手把手帶你使用Paint in 3D和Photon擼一個線上塗鴉畫板

Paint in 3D

Paint in 3D用於在游戲內和編輯器里繪製所有物體。所有功能已經過深度優化，在WebGL、移動端、VR 以及更多平臺用起來都非常好用！

它支持標準管線，以及 LWRP、HDRP 和 URP。通過使用GPU 加速，你的物體將以難以置信的速度被繪製。代碼還經過深度優化來防止GC，和將所有繪製操作一起批次完成。

跟貼圖系統不同，它是一個紋理繪製解決方案。這意味著你可以繪製你的物體上百萬次，還是無幀率丟失，讓你創作難以想象的游戲。

它在Unity應用商店上的售價是60美元，地址：https://assetstore.unity.com/packages/tools/painting/paint-in-3d-26286。

Photon

Photon中文翻譯為“光子”，為有著15年伺服器後端開發經驗的德國Exit Games公司開發的高效，穩定，可拓展的網路引擎。為目前世界上用戶最廣泛，支持游戲類型最多的專業網路引擎之一，也是Unity應用商店裡用戶評價最高的網路組件。

世界多個知名游戲公司和工作室選用Photon作為其產品的網路支持引擎，其中包括WB華納，Codemaster, 2K, Glu, 微軟游戲工作室，史克威爾艾尼克斯，百代南夢宮，SandBox，雨神電競等知名企業，也有許多工作室和新創企業正在瞭解和試用Photon之中。

它在Unity應用商店上有一個免費應用，地址：https://assetstore.unity.com/packages/tools/network/pun-2-free-119922。

當然，Photon需要註冊賬號、創建應用等操作才能使用，還不瞭解的同學可以去官方網站查閱相關資料。

溫馨提示：Photon的國外伺服器在國內使用比較卡，所以最好去中國官網申請國內的伺服器，申請地址：https://vibrantlink.com/chinacloudapply/。

下麵正式開始。

創建工程

使用Unity Hub創建一個3D項目，然後分別引入Paint in 3D和Photon Unity Networking 2，如下圖：

溫馨提示：在引入Photon Unity Networking 2後，記得配置AppId。

創建簡易畫板

為了方便演示，我們創建一個Quad作為畫板，然後為其添加P3dPaintable、P3dMaterialCloner和P3dPaintableTexture組件，使用它們的預設配置即可，如下圖：

然後，創建一個空的GameObject命名為OneMorePaint，然後向OneMorePaint添加P3dPaintSphere組件，修改P3dPaintSphere組件的Color為紅色，其他配置保持預設不變，如下圖：

再向OneMorePaint添加P3dHitScreen組件，勾選上P3dHitScreen組件的ConnectHits，其他配置保持預設不變，如下圖：

這時候，創建簡易畫板就做好了，運行以後就可以畫畫了，如下圖：

只不過，還是個單機版，我們加上實時線上功能。

連接PUN2伺服器

創建一個C#腳本命名為Launcher，再創建一個空的GameObject命名為LauncherGameObject，把C#腳本Launcher添加到LauncherGameObject中。

編輯C#腳本Launcher為如下內容：

using Photon.Pun;
using Photon.Realtime;
using UnityEngine;

namespace One.More
{
    public class Launcher : MonoBehaviourPunCallbacks
    {
        #region Private Fields
        /// <summary>
        /// This client's version number. Users are separated from each other by gameVersion (which allows you to make breaking changes).
        /// </summary>
        string gameVersion = "1";
        /// <summary>
        /// Keep track of the current process. Since connection is asynchronous and is based on several callbacks from Photon,
        /// we need to keep track of this to properly adjust the behavior when we receive call back by Photon.
        /// Typically this is used for the OnConnectedToMaster() callback.
        /// </summary>
        bool isConnecting;
        #endregion

