[Freeglut-developer] More mouse wheel API

[Fay J. F C. AAC/W. <joh...@eg...>]

(1) Let me repeat a bit about what Windows does with the mouse wheel.  There
is a defined constant called "WHEEL_DELTA" which is currently set to 120.
When a wheel turn event (we've been calling it a "click") comes in, one of
the arguments unpacks to give a value of +WHEEL_DELTA for a turn in one
direction and of -WHEEL_DELTA for a turn in the other direction.  I think
this is a built-in accumulation and is looking forward to the days of
continuous mouse wheels, when this argument will unpack to give different
values than +/-120.

In the interests of cross-platform compatibility, I would like to request
that our "direction" argument be +/-120 instead of +/-1.  I also think this
will help us in the future.

(2) We definitely need mouse coordinates.  Since Windows provides them with
the event (admittedly we have to subtract off the window position, but that
should be simple), shall I change the "freeglut" Windows code to use these
most current coordinates instead of the coordinates from the last motion
event?

(3) I think the suggestion of having "freeglut" call the mouse callback if
there is no mouse wheel callback is an excellent one.  Perhaps we can
specify the following for everybody:
	- If your application specifies a mouse wheel callback, then buttons
4 and 5 (on a multi-button mouse) or the mouse wheel (on a wheeled mouse)
will invoke this callback.
	- If your application does not specify a mouse wheel callback but
specifies a mouse callback, then buttons 4 and 5 (on a multi-button mouse)
or the mouse wheel (on a wheeled mouse) will invoke the mouse callback.
	- If your application does not specify either a mouse callback or a
mouse wheel callback, then all mouse button clicks or wheel turns will be
ignored.
	- If you want the mouse wheel disabled, specify a mouse wheel
callback that does nothing.

I also think that we should NOT distinguish (in our API) between systems
that report mouse wheel events as buttons and systems that do not report
mouse wheel events as buttons.  Removing the platform dependencies is the
whole purpose of this library.  In fact, in my draft mouse wheel handling
code for Windows, I have put in that if there is no mouse wheel callback
then "freeglut" is to call the mouse callback ... twice in a row.

(4) On a different but related subject, should we deprecate
"GLUT_LEFT_BUTTON", "GLUT_MIDDLE_BUTTON", and "GLUT_RIGHT_BUTTON"?  Their
values are 0, 1, and 2 at the moment.  Steve suggested in a separate e-mail
that numerical values were preferable.

John F. Fay
joh...@eg...



-----Original Message-----
From: Steve Baker [mailto:sjb...@ai...]
Sent: Thursday, October 02, 2003 10:27 PM
To: fre...@li...
Subject: Re: [Freeglut-developer] Freeglut 2.0.0 is Released!

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