What is the correct way to handle keyboard input?

[sd]

Hi there,

I have looked at the tutorial on movement (No#4) and also this:
http://www.irrlicht3d.org/wiki/index.ph ... ntReceiver
on bool keys type stuff.

But currently there are a few things I don't understand:

1. Often with the other postings on using bool keys, it seems the state of the key (up/down/pressed/released) is being checked in the IEventReceiver OnEvent method or whatever, but then where are the retreived states stored in the bool array actually used? Are they used in the:

while(device->run()) { ... }

loop?

Or reused in the OnEvent handler? But shouldn't you use some kind of game timing rather than just an keypress detector method?

2. How does ensure the 3D object being moved does so in a consistant timed way? Use an ITimer object or something?

3. Currently I have it all just done from the OnEvent method, changing the position of my 3D object, etc. When I first press the "Left" key and hold it, first the 3D object moves to the left a unit, then pauses a bit, then realizes the key is still held down and continues to move. Why does it have to pause? How to get around that?

Also as a side note, I was a bit confused trying to read the API documentation, and couldn't find anything on the beginScene thing or the SColor thing? Where do I find info on those to learn more?

Thanks,
SD.

[bitplane]

1. Often with the other postings on using bool keys, it seems the state of the key (up/down/pressed/released) is being checked in the IEventReceiver OnEvent method or whatever, but then where are the retreived states stored in the bool array actually used? Are they used in the:

while(device->run()) { ... }
loop?

Yes, usually you'd check MyEventReceiver->AllKeys[KEY_KEY_WHATEVER] in your game loop.

2. How does ensure the 3D object being moved does so in a consistant timed way? Use an ITimer object or something?

Yes, store the time at the last loop (device->getTimer()->getTime()), and use the difference to work out how far you should move the actor (distance=direction*time)

3. Currently I have it all just done from the OnEvent method, changing the position of my 3D object, etc. When I first press the "Left" key and hold it, first the 3D object moves to the left a unit, then pauses a bit, then realizes the key is still held down and continues to move. Why does it have to pause? How to get around that?

There's no way to get around this when the movement code is inside your event receiver. Your event receiver code is called when a key is pressed or released, you need to move your actors every frame, if a key is pressed.

Also as a side note, I was a bit confused trying to read the API documentation, and couldn't find anything on the beginScene thing or the SColor thing? Where do I find info on those to learn more?

beginScene is called at the start of a render loop before drawing anything, SColor is just how the engine holds colours. Which part is confusing you?

[sd]

Thanks, that answers my questions and seems to be just what I was looking for =). Seems I didn't look hard enough into the API docs to find those functions.

Thanks,
SD.

[dlangdev]

3. Currently I have it all just done from the OnEvent method, changing the position of my 3D object, etc. When I first press the "Left" key and hold it, first the 3D object moves to the left a unit, then pauses a bit, then realizes the key is still held down and continues to move. Why does it have to pause? How to get around that?

Thanks,
SD.

Try understanding the code posted below...

Code: Select all

bool CCameraActorFPSSceneNode::OnEvent(const SEvent& event)
{
	if (event.EventType == EET_KEY_INPUT_EVENT)
	{
		const u32 cnt = KeyMap.size();
		for (u32 i=0; i<cnt; ++i)
		{
			if (KeyMap[i].keycode == event.KeyInput.Key)
			{
				CursorKeys[KeyMap[i].action] = event.KeyInput.PressedDown; 
				
				actionState = KeyMap[i].action;

				if ( actionState != oldActionState )
				{
					if ( event.KeyInput.PressedDown )
					{
						if ( actionState == 0 )
						{
							nodeActor->setFrameLoop(1,14);
						}
						if ( actionState == 2 || actionState == 3 )
						{
							nodeActor->setFrameLoop(15,30);
						}
					}
					else
					{
						//nodeActor->setFrameLoop(184,205);
						nodeActor->setFrameLoop(206,250);
					}
					oldActionState = actionState;
				}
				else
				{
					if ( event.KeyInput.PressedDown == false )
					{
						//nodeActor->setFrameLoop(184,205);
						nodeActor->setFrameLoop(206,250);
						oldActionState = -1;
					}
					
				}

				if ( InputReceiverEnabled )
					return true;
			}
		}

		actionState = -1;
		if ( actionState != oldActionState )
		{
			if ( actionState = -1 )
			{
				//nodeActor->setFrameLoop(184,205);
				nodeActor->setFrameLoop(206,250);
			}
			oldActionState = actionState;
		}
	}

	return false;
}