Small mouse flicker

From MSDN:

quote:

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The cursor is a shared resource. A window should move the cursor only when the cursor is in its client area.

The calling process must have WINSTA_WRITEATTRIBUTES access to the window station.

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Do you guarantee that the cursor is still within the client area when you position it? Note that there is no such similar restriction on showing/hiding the cursor.

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Thanks to Kylotan for the idea!

Why even bother putting back to the center? Just keep track of the last position it is in

This isn''t a complex method...

The purpose of hiding the cursor is so it will not be visible. The purpose of moving it back to the center of the window is so that it doesn''t get moved out of the client area. In the mode where the cursor is hidden I want it to be like the mouse isn''t controlling the cursor, but just acting as an input device to control whatever is being controlled by the effect that''s using it.

So yeah, the cursor is guaranteed to be in the client area when I reposition it because I keep it in the center after I measure it''s movement deltas.

All I want is to be able to take mouse input without showing cursor movement. The best/easiest way I could think of was to hide the cursor and keep it in the center of the window after measuring movement. It''s not complex. It basically goes like this every frame:

GetCursorPos();
// store deltas based on movement of the cursor from center of window
SetCursorPos(/*window center*/);

The only issue is that when I want to stop tracking the mouse (when the user exits this mode where the mouse controls the world rather than the cursor), I place the cursor back where it was before tracking started. When I do this, the cursor often flickers in the center of the window for a split second before moving back to its original position, despite the fact that I call SetCursorPos() before ShowCursor().

Any ideas?

So do a bounds check Check wether the mouse has moved out of the client area at all times, this way you do not have to center the mouse...

I really dont see the point of centering the mouse. Just hide it when you dont want to see it and show when you want to...

A boundscheck will let the mouse move around the window, but it will still flash when I re-show it because it won''t be in the place where it originally was.

The point of keeping it in the center is because if I don''t, and it moves out of the window, then it will be visible again. It''s easier to just check it and put it in the window center than to keep it within window bounds if I don''t want it going outside the window.

I am aware of DirectInput.

Does anybody have any idea about the real problem? Thanks for the suggestions, but I have thought over my method, and it seems to me to be fine. I just don''t know why the mouse isn''t positioned and shown in the order that the calls are made.

It is very simple...

Mouse moves
Check for bounds
If within bounds
If mouse moves beyond the bounds place back within the bounds.

Hide mouse

Show mouse should show it at latest position

You can still track the mouse movent even if it''s hidden or not.

ShowCursor(WM_SHOW/WM_HIDE) only hides the icon it does not stop the message loop from reading the mouse movements.

...

I understand what you''re saying, it''s trivial, I know that. However, the method I have chosen involves keeping it in the center.

If I check for bounds etc and show the mouse, effectively the user would have done something to hide the mouse and begin tracking it *hidden* at some point, and when they do something to show it again, it would have moved. That is not what I want.

I know you can track movement if it''s not hidden, what I''m doing requires it to be hidden.

And actually, you pass TRUE and FALSE to ShowCursor, not the windows messages for show and hide. I understand how that works.

I am not asking for critiques on what I''m doing, when I haven''t even explained the exact scenario for which I''m using this. There''s no need to, because my question is simply:

Does anyone know why the mouse would be shown before being moved if you call SetCursorPos() before ShowCursor()? And if so, can any solutions be suggested?

$5 on Mouse Cursor Acceleration Artifact.

Magmai Kai Holmlor

"Oh, like you''ve never written buggy code" - Lee

"What I see is a system that _could do anything - but currently does nothing !" - Anonymous CEO

That''s what I was thinking too, but I didn''t think of showing the cursor on the following frame. That''s a good idea, I''ll try it.

Thanks!