Our SSRT3 GI plugin for Unity is now open-source! Pull requests are welcome for new features or improvements.
Olivier Therrien
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R&D Graphics Programmer at CDRIN
Great survey of rendering techniques using bitmasks: https://www.ea.com/seed/news/coverage-bitmasks
Screen Space Indirect Lighting with Visibility Bitmask
Horizon-based indirect illumination efficiently estimates a diffuse light bounce in screen space by analytically integrating the horizon angle difference between samples along a given direction. Like other horizon-based methods, this technique cannot properly simulate light passing behind thin surfaces. We propose the concept of a visibility bitmask that replaces the two horizon angles by a bit field representing the binary state (occluded / un-occluded) of N sectors uniformly distributed around the hemisphere slice. It allows light to pass behind surfaces of constant thickness while keeping the efficiency of horizon-based methods. It can also do more accurate ambient lighting than bent normal by sampling more than one visibility cone. This technique improves the visual quality of ambient occlusion, indirect diffuse, and ambient light compared to previous screen space methods while minimizing noise and keeping a low performance overhead.
Very nice Shadertoy implementation of our paper "Screen Space Indirect Lighting with Visibility Bitmask" by Mathis: https://shadertoy.com/view/dsGBzW. Well done!
Jendrik IllnerGraphics Programming weekly - Issue 274 - February 12th, 2023 https://www.jendrikillner.com/post/graphics-programming-weekly-issue-274/
It's based on GTAO and the idea is quite simple: Use a bitmask to represent the occlusion of sectors in a hemispherical slice. This allows light to pass behind thin surfaces and can be used to improve AO or implement SSGI.
Final version here: https://link.springer.com/article/10.1007/s00371-022-02703-y
Screen space indirect lighting with visibility bitmask - The Visual Computer
Horizon-based indirect illumination efficiently estimates a diffuse light bounce in screen space by analytically integrating the horizon angle difference between samples along a given direction. Like other horizon-based methods, this technique cannot properly simulate light passing behind thin surfaces. We propose the concept of a visibility bitmask that replaces the two horizon angles by a bit field representing the binary state (occluded/un-occluded) of N sectors uniformly distributed around the hemisphere slice. It allows light to pass behind surfaces of constant thickness while keeping the efficiency of horizon-based methods. It can also do more accurate ambient lighting than bent normal by sampling more than one visibility cone. This technique improves the visual quality of ambient occlusion, indirect diffuse, and ambient light compared to previous screen space methods while minimizing noise and keeping a low performance overhead.
The preprint for our paper Screen Space Indirect Lighting with Visibility Bitmask is now available on arXiv: https://arxiv.org/abs/2301.11376
Screen Space Indirect Lighting with Visibility Bitmask
Horizon-based indirect illumination efficiently estimates a diffuse light bounce in screen space by analytically integrating the horizon angle difference between samples along a given direction. Like other horizon-based methods, this technique cannot properly simulate light passing behind thin surfaces. We propose the concept of a visibility bitmask that replaces the two horizon angles by a bit field representing the binary state (occluded / un-occluded) of N sectors uniformly distributed around the hemisphere slice. It allows light to pass behind surfaces of constant thickness while keeping the efficiency of horizon-based methods. It can also do more accurate ambient lighting than bent normal by sampling more than one visibility cone. This technique improves the visual quality of ambient occlusion, indirect diffuse, and ambient light compared to previous screen space methods while minimizing noise and keeping a low performance overhead.