PrimedFrame 1.0.0

Metroid Prime in VR, running natively on the Valve Steam Frame. PrimedFrame is a fork of Nobbie248's PrimedGun built as a native Linux Arm64 program with frame pacing written for SteamVR. It replaces running PrimedGun's PC build in a Linux container with the Frame's graphics driver mounted in. You need your own Metroid Prime disc image; no game data is included.

The game on the Frame

• A native Linux Arm64 build, launched from the Steam library into the Frame's own SteamVR. No container, no PC.
• PrimedGun's game code, controls and in-VR menu as they are. No desktop window; settings are the ini files and the menu.
• Settings, memory card and save states in plain folders under ~/.local/share/PrimedFrame.

Resolution and frame rate

• Internal resolution 3x (1920x1584 per eye) and 2160 pixel eye images, the panel's native size. The container setup ran 2x and 1728.
• The 120 Hz display, with SteamVR pacing the game at its own 60 frames a second.
• Heavy rooms hold 60 frames a second: 59.5 on average in the heaviest room I know, where the container setup ran 20 to 30.
• No doubled images, and a steady helmet HUD.

What changed under the hood

• The Frame's GPU renders straight to memory instead of in tiles. The stereo geometry shader made every draw run once per tile; the GPU time per frame in the heaviest room went from 19 ms to 6 ms at the old settings (measured headless). That paid for 3x and 2160.
• Eye images are released to SteamVR only after the GPU has finished them, instead of draining the GPU every frame.
• Each game frame goes to SteamVR in its own frame cycle, with one landing per room.
• Head and controller poses are predicted for the refresh the frame really appears on.
• The game's video timing is exactly 60 Hz instead of 59.94, so frames stop drifting against SteamVR's slots.
• The GPU gets the game's drawing every 100 draws, and the eye image is no longer cleared before it is overwritten.
• The shader cache works now. The no-window build never created its folder, so every launch recompiled every shader; only the first launch stutters.
• GPU texture decoding stays off, because the Frame's GPU faults with it on.

Install

• An installer that unpacks the release, seeds the settings, finds your disc image and adds the Steam shortcut with the VR flag and the library art.
• The in-VR menu's settings are saved (the no-window build lost them at exit; its Save and Exit Game buttons work now).
• A launcher that sets SteamVR's per-app settings at every launch (120 Hz, SteamVR pacing the game at 60, no extra prediction, motion smoothing off, 2160 per eye) and keeps session logs.
• Tools to collect logs for a bug report and to remove the program again.

Download

• primedframe-1.0.0-linux-arm64.tar.gz
• SHA256SUMS

Install

Unpack the tarball on the Frame and run its install.sh --rom <your disc image>. The README has the full steps, the settings and the troubleshooting.

Known

• The game's world, enemies and the arm cannon move at 60 frames a second. On the 120 Hz display an object your eye follows can look doubled along its movement. Head movement is corrected at 120.
• A very light jitter is left on the helmet HUD on fast head turns.
• The first launch stutters while the shaders compile.
• A 75 ms hitch at the step from the ship flight intro into play. It is the game's own.
• Played on one Steam Frame with the US disc.

Reporting problems

Open an issue with what you did, what you expected and what happened, and the archive from ~/Games/PrimedFrame/app/tools/collect-logs.sh.

Credits

Nobbie and PrimedGun, iChris4 and Dolphin ReduX, Carl Kenner and the Dolphin VR contributors, josethevrtech and PrimedSteam, the Dolphin team, and Valve. The README has the links and the full list.