QTimer ->start(0) + OpenGL + resize/move window => crash

[spud]

Your third approach seems to be correct since you aren't using animations.
Use QKeyEvent::isAutoRepeat () to find out if your handling an 'real' key press.
For fluid motion when a key is pressed i suggest you start a timer when a key is pressed and kill it when all keys have been released. You could use a QSet to keep track of pressed keys.

//member
QSet<int> pressedKeys;
 
void keyPressEvent(QKeyEvent* e)
{
    if(e->isAutoRepeat())
        return;
    if(pressedKeys.isEmpty())
        startTimer(40);
    pressedKeys.insert(e->key());
}
 
void timerEvent(QTimerEvent* e)
{
    if(pressedKeys.contains(Qt::Key_Up))
       ...;
    if(pressedKeys.contains(Qt::Key_Left))
       ...;
    updateGL();
}
 
void keyReleaseEvent(QKeyEvent* e)
{
    pressedKeys.remove(e->key());
    if(pressedKeys.isEmpty())
        startTimer(40);
}

//member
QSet<int> pressedKeys;

void keyPressEvent(QKeyEvent* e)
{
    if(e->isAutoRepeat())
        return;
    if(pressedKeys.isEmpty())
        startTimer(40);
    pressedKeys.insert(e->key());
}

void timerEvent(QTimerEvent* e)
{
    if(pressedKeys.contains(Qt::Key_Up))
       ...;
    if(pressedKeys.contains(Qt::Key_Left))
       ...;
    updateGL();
}

void keyReleaseEvent(QKeyEvent* e)
{
    pressedKeys.remove(e->key());
    if(pressedKeys.isEmpty())
        startTimer(40);
}

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This way you should be able to catch any combination of keys being pressed.

[anthibug]

I'm going to kill me. This crash was due to a simple division by 0 in my FPS counter. ahah
I discover it after compiling debug libraries and try a debug...
At least I discover some QT functionnalities...

last_time = current_time;
current_time = QTime::currentTime();
elapsed_time = (current_time.second()*1000 + current_time.msec()) - (last_time.second()*1000 + last_time.msec());
[B]this->fps = 1000 / elapsed_time;[/B]

last_time = current_time;
current_time = QTime::currentTime();
elapsed_time = (current_time.second()*1000 + current_time.msec()) - (last_time.second()*1000 + last_time.msec());
[B]this->fps = 1000 / elapsed_time;[/B]

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I don't exactly know why elapsed_time could be set to 0, at least I know it was (only) happening on some resize events.
I'm guessing it's due to the functions call order ; my guest is that :
-when a resize event happens it stops the current function execution
-the rest of the code is not executed until and of resize
-... i don't know

i just did a test and of course, during a resize, my infinite loop function is not called

whatever, this solved my problem :

if(elapsed_time <= 0)
	this->fps = 0;
else
	this->fps = 1000 / elapsed_time;

if(elapsed_time <= 0)
	this->fps = 0;
else
	this->fps = 1000 / elapsed_time;

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so simple....

I'm gonna check on your tips in the following days spud, thanks for helping !
If it works I will improve a LOT my application.

A little preview right there:

[jacek]

elapsed_time = (current_time.second()*1000 + current_time.msec()) - (last_time.second()*1000 + last_time.msec());

Take a look at QTime::msecsTo().

[anthibug]

Thanks jacek, I missed it !

Thanks spud you got the idea : a timer to refresh the scene if their is still a pressed key....
I managed to do this with minor modifications :

void gldrawer::keyPressEvent(QKeyEvent * event)
{
	if(event->isAutoRepeat())
        return;
    if(_activeKeystates == 0)
    	qTimerRedraw.start(0);
	for(KeyStates::iterator it = _keystates.begin();it != _keystates.end();
	            it++)
	{
	    if (event->key() == it->first)
	    {	    	
	        it->second = true;
	        _activeKeystates++;
 
	        break;
	    }
    }
}
 
void gldrawer::keyReleaseEvent(QKeyEvent * event)
{
	for (KeyStates::iterator it = _keystates.begin();it != _keystates.end();
	            it++)
	{
	    if (event->key() == it->first && !event->isAutoRepeat())
	    {
	        it->second = false;
	        _activeKeystates--;
	        break;
	    }
    }
    if(_activeKeystates == 0)
    	qTimerRedraw.stop();
}

void gldrawer::keyPressEvent(QKeyEvent * event)
{
	if(event->isAutoRepeat())
        return;
    if(_activeKeystates == 0)
    	qTimerRedraw.start(0);
	for(KeyStates::iterator it = _keystates.begin();it != _keystates.end();
	            it++)
	{
	    if (event->key() == it->first)
	    {	    	
	        it->second = true;
	        _activeKeystates++;
	        
	        break;
	    }
    }
}

void gldrawer::keyReleaseEvent(QKeyEvent * event)
{
	for (KeyStates::iterator it = _keystates.begin();it != _keystates.end();
	            it++)
	{
	    if (event->key() == it->first && !event->isAutoRepeat())
	    {
	        it->second = false;
	        _activeKeystates--;
	        break;
	    }
    }
    if(_activeKeystates == 0)
    	qTimerRedraw.stop();
}

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where _keystates is a std::map<Qt::Key, bool> (yes I know I could use QMap, I will ...)

Right now CPU is at 0%.
If I push a key (and stay pushed) the scene is continously refreshed : one core is at 100%.
I can push keys with modifiers :-)

Thanks !


----


I'm currently having problems dealing with QSlider :
I have to repaint the scene during a call to my slot corresponding to the "valueChanged" signal of the QSlider. The problem is that it's make the slider freeze/lag.
In can understand that because each time I move the slider it redraws the scene, and that takes time.
The scene is updated in real time according to the position of the slider, but the position of the slider itself is lagging (juste visually)...
Could be a user issue in the future.
I tried the "sliderReleased()" but the problem is that the scene is not updated in real time.

[anthibug]

I managed to do that the same way I did with the keys :
-if the QSlider is moved then repaint (qTimerRedraw.start(0)
-when released stop to repaint

... so easy