fix(win/video): don't offload chroma subsampling math to texture sampler when downscaling

[ns6089]

Description

Don't offload math to texture sampler when subsampling chroma together with downscaling.
Fixes broken chroma when downscaling.
This makes chroma consistent with luma when downscaling, but luma itself is broken if the factor is >2x and half-broken with lesser factors (inconsistent filter radius, linear texture sampler alone can't be used for proper downscaling).
I'm hesitant to touch upscaling because of the potential performance hit.

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Issues Fixed or Closed

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Dependency update (updates to dependencies)
• Documentation update (changes to documentation)
• Repository update (changes to repository files, e.g. .github/...)

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated the in code docstring/documentation-blocks for new or existing methods/components

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 54 lines in your changes missing coverage. Please review.

Project coverage is 9.83%. Comparing base (9d7e90e) to head (bc2bd06).
Report is 108 commits behind head on master.

Files with missing lines	Patch %	Lines
src/platform/windows/display_vram.cpp	0.00%	50 Missing and 4 partials ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##           master   #3014      +/-   ##
=========================================
+ Coverage    9.70%   9.83%   +0.12%     
=========================================
  Files          77     101      +24     
  Lines       14055   17988    +3933     
  Branches     6443    8410    +1967     
=========================================
+ Hits         1364    1769     +405     
- Misses      10071   13337    +3266     
- Partials     2620    2882     +262     

Flag	Coverage Δ
Linux	7.26% <ø> (?)
Windows	5.06% <0.00%> (+<0.01%)	⬆️
macOS-12	10.76% <ø> (-0.02%)	⬇️
macOS-13	10.66% <ø> (-0.02%)	⬇️
macOS-14	10.97% <ø> (+0.01%)	⬆️

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Files with missing lines	Coverage Δ
src/platform/windows/display_vram.cpp	1.84% <0.00%> (+0.17%)	⬆️

... and 56 files with indirect coverage changes

[ns6089]

The code in this pull request is Not a Contribution under LizardByte Individual Contributor License Agreement.
The code in this pull request is shared under GNU GENERAL PUBLIC LICENSE Version 3.

[cgutman]

Reopening now that the CLA has been revoked and this can now be accepted under the GPLv3 terms alone.

[ns6089]

Suggested change

	const bool downscaling = display->width != width || display->height != height;
	const bool downscaling = display->width > width || display->height > height;

[ns6089]

Suggested change

	float3 rgb = image.Sample(def_sampler, input.tex_right_center_left_top.xw).rgb; // top-right
	rgb += image.Sample(def_sampler, input.tex_right_center_left_top.yw).rgb; // top-center
	rgb += image.Sample(def_sampler, input.tex_right_center_left_top.zw).rgb; // top-left
	rgb += image.Sample(def_sampler, input.tex_right_center_left_bottom.xw).rgb; // bottom-right
	rgb += image.Sample(def_sampler, input.tex_right_center_left_bottom.yw).rgb; // bottom-center
	rgb += image.Sample(def_sampler, input.tex_right_center_left_bottom.zw).rgb; // bottom-left
	rgb = CONVERT_FUNCTION(rgb * (1./6));
	float3 rgb = image.Sample(def_sampler, input.tex_right_center_left_top.yw).rgb; // top-center
	rgb += image.Sample(def_sampler, input.tex_right_center_left_bottom.yw).rgb; // bottom-center
	rgb *= 2;
	rgb += image.Sample(def_sampler, input.tex_right_center_left_top.xw).rgb; // top-right
	rgb += image.Sample(def_sampler, input.tex_right_center_left_top.zw).rgb; // top-left
	rgb += image.Sample(def_sampler, input.tex_right_center_left_bottom.xw).rgb; // bottom-right
	rgb += image.Sample(def_sampler, input.tex_right_center_left_bottom.zw).rgb; // bottom-left
	rgb = CONVERT_FUNCTION(rgb * (1./8));

Also just realized we can sightly improve the quality and be consistent with what we do in no scaling path (#1621 (comment)) at pretty much no additional cost.

[ns6089]

Also fixed portrait rotation bug that's been there since that feature got first introduced ns6089@f41242f

[sonarqubecloud]

Quality Gate failed

Failed conditions
7 New issues
7 New Code Smells (required ≤ 0)

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