I saw the Nvidia moon landing GI demo and the corresponding GI demo on the Nvidia youtube channel.

They mention this is coming with their new gpu, is this some hardware supported feature? Does anyone know how it will integrate with other software if that is the case?

Also, in the demo with the sphere, they show the voxel data. I'm assuming that the pixel shader performs a raycast into the voxel data to find the closest voxel? I've never messed with voxels before. I'm not sure how that works. Is the data on the gpu a 3d texture and it will just ray cast from the fragments world position + normal until it hits a non blank texel in the 3d texture and then use that information?

If so, wouldn't that 3d texture be pretty big? for that small scene it looks like it is about 64x64x64 if it is a 3d texture. Maybe I just don't know enough about voxels. I remember the latest Crysis tech pdf mentioning their GI stuff. Were they doing the same type of thing then?

They use spase volume texture to store virtually huge texture with lot of "blank" Inside. It's a DX12 feature.

Actually, they are using Voxel Global Illumination (VXGI) which seems to be very similar to Sparse Voxel Octree Global Illumination (SVOGI) which was first published by Cyril Crassin of NVIDIA in 2011.

From the NVIDIA page on the technology behind VXGI:

In 2011, NVIDIA engineers developed and demonstrated an innovative new approach to computing a fast, approximate form of global illumination dynamically in real time on the GPU. This new GI technology uses a voxel grid to store scene and lighting information, and a novel voxel cone tracing process to gather indirect lighting from the voxel grid. NVIDIA’s Cyril Crassin describes the technique in his paper on the topic and a video from GTC 2012 is available here. Epic’s ‘Elemental’ Unreal Engine 4 tech demo from 2012 used a similar technique.Since that time, NVIDIA has been working on the next generation of this technology—VXGI—that combines new software algorithms and special hardware acceleration in the Maxwell architecture.

VXGI is not a Direct3D 12 specific feature, in fact, SVOGI it was first implemented in OpenGL 4.x and Direct3D 11. Though the technology has (mostly) been available for years, NVIDIA's Maxwell graphics architecture is the first of its kind to have "built-in" support for the technology.

1)They mention this is coming with their new gpu, is this some hardware supported feature?

2)Does anyone know how it will integrate with other software if that is the case?

Thank god nVidia with their Maxwell GPU will shut up all those conspiracy theorists!

*blindingly obvious sarcasm*

I'm confused. Nvidia supports GL_ARB_sparse_texture with both Kepler and Fermi, so why is this a Maxwell only feature?

They're probably using GL_EXT_sparse_texture2.

Who would actually use this middleware though? If VXGI only supports the very latest nVidia GPUs, then you still need to implement your own GI system yourself to support older nVidia cards, and ATI cards, and Intel users... Bit of a poisoned chalice really.