« on: November 12, 2014, 12:09:15 PM »
This requires a GM204 GPU (GTX 980/970) due to the use of the following features: Viewport Multicast, Conservative Raster and Tiled Resources.
In traditional computer graphics, a light contributes diffuse and specular illumination to any surface that has an unobstructed ray to that light. The images resulting from this technique are characteristically black in unlit regions because this over-simplification fails to account for light reflected from other surfaces in the scene.
To improve visuals, most games describe indirect illumination by pre-computing lighting and storing the result statically in vertex data or textures. The results can look very realistic if the scene remains static, but we want to be able to open doors, move lights, and tear down walls. Clearly games would benefit greatly if we could create a "global illumination" solution that computes direct and indirect lighting in real time.
NVIDIA's VXGI computes indirect light by rendering the scene's lit geometry into a 3D voxel grid, then using that grid as an acceleration structure for computing indirect diffuse light and reflections. Indirect diffuse light is calculated by tracing broad cones through the voxel grid in the direction of the surface normal and accumulating the light from those voxels. Reflections are likewise calculated by tracing through the voxel grid in the direction of the reflection vector.
This new technique is made possible from several new features of GeForce GTX 980 including:
"Viewport Multicast" :
Accelerates the rendering of each triangle into the voxel structure(s)
by broadcasting it to the 6 directional render targets rather than
"Conservative Raster" :
Ensures that each triangle in a voxel's space can contribute to that
voxel even if the triangle does not cross that voxel's sample point.
"Tiled Resources" :
Permits us to create a high resolution 3D Texture but only allocate
memory for those regions that are occupied by voxels.
NVIDIA can now employ Voxelized Global Illumination on Geforce GTX 980 to test the validity of the alleged moon landing media.