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double click with glut

Started by mstein Mar 15, 2003 at 8:31 PM 8 replies 5.3k views

Original Post

Mar 15, 2003 at 8:31 PM

I am trying to implement a double click while using GLUT, any ideas. . . I know how to see if the mouse has been clicked twice in a given time frame. I use the ftime function for that. But my problem comes when the user has single clicked, does not double click, and then i have to send the single click event off. Confused . . . me too.

mstein

Mar 15, 2003 at 9:55 PM

okay i will elaborate more.

i have my glutMouseFunc --> mouse()

whenever the mouse is clicked, i call a function in one of my objects, we will call board. THe thing is i want to be able to differentiate between single and doubleclicks. So if the user single clicks, i can pass something like dclick=false to board and if the user doubleclicks i can send dclick = true. Problem is, whenever any click occurs the function of board is called. So if the user does double-click, the function in board will receive a single click event and a double click event. Is there anyway I can wait a half-second after a single-click to see if the user double clicks, and then if they dont, just behave as though the single click occurred, albeit, half a second later.

Kuladus

Mar 16, 2003 at 3:46 AM

the way i would do that is to start a new timer function when the callback for a click is executed. so...

start of program: start clickTimer;

CLICK-> mouse()....check clickTimer; restart clickTimer;

if checkTimer is less then 0.1s then send dbClick to board;
else send singleClick to board;

so you need a timing function called clickTimer obviously. this should be adequate for your needs.

mstein

Mar 16, 2003 at 2:09 PM

i guess i still do not understand how that separates the first click (which may be part of a doubleclick) not getting sent during the callback.

Fruny

Mar 16, 2003 at 2:25 PM

quote:
Original post by mstein
i guess i still do not understand how that separates the first click (which may be part of a doubleclick) not getting sent during the callback.

It does not. GUIs do process the first click as if it was a single click, and then the double click if/when it comes.

An alternative solution would be to register a timer on the first click, and if it expires without a second click being sent, then you process the double click. Otherwise, you process a single click. Of course, the disadvantage is that the GUI would respond immediately to single clicks (latency is a bad thing.)

mstein

Mar 16, 2003 at 2:33 PM

quote:
Of course, the disadvantage is that the GUI would respond immediately to single clicks (latency is a bad thing.)

I assume you mean "wouldn''t".

I am personally lost on the implementation of a timer function. I have used Gluts once, but it seems that for this it would perhaps have to be multi-threaded, so that the mouse event can still get picked up. Please stop me if I am running from the path here. . .

Fruny

Mar 16, 2003 at 2:39 PM

quote:
Original post by mstein
I assume you mean "wouldn''t".

Yes.

quote:

I am personally lost on the implementation of a timer function.

You have no excuse not to learn, it really is trivial.

quote:

I have used Gluts once, but it seems that for this it would perhaps have to be multi-threaded, so that the mouse event can still get picked up.

No.

quote:

Please stop me if I am running from the path here. . .

Stop! Use glutTimerFunc().

mstein

Mar 16, 2003 at 2:42 PM

haha, okay, away I go. . . thank you for your help.

mstein

Mar 16, 2003 at 3:38 PM

got it working . .. my glutMouseFunc just keeps track of clicks and launches the timer . . . the timer it self sends out the click event to my board object.

quote:

Of course, the disadvantage is that the GUI would respond immediately to single clicks (latency is a bad thing.)

Yes, right now the doubleclickspeed is at 500 ms and that was way to slow (well a half second of waiting) . . . when you all doubleclick, how fast do you expect to have to click. I set it to 100 ms and that was too fast. I can do 200 ms just fine, what do you all think.

Fruny

Mar 16, 2003 at 3:59 PM

My machine is set at 250ms. Of course, a single-click is also generated each time.

Edit: Yeah 3600^{th post !

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[edited by - Fruny on March 16, 2003 4:59:43 PM]}

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