chore(vr): add Tracy zones for SSS dispatches

[alandtse]

Summary

Adds Tracy GPU and CPU profiling zones around VR stereo passes and per-eye Screen Space Shadows dispatches. No logic changes — instrumentation only.

Why

Recent VR perf investigation surfaced significant per-frame cost in the VRStereoOptimizations and StereoBlend passes that was previously invisible in Tracy captures. Without these zones, future VR perf work — both validating optimizations and identifying further targets — cannot be measured. The instrumentation gap was the single biggest blocker on data-driven VR perf decisions.

What

Eight zone categories across three files:

• src/Features/VR/StereoBlend.cpp — StereoBlend - Overwrite / StereoBlend - Bilateral (conditional on isOverwriteMode).
• src/Features/VRStereoOptimizations.cpp — StereoOpt - Stencil Write, StereoOpt - Mode Classify (parent), with Mode Classify Bind and Mode Classify Dispatch sub-zones.
• src/Features/ScreenSpaceShadows.cpp — SSS - Left Eye / SSS - Right Eye outer zones at the DispatchEye call sites in DrawShadows(). The pre-existing SSS - Ray March zone inside the Bend dispatch loop was renamed and split into SSS - DispatchEye CB (CB upload per sweep) and SSS - DispatchEye Sweep (the dispatch itself), giving per-sweep granularity. Net effect: the loop is more profilable, not less.

Risk

Zero. Tracy macros (TracyD3D11Zone, ZoneScoped) compile to nothing when TRACY_SUPPORT=OFF (the default).

Validation

• Built successfully with ./BuildRelease.bat ALL (default preset, TRACY_SUPPORT=OFF). No warnings introduced; the only build warning is an unrelated extern/FidelityFX-SDK CMake deprecation.
• Captures with ALL-TRACY will surface the new zones for validation. Sample data (from a test build of these zones on a downstream branch) showed StereoOpt - Mode Classify at ~306 µs/frame and StereoBlend - Overwrite at ~303 µs/frame — costs that were entirely invisible before.

Summary by CodeRabbit

• Chores
  • Enhanced internal performance profiling instrumentation across screen-space shadows, stereo blending, and VR stereo optimization systems for improved performance monitoring and analysis.

[coderabbitai]

📝 Walkthrough

Walkthrough

This PR refactors Tracy profiling instrumentation across three VR/stereo rendering features. ScreenSpaceShadows reorganizes shadow dispatch zones into separate constant-buffer and compute phases with per-eye labeling. StereoBlend adds per-branch profiling zones for overwrite vs. bilateral dispatch modes. VRStereoOptimizations adds instrumentation around stereo stencil classification and write passes, separating shader binding from dispatch operations.

Changes

Cohort / File(s)	Summary
Screen Space Shadows Profiling src/Features/ScreenSpaceShadows.cpp	Reorganizes Tracy zones in DrawShadows: replaces single "SSS - Ray March" zone with separate "SSS - DispatchEye CB" and "SSS - DispatchEye Sweep" zones for distinct phases; adds dedicated per-eye zones ("SSS - Left Eye" / "SSS - Right Eye") for VR dispatch calls.
Stereo Blend Dispatch Profiling src/Features/VR/StereoBlend.cpp	Adds branching Tracy D3D11 zones ("StereoBlend - Overwrite" and "StereoBlend - Bilateral") around compute dispatch calls, with each zone scoped to its respective branch path.
VR Stereo Optimizations Profiling src/Features/VRStereoOptimizations.cpp	Adds Tracy instrumentation separating shader/descriptor binding operations from the compute dispatch call in stereo stencil classification pass; wraps ExecuteStencilWritePass() in dedicated profiling zone.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Possibly related PRs

• chore(tracy): add GPU zone to ForEachLoadedFeature #2165: Directly modifies Tracy profiling instrumentation in ScreenSpaceShadows::DrawShadows with similar zone restructuring patterns.
• feat(tracy): add additional zones #1760: Prior refactoring of ScreenSpaceShadows::DrawShadows Tracy zones that this PR builds upon.
• feat(VR): add edge detection for stereo blending #1948: Modifies StereoBlend.cpp compute dispatch flow with additional Tracy instrumentation for branch differentiation.

Suggested reviewers

• jiayev
• doodlum
• davo0411

Poem

🐰 Hopping through shadows with Tracy's bright light,
We measure each zone—left eye, right eye, just right!
From stereo blends to stencil's delight,
Profiling the profilers, making code shine so bright! ✨

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title accurately describes the main change: adding Tracy instrumentation zones for VR-related and SSS dispatches, which aligns with the core purpose of the pull request.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[github-actions]

No actionable suggestions for changed features.

[coderabbitai]

🧹 Nitpick comments (1)

src/Features/ScreenSpaceShadows.cpp (1)

232-246: Optional: consider an outer Tracy zone for the non-VR path for symmetry.

In VR, both DispatchEye calls are wrapped in "SSS - Left Eye"/"SSS - Right Eye". The non-VR call at Line 233 has no analogous outer zone, so the per-sweep zones appear directly under "Screen Space Shadows". Functionally fine (no profiling gap), but a "SSS - Mono" (or similar) wrapper would make Tracy traces structurally consistent across VR/non-VR captures. Up to you.

♻️ Optional symmetry tweak

 	if (!globals::game::isVR) {
-		DispatchEye(nullptr, GetComputeRaymarch(), lightProjectionF.data(), InvTexSizeX, InvTexSizeY);
+		TracyD3D11Zone(globals::state->tracyCtx, "SSS - Mono");
+		DispatchEye(nullptr, GetComputeRaymarch(), lightProjectionF.data(), InvTexSizeX, InvTexSizeY);
 	} else {

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@src/Features/ScreenSpaceShadows.cpp` around lines 232 - 246, Non-VR path
lacks an outer Tracy zone for symmetry with the VR branch, so wrap the single
DispatchEye call so profiling traces match both branches; when
globals::game::isVR is false, add a TracyD3D11Zone (e.g., "SSS - Mono") around
the call that invokes DispatchEye(nullptr, GetComputeRaymarch(),
lightProjectionF.data(), InvTexSizeX, InvTexSizeY) so it mirrors the "SSS - Left
Eye"/"SSS - Right Eye" zones used when calling GetComputeRaymarchRight() and
CalculateLightProjection(1).

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@src/Features/ScreenSpaceShadows.cpp`:
- Around line 232-246: Non-VR path lacks an outer Tracy zone for symmetry with
the VR branch, so wrap the single DispatchEye call so profiling traces match
both branches; when globals::game::isVR is false, add a TracyD3D11Zone (e.g.,
"SSS - Mono") around the call that invokes DispatchEye(nullptr,
GetComputeRaymarch(), lightProjectionF.data(), InvTexSizeX, InvTexSizeY) so it
mirrors the "SSS - Left Eye"/"SSS - Right Eye" zones used when calling
GetComputeRaymarchRight() and CalculateLightProjection(1).

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 0f2097f0-83ea-4c93-a84d-d2faacf8364a

📥 Commits

Reviewing files that changed from the base of the PR and between 790044b and c0da9df.

📒 Files selected for processing (3)

• src/Features/ScreenSpaceShadows.cpp
• src/Features/VR/StereoBlend.cpp
• src/Features/VRStereoOptimizations.cpp

[github-actions]

✅ A pre-release build is available for this PR:
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