        void Start()
        {
            this.Connect();
        }

        #region MonoBehaviourPunCallbacks Callbacks
        public override void OnConnectedToMaster()
        {
            Debug.Log("PUN Basics Tutorial/Launcher: OnConnectedToMaster() was called by PUN");
            // we don't want to do anything if we are not attempting to join a room.
            // this case where isConnecting is false is typically when you lost or quit the game, when this level is loaded, OnConnectedToMaster will be called, in that case
            // we don't want to do anything.
            if (isConnecting)
            {
                // #Critical: The first we try to do is to join a potential existing room. If there is, good, else, we'll be called back with OnJoinRandomFailed()
                PhotonNetwork.JoinRandomRoom();
                isConnecting = false;
            }
        }
        public override void OnDisconnected(DisconnectCause cause)
        {
            Debug.LogWarningFormat("PUN Basics Tutorial/Launcher: OnDisconnected() was called by PUN with reason {0}", cause);
            isConnecting = false;
        }
        public override void OnJoinRandomFailed(short returnCode, string message)
        {
            Debug.Log("PUN Basics Tutorial/Launcher:OnJoinRandomFailed() was called by PUN. No random room available, so we create one.\nCalling: PhotonNetwork.CreateRoom");
            // #Critical: we failed to join a random room, maybe none exists or they are all full. No worries, we create a new room.
            PhotonNetwork.CreateRoom(null, new RoomOptions());
        }
        public override void OnJoinedRoom()
        {
            Debug.Log("PUN Basics Tutorial/Launcher: OnJoinedRoom() called by PUN. Now this client is in a room.");
        }
        #endregion

        #region Public Methods
        /// <summary>
        /// Start the connection process.
        /// - If already connected, we attempt joining a random room
        /// - if not yet connected, Connect this application instance to Photon Cloud Network
        /// </summary>
        public void Connect()
        {
            // we check if we are connected or not, we join if we are , else we initiate the connection to the server.
            if (PhotonNetwork.IsConnected)
            {
                // #Critical we need at this point to attempt joining a Random Room. If it fails, we'll get notified in OnJoinRandomFailed() and we'll create one.
                PhotonNetwork.JoinRandomRoom();
            }
            else
            {
                // #Critical, we must first and foremost connect to Photon Online Server.
                isConnecting = PhotonNetwork.ConnectUsingSettings();
                PhotonNetwork.GameVersion = gameVersion;
            }
        }
        #endregion
    }
}

這時候，就可以連接到連接PUN2伺服器了，運行以後我們可以看到如下日誌：

實時線上同步

向之前創建的OneMorePaint添加PhotonView組件，使用預設配置即可，如下圖：

創建一個C#腳本命名為OnlinePainting，把C#腳本OnlinePainting添加到OneMorePaint中。

編輯C#腳本OnlinePainting為如下內容：

using PaintIn3D;
using Photon.Pun;
using UnityEngine;

namespace One.More
{
    public class OnlinePainting : MonoBehaviour, IHitPoint, IHitLine
    {
        private PhotonView photonView;
        private P3dPaintSphere paintSphere;

        void Start()
        {
            this.photonView = this.GetComponent<PhotonView>();
            this.paintSphere = this.GetComponent<P3dPaintSphere>();
        }

        public void HandleHitPoint(bool preview, int priority, float pressure, int seed, Vector3 position, Quaternion rotation)
        {
            if (preview)
            {
                return;
            }
            if (this.photonView == null)
            {
                Debug.LogError("PhotonView is not found.");
                return;
            }
            this.photonView.RPC("HandleHitPointRpc", RpcTarget.Others, preview, priority, pressure, seed, position, rotation);
        }

        public void HandleHitLine(bool preview, int priority, float pressure, int seed, Vector3 position, Vector3 endPosition, Quaternion rotation, bool clip)
        {
            if (preview)
            {
                return;
            }
            if (this.photonView == null)
            {
                Debug.LogError("PhotonView is not found.");
                return;
            }
            this.photonView.RPC("HandleHitLinetRpc", RpcTarget.Others, preview, priority, pressure, seed, position, endPosition, rotation, clip);
        }

        [PunRPC]
        public void HandleHitPointRpc(bool preview, int priority, float pressure, int seed, Vector3 position, Quaternion rotation)
        {
            if (this.paintSphere == null)
            {
                Debug.LogError("P3dPaintSphere is not found.");
                return;
            }
            this.paintSphere.HandleHitPoint(preview, priority, pressure, seed, position, rotation);
        }

        [PunRPC]
        public void HandleHitLinetRpc(bool preview, int priority, float pressure, int seed, Vector3 position, Vector3 endPosition, Quaternion rotation, bool clip)
        {
            if (this.paintSphere == null)
            {
                Debug.LogError("P3dPaintSphere is not found.");
                return;
            }
            this.paintSphere.HandleHitLine(preview, priority, pressure, seed, position, endPosition, rotation, clip);
        }
    }
}

線上塗鴉畫板就製作完成了，我們看看運行效果怎麼樣？

運行效果

構建以後，同時啟動兩個客戶端，效果如下：

當然，這隻是簡單的線上塗鴉畫板，你還可以再此基礎上添加更豐富的功能，比如：修改畫筆顏色、修改畫筆大小等等。

最後，謝謝你這麼帥，還給我點贊和關註。