How to do stereoscopic 3D with OpenGL on GTX 560 a

Question

I am using the open source haptics and 3D graphics library Chai3D running on Windows 7. I have rewritten the library to do stereoscopic 3D with Nvidia nvision. I am using OpenGL with GLUT, and using glutInitDisplayMode(GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE | GLUT_STEREO) to initialize the display mode. It works great on Quadro cards, but on GTX 560m and GTX 580 cards it says the pixel format is unsupported. I know the monitors are capable of displaying the 3D, and I know the cards are capable of rendering it. I have tried adjusting the resolution of the screen and everything else I can think of, but nothing seems to work. I have read in various places that stereoscopic 3D with OpenGL only works in fullscreen mode. So, the only possible reason for this error I can think of is that I am starting in windowed mode. How would I force the application to start in fullscreen mode with 3D enabled? Can anyone provide a code example of quad buffer stereoscopic 3D using OpenGL that works on the later GTX model cards?

Answer 1

What you experience has no technical reasons, but is simply product policy of NVidia. Quadbuffer stereo is considered a professional feature and so NVidia offers it only on their Quadro cards, even if the GeForce GPUs would do it as well. This is not a recent development. Already back in 1999 it was like this. For example I had (well still have) a GeForce2 Ultra back then. But technically this was the very same chip like the Quadro, the only difference was the PCI-ID reported back to the system. One could trick the driver into thinking you had a Quadro by tinkering with the PCI-IDs (either by patching the driver or by soldering an additional resistor onto the graphics card PCB).

The stereoscopic 3D mode for Direct3D hack was already supported by my GeForce2 then. Back then the driver duplicated the rendering commands, but applied a translation to the modelview and a skew to the projection matrix. These days it's implemented a shader and multi rendertarget trick.

The NVision3D API does allow you to blit images for specific eyes (this is meant for movie players and image viewers). But it also allows you to emulate quadbuffer stereo: Instead of GL_BACK_LEFT and GL_BACK_RIGHT buffers create two Framebuffer Objects, which you bind and use as if they were quadbuffer stereo. Then after rendering you blit the resulting images (as textures) to the NVision3D API.

With only as little as 50 lines of management code you can build a program that seamlessly works on both NVision3D as well as quadbuffer stereo. What NVidia does is pointless and they should just stop it now and properly support quadbuffer stereo pixelformats on consumer GPUs as well.

Answer 2

Simple: you can't. Not the way you're trying to do it.

There is a difference between having a pre-existing program do things with stereoscopic glasses and doing what you're trying to do. What you are attempting to do is use the built-in stereo support of OpenGL: the ability to create a stereoscopic framebuffer, where you can render to the left and right framebuffers arbitrarily.

NVIDIA does not allow that with their non-Quadro cards. It has hacks in the driver that will force stereo on applications with nVision and the control panel. But NVIDIA's GeForce drivers do not allow you to create stereoscopic framebuffers.

And before you ask, no, I have no idea why NVIDIA doesn't let you control stereo.

Answer 3

Since I was looking into this issue for my own game, I w found this link where somebody hacked the USB protocol. http://users.csc.calpoly.edu/~zwood/teaching/csc572/final11/rsomers/

I didn't follow it through but at the time when I was researching on this it didn't look to hard to make use of this information. So you might have to implement your own code in order to support it in your app, which should be possible. Unfortunately a generic solution would be harder, because then you would have to hack the driver or somehow hook into the OpenGL library and intercept the calls.