/// <summary>
/// Construct a GraphicsContext specifying the implemented OpenGL version.
/// </summary>
/// <param name="deviceContext">
/// A <see cref="IDeviceContext"/> that specify the device context which has to be linked this
/// this Render context.
/// </param>
/// <param name="sharedContext">
/// A <see cref="GraphicsContext"/> that specify the render context which has to be linked this
/// this Render context (to share resource with it).
/// </param>
/// <param name="version">
/// A <see cref="KhronosVersion"/> that specify the minimum OpenGL version required to implement.
/// </param>
/// <param name="flags">
/// A <see cref="GraphicsContextFlags"/> that specify special features to enable in the case they are supported.
/// </param>
/// <exception cref="ArgumentException">
/// Exception thrown in the case <paramref name="version"/> is different from the currently implemented by the derive,
/// and the OpenGL extension WGL_ARB_create_context_profile or WGL_ARB_create_context are not implemented.
/// </exception>
/// <exception cref="ArgumentException">
/// This exception is thrown in the case <paramref name="version"/> specify a forward compatible version (greater than or equal to
/// <see cref="GLVersion.Version_3_2"/>), and the OpenGL extension WGL_ARB_create_context_profile or WGL_ARB_create_context
/// are not implemented.
/// </exception>
/// <exception cref="ArgumentException">
/// This exception is thrown in the case <paramref name="devctx"/> is <see cref="IntPtr.Zero"/>.
/// </exception>
/// <exception cref="InvalidOperationException">
/// This exception is thrown in the case it's not possible to create a valid OpenGL context.
/// </exception>
/// <exception cref="ArgumentException">
/// This exception is thrown if <paramref name="sharedContext"/> is not null and it was created by a thread different from the calling one.
/// </exception>
/// <exception cref="ArgumentException">
/// This exception is thrown if <paramref name="sharedContext"/> is not null and it is disposed.
/// </exception>
public GraphicsContext(IDeviceContext deviceContext, GraphicsContext sharedContext, KhronosVersion version, GraphicsContextFlags flags)
{
try {
IntPtr sharedContextHandle = (sharedContext != null) ? sharedContext._RenderContext : IntPtr.Zero;
#if DEBUG
_ConstructorStackTrace = Environment.StackTrace;
#endif
// Store thread ID of the render context
_RenderContextThreadId = System.Threading.Thread.CurrentThread.ManagedThreadId;
// Store thread ID of the device context
_DeviceContextThreadId = System.Threading.Thread.CurrentThread.ManagedThreadId;
if (deviceContext == null)
throw new ArgumentNullException("deviceContext");
if ((sharedContext != null) && (sharedContext._DeviceContext == null))
throw new ArgumentException("shared context disposed", "hSharedContext");
if ((sharedContext != null) && (sharedContext._RenderContextThreadId != _RenderContextThreadId))
throw new ArgumentException("shared context created from another thread", "hSharedContext");
if ((version != null) && (version != _CurrentVersion) && ((CurrentCaps.PlatformExtensions.CreateContext_ARB == false) && (CurrentCaps.PlatformExtensions.CreateContextProfile_ARB == false)))
throw new ArgumentException("unable to specify OpenGL version when GL_ARB_create_context[_profile] is not supported");
// Store device context handle
_DeviceContext = deviceContext;
_DeviceContext.IncRef();
// Allow version to be null (fallback to current version)
version = version ?? _CurrentVersion;
// Set flags
_ContextFlags = flags;
if ((CurrentCaps.PlatformExtensions.CreateContext_ARB || CurrentCaps.PlatformExtensions.CreateContextProfile_ARB) && (version.Major >= 3)) {
List<int> cAttributes = new List<int>();
#region Context Version
// Requires a specific version
Debug.Assert(Wgl.CONTEXT_MAJOR_VERSION_ARB == Glx.CONTEXT_MAJOR_VERSION_ARB);
Debug.Assert(Wgl.CONTEXT_MINOR_VERSION_ARB == Glx.CONTEXT_MINOR_VERSION_ARB);
cAttributes.AddRange(new int[] {
Wgl.CONTEXT_MAJOR_VERSION_ARB, version.Major,
Wgl.CONTEXT_MINOR_VERSION_ARB, version.Minor
});
#endregion
#region Context Profile
uint contextProfile = 0;
// Check binary compatibility between WGL and GLX
Debug.Assert(Wgl.CONTEXT_PROFILE_MASK_ARB == Glx.CONTEXT_PROFILE_MASK_ARB);
Debug.Assert(Wgl.CONTEXT_CORE_PROFILE_BIT_ARB == Glx.CONTEXT_CORE_PROFILE_BIT_ARB);
Debug.Assert(Wgl.CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB == Glx.CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB);
Debug.Assert(Wgl.CONTEXT_ES_PROFILE_BIT_EXT == Glx.CONTEXT_ES_PROFILE_BIT_EXT);
// By default, Core profile
// Core profile?
if ((flags & GraphicsContextFlags.CoreProfile) != 0)
contextProfile |= Wgl.CONTEXT_CORE_PROFILE_BIT_ARB;
// Compatibility profile?
