PortalPreview

Shows the place a portal leads to inside its frame: wooden, stone, and supported portals added by other mods. The destination is captured once as a frozen 3D scene and kept on disk, and the frame becomes a window onto it: the view has true parallax as you move, opens in a spiral as you approach, blends into the frame with a rippling edge and has smoke drifting along the seam.

The view follows the time of day and the weather at the destination: at night the far side is dark under the stars, in the morning the sun rises there too. The captured scene stays frozen, while optional rain and snow move inside the opening. A little of the destination's mist, snow, embers or dust can also drift out of the portal. Between image updates the view is reconstructed from cached colour and depth instead of rendering the scene again. Updating portal images still costs performance, especially while moving around a hub with several visible portals. The cost depends on the scene, resolution, movement and hardware.

Requirements

• Valheim with BepInEx 5 on Windows.

Recommended (optional)

• FastLoading: faster portal travel and dungeon entrances, so stepping through a portal takes a moment rather than a loading screen.
• ValheimVisuals: water, reflections, materials and ambient occlusion turned up within the game's own ranges, for a better picture everywhere.

Install

1. Close Valheim.
2. Put PortalPreview.dll into Valheim/BepInEx/plugins/.

How it captures

When a portal first shows its view: a portal shows the place at its other end, so that place has to be captured first, and only a place you are at can be.

• A new pair of portals: travel through it once. The portal you leave and the one you arrive at are both captured under that loading screen, and from then on both show their views.
• Two linked portals standing next to each other (a hub): both views appear a moment after linking, no trip needed.
• Portals built before installing the mod, or after a game update: the same as a new pair, one trip through each.
• Capturing a scene can pause the game, so travel captures run under the teleport loading screen and may extend it. Linked portals standing next to each other (a hub) and manual frozenportal refresh captures run locally instead. Capture time depends on the scene and any texture packs in use.
• Snapshot updates decides when an existing scene is replaced: WhenChanged (default) when you leave through the portal and something around it was built, removed, grown or dug since its last capture; EveryTrip on every departure (not again within two minutes); Once keeps the scene until frozenportal refresh. Outdated or incomplete scenes can still request a recovery capture, including with Once.
• A capture waits for a fully black frame and may extend the transition. If it cannot start within three seconds, travel continues with the previous snapshot. A capture already in progress can take longer.
• Wooden and stone portals work in any pairing; the game links them to each other by tag. Portals added by other mods can show previews when their opening can be measured; this does not change their linking or travel rules.
• Saved scenes live in BepInEx/cache/PortalPreview/PortalSnapshots. Scenes and data nothing uses any more (a portal torn down, an older game version, what a recapture left behind) are removed automatically once per session.

Settings

BepInEx/config/ru.ivest.portalpreview.cfg, all live with Configuration Manager. The main ones:

The sections appear with number prefixes in the configuration file and Configuration Manager.

Section	Setting	Default	Meaning
General	Enabled	true	Show portal views.
General	Hardware profile	Auto	Choose image resolution and the number of visible views and resident snapshots from your hardware (Auto/Low/Medium/High/Ultra). Resolution, Max visible portals and Max resident snapshots follow the profile at 0; a positive value overrides that setting.
Portal views	Approach radius	15	How close to a portal its view opens, in metres.
Portal views	Always visible	false	Show views at any distance while in sight.
Portal views	One-sided view	false	Show the view only from the front, the side travellers come out of.
Portal views	Spiral duration	1.2	Seconds the spiral takes to open or close.
Portal views	Max visible portals	0	Maximum simultaneous views. 0 follows the hardware profile. More views cost more video memory and rendering time.
Effects	Portal atmosphere	true	Let some of the destination's mist, snow, embers or dust drift out of an open portal. Older scenes may need a new capture.
Effects	Moving weather	true	Animate rain and snow inside outdoor views. Requires Shader reconstruction and a scene captured with this option enabled.
Effects	Follow time of day	true	Light the view for the current time and weather at its destination. False keeps the captured lighting.
Effects	Hide game flames and fog	true	Hide the connected portal's flames, swirling fog and sparks drawn into the opening. Runes, light and sound stay.
Effects	Edge style	Ripple	How the picture meets the frame: Ripple, Vortex, Glow, Smoke or None.
Effects	Edge smoke	true	Smoke puffs along the seam between the view and the frame.
Quality	Preview quality	High	How often the scene image is updated as you move, with Shader reconstruction enabled. High: every 0.3 m. Medium: every 0.6 m. Both update once more when you stop. Low keeps the opening capture, with less exact parallax up close. Auto uses Medium on the Low hardware profile, High otherwise.
Quality	Resolution	0	Portal image resolution limit; 0 follows the hardware profile. Higher values make image updates more expensive.
Quality	Adaptive resolution	true	Match image resolution to the portal's size on screen, up to the configured limit.
Quality	Panorama resolution	0	Detail of the distant landscape and clouds in new captures: 0 follows the profile, or choose 512, 1024 or 2048. Higher values use more memory and take longer to capture. Existing scenes keep their resolution until captured again.
Quality	Hidden geometry	Auto	Omit hidden geometry from new captures while retaining needed shadows. Auto enables this on Low and Medium profiles. Narrow gaps can show visual errors; changing it requires a new capture.
Snapshots	Snapshot updates	WhenChanged	Replace a saved scene when its surroundings change (WhenChanged), on departure with a two-minute minimum interval (EveryTrip), or only on request apart from recovery captures (Once).
Snapshots	Max resident snapshots	0	Scenes kept in RAM. 0 follows the hardware profile; scenes on disk are retained.

Console (F5): frozenportal status, on, off, refresh (recapture nearby portals), cleanup (remove stale saved scenes now), lighting (compare the lighting the mod computes where you stand with the game's own).

Errors and rate-limited warnings about preview work over 50 ms reach the log. For detailed captures, loads and frame costs, use frozenportal log on in the console (off with frozenportal log off), or launch with -portalpreview-log.

Multiplayer

Client-side. Each player captures the portals they use; nothing is sent over the network.

Problems and feedback

Write to me on Discord: https://discord.com/users/683075123816824940. Attach BepInEx/LogOutput.log from the game folder, or from the profile folder with a mod manager (r2modman: Settings → Browse profile folder), and say what you did when it happened. If a portal shows no view, add the output of frozenportal status typed in the F5 console next to it (the console needs the -console launch option), and start the game with -portalpreview-log so the log says what the preview did.