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Fallout 4 VR extension (IVPrismaUIVR1)

Status: preview, separate from the public desktop 2.1.0 release.

PrismaUI_F4VR.dll is a separate provider built against CommonLibF4VR. The VR provider and spatial API have compile/deterministic-test coverage, but the desktop framework-v2.1.0 release does not constitute headset/runtime acceptance for Fallout 4 VR. Do not advertise VR support as released until the VR provider has its own acceptance and publication.

Provider model​

Flat Fallout 4 and Fallout 4 VR use different provider DLLs:

Fallout 4 desktop -> PrismaUI_F4.dll
Fallout 4 VR      -> PrismaUI_F4VR.dll

The shared header knows both provider names. The VR extension is additive and does not alter the desktop V1-V10 vtable layout.

The current framework architecture is Ultralight-based. Do not apply the retired legacy-runtime Host/subprocess model to the VR preview.

Requesting the APIs​

#include "PrismaUI_F4_API.h"
#include "PrismaUI_F4VR_API.h"

auto* ui = PRISMA_UI_API::RequestPluginAPI<PRISMA_UI_API::IVPrismaUI10>();
auto* vr = PRISMA_UI_VR_API::RequestPluginVRAPI<PRISMA_UI_VR_API::IVPrismaUIVR1>();

if (!vr) {
    // Not running against a provider that exposes the VR extension.
}

Treat a non-null VR interface as API availability, not proof that every optional spatial feature is available. Query capabilities.

Presentation modes​

ModeBehavior
HeadLockedQuadFixed relative to the headset
WorldBillboardWorld-positioned and faces the viewer
WorldQuadWorld-positioned and uses the supplied orientation

Pixel dimensions control page resolution. Physical dimensions control world-space size.

Submit a spatial placement​

PRISMA_UI_VR_API::SpatialUpdateV1 update{};
update.structSize       = sizeof(update);
update.coordinateSpace  = PRISMA_UI_VR_API::SpatialCoordinateSpace::GameWorld;
update.presentationMode = PRISMA_UI_VR_API::SpatialPresentationMode::WorldBillboard;
update.sequence         = ++mySequence;
update.pose.position[0] = x;
update.pose.position[1] = y;
update.pose.position[2] = z;
update.pose.orientation[3] = 1.0f;
update.dimensions.pixelWidth     = 1024;
update.dimensions.pixelHeight    = 768;
update.dimensions.physicalWidth  = 60.0f;
update.dimensions.physicalHeight = 45.0f;

const auto result = vr->SubmitSpatialUpdate(view, &update);

Updates are latest-only. If a newer update replaces a pending one, PendingUpdateReplaced is a successful coalescing result, not a hard failure.

Use state readback when you need to distinguish accepted from applied sequence numbers.

Pointer input​

World-space pointer input is submitted as a ray and translated into page input when the provider can resolve a hit.

PRISMA_UI_VR_API::SpatialPointerUpdateV1 pointer{};
pointer.structSize   = sizeof(pointer);
pointer.flags        = PRISMA_UI_VR_API::SpatialPointerUpdate_Active;
pointer.buttonLevels = trigger
    ? PRISMA_UI_VR_API::SpatialPointerButton_Primary
    : 0;
pointer.sequence     = ++myPointerSequence;
pointer.maxDistance  = 400.0f;
pointer.pointerSourceId =
    PRISMA_UI_VR_API::SpatialPointerSource_PhysicalRightController;

vr->SubmitSpatialPointerUpdate(view, &pointer);

Call CancelSpatialPointer when the source goes away or a view is hidden during interaction so held/hover state is not left behind.

Read back pointer state​

PRISMA_UI_VR_API::SpatialPointerStateV1 state{};
state.structSize = sizeof(state);

if (vr->GetSpatialPointerState(view, &state) ==
    PRISMA_UI_VR_API::SpatialResult::Success) {
    const bool hitting = state.hitDistance >= 0.0f;
}

Useful fields include accepted/applied sequence numbers, hit pixel/UV coordinates, held button levels, replaced-pending count, and the most recent apply result.

Capabilities​

Query GetSpatialCapabilities instead of assuming optional features:

  • supported presentation modes;
  • maximum pixel dimensions;
  • spatial view/resource limits;
  • feature bits such as scene-depth occlusion;
  • native network-policy capability where implemented.

An API shape existing in the header does not make an optional feature available on every provider/runtime.

Network policy​

VR network-policy methods use the same framework-wide safety model as the current Ultralight architecture.

Important semantics:

  • file:// is not a supported Prisma content path;
  • local Prisma/plugin assets use the confined Prisma content path;
  • private/loopback targets remain subject to native safety policy and explicit narrow exceptions;
  • redirects are checked through the same policy boundary;
  • LocalOnly adds a strict no-remote restriction;
  • Unrestricted means the normal Prisma-approved network path, not “disable all Prisma security”;
  • RemoteNoFile is retained for ABI compatibility and does not enable arbitrary local filesystem URLs.

Do not repeat the old legacy-runtime note that LocalOnly is merely a one-way injected page script. The current policy contract is documented in the Matrix network-policy semantics and is intentionally backend-safe rather than legacy-runtime-specific.

Because VR remains a preview, runtime verification of network-policy behavior is still part of the VR acceptance gate.

Results​

Spatial methods return SpatialResult. Treat success/replacement, unsupported, not-ready, and validation failures according to the method contract rather than assuming a failed frame means the provider is absent.

Release boundary​

The public desktop 2.1.0 package and its validation do not make these statements:

  • that PrismaUI_F4VR.dll is publicly released;
  • that headset interaction has been manually accepted;
  • that every desktop feature has been live-tested in Fallout 4 VR;
  • that desktop release hashes cover VR artifacts.

Keep VR dependencies optional until the VR release is explicitly published.