#region --- License ---
/* Licensed under the MIT/X11 license.
* Copyright (c) 2006-2008 the OpenTK Team.
* This notice may not be removed from any source distribution.
* See license.txt for licensing detailed licensing details.
*/
#endregion
using System;
using System.Collections.Generic;
using System.Text;
using System.Diagnostics;
using OpenTK.Platform;
namespace OpenTK.Graphics
{
/// <summary>
/// Represents and provides methods to manipulate an OpenGL render context.
/// </summary>
public sealed class GraphicsContext : IGraphicsContext, IGraphicsContextInternal
{
#region --- Fields ---
IGraphicsContext implementation; // The actual render context implementation for the underlying platform.
List<IDisposable> dispose_queue = new List<IDisposable>();
bool disposed;
// Indicates that this context was created through external means, e.g. Tao.Sdl or GLWidget#.
// In this case, We'll assume that the external program will manage the lifetime of this
// context - we'll not destroy it manually.
//bool is_external;
bool check_errors = true;
static bool share_contexts = true;
static bool direct_rendering = true;
readonly static object context_lock = new object();
// Maps OS-specific context handles to GraphicsContext weak references.
readonly static Dictionary<ContextHandle, WeakReference> available_contexts = new Dictionary<ContextHandle, WeakReference>();
#endregion
#region --- Constructors ---
static GraphicsContext()
{
GetCurrentContext = Factory.Default.CreateGetCurrentGraphicsContext();
}
// Necessary to allow creation of dummy GraphicsContexts (see CreateDummyContext static method).
GraphicsContext(ContextHandle handle)
{
implementation = new OpenTK.Platform.Dummy.DummyGLContext(handle);
lock (context_lock)
{
available_contexts.Add((implementation as IGraphicsContextInternal).Context, new WeakReference(this));
}
}
/// <summary>
/// Constructs a new GraphicsContext with the specified GraphicsMode and attaches it to the specified window.
/// </summary>
/// <param name="mode">The OpenTK.Graphics.GraphicsMode of the GraphicsContext.</param>
/// <param name="window">The OpenTK.Platform.IWindowInfo to attach the GraphicsContext to.</param>
public GraphicsContext(GraphicsMode mode, IWindowInfo window)
: this(mode, window, 1, 0, GraphicsContextFlags.Default)
{ }
/// <summary>
/// Constructs a new GraphicsContext with the specified GraphicsMode, version and flags, and attaches it to the specified window.
/// </summary>
/// <param name="mode">The OpenTK.Graphics.GraphicsMode of the GraphicsContext.</param>
/// <param name="window">The OpenTK.Platform.IWindowInfo to attach the GraphicsContext to.</param>
/// <param name="major">The major version of the new GraphicsContext.</param>
/// <param name="minor">The minor version of the new GraphicsContext.</param>
/// <param name="flags">The GraphicsContextFlags for the GraphicsContext.</param>
/// <remarks>
/// Different hardware supports different flags, major and minor versions. Invalid parameters will be silently ignored.
/// </remarks>
public GraphicsContext(GraphicsMode mode, IWindowInfo window, int major, int minor, GraphicsContextFlags flags)
{
bool designMode = false;
if (mode == null && window == null)
designMode = true;
else if (mode == null) throw new ArgumentNullException("mode", "Must be a valid GraphicsMode.");
else if (window == null) throw new ArgumentNullException("window", "Must point to a valid window.");
// Silently ignore invalid major and minor versions.
if (major <= 0)
major = 1;
if (minor < 0)
minor = 0;
Debug.Print("Creating GraphicsContext.");
try
{
Debug.Indent();
Debug.Print("GraphicsMode: {0}", mode);
Debug.Print("IWindowInfo: {0}", window);
IGraphicsContext shareContext = null;
if (GraphicsContext.ShareContexts)
{
lock (context_lock)
{
// A small hack to create a shared context with the first available context.
