[Bf-gamedev] Bf-gamedev Digest, Vol 13, Issue 7

[James Sheridan]

Hi Dalai, thanks for getting back to me


>>> The entire BGE dome rendering code is in KX_Dome.cpp.

Yeah this looks like the perfect place to implement the sharing of the rendered texture


>>> 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).

Spout needs access to the opengl texture/fbo so I doubt it could be done via python, plus there is no python wrapper for spout.


>>> 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.

Spout can use the interop extension to access opengl textures - I'm currently using it in openframeworks which is opengl based to receive the spout textures from unity which is d3d based but I'm sure you can also go from opengl to opengl as well.   Syphon is also opengl and we'd almost prefer to use OSX but have the warper running on windows as well so its not a strict requirement.



>>> 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.

This is how we've done things in the past using the blackmagic cards but it adds to much latency and and complexity to the setup - and its so much easier if everything just runs off the one machine.


>>> 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.

Yeah that would be great as we would just be need a cylindrical pano and if we used the current spherical pano would just be throwing away a heap of pixels/performance


>> 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).

We'll either be using a 2013 mac pro with dual d500's or a pretty recent pc, think its quad core i7 with dual geforce 780ti's - from what I could gather most of the heavy lifting for the spherical panorama is being done on the GPU, is that correct?

Cheers - James

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