When using particular types of upscaling, (CAS, FSR, Catmull) the
film grain quality produced by HDRP was lower than expected.

This was caused by errors in the UV scale calculations for the grain
texture.

This change fixes the issue by modifying the scale calculations to
use the final viewport size rather than the size of the current
scaled/unscaled viewport. This works because film grain is always
handled by "FinalPass" which always renders at final viewport size
anyways.

This change also fixes a few cases where the current resolution group
would have been incorrect when CAS or FSR were being used as the
upscaling method.

…noiser #6119

…r limitations (#6126)

Co-authored-by: Sean Puller <sean.puller@unity3d.com>

* Initial commit MRP implementation

* Barn door application

* Add dominant marschner lobe direction skeleton

* Finalize rect light MRP for marschner, handle forward + backward hemisphere scattering.

* Force pathtracer to far-field in case users use geometry with bad normals.

* com.unity.render-pipelines.high-definition/Runtime/Material/Hair/MultipleScattering/HairMultipleScattering.hlsl

* Fix SH ringing for multiple scattering

* Add trivial support for cookies

* Add Kajiya support for area light approximation (non-LTC)

* remove Line area light MRP for now

* Remove area rect reference

* Update area light hair test scene and reference images

* Select cookie mip based on solid angle, rename some functions, temporarily add back rect ref

* Remove the useless div-by-1 and add a comment to explain the removal of the divide by PI

* Add a comment to further explain the normalization we do on the longitudinal distribution

* Remove the ref once again

* Update test images for metal and vulkan

* Add a zero-div guard to silence compiler warning

…cumulation. #6197

* Fixed grammar errors

* fixed passive voice in decal doc

* Update Decal.md

* Update Decal.md

* Update Decal.md

… removed in #9d6db83478c213bc066e5f728d94b7faa6662543 (#6104)

* updated fog override screenshot

* changed Depth Extent to Volumetric Fog Distance

…stant slowdown in large scenes. Merged editor guards blocks. (#6168)

* Update tooltip

* Update ProbeVolumeUI.Skin.cs

…eing properly intialized. #6194

…6193

* Minor fix for SSS + fog.

* Comments.