[PD] [GEM-dev] Oculus Rift distortion/support

[Cyrille Henry]

hello Michael,

i copy this mail to pd list, since it is of generic interest.


but first : did anyone have a working example of oculus rift in GEM?

Rendering on stereo is a nice idea, but as you noticed, in order to "sumarized" all the object it's easier to render in a framebuffer then distord this resulting image.

Ideally, you would use stereo parametter to render in a framebuffer, then render the framebuffer through a shader in the main windows (whitout stereo).
but i dont thing you can do that in Gem.


Here is how i would do it.
2 framebuffer, and an abstraction that render primitive in the 2 framebuffer.
then render this 2 framebuffer in the main windows with a shader, or merge this 2 FB in a 3d one and render this last FB with the shader.

some things need to be adjusted (angle of view of the virtual cam / eyes distance /framebuffer size, etc).
and the shader has to be added...

Cheers
c

Le 26/10/2013 17:58, Michael Mihocic a écrit :
> Hi Cyrille,
>
> I am still working on the Oculus Rift implementation and I finally managed to get some basic knowledge with shaders. However, now I know how to use shaders in Gem and on my Windows OS and I already played around with simple barrrel distortion examples... Thank you again for your previous support!!
>
> You proposed a solution (your Email below) how to implement the barrel distortion to our virtual world:
> /"1st : left eye view without distortion, rendered in a frame buffer //
> //2nd : right eye view (no distortion / framebuffer) //
> //3rd : using the 2 previous texture and a shader, render the final image"/
>
> I'm still having some questions:
> 1.) Our current world is using the gemwin "stereo" parameter to create 2 images (-> actually it is one Gem window, but we adjusted resolution and size to fit it to our old HMD and each eye can see only half of the image; see attachement).
> I'm wondering if it possible to use just ONE shader to render the entire image in one step?? But I'm not sure if this is possible with texturing??
> If not: Will I still be able to use the "stereo" parameter in gemwin??
>
> 2.) As you can see in my screenshot: our world consists of many objects (cubes, lines, fadecrosses, spheres, ...). How can I summarize those objects, before processing them? Do I need to use a gemframebuffer for every single object??
>
> My plan is to finish in 1(-2) months. If everything is working, I will provide the example patch & shaders to the pd/Gem community.
>
> Best regards, Michael
>
>
> Our current view:
>
>
> Desired Rift distortion:
>
>
>
>
> -------- Original-Nachricht --------
> Betreff: Re: [GEM-dev] Oculus Rift distortion/support
> Von: Cyrille Henry <ch at chnry.net>
> An: Michael Mihocic <michael.mihocic at oeaw.ac.at>
> Kopie (CC): gem-dev at iem.at
> Datum: 25.07.2013 12:17
>> hello,
>>
>> one have to use shader in order create the image distortion.
>>
>> i think oculus should provide standard shader that you have to insert in your rendering process.
>>
>> the only problem is that you have to do 2 rendering : one for each eye.
>> The best solution is to do a 3 pass rendering :
>> 1st : left eye view without distortion, rendered in a frame buffer
>> 2nd : right eye view (no distortion / framebuffer)
>> 3rd : using the 2 previous texture and a shader, render the final image
>>
>> cheers
>> c
>>
>>
>> Le 25/07/2013 12:04, Michael Mihocic a écrit :
>>> Dear list,
>>>
>>> we are using GEM with a head-mounted-display to present a virtual world to subjects performing acoustic localization experiments.
>>>
>>> Now we plan to switch from our current HMD to Oculus Rift (an upcoming virtual reality head-mounted display). Therefore we need to modify our image and add (asymetric) barrel distortion to the represented image. (The image distortion is compensated by the lenses in Oculus Rift.)
>>>
>>> My questions now:
>>> - Is there an easy solution to implement barrel distortion to the rendered window in GEM?
>>> - Does anybody of you already have some experience with GEM together with Oculus Rift?
>>>
>>> Since attachments should be avoided in this list, I do not send any example pictures of the distortion or our current presented world. If you are interested you can either contact me and I can send you some screenshots, or you can google for example images/videos of Oculus Rift distortion.
>>>
>>> Thanks in advance and best regards, Michael
>>>
>
> --
> Michael Mihocic
> Psychoacoustics & Experimental Audiology
> Acoustics Research Institute <http://www.kfs.oeaw.ac.at/>
> Austrian Academy Of Sciences <http://www.oeaw.ac.at/>
> Wohllebengasse 12-14 / 1
> A-1040 Vienna, Austria
> Tel: +43 (1) 51581 2515 (Office)
> Tel: +43 (1) 51581 2525 (Lab)
> Fax: +43 (1) 51581 2530
> michael.mihocic at oeaw.ac.at <mailto:michael.mihocic at oeaw.ac.at>

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