Event message with Windows Form and OpenGl - C# - windows

Question

just want to know if that is a normal behaviour and if there is anything that could prevent it.
I am using OpenGL and TaoClassic (might not be relevant to the issue but well) on a Windows Form.
At the moment, I have a very basic square that moves around the window and when reaching the edges of the window, then the velocity is inverted (x when left/right, y when top/bottom).
So far nothing fancy.
Where it gets fancy is as the object moves along, if I click on the border of the form, then the application stops, new drawing are not happening but the application partially keeps updating. I say partially because from the code below the first two lines keep on running while the "collision" detection is not
transform.position.x += velocity.x * xSign * Time.deltaTime;
transform.position.y += velocity.y * ySign * Time.deltaTime;
if (penguin.transform.position.x + penguin.sprite.texture.width / 2f > Engine.Screen.Width ||
penguin.transform.position.x - penguin.sprite.texture.width / 2f < 0) xSign *= -1;
if (penguin.transform.position.y + penguin.sprite.texture.height / 2f > Engine.Screen.Height ||
penguin.transform.position.y - penguin.sprite.texture.height / 2f < 0) ySign *= -1;
no genius trick. When I release the mouse button, then the object jumps to the position it should be meaning the update kept running on the back. But if I keep pressing long enough, the object gets out of bound but does not bounce. When I release, I get my square out of window and starting to jitter at the borders.
I got this:
protected override void OnClientSizeChanged(EventArgs e)
{
base.OnClientSizeChanged(e);
Engine.Screen.Width = this.ClientSize.Width;
Engine.Screen.Height = this.ClientSize.Height;
// This is just to set the window size and the position of origin
App.SetProjection2D(Engine.Screen.Width, Engine.Screen.Height, App.Projection);
Gl.glViewport(0, 0, Engine.Screen.Width, Engine.Screen.Height);
}
and here is PeekMessage of the application:
private void OnApplicationEnterIdle(object sender, EventArgs e)
{
Message msg;
while (!PeekMessage(out msg, IntPtr.Zero, 0, 0, 0))
{
_timer.SetTime();
Input.Update();
_callback();
}
}
I would guess the problem lies in one of those. The Update and Draw methods are called from the _callback(); method
Just for info, when clicking on the form, it does not stop the application so it has to do with the event based on clicking on borders.
Any idea?

Answer 1

It is normal behaviour. Moving and resizing events are blocking (that's the way default WndProc works) and OnApplicationEnterIdle isn't called.
AFAIK the only way to continue updating when window is resized is to use different thread for rendering. In that case, only main thread will block on move and resize events, while rendering thread will continue updating viewport.