foreach (WeakReference r in GraphicsContext.available_contexts.Values)
{
shareContext = (IGraphicsContext)r.Target;
break;
}
}
}
// Todo: Add a DummyFactory implementing IPlatformFactory.
if (designMode)
implementation = new Platform.Dummy.DummyGLContext();
else
implementation = Factory.Default.CreateGLContext(mode, window, shareContext, DirectRendering, major, minor, flags);
lock (context_lock)
{
available_contexts.Add((this as IGraphicsContextInternal).Context, new WeakReference(this));
}
//(implementation as IGraphicsContextInternal).LoadAll();
}
finally
{
Debug.Unindent();
}
}
#endregion
#region --- Static Members ---
#region public static GraphicsContext CreateDummyContext()
/// <summary>
/// Creates a dummy GraphicsContext to allow OpenTK to work with contexts created by external libraries.
/// </summary>
/// <returns>A new, dummy GraphicsContext instance.</returns>
/// <remarks>
/// <para>Instances created by this methodwill not be functional. Instance methods will have no effect.</para>
/// </remarks>
public static GraphicsContext CreateDummyContext()
{
ContextHandle handle = GetCurrentContext();
if (handle == ContextHandle.Zero)
throw new InvalidOperationException("No GraphicsContext is current on the calling thread.");
return CreateDummyContext(handle);
}
public static GraphicsContext CreateDummyContext(ContextHandle handle)
{
if (handle == ContextHandle.Zero)
throw new ArgumentOutOfRangeException("handle");
return new GraphicsContext(handle);
}
#endregion
#region public static void Assert()
/// <summary>
/// Checks if a GraphicsContext exists in the calling thread and throws a GraphicsContextException if it doesn't.
/// </summary>
/// <exception cref="GraphicsContextMissingException">Generated when no GraphicsContext is current in the calling thread.</exception>
public static void Assert()
{
if (GraphicsContext.CurrentContext == null)
throw new GraphicsContextMissingException();
}
#endregion
#region public static IGraphicsContext CurrentContext
internal delegate ContextHandle GetCurrentContextDelegate();
internal static GetCurrentContextDelegate GetCurrentContext;
/// <summary>
/// Gets the GraphicsContext that is current in the calling thread.
/// </summary>
public static IGraphicsContext CurrentContext
{
get
{
lock (context_lock)
{
if (available_contexts.Count > 0)
{
ContextHandle handle = GetCurrentContext();
if (handle.Handle != IntPtr.Zero)
return (GraphicsContext)available_contexts[handle].Target;
}
return null;
}
}
}
#endregion
#region public static bool ShareContexts
/// <summary>Gets or sets a System.Boolean, indicating whether GraphicsContext resources are shared</summary>
/// <remarks>
/// <para>If ShareContexts is true, new GLContexts will share resources. If this value is
/// false, new GLContexts will not share resources.</para>
/// <para>Changing this value will not affect already created GLContexts.</para>
/// </remarks>
public static bool ShareContexts { get { return share_contexts; } set { share_contexts = value; } }
#endregion
#region public static bool DirectRendering
/// <summary>Gets or sets a System.Boolean, indicating whether GraphicsContexts will perform direct rendering.</summary>
/// <remarks>
/// <para>
/// If DirectRendering is true, new contexts will be constructed with direct rendering capabilities, if possible.
/// If DirectRendering is false, new contexts will be constructed with indirect rendering capabilities.
/// </para>
/// <para>This property does not affect existing GraphicsContexts, unless they are recreated.</para>
/// <para>
/// This property is ignored on Operating Systems without support for indirect rendering, like Windows and OS X.
/// </para>
/// </remarks>
public static bool DirectRendering
{
get { return direct_rendering; }
set { direct_rendering = value; }
}
#endregion
#endregion
#region --- Internal Members ---
List<ErrorCode> error_list = new List<ErrorCode>();
// Retrieve all OpenGL errors to clear the error list.
