // 50 meters max from the origin
    rayTo.set(ray.direction).scl(50f).add(rayFrom);

    // we reuse the ClosestRayResultCallback, thus we need to reset its
    // values
    callback.setCollisionObject(null);
    callback.setClosestHitFraction(1f);
    callback.getRayFromWorld().setValue(rayFrom.x, rayFrom.y, rayFrom.z);
    callback.getRayToWorld().setValue(rayTo.x, rayTo.y, rayTo.z);

    collisionWorld.rayTest(rayFrom, rayTo, callback);

    if (callback.hasHit()) {
        return callback.getCollisionObject();
    }

    return null;
}

现在您还需要一个对点击事件作出反应的 InputProcessor.

Now what else you need is an InputProcessor that reacts on the click events.

public class BulletInputProcessor extends InputAdapter {

    private Viewport pickingViewport;
    private btCollisionWorld collisionWorld;

    // a constructor which takes a Viewport and the collision world and stores them
    public BulletInputProcessor(...) { ... }

    @Override
    public boolean touchUp(int screenX, int screenY, int pointer, int button) {
        if (button == Input.Buttons.LEFT) {
            Ray pickRay = pickingViewport.getPickRay(screenX, screenY);

            btCollisionObject body = BulletUtil.rayTest(collisionWorld, pickRay);
            if (body != null) {
                // do whatever you want with this body now
                return true;
            }
        }

        return false;
    }
}

Viewport 负责创建拾取Ray.您应该在此处使用管理用于渲染世界的 PerspectiveCamera 的视口.不要忘记通过 Gdx.input.setInputProcessor(new BulletInputProcessor(collisionWorld, viewport)) 注册输入处理器.

The Viewport is responsible to create the picking Ray. You should use the viewport here which manages the PerspectiveCamera that you use to render the world. Don't forget to register the input processor via Gdx.input.setInputProcessor(new BulletInputProcessor(collisionWorld, viewport)).

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