---
phase: 10.1-setdisplayeyetohead-spike
verified: 2026-03-24T14:00:00Z
status: passed
score: 4/4 success criteria verified
re_verification: false
---

# Phase 10.1: SetDisplayEyeToHead Spike Verification Report

**Phase Goal:** Test whether SetDisplayEyeToHead works from the sidecar driver for the HMD it doesn't own (device 0). This is the critical gate for Phase 11's IPD implementation.
**Verified:** 2026-03-24T14:00:00Z
**Status:** PASSED
**Re-verification:** No — initial verification

---

## Goal Achievement

### Observable Truths (from ROADMAP.md Success Criteria)

| # | Truth | Status | Evidence |
|---|-------|--------|----------|
| 1 | SetDisplayEyeToHead called from sidecar with device 0 either changes or does not change rendered eye separation (result documented) | VERIFIED | FINDINGS.md SPIKE-01: PASS — visual eye separation changed across 48/55/63/75mm values, human confirmed |
| 2 | Euler angle decomposition of lighthouse config rotation matrices produces expected yaw values | VERIFIED | FINDINGS.md SPIKE-02: PASS — left_yaw=+2.00, right_yaw=-2.00, opposite signs confirm correct eye order. Note: actual values ~2 deg not ~6.17 deg; discrepancy documented and explained (6.17 was estimate, 2 deg is real config value) |
| 3 | If successful, repeated calls confirmed to work (live-change, not one-shot) | VERIFIED | FINDINGS.md SPIKE-03: PASS — cached rotation enables instant repeated calls; first call is slow (~20s) due to lighthouse_console, all subsequent calls instant |
| 4 | A clear go/no-go decision is recorded with evidence | VERIFIED | FINDINGS.md "Go/No-Go Decision: GO" with rationale for all three SPIKE criteria and Phase 11 impact |

**Score:** 4/4 success criteria verified

---

### Required Artifacts

| Artifact | Expected | Status | Details |
|----------|----------|--------|---------|
| `src/driver/device_provider.h` | HandleEyeToHeadSet and ReadEyeToHeadRotation declarations | VERIFIED | Line 40: `void HandleEyeToHeadSet(float mm, char* response, size_t responseSize);` Line 41: `bool ReadEyeToHeadRotation(float leftRot[3][3], float rightRot[3][3]);` Also: m_cachedLeftRot, m_cachedRightRot, m_bEyeToHeadCached at lines 44-46 |
| `src/driver/device_provider.cpp` | eyetohead_set dispatch, config reading, matrix construction, SetDisplayEyeToHead call | VERIFIED | Line 310: dispatch; Line 791: SetDisplayEyeToHead(0, left, right); Lines 715-717: atan2f Euler decomp; Lines 675-707: tracking_to_eye_transform + eye_to_head parsing; Line 533: openvrpaths.vrpath config discovery |
| `.planning/phases/10.1-setdisplayeyetohead-spike/10.1-FINDINGS.md` | Spike results, evidence, go/no-go decision | VERIFIED | File exists; contains SPIKE-01 PASS, SPIKE-02 PASS, SPIKE-03 PASS, Go/No-Go: GO with full evidence |
| `build/driver/BeyondProximity/bin/win64/driver_BeyondProximity.dll` | Built driver DLL | VERIFIED | File exists |
| `build/driver/BeyondProximity/bin/win64/beyond_prox_ctl.exe` | Built CLI tool | VERIFIED | File exists |

---

### Key Link Verification

| From | To | Via | Status | Details |
|------|----|-----|--------|---------|
| `HandlePipeCommand` | `HandleEyeToHeadSet` | `strncmp(cmd, "eyetohead_set ", 14)` dispatch | VERIFIED | Line 310 in device_provider.cpp — dispatch present, routes to HandleEyeToHeadSet when mm in 48-75 range |
| `HandleEyeToHeadSet` | `VRServerDriverHost()->SetDisplayEyeToHead` | direct call with device 0 | VERIFIED | Lines 790-792: `vr::VRServerDriverHost()->SetDisplayEyeToHead(vr::k_unTrackedDeviceIndex_Hmd, left, right)` |
| `ReadEyeToHeadRotation` | lighthouse config JSON | `lighthouse_console.exe downloadconfig` then `tracking_to_eye_transform` -> `eye_to_head` | VERIFIED | Lines 533+: openvrpaths.vrpath discovery; lines 675-707: tracking_to_eye_transform / eye_to_head parsing |
| `HandleEyeToHeadSet` | `Prop_UserIpdMeters_Float` | `VRProperties()->SetFloatProperty` | VERIFIED | Lines 798-800: SetFloatProperty(hmdProps, Prop_UserIpdMeters_Float, ipdMeters) |
| Rotation matrices | cached storage | `m_bEyeToHeadCached` flag | VERIFIED | Lines 745-757 in cpp; lines 44-46 in header — caching prevents repeated lighthouse_console spawns |

