Visual Comparison & Quality Gates

Saving 4 milliseconds of frame time is counterproductive if your game’s visual presentation becomes unacceptably blurry or shadows disappear completely.

DeviceFit integrates a Visual Quality Gate (CapturesComparisonWindow.cs) into the decision loop.

Candidate Trial ──> Checkpoint Still Capture ──> Structural Dissimilarity ──> Side-by-Side Review ──> Apply Decision

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Checkpoint Still Captures

When authoring a camera route, you can mark specific waypoints as isVisualCheckpoint = true. During candidate trial runs:

1. The camera pauses at the designated checkpoint transform.
2. The scene renders a high-resolution uncompressed still frame.
3. The image is saved into the experiment capture directory with metadata recording the candidate ID and camera transform.

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Side-by-Side & Difference Heatmaps

In the Captures & Comparisons window (Tools > Decnet > DeviceFit > Captures & Comparisons), you can inspect:

1. Split-Screen Wipe: An interactive slider allowing you to wipe between the Baseline frame and Candidate frame.
2. Absolute Pixel Difference Heatmap: Highlights regions where color values deviate by $> 5\%$.
3. Hero Mask Regions: Focuses quality validation on central gameplay areas (e.g. player character or reticle) while allowing greater compression in peripheral regions.

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Resolution Transparency & Dimension Checks (DF-T08)

Lowering render scale (e.g. from 1.0 to 0.75) is an effective way to relieve fill-rate bottlenecks. However, comparing images of different resolutions with naive pixel difference algorithms produces artificial $100\%$ mismatch scores.

In DF-T08_VisualTruth_InvalidDimensions_BlocksFalsePixelDiff, DeviceFit enforces:

1. Dimension Validation: If baseline and candidate captures differ in pixel dimensions, false pixel-difference scores are blocked.
2. Resolution Tradeoff Disclosure: Any candidate that modifies render scale or dynamic resolution is explicitly labeled with a Resolution Disclosure Notice in reports and UI: [Notice] Frame time reduction achieved by 15% render scale downsampling (1080p -> 918p).