Rift Developing: Screen Switching

[marbas]

Hi! This is my first post on MTBS. I've been lurking around a little here since the kickstarter was introduced. It's great to read all you folks posting about hardware DIY and concept ideas for Rift content

I own the Vuzix VR920 HMD, which I bought some 5 years ago, because I wanted to experiment with serious-game software developing. I was quite disappointed with the immersion level of this device. I could accept the small FOV if only the head tracker would deliver good readings. But that sucked even more than the narrow FOV Since then I haven't considered buying another HMD again. Atleast not from Vuzix!

That was until I found the Rift! Thanks to Palmer & Carmack for bringing reality back into virtuality

Other than braistorming about exotic content ideas for the Rift, I've done some reflections about the development process itself.
Obviously the coding must be done on a regular monitor, and testing (mostly) on the HMD. I see this becoming a long-winded process wearing on and off the HMD for each testing session.
Especially the process of switching between monitor and HMD displays.

One easy solution to this could be for the developer to implement a button in the game GUI to switch back to monitor display before wearing off the HMD.
Another idea could be to implement a button on the HMD hardware (consumer version) that does the switching mentioned above.
Yet another similar hardware solution could be to let the HMD auto-sense when it is strapped on, and automatically switch the displays accordingly.

Any thoughts on this?

Thanks,
Mario

[ElecTriX]

I agree on this.

A fast and easy way to switch between HMD and displays is a must!

[mm0zct]

Is there a problem with the typical dual monitor setup method? The Rift is set as the "Primary" monitor in windows, so that fullscreen 3d applications open there, but move everything else over to your monitor display, including your taskbar. Now you can develop happily on your monitor, and when you launch a game it will start on the Rift. Tell windows to use the monitor as the primary display when you don't want to run something on the Rift, or just unplug it.

Windows 7 handles this all very well with my 22" Zalman and 27" Dell, with the Dell being the primary work/dev and 2D gaming display and the Zalman being only for 3d gaming and as a secondary monitor.

In some ways I actually have the setup backwards, full-screen gaming on the Dell with everything else dumped on the Zalman so I can keep track of IMs etc.

[AntonieB]

My guess is that will work perfectly

[marbas]

Well yes, I guess the dual monitor setup should work just fine. As long as it doesn't hurt rendering performance having both displays enabled.

[Cymatic]

I second the dual monitor setup. I have been using Unity3d. With it you can have the main program open on your primary monitor, then break off the 'Game' window, move it to the secondary monitor and maximize it.

[marbas]

I guess that in the videos we have seen with Carmack and Palmer showcasing the HMD, the pc setup use a dual display in clone mode. This is good for spectators/friends watching the gameplay. For this purpose it would be nice to output a single unwarped image to the monitor.

[mm0zct]

An extra unwarped version of the game is a very different requirement, this requires the game to setup 2 completely different 3d (in the traditional sense) viewports on different displays, and render the game for the Rift and the monitor, effectively rendering 3x, this would have significant performance impact, and I'm not really sure why you would need to do this.

[Cymatic]

I guess that in the videos we have seen with Carmack and Palmer showcasing the HMD, the pc setup use a dual display in clone mode. This is good for spectators/friends watching the gameplay. For this purpose it would be nice to output a single unwarped image to the monitor.

I could see value in this for a party situation, or if someone down the line makes this into an amusement attraction like a kiosk in a mall.
It would probably be better to have a dedicated machine in spectator mode rather than have one machine attempting to render 3 instances of the game environment.

[cybereality]

For the Rift dev kits you will probably just have to setup dual monitors to mirror the main display (both the Rift and the monitor show the same thing).

However the kind of automatic setup you want actually works with HDMI devices like the HMZ-T1. For example, on my setup I have 2 1080P monitors and then the HMZ hooked up as a 3rd (disabled) display. When I turn the HMZ on, my second monitor turns off, and the primary monitor switches to 720P mode to mirror the HMZ. When I turn it off everything goes back to normal. Very convenient.

If the future consumer version of the Rift uses HDMI, then I bet this same thing may be possible.

[Pyry]

An extra unwarped version of the game is a very different requirement, this requires the game to setup 2 completely different 3d (in the traditional sense) viewports on different displays, and render the game for the Rift and the monitor, effectively rendering 3x, this would have significant performance impact, and I'm not really sure why you would need to do this.

Probably most people will implement the warping by first rendering a traditional perspective camera to an offscreen buffer of some sort, and then using a shader to warp the image to the framebuffer associated with the Rift's display, in which case rendering the unwarped camera view is just a matter of copying the offscreen buffer to another visible buffer, which is cheap. You might even be able to avoid the offscreen buffer by rendering the unwarped view to the companion monitor, and then using that to render the warped view to the Rift, but I suspect that that might run into all sorts of issues (i.e., I'm not sure if OpenGL will let you bind either the front or backbuffer as a texture source).

[cybereality]

@Pyry: Yes, this may in fact be possible with a DirectX driver (like the one I'm working on). I can't promise anything, but I will look into it.

[Pyry]

It probably isn't worth it, performance wise, unless you're on really old hardware with poor support for offscreen rendering.

[WiredEarp]

Back in the day, to get 3D display on a monitor, it had to be the primary display. I'm not sure if this was a nvidia or a DirectX thing. Does this limitation still apply?

[cybereality]

Back in the day, to get 3D display on a monitor, it had to be the primary display. I'm not sure if this was a nvidia or a DirectX thing. Does this limitation still apply?

Yes, its still like this when the monitors are independent. But if you mirror the primary monitor onto the second, then they both show the same thing. This will not usually work for page-flipped 3D (ie 3D Vision glasses, etc.) but for side-by-side 3D its just really a normal 2D image so its fine.

[blam]

I use a HMZ-T1 with an nvidia graphics card in windows 7. When I switch on the HMZ-T1 it takes over from my two monitors, and when I switch it off it automatically switches back. Handles the resolution change for me too, the only thing I have to do is turn stereoscopic off and on in the nvidia driver, since my monitors are 2D. I assume the same thing would work with the rift if it has an on/off switch.