[osg-users] Slave Cameras projection matrices and aspect ratio

[Joseanibal Colon Ramos]

Hi Robert,

Thanks, you are right. I tested my config file separately and it worked
fine. I re-included the

Lens {
    Perspective 42.4 45.0 1.0 100.0;
}

in the configuration file and avoided messing with the FOV, aspect ratio
parameters inside my code by avoiding making calls to
"setProjectionMatrixAsPerspective(*)" with conflicting values. I allow OSG
to do its job now and it is doing the right thing. I am getting the same
results I used to get on OSG 1.2 Perfect. Thanks for the OSG viewer hint.

-J


On Fri, July 25, 2008 8:19 am, Robert Osfield wrote:
> Hi Jose,
>
> I tried the .cfg out and it works, but since osgviewer cow.osg -c
> your.cfg doesn't contain your specific master projection matrix nor
> have your profiling code I can't really test what your are seeing at
> your end.
>
> Given I'm busy working getting a 2.6 rc1 out the door, and am away
> from tomorrow there is little time I have to further chase this up.
>
> As a general note, the slave projection matrices are update on each
> frame by multiplying the master camera's projection  matrix by the
> slave projection offset matrix.  This means updates to the slaves
> projection matrix will be overwritten, which is why you aren't seeing
> these changes.
>
> As to why you are seeing different values, I'm afraid I can't give a
> specific reason for this, one would have to look at your specific code
> against osgProducer and against osgViewer, and these both cases so you
> can see it first hand and profile the values.
>
> Robert.
>
> On Thu, Jul 24, 2008 at 10:57 PM, Joseanibal Colon Ramos
> <jcolon at email.arc.nasa.gov> wrote:
>> Thanks Robert,
>>
>> Here is the Producer config file I am using:
>>
>> *******************************************************
>> Camera "Camera-1"
>> {
>>    RenderSurface "Window-1"
>>    {
>>             Visual  { SetSimple }
>>             Screen 0;
>>             WindowRect 0 30 426 341;
>>             Border on;
>>             InputRectangle -1.0 1.0 -1.0 1.0;
>>    }
>>
>>    Offset {
>>           Rotate 42.4 0 1 0;
>>    }
>> }
>>
>> Camera "Camera-2"
>> {
>>    RenderSurface "Window-2"
>>    {
>>            Visual  { SetSimple }
>>            Screen 0;
>>            WindowRect 426 30 426 341;
>>            Border on;
>>             InputRectangle -1.0 1.0 -1.0 1.0;
>>    }
>>
>>    Offset {
>>            Rotate 0.0 0 1 0;
>>    }
>> }
>>
>>
>> Camera "Camera-3"
>> {
>>    RenderSurface "Window-3"
>>    {
>>            Visual  { SetSimple }
>>            Screen 0;
>>            WindowRect 852 30 426 341;
>>            Border on;
>>             InputRectangle -1.0 1.0 -1.0 1.0;
>>    }
>>
>>    Offset {
>>            Rotate -42.4 0 1 0;
>>    }
>> }
>>
>>
>> InputArea
>> {
>>    RenderSurface "Window-1" ;
>>    RenderSurface "Window-2" ;
>>    RenderSurface "Window-3" ;
>> }
>> *******************************************************
>>
>> I have tested and compared it with OSG 2.4 and OSG 1.2 with (very)
>> slightly different results. I need the results to be exactly the same as
>> in OSG 1.2.
>>
>> My understanding is that the "InputArea" is no longer required, but is
>> is
>> still there for backwards compatibility with OSG 1.2 . For each
>> RenderSurface block I used to have a Lens configuration block like this
>> one:
>>  Lens {
>>            Perspective 42.4 45.0 1.0 100.0;
>>    }
>> but I no longer use it because I set the parameters in my code as:
>>
>> vwr.getCamera()->setProjectionMatrixAsPerspective(VerticalFOV,
>> AspectRatio,
>> NearClip, FarClip);  //for the master cam.
>>
>> I've tried doing it for each of the Slave cams as well:
>> vwr.getSlave(int i)._camera->setProjectionMat..... (same thing) . but it
>> doesn't change anything.
>>
>> In this example:
>> AspectRatio = 1.33
>> VerticalFOV = 42.4/AspectRatio
>> NearClip = doesn't matter right now
>> FarClip = doesn't matter right now
