Source/OpenTK/GameWindow.cs

#region License
//
// The Open Toolkit Library License
//
// Copyright (c) 2006 - 2009 the Open Toolkit library.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights to 
// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
// the Software, and to permit persons to whom the Software is furnished to do
// so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
// OTHER DEALINGS IN THE SOFTWARE.
//
#endregion

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Diagnostics;
using System.Drawing;
using System.Threading;
using OpenTK.Graphics;
using OpenTK.Input;
using OpenTK.Platform;

namespace OpenTK
{
    public class GameWindow : NativeWindow, IGameWindow, IDisposable
    {
        #region --- Fields ---

        object exit_lock = new object();

        IGraphicsContext glContext;

        bool isExiting = false;

        double update_period, render_period;
        double target_update_period, target_render_period;
        // TODO: Implement these:
        double update_time, render_time;
        VSyncMode vsync;

        Stopwatch update_watch = new Stopwatch(), render_watch = new Stopwatch();
        double next_render = 0.0, next_update = 0.0;
        FrameEventArgs update_args = new FrameEventArgs();
        FrameEventArgs render_args = new FrameEventArgs();

        #endregion

        #region --- Contructors ---

        #region public GameWindow()

        public GameWindow()
            : this(640, 480, GraphicsMode.Default, "OpenTK Game Window", 0, DisplayDevice.Default) { }

        #endregion

        #region public GameWindow(int width, int height)

        public GameWindow(int width, int height)
            : this(width, height, GraphicsMode.Default, "OpenTK Game Window", 0, DisplayDevice.Default) { }

        #endregion

        #region public GameWindow(int width, int height, GraphicsMode mode)

        public GameWindow(int width, int height, GraphicsMode mode)
            : this(width, height, mode, "OpenTK Game Window", 0, DisplayDevice.Default) { }

        #endregion

        #region public GameWindow(int width, int height, GraphicsMode mode, string title)

        public GameWindow(int width, int height, GraphicsMode mode, string title)
            : this(width, height, mode, title, 0, DisplayDevice.Default) { }

        #endregion

        #region public GameWindow(int width, int height, GraphicsMode mode, string title, GameWindowFlags options)

        public GameWindow(int width, int height, GraphicsMode mode, string title, GameWindowFlags options)
            : this(width, height, mode, title, options, DisplayDevice.Default) { }

        #endregion

        #region public GameWindow(int width, int height, GraphicsMode mode, string title, GameWindowFlags options, DisplayDevice device)

        public GameWindow(int width, int height, GraphicsMode mode, string title, GameWindowFlags options, DisplayDevice device)
            : this(width, height, mode, title, options, device, 1, 0, GraphicsContextFlags.Default)
        { }

        #endregion

        #region public GameWindow(int width, int height, GraphicsMode mode, string title, GameWindowFlags options, DisplayDevice device, int major, int minor, GraphicsContextFlags flags)

        public GameWindow(int width, int height, GraphicsMode mode, string title, GameWindowFlags options, DisplayDevice device,
            int major, int minor, GraphicsContextFlags flags)
            : this(width, height, mode, title, options, device, major, minor, flags, null)
        { }

        #endregion

        #region public GameWindow(int width, int height, GraphicsMode mode, string title, GameWindowFlags options, DisplayDevice device, int major, int minor, GraphicsContextFlags flags, IGraphicsContext sharedContext)

        public GameWindow(int width, int height, GraphicsMode mode, string title, GameWindowFlags options, DisplayDevice device,
                          int major, int minor, GraphicsContextFlags flags, IGraphicsContext sharedContext)
            : base(width, height, title, options,
                   mode == null ? GraphicsMode.Default : mode,
                   device == null ? DisplayDevice.Default : device)
        {
            try
            {
                glContext = new GraphicsContext(mode == null ? GraphicsMode.Default : mode, WindowInfo, major, minor, flags);
                glContext.MakeCurrent(WindowInfo);
                (glContext as IGraphicsContextInternal).LoadAll();

                VSync = VSyncMode.On;

                //glWindow.WindowInfoChanged += delegate(object sender, EventArgs e) { OnWindowInfoChangedInternal(e); };
            }
            catch (Exception e)
            {
                Debug.Print(e.ToString());
                base.Dispose();
                throw;
            }
        }

        #endregion

        #endregion

        #region --- Public Members ---

        #region Methods

        #region Dispose

        public override void Dispose()
        {
            try
            {
                Dispose(true);
            }
            finally
            {
                try
                {
                    if (glContext != null)
                    {
                        glContext.Dispose();
                        glContext = null;
                    }
                }
                finally
                {
                    base.Dispose();
                }
            }
            GC.SuppressFinalize(this);
        }

