Embed a Unity3D Application in a WPF Application

Question

I want to develop new CAD software in WPF, and instead of using WPF 3D, can I use Unity3D as a graphics engine that can rotate, pan, scale and view 3D graphics based on my data objects in WPF?

The reason I ask this question is: Unity is a game engine, it uses C # as a script, but it does not provide integration from a WPF application (implements Unity in WPF).

I asked a question on the unity forum, did not find a good answer, so I asked for a wider audience.

Answer 1

This can be done, but it is worth noting that it will only work on Windows.

This was difficult to do, but recently Unity (4.5.5p1) added a command -parentHWNDthat can be used for a program in another program. All you have to do is create your own Unity application, and then from WPF, launch it using the API Process. Then you can pass the parameter -parentHWNDto the Unity application.

process.StartInfo.FileName = "YourUnityApp.exe";
process.StartInfo.Arguments = "-parentHWND " + panel1.Handle.ToInt32() + " " + Environment.CommandLine;

You can use TCP or Named Pipes to switch between them .

The following is a complete sample embed code on the Unity website. You can get the whole project here . Be sure to specify the Unity build exe file "UnityGame.exe", then place it in the same directory as the exe WPF program.

namespace Container
{
    public partial class Form1 : Form
    {
        [DllImport("User32.dll")]
        static extern bool MoveWindow(IntPtr handle, int x, int y, int width, int height, bool redraw);

        internal delegate int WindowEnumProc(IntPtr hwnd, IntPtr lparam);
        [DllImport("user32.dll")]
        internal static extern bool EnumChildWindows(IntPtr hwnd, WindowEnumProc func, IntPtr lParam);

        [DllImport("user32.dll")]
        static extern int SendMessage(IntPtr hWnd, int msg, IntPtr wParam, IntPtr lParam);

        private Process process;
        private IntPtr unityHWND = IntPtr.Zero;

        private const int WM_ACTIVATE = 0x0006;
        private readonly IntPtr WA_ACTIVE = new IntPtr(1);
        private readonly IntPtr WA_INACTIVE = new IntPtr(0);

        public Form1()
        {
            InitializeComponent();

            try
            {
                process = new Process();
                process.StartInfo.FileName = "UnityGame.exe";
                process.StartInfo.Arguments = "-parentHWND " + panel1.Handle.ToInt32() + " " + Environment.CommandLine;
                process.StartInfo.UseShellExecute = true;
                process.StartInfo.CreateNoWindow = true;

                process.Start();

                process.WaitForInputIdle();
                // Doesn't work for some reason ?!
                //unityHWND = process.MainWindowHandle;
                EnumChildWindows(panel1.Handle, WindowEnum, IntPtr.Zero);

                unityHWNDLabel.Text = "Unity HWND: 0x" + unityHWND.ToString("X8");
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message + ".\nCheck if Container.exe is placed next to UnityGame.exe.");
            }

        }

        private void ActivateUnityWindow()
        {
            SendMessage(unityHWND, WM_ACTIVATE, WA_ACTIVE, IntPtr.Zero);
        }

        private void DeactivateUnityWindow()
        {
            SendMessage(unityHWND, WM_ACTIVATE, WA_INACTIVE, IntPtr.Zero);
        }

        private int WindowEnum(IntPtr hwnd, IntPtr lparam)
        {
            unityHWND = hwnd;
            ActivateUnityWindow();
            return 0;
        }

        private void panel1_Resize(object sender, EventArgs e)
        {
            MoveWindow(unityHWND, 0, 0, panel1.Width, panel1.Height, true);
            ActivateUnityWindow();
        }

        // Close Unity application
        private void Form1_FormClosed(object sender, FormClosedEventArgs e)
        {
            try
            {
                process.CloseMainWindow();

                Thread.Sleep(1000);
                while (!process.HasExited)
                    process.Kill();
            }
            catch (Exception)
            {

            }
        }

        private void Form1_Activated(object sender, EventArgs e)
        {
            ActivateUnityWindow();
        }

        private void Form1_Deactivate(object sender, EventArgs e)
        {
            DeactivateUnityWindow();
        }
    }
}