Depth of Field implementation using render passes

[mvaligursky]

Implementation of DOF effect using render passes, and its integration to CameraFrame.

Algorithm:

• CoC texture is rendered, containing near and far values for circle of confusion (blur amount)
• far blur texture is rendered by downscaling the scene color texture premultiplied by the CoC far, to avoid sharp objects being blurred into the background
• blur texture generated, containing either near or far blur, based on the CoC
• this is then used (or upscaled when low res) during the composition
• there are two quality levels, related to the texture resolutions used by these render passes

Public API (see code for JSDocs)

CameraFrame.dof = {
        enabled: false,
        focusDistance: 100,
        focusRange: 10,
        blurRadius: 3,
        blurRings: 4,
        blurRingPoints: 5,
        highQuality: true
    };

// new module to expose generic kernel generation functionality
static Kernel.concentric(numRings, numPoints)

Other changes (related to recent change to expose screen depth in linear space)

• fixes to linear depth generation (clear color was not handled correctly), which fixes few small issues with passes depending on this (TAA, SSAO)
• TAA reprojection fix due to not using linear depth correctly.

Performance

References

• https://web.archive.org/web/20170611154038/http://www.crytek.com/download/Sousa_Graphics_Gems_CryENGINE3.pdf
• https://www.slideshare.net/slideshow/so4-flexible-shadermanagmentandpostprocessing/4678893
• https://pixelmischiefblog.wordpress.com/2016/11/25/bokeh-depth-of-field/
• https://catlikecoding.com/unity/tutorials/advanced-rendering/depth-of-field/
• https://github.com/GPUOpen-LibrariesAndSDKs/FidelityFX-SDK/blob/main/docs/techniques/depth-of-field.md

DOF Example

DOF disabled:

DOF enabled:

DOF more extreme settings

Debug CoC rendering