使用Unity实现VR中在黑板上写字（初级篇）

usingSystem.Linq;
usingUnityEngine;
/// <summary>
///画板
/// </summary>
public classBoard : MonoBehaviour
{
    //当画笔移动速度很快时，为了不出现断断续续的点，所以需要对两个点之间进行插值，lerp就是插值系数
    [Range(0, 1)]
    public float lerp = 0.05f;
    //初始化背景的图片
    publicTexture2D initailizeTexture;
    //当前背景的图片
    privateTexture2D currentTexture;
    //画笔所在位置映射到画板图片的UV坐标
    privateVector2 paintPos;
    private bool isDrawing = false;//当前画笔是不是正在画板上
    //离开时画笔所在的位置 
    private intlastPaintX;
    private intlastPaintY;
    //画笔所代表的色块的大小
    private int painterTipsWidth = 30;
    private int painterTipsHeight = 15;
    //当前画板的背景图片的尺寸
    private inttextureWidth;
    private inttextureHeight;
    //画笔的颜色
    privateColor32[] painterColor;
    privateColor32[] currentColor;
    privateColor32[] originColor;
    private voidStart()
    {
        //获取原始图片的大小 
        Texture2D originTexture = GetComponent<MeshRenderer>().material.mainTexture asTexture2D;
        textureWidth = originTexture.width;//1920   
        textureHeight = originTexture.height;//1080
        //设置当前图片
        currentTexture = new Texture2D(textureWidth, textureHeight, TextureFormat.RGBA32, false, true);
        currentTexture.SetPixels32(originTexture.GetPixels32());
        currentTexture.Apply();
        //赋值给黑板
        GetComponent<MeshRenderer>().material.mainTexture =currentTexture;
        //初始化画笔的颜色
        painterColor = Enumerable.Repeat<Color32>(new Color32(255, 0, 0, 255), painterTipsWidth * painterTipsHeight).ToArray<Color32>();
    }
    private voidLateUpdate()
    {
        //计算当前画笔，所代表的色块的一个起始点
        int texPosX = (int)(paintPos.x * (float)textureWidth - (float)(painterTipsWidth / 2));
        int texPosY = (int)(paintPos.y * (float)textureHeight - (float)(painterTipsHeight / 2));
        if(isDrawing)
        {
            //改变画笔所在的块的像素值
currentTexture.SetPixels32(texPosX, texPosY, painterTipsWidth, painterTipsHeight, painterColor);
            //如果快速移动画笔的话，会出现断续的现象，所以要插值
            if (lastPaintX != 0 && lastPaintY != 0)
            {
                int lerpCount = (int)(1 /lerp);
                for (int i = 0; i <= lerpCount; i++)
                {
                    int x = (int)Mathf.Lerp((float)lastPaintX, (float)texPosX, lerp);
                    int y = (int)Mathf.Lerp((float)lastPaintY, (float)texPosY, lerp);
                    currentTexture.SetPixels32(x, y, painterTipsWidth, painterTipsHeight, painterColor);
                }
            }
            currentTexture.Apply();
            lastPaintX =texPosX;
            lastPaintY =texPosY;
        }
        else
        {
            lastPaintX = lastPaintY = 0;
        }
    }
    /// <summary>
    ///设置当前画笔所在的UV位置
    /// </summary>
    /// <param name="x"></param>
    /// <param name="y"></param>
    public void SetPainterPositon(float x, floaty)
    {
        paintPos.Set(x, y);
    }
    /// <summary>
    ///画笔当前是不是在画画
    /// </summary>
    public boolIsDrawing
    {
        get
        {
            returnisDrawing;
        }
        set
        {
            isDrawing =value;
        }
    }
    /// <summary>
    ///使用当前正在画板上的画笔的颜色
    /// </summary>
    /// <param name="color"></param>
    public voidSetPainterColor(Color32 color)
    {
        if (!painterColor[0].IsEqual(color))
        {
            for (int i = 0; i < painterColor.Length; i++)
            {
                painterColor[i] =color;
            }
        }
    }
}
public static classMethodExtention
{
    /// <summary>
    ///用于比较两个Color32类型是不是同种颜色
    /// </summary>
    /// <param name="origin"></param>
    /// <param name="compare"></param>
    /// <returns></returns>
    public static bool IsEqual(thisColor32 origin, Color32 compare)
    {
        if (origin.g == compare.g && origin.r ==compare.r)
        {
            if (origin.a == compare.a && origin.b ==compare.b)
            {
                return true;
            }
        }
        return false;
    }
}

usingUnityEngine;
public classPainter : MonoBehaviour
{
    /// <summary>
    ///画笔的颜色
    /// </summary>
    publicColor32 penColor;
    publicTransform rayOrigin;
    privateRaycastHit hitInfo;
    //这个画笔是不是正在被手柄抓着
    private boolIsGrabbing;
    private static Board board;//设置成类型的成员，而不是类型实例的成员，因为所有画笔都是用的同一个board
    private voidStart()
    {
        //将画笔部件设置为画笔的颜色，用于识别这个画笔的颜色
        foreach (var renderer in GetComponentsInChildren<MeshRenderer>())
        {
            if (renderer.transform ==transform)
            {
                continue;
            }
            renderer.material.color =penColor;
        }
        if (!board)
        {
            board = FindObjectOfType<Board>();
        }
    }
    private voidUpdate()
    {
        Ray r = newRay(rayOrigin.position, rayOrigin.forward);
        if (Physics.Raycast(r, out hitInfo, 0.1f))
        {
            if (hitInfo.collider.tag == "Board")
            {
                //设置画笔所在位置对应画板图片的UV坐标 
board.SetPainterPositon(hitInfo.textureCoord.x, hitInfo.textureCoord.y);
                //当前笔的颜色
board.SetPainterColor(penColor);
                board.IsDrawing = true;
                IsGrabbing = true;
            }
        }
        else if(IsGrabbing)
        {
            board.IsDrawing = false;
            IsGrabbing = false;
        }
    }
}