        #endregion

        #region Exit

        public virtual void Exit()
        {
            Close();
        }

        #endregion

        #region MakeCurrent

        public void MakeCurrent()
        {
            EnsureUndisposed();
            Context.MakeCurrent(WindowInfo);
        }

        #endregion

        #region OnClose

        protected override void OnClosing(System.ComponentModel.CancelEventArgs e)
        {
            base.OnClosing(e);
            if (!e.Cancel)
            {
                isExiting = true;
                OnUnloadInternal(EventArgs.Empty);
            }
        }


        #endregion

        #region OnLoad

        protected virtual void OnLoad(EventArgs e)
        {
            if (Load != null) Load(this, e);
        }

        #endregion

        #region OnUnload

        protected virtual void OnUnload(EventArgs e)
        {
            if (Unload != null) Unload(this, e);
        }

        #endregion

        #region public void Run()

        public void Run()
        {
            Run(0.0, 0.0);
        }

        #endregion

        #region public void Run(double updateFrequency)

        public void Run(double updateRate)
        {
            Run(updateRate, 0.0);
        }

        #endregion

        #region public void Run(double updates_per_second, double frames_per_second)

        public void Run(double updates_per_second, double frames_per_second)
        {
            EnsureUndisposed();

            try
            {
                if (updates_per_second < 0.0 || updates_per_second > 200.0)
                    throw new ArgumentOutOfRangeException("updates_per_second", updates_per_second,
                                                          "Parameter should be inside the range [0.0, 200.0]");
                if (frames_per_second < 0.0 || frames_per_second > 200.0)
                    throw new ArgumentOutOfRangeException("frames_per_second", frames_per_second,
                                                          "Parameter should be inside the range [0.0, 200.0]");

                TargetUpdateFrequency = updates_per_second;
                TargetRenderFrequency = frames_per_second;

                Visible = true;   // Make sure the GameWindow is visible.
                OnLoadInternal(EventArgs.Empty);
                OnResize(EventArgs.Empty);

                // On some platforms, ProcessEvents() does not return while the user is resizing or moving
                // the window. We can avoid this issue by raising UpdateFrame and RenderFrame events
                // whenever we encounter a size or move event.
                Move += DispatchUpdateAndRenderFrame;
                Resize += DispatchUpdateAndRenderFrame;

                Debug.Print("Entering main loop.");
                update_watch.Start();
                render_watch.Start();
                while (true)
                {
                    ProcessEvents();
                    if (Exists && !IsExiting)
                        DispatchUpdateAndRenderFrame(this, EventArgs.Empty);
                    else
                        return;
                }
            }
            finally
            {
                Move -= DispatchUpdateAndRenderFrame;
                Resize -= DispatchUpdateAndRenderFrame;

                if (Exists)
                {
                    // TODO: Should similar behaviour be retained, possibly on native window level?
                    //while (this.Exists)
                    //    ProcessEvents(false);
                }
            }
        }

        void DispatchUpdateAndRenderFrame(object sender, EventArgs e)
        {
            RaiseUpdateFrame(update_watch, ref next_update, update_args);
            RaiseRenderFrame(render_watch, ref next_render, render_args);
        }

        void RaiseUpdateFrame(Stopwatch update_watch, ref double next_update, FrameEventArgs update_args)
        {
            int num_updates = 0;
            double total_update_time = 0;

            // Cap the maximum time drift to 1 second (e.g. when the process is suspended).
            double time = update_watch.Elapsed.TotalSeconds;
            if (time <= 0)
                return;
            if (time > 1.0)
                time = 1.0;

            // Raise UpdateFrame events until we catch up with our target update rate.
            while (next_update - time <= 0 && time > 0)
            {
                next_update -= time;
                update_args.Time = time;
                OnUpdateFrameInternal(update_args);
                time = update_time = update_watch.Elapsed.TotalSeconds - time;
                // Stopwatches are not accurate over long time periods.
                // We accumulate the total elapsed time into the time variable
                // while reseting the Stopwatch frequently.
                update_watch.Reset();
                update_watch.Start();

                // Don't schedule a new update more than 1 second in the future.
                // Sometimes the hardware cannot keep up with updates
                // (e.g. when the update rate is too high, or the UpdateFrame processing
                // is too costly). This cap ensures  we can catch up in a reasonable time
                // once the load becomes lighter.
                next_update += TargetUpdatePeriod;
                next_update = Math.Max(next_update, -1.0);

                total_update_time += update_time;

                // Allow up to 10 consecutive UpdateFrame events to prevent the
                // application from "hanging" when the hardware cannot keep up
                // with the requested update rate.
                if (++num_updates >= 10 || TargetUpdateFrequency == 0.0)
                    break;
            }

