[Bf-gamedev] Using the Blender Games Engine for immersive training in a 360 projection dome

[Dalai Felinto]

Hi James,
I'm not familiar with syphon/spout so I may be missing something here.

The entire BGE dome rendering code is in KX_Dome.cpp. That said I
wonder if it's not possible to accomplish what you suggest via Python
(eventually extending BGL) using a scene.post_render callback. If it
has to be a low-level setup before you even create the windows than
this would need to be tackled at "Ghost" level (Blender's internal
window manager system).

>From a quick look at those solutions, it seems Spout wouldn't work in
Blender since it's based on Directx. Blender does have a branch that
would eventually allow for DirectX backend (the so called viewport
project), but I don't think it's in a usable state at the moment.

I wonder if you can afford a dedicated machine that can take the
output of the BGE computer as direct input and handle the blending,
warping and splitting there. Last time I had such a requirement [*] we
were outputting a 4k texture of a chopped equirectangular panorama
(Stereo > Dome > Spherical Panoramic) and outputting it via both
output ports of the graphic card.

Note, in my case I really needed real-time performance so I patched
the dome code to work with an arbitrary vertical field of view X 360
horizontal FoV. I can dig this patch again if that would help you, we
can discuss that in private.

Also I would recommend a machine with a really good dual-core system
(as oppose to things like i7), so the BGE can perform better (the BGE
is mainly single-core at the moment).

[*] - http://dalaifelinto/?page_id=445

Cheers,
Dalai
--
blendernetwork.org/dalai-felinto
www.dalaifelinto.com


2014-10-07 10:23 GMT-03:00 James Sheridan <sheridanis at gmail.com>:
>
> Hi All,
>
> I've been doing some research into getting the Blender Game Engine working
> in one of our domes
>
> www.igloovision.com
> https://www.dropbox.com/s/k81iquleisiocsd/Igloo%20St%20Pauls%20Draft%203.mov?dl=0
>
> Our domes use a cylindrical (or spherical....we just chop the top and bottom
> off) panoramic projection that is ideally 8000x1100 but anything above
> 6400x950 looks ok.   We do all of the image slicing, warping and edge
> blending in a custom app but need a way to get the image out of the BGE and
> into our app.    In unity we use 5 cameras oriented around the y axis each
> with a fisheye effect to approximate a cylindrical camera - we then use
> syphon under osx and spout under windows to output these camera textures to
> our warping and edge blending app.   Where looking to do a research project
> with Loughborough University and where we build an immersive training
> scenario in the dome and we're after some help advice with this.
>
> As Syphon and Spout are both open source and widely used adding in support
> for them would mean not only support for our (and others) domes but also a
> wide range of other tool and uses like VJing, museum installations etc and
> is something others have already been asking for
>
> http://blenderartists.org/forum/showthread.php?345832-Syphon-support-in-the-game-engine
> http://blenderartists.org/forum/showthread.php?298055-Live-Real-Time-Output-of-Animation
> http://pyppet.blogspot.co.uk/2012/01/pyppet2-audio-analysis.html
>
> In this regards to getting syphon and/or spout added into the BGE we were
> wondering
>
> Where in the codebase should I start looking to share the render texture
> produced by the spherical dome render via syphon and/or spout?
> Would anyone (preferably one of the BGE module owners) be able to provide
> timely support for this project for a small consulting fee?
> Would anyone be available to do this work and do you have a ball park figure
> for what it would cost?
> Does anyone have any feelings about what the performance differences might
> be for a large (100,000+ vertex) textured model between the spherical
> panoramic renderer and the approach we have done with unity which is just 5
> normal renders oriented?
>
> Regards James
>
> _______________________________________________
> Bf-gamedev mailing list
> Bf-gamedev at blender.org
> http://lists.blender.org/mailman/listinfo/bf-gamedev
>