---

### Requirements Coverage

| Requirement | Source Plan | Description | Status | Evidence |
|-------------|------------|-------------|--------|----------|
| SPIKE-01 | 10.1-01-PLAN.md, 10.1-02-PLAN.md | SetDisplayEyeToHead from sidecar changes rendering for device 0 | SATISFIED | FINDINGS.md: PASS — visual change confirmed by user across 48/55/63/75mm |
| SPIKE-02 | 10.1-01-PLAN.md, 10.1-02-PLAN.md | Euler angle decomposition validates lighthouse config rotation matrices | SATISFIED | FINDINGS.md: PASS — left_yaw=+2.00, right_yaw=-2.00, intrinsic XYZ convention validated |
| SPIKE-03 | 10.1-01-PLAN.md, 10.1-02-PLAN.md | Repeated calls produce live rendering changes (not one-shot) | SATISFIED | FINDINGS.md: PASS — caching enables instant repeated calls |

**Orphaned requirements check:** REQUIREMENTS.md does not define SPIKE-01/02/03 as named entries — these IDs exist only in ROADMAP.md and the PLAN frontmatter. All three are accounted for across both plans and all three are marked SATISFIED. No orphaned SPIKE requirements.

---

### Anti-Patterns Found

| File | Line | Pattern | Severity | Impact |
|------|------|---------|----------|--------|
| None found | — | — | — | — |

Scanned `src/driver/device_provider.h` and `src/driver/device_provider.cpp` and `.planning/phases/10.1-setdisplayeyetohead-spike/10.1-FINDINGS.md` for TODO/FIXME/placeholder/return null/empty handlers. None found. FINDINGS.md contains actual command output and Euler values (not placeholder text).

---

### Human Verification Required

Human visual verification was completed as part of Plan 02 (Task 2 checkpoint). The user confirmed:

- Eye separation changes visually in HMD: YES
- 48mm vs 75mm produces dramatic visible difference: YES
- Intermediate values (55mm, 63mm) produce proportional shifts: YES
- Repeated calls produce live changes (not one-shot): YES

No further human verification required for this phase.

---

### Commit Verification

All commits referenced in SUMMARY.md were verified present in git log:

| Commit | Description | Present |
|--------|-------------|---------|
| `fcd4c72` | feat(10.1-01): implement eyetohead_set pipe command | YES |
| `01e37d8` | fix(10.1-02): CLI allowlist fix | YES |
| `bb6b623` | fix(10.1-02): JSON parser multi-line fix | YES |
| `60db6cc` | fix(10.1-02): Euler convention fix | YES |
| `8e5cf67` | fix(10.1-02): config reading via lighthouse_console | YES |
| `32008b1` | fix(10.1-02): rotation matrix caching | YES |
| `b6e7e5f` | docs(10.1-02): FINDINGS.md with GO decision | YES |

---

### Notable Implementation Deviations (Not Gaps)

These are documented deviations that represent correct behavior, not failures:

1. **Yaw values ~2 deg not ~6.17 deg** — The plan estimated ~6.17 deg from VAP alignment code constants. Actual lighthouse config encodes ~2 deg yaw and ~5 deg pitch. The implementation reads from the real config (correct behavior); the expectation in the plan was a rough estimate.

2. **Config reading changed from lhr-* directory scan to lighthouse_console.exe downloadconfig** — The plan specified scanning the lhr-* directories. During testing, stale files were found unreliable. The fix (commit `8e5cf67`) uses live config from lighthouse_console, which is the superior approach.

3. **Rotation matrix caching added** — Not in original plan but required for usability (eliminates ~20s tracking disruption per call). Correctly declared in header (lines 44-46) and implemented in cpp (lines 745-757).

---

### Gaps Summary

No gaps. All four ROADMAP.md success criteria are verified. All three SPIKE requirements are satisfied. Build artifacts exist. FINDINGS.md contains actual test evidence (not placeholders). All key links confirmed wired in the codebase. Human visual verification completed.

Phase 10.1 goal achieved: SetDisplayEyeToHead from the sidecar works for device 0, and the go/no-go decision for Phase 11 is GO.

---

_Verified: 2026-03-24T14:00:00Z_
_Verifier: Claude (gsd-verifier)_