Upstream PR 2984 OpenGL Render to Vertex

Upstream PR #2984 — OpenGL render-to-vertex-buffer support

Upstream work · Actionable research · Research and retired work

Current disposition — November 1, 2026

Reviewed: November 1, 2026. Fork source: b7140848 (full SHA b71408480a3a979a9c584663e1d1f400904c8bb7). Latest stable checked: v0.8.136-0-g458730bf5373, September 30, source 458730bf5373f1f0d027450fef7443e3af7a3ae1. GitHub state, branch recommendation, source presence and release availability are separate facts. See current status and release versus main.

Current field	November 1, 2026 observation
GitHub source	Upstream #2984
GitHub state / draft	Open / No
Current head	cc576956ee5bd5645cc48891f8210632c5aab06a
Originally reviewed head	cc576956ee5bd5645cc48891f8210632c5aab06a
Last metadata update (UTC)	2026-10-18T20:59:12Z
Head versus original review	Same recorded head; metadata/state updates do not indicate a new proposal-code head.
Current action	Open proposal; refresh integration and focused tests before handoff.
Fork/release availability	This upstream proposal’s GitHub state does not establish full fork/release inclusion. The historical overlap below is scoped to its recorded fork baseline; use the current feature register for delivered fork behavior.

The current head matches the recorded September review head. Later updated_at metadata does not establish changed proposal code. The original fork overlap remains a dated source comparison, not a fresh integration or native qualification result.

This refresh checked GitHub identity/state and the specific source boundaries named above. It did not rerun native games, XISO timings or integration qualification. Historical performance claims remain attached to their original heads.

Historical review — September 21, 2026

The review below is preserved as written, including its original state, head, fork baseline and proposed handoff. Its present-tense statements apply to that dated review; the current disposition above governs today’s action.

← Upstream Work

Field	Value
Upstream PR	xemu-project/xemu#2984
State at 2026-09-21 audit	Open
Reviewed upstream head	cc576956ee5bd5645cc48891f8210632c5aab06a
Last upstream update seen	2026-09-18
Reviewed upstream base	f9b14039e5bb56ae2d8f028e31e7cc19f13f7e12
Fork baseline	82d04d84bdb3de956f20c3537e1da2cece0e8da2
Relationship	Partial overlap
Related fork work	Mainkill1/xemu#125
Contribution priority	Highest
Upstream contact status	No comment posted by this audit.

Summary

Upstream adds OpenGL render-to-vertex-buffer support, including native-resolution treatment for surfaces later consumed as vertex data. Fork #125 covers the surface-reconciliation and exact-fetch portion, not the full scaling design.

Upstream scope

The proposal downloads GPU-authored surfaces before vertex use and remembers surfaces used as vertex data so future rendering can use a compatible native-resolution representation.

Corresponding fork work

Fork #125 computes the actual fetched range, downloads overlapping GPU-owned surfaces, and invalidates the quick upload skip when the download changed guest bytes.

Difference that must remain explicit

The per-surface scale policy is separate and needs its own qualification at increased render scales. The reviewed 16-address history stops incrementing at 16 while replacement uses count % 16, which repeatedly selects slot zero after full capacity unless another cursor exists.

Transferable regression and review cases

• A downloaded GPU surface overlaps a vertex range already covered by the GL mirror; quick-upload skip must not suppress copying the new bytes.
• Element size different from stride, zero stride, first/last vertex offsets, and exact boundary overlap.
• Native and increased render scales produce equivalent vertex input.
• More than 16 distinct surface addresses exercise an explicit ring or deliberate retention policy.

Suggested upstream handoff

Offer #125’s fetch-range helper, quick-skip invalidation, and XemuGpuSurfaceVertexAttributeReadback. State clearly that native-resolution surface selection remains upstream-specific.

Claims this page does not support

• It does not prove the upstream branch merges cleanly with current upstream.
• It does not prove a native correctness or performance result unless a linked exact-head run says so.
• It does not transfer favorable performance percentages between hardware, renderers, games, or source heads.
• It does not authorize posting a comment or review upstream.

Before sending anything upstream

• Refresh the PR state, head SHA, description, changed files, and newest review comments.
• Recheck the corresponding fork implementation on current main.
• Run or cite the narrow regression on an exact source state.
• Verify every public link and remove private paths, captures, game data, credentials, and internal logs.
• Phrase source concerns as source concerns and reproductions as reproductions.
• State the uncovered behavior and evidence limit.
• Add the posted URL and upstream response to this page.

Tracking log

Date	Upstream head	Action	Result
2026-09-21	cc576956ee5b	Fork/upstream source comparison recorded	Handoff prepared; nothing posted

References

• Upstream PR #2984
• Fork repository
• Upstream Work
• Pull Request Lessons