Forum Discussion
How does the Gear VR runtime handle lens distortion & chromatic aberration?
From a high level perspective, I know that scene geometry is first rendered to an eye buffer, which a VR runtime then applies lens distortion & chromatic aberration correction. How does Gear VR specif...
The distortion correction I assumed was a simple function that calculates where to sample the eye textures in order to achieve the distortion correction.
Chromatic aberration correction can be done one of two ways: low-quality/cheap, high-quality/expensive.
The cheap correction involves offsetting where the red and blue channels are being sampled from in the eye textures. The end result is that the 'corrected' image has distinct separation of the red/green/blue channels as opposed to a smooth spectrum of colors. Chromatic aberration spreads the light into a smooth spectrum of ROYGBIV, not just 3 discrete colors. This is also the exact same way that games/demoscene perform a fast and cheap chromatic aberration effect via post processing, but it's simply not accurate. The end result with the cheap correction is that you will still see some division of the colors through the lenses no matter how much the 'correction' is tweaked.
The correct way to generate or correct for chromatic aberration is by taking many samples along the vector that the colors spread (i.e. away/toward center of image/lens) around each pixel. This will more closely model the spectral continuum of hue that refraction imparts. Also, hello from reddit :)
https://reshade.me/forum/shader-presentation/1133-yaca-yet-another-chromatic-aberration
Chromatic aberration correction can be done one of two ways: low-quality/cheap, high-quality/expensive.
The cheap correction involves offsetting where the red and blue channels are being sampled from in the eye textures. The end result is that the 'corrected' image has distinct separation of the red/green/blue channels as opposed to a smooth spectrum of colors. Chromatic aberration spreads the light into a smooth spectrum of ROYGBIV, not just 3 discrete colors. This is also the exact same way that games/demoscene perform a fast and cheap chromatic aberration effect via post processing, but it's simply not accurate. The end result with the cheap correction is that you will still see some division of the colors through the lenses no matter how much the 'correction' is tweaked.
The correct way to generate or correct for chromatic aberration is by taking many samples along the vector that the colors spread (i.e. away/toward center of image/lens) around each pixel. This will more closely model the spectral continuum of hue that refraction imparts. Also, hello from reddit :)
https://reshade.me/forum/shader-presentation/1133-yaca-yet-another-chromatic-aberration