/// <summary>
///
/// </summary>
/// <param name="wnd"></param>
/// <exception cref="AccessViolationException">OpenGL subsystem encountered an access violation, try updating graphics drivers</exception>
/// <exception cref="InvalidOperationException">Unable to create OpenGL context</exception>
/// <exception cref="NotSupportedException">OpenGL 3.2 is not supported by this system</exception>
/// <example>
/// public class DisplayForm : Form
/// {
/// private WglContext ctx;
/// protected override virtual void OnHandleCreated(EventArgs e)
/// {
/// ctx = new WglContext();
/// ctx.CreateContext(this.Handle);
/// }
/// protected override virtual void OnClosing(ClosingEventArgs e)
/// {
/// ctx.Dispose();
/// }
/// }
/// </example>
public override void CreateContext(IntPtr wnd, IntPtr draw, OpenGLContext share)
{
// Force OpenGL library to link
// or we will not be able to create a context
linker = GetLinker();
hwnd = wnd;
display = hwnd;
int pixel_format = 0;
bool valid = false;
PIXELFORMATDESCRIPTOR desc = new PIXELFORMATDESCRIPTOR();
if (draw == IntPtr.Zero)
{
drawable = GetDC(wnd);
}
else
{
drawable = draw;
}
desc.nSize = (short)Marshal.SizeOf(desc);
desc.nVersion = 1;
desc.dwFlags = PixelFormatFlags.PFD_DOUBLEBUFFER | PixelFormatFlags.PFD_DRAW_TO_WINDOW | PixelFormatFlags.PFD_SUPPORT_OPENGL;
desc.cDepthBits = 32;
desc.cColorBits = 32;
pixel_format = ChoosePixelFormat(drawable, ref desc);
SetPixelFormat(drawable, pixel_format, ref desc);
// Create legacy OpenGL context
handle = wglCreateContext(drawable);
wglMakeCurrent(drawable, handle);
wglGetExtensionStringARB = GetProc <GetExtensionsStringARB>("wglGetExtensionStringARB");
wglChoosePixelFormatARB = GetProc <ChoosePixelFormatARB>("wglChoosePixelFormatARB");
wglGetPixelFormatAttribfvARB = GetProc <GetPixelFormatAttribfvARB>("wglGetPixelFormatAttribfvARB");
wglGetPixelFormatAttribivARB = GetProc <GetPixelFormatAttribivARB>("wglGetPixelFormatAttribivARB");
string ext = "";
if (wglGetExtensionStringARB != null)
{
ext = Marshal.PtrToStringAnsi(wglGetExtensionStringARB(drawable));
}
var extensions = ext.Split(' ');
if (drawable != IntPtr.Zero && wglChoosePixelFormatARB != null)
{
var fAttributes = new float[] { 0, 0 };
var iAttributes = new int[]
{ WGL_DRAW_TO_WINDOW_ARB, 1,
WGL_SUPPORT_OPENGL_ARB, 1,
WGL_ACCELERATION_ARB, WGL_FULL_ACCELERATION_ARB,
WGL_COLOR_BITS_ARB, 24,
WGL_ALPHA_BITS_ARB, 8,
WGL_DEPTH_BITS_ARB, 24,
WGL_STENCIL_BITS_ARB, 8,
WGL_DOUBLE_BUFFER_ARB, 1,
WGL_SAMPLE_BUFFERS_ARB, 1,
WGL_SAMPLES_ARB, samples, // Check For 4x Multisampling
0, 0 };
uint num_formats = 0;
valid = wglChoosePixelFormatARB(drawable, iAttributes, fAttributes, 1, ref pixel_format, ref num_formats) && num_formats > 0;
if (valid)
{
wglMakeCurrent(IntPtr.Zero, IntPtr.Zero);
wglDeleteContext(handle);
SetPixelFormat(drawable, pixel_format, ref desc);
handle = wglCreateContext(drawable);
wglMakeCurrent(drawable, handle);
}
}
wglCreateContextAttribsARB = GetProc <CreateContextAttribsARB>("wglCreateContextAttribsARB");
var s = OpenGL.glGetString((uint)OpenGL.Const.GL_VERSION);
var str = Marshal.PtrToStringAnsi(s);
var sub = str.Split('.');
int major = 0;
int minor = 0;
int revision = 0;
int.TryParse(sub[0], out major);
int.TryParse(sub[1], out minor);
if (sub.Length >= 3)
{
int.TryParse(sub[0], out revision);
}
Glorg2.Debugging.Debug.WriteLine("OpenGL version " + major + "." + minor + " supported by your system.");
if (major < 3)
{
throw new NotSupportedException("OpenGL 3 is not supported.");
}
if (minor < 2 && major == 3)
{
System.Diagnostics.Debug.WriteLine("OpenGL 3.2 is not supported. Consider upgrading display drivers.");
}
if (wglCreateContextAttribsARB != null)
{
int[] attribs = new int[]
{
WGL_CONTEXT_MAJOR_VERSION_ARB, major,
WGL_CONTEXT_MINOR_VERSION_ARB, minor,
WGL_CONTEXT_FLAGS_ARB, WGL_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB,
WGL_CONTEXT_PROFILE_MASK_ARB, WGL_CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB,
0
};
IntPtr share_ctx = IntPtr.Zero;
if (share != null)
{
share_ctx = share.Handle;
}
IntPtr newhandle = wglCreateContextAttribsARB(drawable, share_ctx, attribs);
if (newhandle != IntPtr.Zero)
{
wglMakeCurrent(IntPtr.Zero, IntPtr.Zero);
var err = OpenGL.glGetError();
wglDeleteContext(handle);
handle = IntPtr.Zero;
if (newhandle != IntPtr.Zero) // If OpenGL 3.0 context creation failed, fallback to legacy 2.x
{
handle = newhandle;
}
else
{
throw new NotSupportedException("Could not initialize OpenGL " + major + "." + minor + " : " + err.ToString());
}
}
else if (share_ctx != IntPtr.Zero)
{
wglShareLists(handle, share_ctx);
}
}
else
{
throw new NotSupportedException("OpenGL 3.2 is not supported by your system.");
}
if (handle != IntPtr.Zero)
{
wglMakeCurrent(drawable, handle);
}
else
{
throw new NotSupportedException("Could not create OpenGL context");
}
}
