设备工作空间变换教程

本教程在 基础力反馈 教程的基础上进行扩展，演示如何使用空间变换属性和方法来调整 Inverse3 设备的位置、旋转和缩放。

简介

在为基础力反馈搭建场景之后，您可能会注意到，对 Haptic Origin 或 Haptic Controller 进行移动、缩放或旋转等调整时，触觉反馈并不会如预期般变化。 反馈仍然对应于位于设备前方的一个不可见球体，不受这些变换的影响。

出现这种偏差的原因在于，力计算使用的是设备光标真实的、未经变换的坐标。 为解决此问题，我们将利用 Inverse3 Controller 组件提供的 线程安全的缓存变换矩阵，从而将世界空间变换应用于触觉反馈计算中。

场景设置

从 基础力反馈教程 中的场景开始，并确保 Inverse3 Controller 的左右手设置与您的设备相匹配。 旋转 Haptic Controller，使 Haply 徽标朝向摄像机，并根据需要调整 Haptic Origin 的缩放，以扩大光标范围或调整其位置。

力反馈脚本修改

从基础力反馈教程中复制 SphereForceFeedback.cs 脚本，并在 OnDeviceStateChanged 回调中进行以下调整：

• 将 device.CursorLocalPosition 替换为 device.CursorPosition。
• 将 device.CursorLocalVelocity 替换为 device.CursorVelocity。
• 将 device.CursorSetLocalForce(force) 替换为 device.CursorSetForce(force)。

private void OnDeviceStateChanged(object sender, Inverse3EventArgs args)
{
    var inverse3 = args.DeviceController;
    var force = ForceCalculation(inverse3.CursorPosition, inverse3.CursorVelocity,
        _cursorRadius, _ballPosition, _ballRadius);

    inverse3.SetCursorForce(force);
}

游戏体验

握住 Inverse3 光标并进入播放模式。与前一个示例相同，尝试触碰球体。 现在您应该能够体验到准确的触觉反馈，它反映了对 Haptic Origin 和 Haptic Controller 所施加的变换。

源文件

本示例的完整场景及相关文件，可以从 Unity 包管理器中的 Tutorials 示例导入。

示例场景包含用于在运行时调整 Haptic Controller 和 Haptic Origin 的额外脚本。

SphereForceFeedback.cs

/*
 * Copyright 2024 Haply Robotics Inc. All rights reserved.
 */

using Haply.Inverse.DeviceControllers;
using Haply.Inverse.DeviceData;
using UnityEngine;

namespace Haply.Samples.Tutorials._3_DeviceSpaceTransform
{
    public class SphereForceFeedback : MonoBehaviour
    {
        // must assign in inspector
        public Inverse3Controller inverse3;

        [Range(0, 800)]
        // Stiffness of the force feedback.
        public float stiffness = 300f;

        [Range(0, 3)]
        public float damping = 1f;

        private Vector3 _ballPosition;
        private float _ballRadius;
        private float _cursorRadius;

        /// <summary>
        /// Stores the cursor and sphere transform data for access by the haptic thread.
        /// </summary>
        private void SaveSceneData()
        {
            var t = transform;
            _ballPosition = t.position;
            _ballRadius = t.lossyScale.x / 2f;

            _cursorRadius = inverse3.Cursor.Radius;
        }

        /// <summary>
        /// Saves the initial scene data cache.
        /// </summary>
        private void Awake()
        {
            inverse3 ??= FindFirstObjectByType<Inverse3Controller>();
            inverse3.Ready.AddListener((device, args) => SaveSceneData());
        }

        /// <summary>
        /// Subscribes to the DeviceStateChanged event.
        /// </summary>
        private void OnEnable()
        {
            inverse3.DeviceStateChanged += OnDeviceStateChanged;
        }

        /// <summary>
        /// Unsubscribes from the DeviceStateChanged event.
        /// </summary>
        private void OnDisable()
        {
            inverse3.DeviceStateChanged -= OnDeviceStateChanged;
            inverse3.Release();
        }

        /// <summary>
        /// Calculates the force based on the cursor's position and another sphere position.
        /// </summary>
        /// <param name="cursorPosition">The position of the cursor.</param>
        /// <param name="cursorVelocity">The velocity of the cursor.</param>
        /// <param name="cursorRadius">The radius of the cursor.</param>
        /// <param name="otherPosition">The position of the other sphere (e.g., ball).</param>
        /// <param name="otherRadius">The radius of the other sphere.</param>
        /// <returns>The calculated force vector.</returns>
        private Vector3 ForceCalculation(Vector3 cursorPosition, Vector3 cursorVelocity, float cursorRadius,
            Vector3 otherPosition, float otherRadius)
        {
            var force = Vector3.zero;

            var distanceVector = cursorPosition - otherPosition;
            var distance = distanceVector.magnitude;
            var penetration = otherRadius + cursorRadius - distance;

            if (penetration > 0)
            {
                // Normalize the distance vector to get the direction of the force
                var normal = distanceVector.normalized;

                // Calculate the force based on penetration
                force = normal * penetration * stiffness;

                // Apply damping based on the cursor velocity
                force -= cursorVelocity * damping;
            }

            return force;
        }

        /// <summary>
        /// Event handler that calculates and send the force to the device when the cursor's position changes.
        /// </summary>
        /// <param name="sender">The Inverse3 data object.</param>
        /// <param name="args">The event arguments containing the device data.</param>
        private void OnDeviceStateChanged(object sender, Inverse3EventArgs args)
        {
            var inverse3 = args.DeviceController;
            // Calculate the ball force. Using 'device.Position' instead of 'device.LocalPosition'
            // ensures the force calculation considers the device's offset and rotation in world space.
            var force = ForceCalculation(inverse3.CursorPosition, inverse3.CursorVelocity,
                _cursorRadius, _ballPosition, _ballRadius);

            // Apply the calculated force to the cursor. Using 'device.CursorSetForce' instead of
            // 'device.CursorSetLocalForce' ensures that the force vector is correctly converted
            // from world space to the device's local space.
            inverse3.SetCursorForce(force);
        }
    }
}