[Interest] [Qt3D] Camera controller

[Sean Harmer]

Aha, a timely guinea pig :)

We've just merged in a bunch of changes to extend the Qt3DInput library. 
Please take a look at:

http://code.qt.io/cgit/qt/qt3d.git/tree/examples/qt3d/simple-qml/CameraController.qml

for an example where we exercise the new API a little. We are in the 
process of folding something back into Qt3D proper to act as a camera 
(or anything else with a transform component) controller, but you can 
easily roll your own custom one with what is there now.

The basic concepts are:

1) Instantiate 1 or more QAbstractPhysicalDevice's - MouseController, 
KeyboardController so far. These will be renamed to something without 
Controller appended shortly. These house a set of "axes" and "buttons". 
The axes can be processed in some simple ways as specified by an 
AxisSettings object.  E.g. for a gamepad controller or other analogue 
devices we can support deadzones 
(https://codereview.qt-project.org/#/c/143265/) and hopefully tomorrow, 
low pass filtering. We also have the ability to add more devices by way 
of plugins. We have a WIP plugin for the PS3 SixAxis controller for e.g.

2) The physical devices can be mapped onto LogicalDevices as shown in 
the simple-qml example above. This mapping takes the form of specifying 
axes and actions on the logical device and declaring which physical 
device axis/buttons they originate from. Support for chords and 
sequences will land shortly. The logical device allows you to customise 
the input within your application to map through to some named axes and 
actions in your application and allows support for multiple input 
devices and dynamically reconfiguring them.

3) Instantiate a AxisActionHandler component and associate a logical 
device with it. The handler's actionStarted(), actionFinished() and 
axisValueChanged() signals will be fired as appropriate for you to react 
to in a signal handler.

4) If you need to perform smooth animations per frame as a result of 
input, also instantiate a LogicComponent and implement it's signal 
handler which gets the frame delta-time passed in as an argument. Use 
this to multiply your calculated velocity (or whatever) by.

Hope this helps. If you have ideas for how to improve this then please 
let us know.

Cheers,

Sean

On 08/12/2015 14:51, Nye wrote:
> Hello,
> I wish to have the camera movement bound to a certain "slice" of the 
> world space. I didn't see that to be available through the default 
> implementation, so I assume I'd have to write my own component that 
> implements the input aspect and attach it to my camera. I've gone 
> through the sources, because at this point the documentation is pretty 
> thin. Unfortunately, I don't seem able to grasp at this point how the 
> aspect will notify my component of the input events. I have 2 questions:
> 1. For my case, am I assuming correctly that I'd need my own component 
> to realize that functionality?
> 2. If I do need a separate component, how can I make it? I understand 
> that I have to subclass from QComponent, but how would I be notified 
> for the input events occurring? Do I need to implement some other 
> classes to make it work (I saw a number of "functors" created in 
> Qt3D's source)?
>
> Any help is greatly appreciated.
>
> Kind regards,
> Konstantin.
>
>
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> Interest mailing list
> Interest at qt-project.org
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