设备工作区转换教程

本教程扩展了 基本力反馈 教程，演示如何调整"...... "的位置、旋转和缩放。 Inverse3 设备的空间转换特性和方法。

导言

为基本力反馈设置场景后，您可能会注意到，对触觉原点或触觉控制器的调整（如移动、缩放或旋转）并不会如预期那样影响触觉反馈。 反馈仍对应于设备前方的一个不可见球体，不受这些变换的影响。

之所以会出现这种差异，是因为力计算使用的是设备光标的真实、未转换的坐标。 为了解决这个问题，我们将利用Inverse3 Controller组件提供的线程安全缓存变换矩阵，从而将世界空间变换应用于触觉反馈计算。

场景设置

从 "基本力反馈 "教程中的场景开始，确保Inverse3 控制器的手柄与您的设备相匹配。 旋转触觉控制器，使 Haply 徽标面向摄像头，并根据需要调整触觉原点刻度，以增强光标范围或调整其位置。

力反馈脚本更改

复制 SphereForceFeedback.cs 基本强制反馈教程中的脚本，并在 OnDeviceStateChanged 回调：

• 更换 device.CursorLocalPosition 与 device.CursorPosition.
• 更换 device.CursorLocalVelocity 与 device.CursorVelocity.
• 更换 device.CursorSetLocalForce(force) 与 device.CursorSetForce(force).

private void OnDeviceStateChanged(Inverse3 device) {
    var force = ForceCalculation(device.CursorPosition, device.CursorVelocity,
        _cursorRadius, _ballPosition, _ballRadius);

    device.CursorSetForce(force);
}

游戏体验

按住 Inverse3 光标并进入播放模式。尝试像上一个示例那样触摸球体。 现在你应该体验到精确的触觉反馈，它反映了应用于触觉原点和触觉控制器的变换。

源文件

本示例的完整场景和相关文件可从 Unity 包管理器中的教程示例导入。

示例场景包括用于运行时调整触觉控制器和触觉原点的附加脚本。

SphereForceFeedback.cs

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

using Haply.Inverse.Unity;
using UnityEngine;
using UnityEngine.Serialization;

namespace Haply.Samples.Tutorials._3_DeviceSpaceTransform
{
    public class SphereForceFeedback : MonoBehaviour
    {
        // must assign in inspector
        public Inverse3 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.Model.transform.lossyScale.x / 2f;
        }

        /// <summary>
        /// Saves the initial scene data cache.
        /// </summary>
        private void Awake()
        {
            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;
        }

        /// <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="device">The Inverse3 device instance.</param>
        private void OnDeviceStateChanged(Inverse3 device)
        {
            // Calculate the ball force. Using 'device.CursorPosition' instead of 'device.CursorLocalPosition'
            // ensures the force calculation considers the device's offset and rotation in world space.
            var force = ForceCalculation(device.CursorPosition, device.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.
            device.CursorSetForce(force);
        }
    }
}