            // Calculate statistics 
            if (num_updates > 0)
            {
                update_period = total_update_time / (double)num_updates;
            }
        }

        void RaiseRenderFrame(Stopwatch render_watch, ref double next_render, FrameEventArgs render_args)
        {
            // Cap the maximum time drift to 1 second (e.g. when the process is suspended).
            double time = render_watch.Elapsed.TotalSeconds;
            if (time > 1.0)
                time = 1.0;
            if (time <= 0)
                return;
            double time_left = next_render - time;

            if (time_left <= 0.0)
            {
                // Schedule next render event. The 1 second cap ensures
                // the process does not appear to hang.
                next_render = time_left + TargetRenderPeriod;
                if (next_render < -1.0)
                    next_render = -1.0;

                render_watch.Reset();
                render_watch.Start();

                if (time > 0)
                {
                    // Todo: revisit this code. Maybe check average framerate instead?
                    // Note: VSyncMode.Adaptive enables vsync by default. The code below
                    // is supposed to disable vsync if framerate becomes too low (half of target
                    // framerate in the current approach) and reenable once the framerate
                    // rises again.
                    // Note 2: calling Context.VSync = true repeatedly seems to cause jitter on
                    // some configurations. If possible, we should avoid repeated calls.
                    // Note 3: we may not read/write the VSync property without a current context.
                    // This may come to pass if the user has moved rendering to his own thread.
                    if (Context.IsCurrent && VSync == VSyncMode.Adaptive && TargetRenderPeriod != 0)
                    {
                        // Check if we have enough time for a vsync
                        if (RenderTime > 2.0 * TargetRenderPeriod)
                            Context.VSync = false;
                        else
                            Context.VSync = true;
                    }

                    render_period = render_args.Time = time;
                    OnRenderFrameInternal(render_args);
                    render_time = render_watch.Elapsed.TotalSeconds;
                }
            }
        }

        #endregion

        #region SwapBuffers

        public void SwapBuffers()
        {
            EnsureUndisposed();
            this.Context.SwapBuffers();
        }

        #endregion

        #endregion

        #region Properties

        #region Context

        public IGraphicsContext Context
        {
            get
            {
                EnsureUndisposed();
                return glContext;
            }
        }

        #endregion

        #region IsExiting

        public bool IsExiting
        {
            get
            {
                EnsureUndisposed();
                return isExiting;
            }
        }

        #endregion

        #region Joysticks

        public IList<JoystickDevice> Joysticks
        {
            get { return InputDriver.Joysticks; }
        }

        #endregion

        #region Keyboard

        public KeyboardDevice Keyboard
        {
            get { return InputDriver.Keyboard.Count > 0 ? InputDriver.Keyboard[0] : null; }
        }

        #endregion

        #region Mouse

        public MouseDevice Mouse
        {
            get { return InputDriver.Mouse.Count > 0 ? InputDriver.Mouse[0] : null; }
        }

        #endregion

        #region --- GameWindow Timing ---

        // TODO: Disabled because it is not reliable enough. Use vsync as a workaround.

        //#region public bool AllowSleep

        //public bool AllowSleep
        //{
        //    get { return allow_sleep; }
        //    set { allow_sleep = value; }
        //}

        //#endregion

        #region RenderFrequency

        public double RenderFrequency
        {
            get
            {
                EnsureUndisposed();
                if (render_period == 0.0)
                    return 1.0;
                return 1.0 / render_period;
            }
        }

        #endregion

        #region RenderPeriod

        public double RenderPeriod
        {
            get
            {
                EnsureUndisposed();
                return render_period;
            }
        }

        #endregion

        #region RenderTime

        public double RenderTime
        {
            get
            {
                EnsureUndisposed();
                return render_time;
            }
            protected set
            {
                EnsureUndisposed();
                render_time = value;
            }
        }

        #endregion

        #region TargetRenderFrequency

        public double TargetRenderFrequency
        {
            get
            {
                EnsureUndisposed();
                if (TargetRenderPeriod == 0.0)
                    return 0.0;
                return 1.0 / TargetRenderPeriod;
            }
            set
            {
                EnsureUndisposed();
                if (value < 1.0)
                {
                    TargetRenderPeriod = 0.0;
                }
                else if (value <= 200.0)
                {
                    TargetRenderPeriod = 1.0 / value;
                }
                else Debug.Print("Target render frequency clamped to 200.0Hz."); // TODO: Where is it actually performed?
            }
        }

        #endregion

        #region TargetRenderPeriod

        public double TargetRenderPeriod
        {
            get
            {
                EnsureUndisposed();
                return target_render_period;
            }
            set
            {
                EnsureUndisposed();
                if (value <= 0.005)
                {
                    target_render_period = 0.0;
                }
                else if (value <= 1.0)
                {
                    target_render_period = value;
                }
                else Debug.Print("Target render period clamped to 1.0 seconds.");
            }
        }