// See http://www.opengl.org/documentation/specs/man_pages/hardcopy/GL/html/gl/geterror.html
[Conditional("DEBUG")]
internal void ResetErrors()
{
if (check_errors)
{
while (GL.GetError() != ErrorCode.NoError)
{ }
}
}
// Retrieve all OpenGL errors and throw an exception if anything other than NoError is returned.
[Conditional("DEBUG")]
internal void CheckErrors()
{
if (check_errors)
{
error_list.Clear();
ErrorCode error;
do
{
error = GL.GetError();
error_list.Add(error);
} while (error != ErrorCode.NoError);
if (error_list.Count != 1)
{
StringBuilder sb = new StringBuilder();
foreach (ErrorCode e in error_list)
{
if (e != ErrorCode.NoError)
{
sb.Append(e.ToString());
sb.Append(", ");
}
else
break;
}
sb.Remove(sb.Length - 2, 2); // Remove the last comma
throw new OpenGLErrorException(sb.ToString());
}
}
}
#endregion
#region --- Private Members ---
#region void ContextDestroyed(IGraphicsContext context, EventArgs e)
/// <summary>
/// Handles the Destroy event.
/// </summary>
/// <param name="context">The OpenTK.Platform.IGraphicsContext that was destroyed.</param>
/// <param name="e">Not used.</param>
[Obsolete]
void ContextDestroyed(IGraphicsContext context, EventArgs e)
{
this.Destroy -= ContextDestroyed;
//available_contexts.Remove(((IGraphicsContextInternal)this).Context);
}
#endregion
#endregion
#region --- IGraphicsContext Members ---
/// <summary>
/// Gets or sets a System.Boolean, indicating whether automatic error checking should be performed.
/// Influences the debug version of OpenTK.dll, only.
/// </summary>
/// <remarks>Automatic error checking will clear the OpenGL error state. Set CheckErrors to false if you use
/// the OpenGL error state in your code flow (e.g. for checking supported texture formats).</remarks>
public bool ErrorChecking
{
get { return check_errors; }
set { check_errors = value; }
}
/// <summary>
/// Creates an OpenGL context with the specified direct/indirect rendering mode and sharing state with the
/// specified IGraphicsContext.
/// </summary>
/// <param name="direct">Set to true for direct rendering or false otherwise.</param>
/// <param name="source">The source IGraphicsContext to share state from.</param>.
/// <remarks>
/// <para>
/// Direct rendering is the default rendering mode for OpenTK, since it can provide higher performance
/// in some circumastances.
/// </para>
/// <para>
/// The 'direct' parameter is a hint, and will ignored if the specified mode is not supported (e.g. setting
/// indirect rendering on Windows platforms).
/// </para>
/// </remarks>
void CreateContext(bool direct, IGraphicsContext source)
{
this.Destroy += ContextDestroyed;
lock (context_lock)
{
available_contexts.Add((this as IGraphicsContextInternal).Context, new WeakReference(this));
}
//OpenTK.Graphics.OpenGL.GL.Clear(OpenTK.Graphics.OpenGL.ClearBufferMask.ColorBufferBit);
//if (StaticGetCurrentContext == null)
// StaticGetCurrentContext = implementation.GetCurrentContext;
}
/// <summary>
/// Swaps buffers on a context. This presents the rendered scene to the user.
/// </summary>
public void SwapBuffers()
{
implementation.SwapBuffers();
}
/// <summary>
/// Makes the GraphicsContext the current rendering target.
/// </summary>
/// <param name="window">A valid <see cref="OpenTK.Platform.IWindowInfo" /> structure.</param>
/// <remarks>
/// You can use this method to bind the GraphicsContext to a different window than the one it was created from.
/// </remarks>
public void MakeCurrent(IWindowInfo window)
{
implementation.MakeCurrent(window);
}
/// <summary>
/// Gets a System.Boolean indicating whether this Context is current in the calling thread.
/// </summary>
public bool IsCurrent
{
get { return implementation.IsCurrent; }
//set { implementation.IsCurrent = value; }
}
/// <summary>
/// Raised when a Context is destroyed.
