Novolis Docs
novolis-governance / imports-todo/internal-novolis-audit/simulation-viewpose-to-rendering-bridge.md

Simulation `ViewPose` → Rendering `CameraSnapshot` bridge

Policies that keep the org coherent

dotnetgovernancenovolis

What

Standardize how apps connect platform observers (Simulation) to ray tracing (Rendering) without forbidden package references.

Types today:

PackageTypeRole
`Novolis.Simulation.View``ViewPose`Position, target, up, FOV° — compose-time observer
`Novolis.Rendering.Runtime``CameraSnapshot`Orthonormal basis + vertical FOV radians + aspect
`Novolis.Math.Geometry``ViewBasis`Basis construction + primary ray direction

Gap: Every trace app repeats:

CameraSnapshot.LookAt(pose.Position, pose.Target, pose.Up, pose.FieldOfViewDegrees, aspect);

Dogfood (RaytraceHello, SilkTrace*) calls CameraSnapshot directly; simulation-first games (DoomLite3D, ArtillerySimulator) build ViewPose then bridge manually.

Why

  • library-boundaries.md: Rendering must not reference Simulation; Simulation must not reference Rendering.
  • A shared “bridge” package is usually overkill for a one-liner; the problem is discoverability and drift (different FOV conventions, up-axis fixes).
  • Documenting the canonical bridge prevents apps from reimplementing LookAt math incorrectly.

How

Recommended: app-layer extension (no new package)

Add to dogfooding shared helpers or copy into each app:

static CameraSnapshot ToCameraSnapshot(this ViewPose pose, float aspectRatio) =>
    CameraSnapshot.LookAt(
        pose.Position,
        pose.Target,
        pose.Up,
        pose.FieldOfViewDegrees,
        aspectRatio);

Place in novolis-dogfooding shared project if one exists, or document in novolis-dogfooding/docs/design.md.

Platform improvements (allowed)

  1. `CameraSnapshot.LookAt` — delegate to ViewBasis (see rendering-viewbasis-ray-generation.md) so Simulation and Rendering share basis math via Math only.
  2. `Simulation.View` XML docs — “For path tracing, apps map to CameraSnapshot.LookAt at compose time; Rendering does not reference Simulation.”
  3. Optional `ViewPose` helper on Simulation side — only if it does not reference Rendering:
  • e.g. ViewPose.ToLookAtArgs() returning (position, target, up, fovDegrees) tuple for apps — rarely worth it.

Do not

  • Add CameraSnapshot.FromViewPose(ViewPose) on Rendering (would require Rendering → Simulation).
  • Add Novolis.Simulation.View reference to Novolis.Rendering.*.

Pick / mouse rays

  • Document that screen-space picking should use ViewBasis.PrimaryRayDirection with the same basis as CameraSnapshot (see RagdollPlay BuildPickRay — candidate to align in dogfood doc).

Acceptance

  • novolis-dogfooding/docs or governance imports-todo cross-link shows the one-liner bridge.
  • No new forbidden dependency edges in solution graphs.
  • At least one dogfood app uses the shared extension after rendering-viewbasis-ray-generation.md lands.