if ((flags & GraphicsContextFlags.CompatibilityProfile) != 0)
contextProfile |= Wgl.CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB;
// OpenGL ES profile?
if ((flags & GraphicsContextFlags.EmbeddedProfile) != 0)
contextProfile |= Wgl.CONTEXT_ES_PROFILE_BIT_EXT;
if (contextProfile != 0) {
cAttributes.AddRange(new int[] {
Wgl.CONTEXT_PROFILE_MASK_ARB, unchecked((int)contextProfile)
});
}
#endregion
#region Context Flags
uint contextFlags = 0;
// Check binary compatibility between WGL and GLX
Debug.Assert(Wgl.CONTEXT_FLAGS_ARB == Glx.CONTEXT_FLAGS_ARB);
Debug.Assert(Wgl.CONTEXT_FORWARD_COMPATIBLE_BIT_ARB == Glx.CONTEXT_FORWARD_COMPATIBLE_BIT_ARB);
Debug.Assert(Wgl.CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB == Glx.CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB);
Debug.Assert(Wgl.CONTEXT_DEBUG_BIT_ARB == Glx.CONTEXT_DEBUG_BIT_ARB);
Debug.Assert(Wgl.CONTEXT_ROBUST_ACCESS_BIT_ARB == Glx.CONTEXT_ROBUST_ACCESS_BIT_ARB);
Debug.Assert(Wgl.CONTEXT_RESET_ISOLATION_BIT_ARB == Glx.CONTEXT_RESET_ISOLATION_BIT_ARB);
if (((flags & GraphicsContextFlags.CompatibilityProfile) != 0) && (_CurrentCaps.GlExtensions.Compatibility_ARB == false))
throw new NotSupportedException("compatibility profile not supported");
if (((flags & GraphicsContextFlags.Robust) != 0) && (_CurrentCaps.GlExtensions.Robustness_ARB == false && _CurrentCaps.GlExtensions.Robustness_EXT == false))
throw new NotSupportedException("robust profile not supported");
// Context flags: debug context
if ((flags & GraphicsContextFlags.Debug) != 0)
contextFlags |= Wgl.CONTEXT_DEBUG_BIT_ARB;
// Context flags: forward compatible context
if ((flags & GraphicsContextFlags.ForwardCompatible) != 0)
contextFlags |= Wgl.CONTEXT_FORWARD_COMPATIBLE_BIT_ARB;
// Context flags: robust behavior
if ((flags & GraphicsContextFlags.Robust) != 0)
contextFlags |= Wgl.CONTEXT_ROBUST_ACCESS_BIT_ARB;
// Context flags: reset isolation
if ((flags & GraphicsContextFlags.ResetIsolation) != 0)
contextFlags |= Wgl.CONTEXT_RESET_ISOLATION_BIT_ARB;
if (contextFlags != 0) {
cAttributes.AddRange(new int[] {
Wgl.CONTEXT_FLAGS_ARB, unchecked((int)contextFlags)
});
}
#endregion
// End of attributes
cAttributes.Add(0);
// Create rendering context
int[] contextAttributes = cAttributes.ToArray();
_RenderContext = _DeviceContext.CreateContextAttrib(sharedContextHandle, contextAttributes);
Debug.Assert(_RenderContext != IntPtr.Zero);
} else {
// Create rendering context
_RenderContext = _DeviceContext.CreateContext(sharedContextHandle);
Debug.Assert(_RenderContext != IntPtr.Zero);
}
if (_RenderContext == IntPtr.Zero)
throw new InvalidOperationException(String.Format("unable to create context {0}", version));
// Allow the creation of a GraphicsContext while another GraphicsContext is currently current to the
// calling thread: restore currency after the job get done
GraphicsContext prevContext = GetCurrentContext();
IDeviceContext prevContextDevice = (prevContext != null) ? prevContext._CurrentDeviceContext : null;
// This will cause OpenGL operation flushed... not too bad
MakeCurrent(deviceContext, true);
// Get the current OpenGL implementation supported by this GraphicsContext
_Version = KhronosVersion.Parse(Gl.GetString(StringName.Version));
// Get the current OpenGL Shading Language implementation supported by this GraphicsContext
_ShadingVersion = KhronosVersion.Parse(Gl.GetString(StringName.ShadingLanguageVersion));
// Query context capabilities
_CapsStack.Push(GraphicsCapabilities.Query(this, deviceContext));
// Determine this GraphicsContext object namespace
if (sharedContext != null) {
// Sharing same object name space
_ObjectNameSpace = sharedContext._ObjectNameSpace;
} else {
// Reserved object name space
_ObjectNameSpace = Guid.NewGuid();
}
// Create shader include library (GLSL #include support)
_ShaderIncludeLibrary = new ShaderIncludeLibrary();
_ShaderIncludeLibrary.Create(this);
// Restore previous current context, if any. Otherwise, make uncurrent
if (prevContext != null)
prevContext.MakeCurrent(prevContextDevice, true);
else
MakeCurrent(deviceContext, false);
} catch {
// Rethrow the exception
throw;
}
}