/// </summary>
[Obsolete]
public event DestroyEvent<IGraphicsContext> Destroy
{
add { implementation.Destroy += value; }
remove { implementation.Destroy -= value; }
}
/// <summary>
/// Gets or sets a value indicating whether VSync is enabled.
/// </summary>
public bool VSync
{
get { return implementation.VSync; }
set { implementation.VSync = value; }
}
/// <summary>
/// Updates the graphics context. This must be called when the render target
/// is resized for proper behavior on Mac OS X.
/// </summary>
/// <param name="window"></param>
public void Update(IWindowInfo window)
{
implementation.Update(window);
}
#endregion
#region --- IGraphicsContextInternal Members ---
/// <summary>
/// Gets the platform-specific implementation of this IGraphicsContext.
/// </summary>
IGraphicsContext IGraphicsContextInternal.Implementation
{
get { return implementation; }
}
/// <summary>
/// Loads all OpenGL extensions.
/// </summary>
void IGraphicsContextInternal.LoadAll()
{
(implementation as IGraphicsContextInternal).LoadAll();
}
/// <summary>
/// Gets a handle to the OpenGL rendering context.
/// </summary>
ContextHandle IGraphicsContextInternal.Context
{
get { return ((IGraphicsContextInternal)implementation).Context; }
}
/// <summary>
/// Gets the GraphicsMode of the context.
/// </summary>
public GraphicsMode GraphicsMode
{
get { return (implementation as IGraphicsContext).GraphicsMode; }
}
/// <summary>
/// Registers an OpenGL resource for disposal.
/// </summary>
/// <param name="resource">The OpenGL resource to dispose.</param>
void IGraphicsContextInternal.RegisterForDisposal(IDisposable resource)
{
GC.KeepAlive(resource);
dispose_queue.Add(resource);
}
/// <summary>
/// Disposes all registered OpenGL resources.
/// </summary>
void IGraphicsContextInternal.DisposeResources()
{
foreach (IDisposable resource in dispose_queue)
resource.Dispose();
dispose_queue.Clear();
}
/// <summary>
/// Gets the address of an OpenGL extension function.
/// </summary>
/// <param name="function">The name of the OpenGL function (e.g. "glGetString")</param>
/// <returns>
/// A pointer to the specified function or IntPtr.Zero if the function isn't
/// available in the current opengl context.
/// </returns>
IntPtr IGraphicsContextInternal.GetAddress(string function)
{
return (implementation as IGraphicsContextInternal).GetAddress(function);
}
#endregion
#region --- IDisposable Members ---
/// <summary>
/// Disposes of the GraphicsContext.
/// </summary>
public void Dispose()
{
this.Dispose(true);
GC.SuppressFinalize(this);
}
void Dispose(bool manual)
{
if (!disposed)
{
Debug.Print("Disposing context {0}.", (this as IGraphicsContextInternal).Context.ToString());
lock (context_lock)
{
available_contexts.Remove((this as IGraphicsContextInternal).Context);
}
if (manual)
{
if (implementation != null)
implementation.Dispose();
}
disposed = true;
}
}
//~GraphicsContext()
//{
// this.Dispose(false);
//}
#endregion
}
#region public class GraphicsException : Exception
/// <summary>Represents errors related to Graphics operations.</summary>
public class GraphicsException : Exception
{
/// <summary>Constructs a new GraphicsException.</summary>
public GraphicsException() : base() { }
/// <summary>Constructs a new GraphicsException with the specified excpetion message.</summary>
/// <param name="message"></param>
public GraphicsException(string message) : base(message) { }
}
#endregion
#region class GraphicsErrorException : GraphicsException
// This is private by design. These exceptions are only thrown in debug builds of
// OpenTK and the user should *not* handle them.
// If some specific OpenGL error is generated by design, the user should
// turn off automatic error checking for that portion of the code, using
// 'GraphicsContext.ErrorChecking = false'.
class OpenGLErrorException : GraphicsException
{
public OpenGLErrorException(string message) : base(message) { }
}
#endregion
}