/// <summary>
/// Creates an OpenGL context from a Unix/Linux platform.
/// </summary>
/// <returns>
/// A <see cref="IDeviceContext"/> that specify the device context.
/// </returns>
private static IntPtr CreateEglSimpleContext(IDeviceContext rDevice)
{
NativeDeviceContext eglDeviceCtx = (NativeDeviceContext)rDevice;
IntPtr ctx;
List <int> configAttribs = new List <int>();
if (eglDeviceCtx.Version >= Egl.Version_120)
{
configAttribs.AddRange(new int[] { Egl.RENDERABLE_TYPE, Egl.OPENGL_ES2_BIT });
}
configAttribs.AddRange(new int[] {
Egl.RED_SIZE, 8,
Egl.GREEN_SIZE, 8,
Egl.BLUE_SIZE, 8,
});
configAttribs.Add(Egl.NONE);
int[] configCount = new int[1];
IntPtr[] configs = new IntPtr[8];
if (Egl.BindAPI(Egl.OPENGL_ES_API) == false)
{
throw new InvalidOperationException("no ES API");
}
if (Egl.ChooseConfig(eglDeviceCtx.Display, configAttribs.ToArray(), configs, configs.Length, configCount) == false)
{
throw new InvalidOperationException("unable to choose configuration");
}
if (configCount[0] == 0)
{
throw new InvalidOperationException("no available configuration");
}
List <int> contextAttribs = new List <int>();
if (eglDeviceCtx.Version >= Egl.Version_130)
{
contextAttribs.AddRange(new int[] { Egl.CONTEXT_CLIENT_VERSION, 2 });
}
contextAttribs.Add(Egl.NONE);
if ((ctx = Egl.CreateContext(eglDeviceCtx.Display, configs[configs.Length - 1], IntPtr.Zero, contextAttribs.ToArray())) == IntPtr.Zero)
{
throw new InvalidOperationException("unable to create context");
}
List <int> surfaceAttribs = new List <int>();
surfaceAttribs.Add(Egl.NONE);
// Egl.RENDER_BUFFER, Egl.BACK_BUFFER,
eglDeviceCtx.Surface = Egl.CreateWindowSurface(eglDeviceCtx.Display, configs[configs.Length - 1], eglDeviceCtx.NativeWindow, surfaceAttribs.ToArray());
return(ctx);
}