        #endregion

        #region TargetUpdateFrequency

        public double TargetUpdateFrequency
        {
            get
            {
                EnsureUndisposed();
                if (TargetUpdatePeriod == 0.0)
                    return 0.0;
                return 1.0 / TargetUpdatePeriod;
            }
            set
            {
                EnsureUndisposed();
                if (value < 1.0)
                {
                    TargetUpdatePeriod = 0.0;
                }
                else if (value <= 200.0)
                {
                    TargetUpdatePeriod = 1.0 / value;
                }
                else Debug.Print("Target update frequency clamped to 200.0Hz."); // TODO: Where is it actually performed?
            }
        }

        #endregion

        #region TargetUpdatePeriod

        public double TargetUpdatePeriod
        {
            get
            {
                EnsureUndisposed();
                return target_update_period;
            }
            set
            {
                EnsureUndisposed();
                if (value <= 0.005)
                {
                    target_update_period = 0.0;
                }
                else if (value <= 1.0)
                {
                    target_update_period = value;
                }
                else Debug.Print("Target update period clamped to 1.0 seconds."); // TODO: Where is it actually performed?
            }
        }

        #endregion

        #region UpdateFrequency

        public double UpdateFrequency
        {
            get
            {
                EnsureUndisposed();
                if (update_period == 0.0)
                    return 1.0;
                return 1.0 / update_period;
            }
        }

        #endregion

        #region UpdatePeriod

        public double UpdatePeriod
        {
            get
            {
                EnsureUndisposed();
                return update_period;
            }
        }

        #endregion

        #region UpdateTime

        public double UpdateTime
        {
            get
            {
                EnsureUndisposed();
                return update_time;
            }
        }

        #endregion

        #endregion

        #region VSync

        public VSyncMode VSync
        {
            get
            {
                EnsureUndisposed();
                GraphicsContext.Assert();
                return vsync;
            }
            set
            {
                EnsureUndisposed();
                GraphicsContext.Assert();
                Context.VSync = (vsync = value) != VSyncMode.Off;
            }
        }

        #endregion

        #region WindowState

        public override WindowState WindowState
        {
            get
            {
                return base.WindowState;
            }
            set
            {
                base.WindowState = value;
                Debug.Print("Updating Context after setting WindowState to {0}", value);

                if (Context != null)
                    Context.Update(WindowInfo);
            }
        }
        #endregion

        #endregion

        #region Events

        public event EventHandler<EventArgs> Load;

        public event EventHandler<FrameEventArgs> RenderFrame;

        public event EventHandler<EventArgs> Unload;

        public event EventHandler<FrameEventArgs> UpdateFrame;

        #endregion

        #endregion

        #region --- Protected Members ---

        #region Dispose

        protected virtual void Dispose(bool manual) { }

        #endregion

        #region OnRenderFrame

        protected virtual void OnRenderFrame(FrameEventArgs e)
        {
            if (RenderFrame != null) RenderFrame(this, e);
        }

        #endregion

        #region OnUpdateFrame

        protected virtual void OnUpdateFrame(FrameEventArgs e)
        {
            if (UpdateFrame != null) UpdateFrame(this, e);
        }

        #endregion

        #region OnWindowInfoChanged

        protected virtual void OnWindowInfoChanged(EventArgs e) { }

        #endregion

        #region OnResize

        protected override void OnResize(EventArgs e)
        {
            base.OnResize(e);
            glContext.Update(base.WindowInfo);
        }

        #endregion

        #endregion

        #region --- Private Members ---

        #region OnLoadInternal

        private void OnLoadInternal(EventArgs e)
        {
            OnLoad(e);
        }

        #endregion

        #region OnRenderFrameInternal

        private void OnRenderFrameInternal(FrameEventArgs e) { if (Exists && !isExiting) OnRenderFrame(e); }

        #endregion

        #region OnUnloadInternal

        private void OnUnloadInternal(EventArgs e) { OnUnload(e); }

        #endregion

        #region OnUpdateFrameInternal

        private void OnUpdateFrameInternal(FrameEventArgs e) { if (Exists && !isExiting) OnUpdateFrame(e); }

        #endregion

        #region OnWindowInfoChangedInternal

        private void OnWindowInfoChangedInternal(EventArgs e)
        {
            glContext.MakeCurrent(WindowInfo);

            OnWindowInfoChanged(e);
        }

        #endregion

        #endregion
    }

    #region public enum VSyncMode

    public enum VSyncMode
    {
        Off = 0,
        On,
        Adaptive,
    }

    #endregion
}

---