/// <summary>
/// Creates a context, specifying attributes.
/// </summary>
/// <param name="sharedContext">
/// A <see cref="IntPtr"/> that specify a context that will share objects with the returned one. If
/// it is IntPtr.Zero, no sharing is performed.
/// </param>
/// <param name="attribsList">
/// A <see cref="T:Int32[]"/> that specifies the attributes list.
/// </param>
/// <param name="api">
/// A <see cref="KhronosVersion"/> that specifies the API to be implemented by the returned context. It can be null indicating the
/// default API for this DeviceContext implementation. If it is possible, try to determine the API version also.
/// </param>
/// <returns>
/// A <see cref="IntPtr"/> that represents the handle of the created context. If the context cannot be
/// created, it returns IntPtr.Zero.
/// </returns>
/// <exception cref="ArgumentNullException">
/// Exception thrown if <paramref name="attribsList"/> is null.
/// </exception>
/// <exception cref="ArgumentException">
/// Exception thrown if <paramref name="attribsList"/> length is zero or if the last item of <paramref name="attribsList"/>
/// is not zero.
/// </exception>
public override IntPtr CreateContextAttrib(IntPtr sharedContext, int[] attribsList, KhronosVersion api)
{
if (attribsList == null)
{
throw new ArgumentNullException(nameof(attribsList));
}
if (attribsList.Length == 0)
{
throw new ArgumentException("zero length array", nameof(attribsList));
}
if (attribsList[attribsList.Length - 1] != Egl.NONE)
{
throw new ArgumentException("not EGL_NONE-terminated array", nameof(attribsList));
}
IntPtr context;
// Select surface pixel format automatically
if (_NativeSurface != null && _NativeSurface.Handle != IntPtr.Zero)
{
int[] configId = new int[1];
if (Egl.QuerySurface(Display, EglSurface, Egl.CONFIG_ID, configId) == false)
{
throw new InvalidOperationException("unable to query EGL surface config ID");
}
_Config = ChoosePixelFormat(Display, configId[0]);
}
// Bind API
if (Version >= Egl.Version_120)
{
uint apiEnum;
switch (api.Api)
{
case KhronosVersion.ApiGles2:
case KhronosVersion.ApiGles1:
case null:
// Default
apiEnum = Egl.OPENGL_ES_API;
break;
case KhronosVersion.ApiGl:
apiEnum = Egl.OPENGL_API;
break;
case KhronosVersion.ApiVg:
apiEnum = Egl.OPENVG_API;
break;
default:
throw new InvalidOperationException($"'{api}' API not available");
}
if (Egl.BindAPI(apiEnum) == false)
{
throw new InvalidOperationException("no ES API");
}
}
else if (api != null && api.Api != KhronosVersion.ApiGles2 && api.Api != KhronosVersion.ApiGles1)
{
throw new InvalidOperationException($"'{api}' API not available");
}
// Create context
if ((context = Egl.CreateContext(Display, _Config, sharedContext, attribsList)) == IntPtr.Zero)
{
throw new EglException(Egl.GetError());
}
// Create native surface (pixel format pending)
// @todo Back-buffer?
if (_NativeSurface != null && _NativeSurface.Handle == IntPtr.Zero)
{
_NativeSurface.CreateHandle(_Config, new[] { Egl.NONE });
}
return(context);
}
