Hi Chris,
I've just scanned your email quickly as I have tone of emails to get
through this morning. Here's a couple of high level suggestion to get
your on your way:
1) You conceptually have a single View, with multiple Cameras - the
osgViewer library is designed to fit this
concept so you should use a single osgViewer::View(or Viewer is
is subclassed from View) and then multiple
slave Camera to provide the different components of the view.
2) For rendering cubes you don't use asymmetric frustums, but
rotated ones, so you modify the view matrix
offset and don't need to touch the perspective matrix.
3) The osgView::View::setUpViewFor3DSphericalDisplay(..)
implementation found in src/osgViewer/View.cpp
provides an example of setting up the slave Camara's of a View
to render the scene into the 6 faces of
cubemap and then has final slave Camera that renders the
results to the screen with distortion correction.
This is rather more sophisticated than you need as you won't
need 6 cameras, render to texture or the
distortion correction step, but if you can understand how it
works then your setup will be straight forward.
Please note the use of view matrix offsets to get the cube map positions.
Robert.
On Fri, Oct 7, 2011 at 9:13 AM, Christopher Geelen
<[email protected]> wrote:
> Hello,
>
> This will be my first post, so feel free to correct me when I'm forgetting to
> explain some facts/not include neccesary files, when this seems obvious.
>
> Let me first explain the situation. Last years december TheVirus (Bart Jan)
> posted some questions here, about setting up a view across multiple screens,
> when these screens are perpendicular to each other. To quote the situation:
>
>
> TheVirus wrote:
>> I want to build an app which should have one camera (or two identical,
>> meaning that they are at the same position, facing the same direction, if
>> that is more convenient) and multiple screens. The screens will be aligned
>> in a 90 degree angle towards each other. So they are perpendicular:
>> top view:
>>
>> Code:
>>
>> | <- 1
>> | 2
>> | |
>> | v
>> |________
>>
>>
>> O
>>
>>
>>
>> Where O is the eye or camera. It's like looking at a box with holes in all
>> sides and you want to see the inside. And the screens on which I want to
>> project are the sides of the box.
>>
>> [..]
>>
>>
>> In the PcubeE paper they say:
>> To generate perspective-corrected images on each screen of pCubee, we use a
>> standard off-axis projection scheme as described by Deering [9]. This is
>> done in OSG by creating three View objects that correspond to the three
>> visible screens on pCubee. The camera for each View is located at the user’s
>> eye-position (which I will set manually at like right in the middle of the
>> two screens, so at 45 degrees), oriented perpendicular to its corresponding
>> virtual screen, and given a view frustum that passes through the corners of
>> its virtual screen.
>>
>> [/i]
>
>
> Now, months later, I am assigned to finish the task Bart Jan started. We have
> created a cube, and our goal is to set up views so that we can 'look' inside
> the box. The purpose is to make it all embedded.
> Since then, I already made quite some progress (to say it myself) with
> learning OSG and to apply it to a BeagleBoard (which is where the application
> will run, eventually). The code is made to run at three different processors,
> but within the code they will communicate to each other through a serial
> connection. The code is attached to this post, but please note that this code
> is adjusted from the Beagleboard to make it work on the PC (Visual Studio),
> so it may seem a bit loose. Still this was neccessary to disable sensors etc,
> and to make it possible to run at just one screen/processor.
> To explain the functionality: In Box.cpp and CreateWindows.cpp you must
> define at which screen you are looking. BART = on top, MARTIJN = front/back
> and GERTJAN = from the side. With the keys 'a'/'d' you can simulate the
> sensor functionality, this represents rotating the cube around one axis.
>
> In this code I am rotating the camera by setting the view matrix with the
> eye, center, up vectors. This is working. Note that I am setting the radius
> hardcoded (r = 10). Since the camera will start on-axis, that is facing the
> screen and looking directly inside the box, you will see all three objects.
> But when this camera is rotated, the projection matrix has to be adjusted, so
> that you can see a perspective view, only at one side of the 'box'.
> Eventually this view should dissapear, when the camera is at such a position,
> that it cannot see that side of the box.
>
> And this is where the trouble begins. I am having trouble understanding how
> to correctly set up this projection matrix. If I understand correctly, I have
> to adjust the left/right settings of the frustum, so this will coincide with
> the left and right boundaries of the box. But how can I calculate these
> correctly? I have already tried some calculations with trigonometry, but
> these don't produce the result I am looking for. I'm beginning to think I may
> have a wrong understanding of where and how the frustum is defined, so please
> help. In the code, the frustum is calculated in the CustomCamera.cpp, when
> key 'a' is pressed.
>
> I know there will be additional questions to further clear out this problem,
> because I may forget something to tell that seems obvious for me, so please
> don't hesitate to ask.
>
> Thank you!
>
> Chris[/quote]
>
> ------------------
> Read this topic online here:
> http://forum.openscenegraph.org/viewtopic.php?p=43246#43246
>
>
>
>
> Attachments:
> http://forum.openscenegraph.org//files/main_502.cpp
> http://forum.openscenegraph.org//files/customcamera_503.h
> http://forum.openscenegraph.org//files/customcamera_141.cpp
> http://forum.openscenegraph.org//files/createwindows_156.cpp
> http://forum.openscenegraph.org//files/box_158.cpp
>
>
> _______________________________________________
> osg-users mailing list
> [email protected]
> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
>
_______________________________________________
osg-users mailing list
[email protected]
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
