1. [Publications](/publications)
2. Fast Global Illumination Approximations on Deep G-Buffers
 
 # Fast Global Illumination Approximations on Deep G-Buffers

  ![](/sites/default/files/styles/wide/public/pubs/2014-06_Fast-Global-Illumination/icon.png?itok=RgkNvD3-)

 Deep Geometry Buffers (G-buffers) combine the fine-scale and efficiency of screen-space data with much of the robustness of voxels. We introduce a new hardware-aware method for computing two-layer deep G-buffers and show how to produce dynamic indirect radiosity, ambient occlusion (AO), and mirror reflection from them in real-time. Our illumination computation approaches the performance of today’s screen-space AO-only rendering passes on current GPUs and far exceeds their quality. Our G-buffer generation method is order-independent, guarantees a minimum separation between layers, operates in a (small) bounded memory footprint, and avoids any sorting. Moreover, to address the increasingly expensive cost of pre-rasterization computations, our approach requires only a single pass over the scene geometry. We show how to apply Monte Carlo sampling and reconstruction to these to efficiently compute global illumination terms from the deep G-buffers.

The resulting illumination captures small-scale detail and dynamic illumination effects and is more substantially more robust than screen space estimates. It necessarily still view-dependent and lower-quality than offline rendering. However, it is real-time, temporally coherent, and plausible based on visible geometry. Furthermore, the lighting algorithms automatically identify undersampled areas to fill from broad-scale or precomputed illumination. All techniques described are both practical today for real-time rendering and designed to scale with near-future hardware architecture and content trends. We include pseudocode for deep G-buffer generation, and source code and a demo for the global illumination sampling and filtering.



 ## Authors



Michael Mara (NVIDIA)

Morgan McGuire (NVIDIA)

Derek Nowrouzezahrai (University of Montreal)

[David Luebke](/person/david-luebke)

 

 

 ## Publication Date



Sunday, June 1, 2014

 

 ## Published in



[NVIDIA Technical Report](http://research.nvidia.com)

 

 ## Research Area



[Computer Graphics](/research-area/computer-graphics)

 

 

 ## External Links



[Video](http://graphics.cs.williams.edu/papers/DeepGBuffer14/Mara2014DeepGBuffer.mp4)

 

 

 ## Uploaded Files



[paper.pdf](https://research.nvidia.com/sites/default/files/pubs/2014-06_Fast-Global-Illumination/paper.pdf "Open file in new window")42.36 MB