>>
>>
>>
>>
>> Whe I run my program (version OSG 2.4) I get the following runtime
>> values:
>>
>> Master cam: (fov, aspect, near, far)31.807951987997, 1.333, 0.02,
>> 199.9999
>>
>> Slave cam # 0 (fov, aspect, near, far): 31.8079530956935,
>> 1.31249230769231, 305.702400933255, 70223.0343790709
>>
>> Slave cam # 1 (fov, aspect, near, far): 31.8079530956935,
>> 1.31249230769231, 443.807876894962, 43394.6435810508
>>
>> Slave cam # 2 (fov, aspect, near, far): 31.8079530956935,
>> 1.31249230769231, 292.024441391996, 54427.4475917436
>>
>> You may ignore the Near/Far values. You can notice how the slave cams
>> manipulated the aspect ratio slightly. The VerticalFOV seems right.
>>
>>
>>
>>
>>
>> When I run OSG 1.2 I get this:
>> (no master cam concept)
>>
>> camera 0 FOV(h,v) = 42.4,31.808
>>     aspect_ratio : 1.36129
>>
>> camera 1 FOV(h,v) = 42.4,31.808
>>     aspect_ratio : 1.36129
>>
>> camera 2 FOV(h,v) = 42.4,31.808
>>     aspect_ratio : 1.36129
>>
>> I don't know how the aspect ration became that value either, because the
>> aspect ratio should have been forced to 1.33. Anyways this works fine.
>>
>> I'd like to get the OSG 1.2 results, although none of these numbers
>> quite
>> make sense to me, and the corresponding values of each version are very
>> close. I'll also provide the projection matrices which are a bit off as
>> well:
>>
>> OSG2.4:
>> Slave cam 0:
>> projectionMatrix : {
>>        2.67399874028772 0 0 0
>>        0 3.50960277740655 0 0
>>        0 0 -1.00874468153415 -1
>>        0 0 -614.078072006898 0
>> }
>> Slave cam 1:
>> projectionMatrix : {
>>        2.67399874028772 0 0 0
>>        0 3.50960277740655 0 0
>>        0 0 -1.02066585525608 -1
>>        0 0 -896.787423135345 0
>> }
>> Slave cam2:
>>        projectionMatrix : {
>>        2.67399874028772 0 0 0
>>        0 3.50960277740655 0 0
>>        0 0 -1.01078866385069 -1
>>        0 0 -587.199436318357 0
>> }
>>
>> What they should be: (OSG 1.2):
>> Cam 0:
>> 2.57815,0,0,0
>> 0,3.5096,0,0
>> 0,0,-1,-1
>> 0,0,-20,0
>>
>> Cam 1:
>> 2.57815,0,0,0
>> 0,3.5096,0,0
>> 0,0,-1,-1
>> 0,0,-20,0
>>
>> Cam2:
>> 2.57815,0,0,0
>> 0,3.5096,0,0
>> 0,0,-1,-1
>> 0,0,-20,0
>>
>> (all the same). In OSG 2.4, if I hard-code my Master cam's
>> projectionMatrix to be like the one printed out in OSG 1.2 I get the
>> good
>> image result.
>>
>> The big question is: What parameter is off? Why? and How do I fix it?
>> Any help with anything here mentioned will be VERY welcomed!!
>> Thanks,
>>
>> -Jose
>>
>>
>>
>>
>>
>>
>>
>>
>> On Thu, July 24, 2008 3:12 am, Robert Osfield wrote:
>>> Hi Joseanibal,
>>>
>>> Could you provide a Producer .cfg that you are having problem with.
>>> Could you also please specify which versions of the OSG you've tried.
>>>
>>> Robert.
>>>
>>> On Thu, Jul 24, 2008 at 3:43 AM, Joseanibal Colon Ramos
>>> <jcolon at email.arc.nasa.gov> wrote:
>>>> Hi Anyone,
>>>>
>>>> I need to fix this ASAP. I am using OSG 2.4+ with old Producer Config
>>>> files. OSG creates slave cameras for my multiple window configuration
>>>> (one
>>>> for each). The resulting settings are not quite like specified in my
>>>> configuration file. Field of Views are mostly OK, but it is altering
>>>> the
>>>> aspect ratios of the slave cams and providing me with an image
>>>> slightly
>>>> off from how it should be. I've tried setting the Slave cams'
>>>> projection
>>>> matrix, (setProjectionMatrixAsPerspective) with particular aspect
>>>> ratios
>>>> etc, but the aspect ratio value is being overriden somewhere and
>>>> adjusted
>>>> a little bit. However, the Master cam's aspect ratio is correct. How
>>>> do
>>>> I
>>>> correctly set the Slave cam's aspect ratios?? and Why are the Producer
>>>> Configuration files not doing what they used to in OSG 1.2  ?? Anyone
>>>> please let me know soon, THANKS!
>>>>
>>>> -JCOLON
>>>>
>>>>
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>>
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