ARKit - 在用户的电话方向上施加力量 [英] ARKit - Applying Force in User's Phone Direction

问题描述

我有以下代码创建一个SCNBox并在屏幕上拍摄它。这可以工作，但只要我在任何其他方向转动手机，那么力量冲动就不会更新，并且它总是在相同的旧位置拍摄盒子。

I have the following code that creates a SCNBox and shoots it on the screen. This works but as soon as I turn the phone in any other direction then the force impulse does not get updated and it always shoots the box in the same old position.

这里是代码：

@objc func tapped(recognizer :UIGestureRecognizer) {

        guard let currentFrame = self.sceneView.session.currentFrame else {
            return
        }

        /
        let box = SCNBox(width: 0.2, height: 0.2, length: 0.2, chamferRadius: 0)

        let material = SCNMaterial()
        material.diffuse.contents = UIColor.red
        material.lightingModel = .constant

        var translation = matrix_identity_float4x4
        translation.columns.3.z = -0.01

        let node = SCNNode()
        node.geometry = box
        node.geometry?.materials = [material]

        print(currentFrame.camera.transform)

        node.physicsBody = SCNPhysicsBody(type: .dynamic, shape: nil)

        node.simdTransform = matrix_multiply(currentFrame.camera.transform, translation)
        node.physicsBody?.applyForce(SCNVector3(0,2,-10), asImpulse: true)

        self.sceneView.scene.rootNode.addChildNode(node)


    }

第26行是我施加部队的地方，但没有考虑用户当前的电话方向。我该如何解决这个问题？

Line 26 is where I apply the force but it does not take into account the user's current phone orientation. How can I fix that?

推荐答案

在第26行，你将一个常量向量传递给 applyForce 。该方法在世界空间中采用向量，因此传递常量向量意味着您始终在相同方向上施加力 - 如果您想要基于相机或其他指向的方向的方向，则需要根据该方向计算向量。

On line 26 you're passing a constant vector to applyForce. That method takes a vector in world space, so passing a constant vector means you're always applying a force in the same direction — if you want a direction that's based on the direction the camera or something else is pointing, you'll need to calculate a vector based on that direction.

（新）SCNNode属性 worldFront 可能在这里有用 - 它为您提供节点指向的方向，自动转换为世界空间，因此它对物理方法很有用。 （虽然你可能想要缩放它。）

The (new) SCNNode property worldFront might prove helpful here — it gives you the direction a node is pointing, automatically converted to world space, so it's useful with physics methods. (Though you might want to scale it.)

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