动态场景中的力反馈教程

因为触觉线程的速度比物理线程快一个数量级。 线程的速度快一个数量级，因此在每个 FixedUpdate() 调用。这导致用于计算物理变化的场景数据与用于计算触觉反馈的 触觉线程中用于计算触觉反馈的数据不一致。

在此示例中，我们展示了一种线程安全方法，用于同步场景数据和触觉循环。 与触觉循环同步的线程安全方法。

场景设置

• 如力度和光标位置所示，添加触觉线程和光标
• 创建一个 球体 人称 移动球 并将其位置设置为 (0, 0.15, -0.15) 及其规模 (0.1, 0.1, 0.1)

触觉环路

添加新的 C# 脚本 人称 MovingBallForce.cs 到 移动球 游戏对象。该脚本的源代码如下。

using Haply.HardwareAPI.Unity;
using UnityEngine;

public class MovingBallForce : MonoBehaviour
{
    // Thread-safe scene data struct
    private struct AdditionalData
    {
        public Vector3 ballPosition;
        
        // cursor radius + ball radius
        public float radiuses;
    }
    
    [Range(0, 800)]
    public float stiffness = 600f;
    
    // Moving/scaling speed (by pressing arrow keys)
    public float speed = 0.2f;
    
    private HapticThread m_hapticThread;

    private void Awake ()
    {
        // Find the HapticThread object before the our first FixedUpdate() call
        m_hapticThread = FindObjectOfType<HapticThread>();
        
        // Run the haptic loop with an initial state returned by AdditionalData.
        var initialState = GetAdditionalData();
        m_hapticThread.onInitialized.AddListener(() => m_hapticThread.Run(ForceCalculation, initialState));
    }

    private void FixedUpdate ()
    {
        // Change the scale of the ball
        if ( Input.GetKey( KeyCode.UpArrow ) )
            transform.localScale += Vector3.one * (Time.fixedDeltaTime * speed);
        else if ( Input.GetKey( KeyCode.DownArrow ) )
            transform.localScale -= Vector3.one * (Time.fixedDeltaTime * speed);

        // Move the ball
        if ( Input.GetKey( KeyCode.LeftArrow ) )
            transform.transform.position += Vector3.left * (Time.fixedDeltaTime * speed);
        else if (Input.GetKey(KeyCode.RightArrow))
            transform.transform.position += Vector3.right * (Time.fixedDeltaTime * speed);

        // Update AdditionalData with the latest physics data
        m_hapticThread.SetAdditionalData(GetAdditionalData());
    }

    // Method used by HapticThread.Run(ForceCalculation) and HapticThread.GetAdditionalData()
    // to synchronize dynamic data between the unity scene and the haptic thread 
    private AdditionalData GetAdditionalData ()
    {
        AdditionalData additionalData;

        additionalData.ballPosition = transform.localPosition;
        additionalData.radiuses = (transform.localScale.x + m_hapticThread.avatar.localScale.x) / 2f;

        return additionalData;
    }

    // Calculate the force to apply when the cursor touches the ball.
    // This is done through additionalData to keep things thread-safe.
    private Vector3 ComputeForce ( in Vector3 position, in Vector3 velocity, in AdditionalData additionalData )
    {
        var force = Vector3.zero;

        var distance = Vector3.Distance( position, additionalData.ballPosition );

        if ( distance < additionalData.radiuses )
        {
            var penetration = additionalData.radiuses - distance;
            force = (position - additionalData.ballPosition) / distance * penetration * stiffness;
        }

        return force;
    }
}

进入游戏模式，使用箭头键移动球体并调整其大小。你应该能看到并感觉到球体大小和位置的变化。

源文件

本示例使用的最终场景和所有相关文件都可以从 Unity 的软件包管理器中导入。