Skip to content

Video Slideshow MultiType Roadmap

Jump to bottom
Bradley Brown edited this page Aug 13, 2026 · 1 revision

Multi-Type Video Slideshow — Feasibility & Roadmap

Status: P1 shipped (2026-07-22, #91). P2–P4 planned. Spun out of the Animation Roadmap open follow-ups (2026-07-03) as its own project because the fix is real engine work, not an animation follow-up patch.

Tracking issues: #91 (P1, done) · #92 (P2) · #93 (P3) · #94 (P4).

Problem (original)

The video slideshow pool was Mandelbrot-only. The gate lived in FractalRenderHost.Video.cs VideoSlideshowLoop (the region filter, and a per-leg ViewState.FractalType = FractalType.Mandelbrot force).

Note: single-shot video zoom was never Mandelbrot-only — it dispatches to the alt calculator via SelectAltCalculator(ViewState.FractalType) + SyncAltCalculatorForVideoFrame, driven by the live ViewState.FractalParameters. Only the unattended slideshow pool was gated.

Why it was Mandelbrot-only

FractalRegion captured a geometric target (center, zoom, iterations, quality) plus a few extras (UserBulb source+camera, UserEquation/Sandbox by name, lighting override) but carried no core per-family 2D parameters — no Julia constant, no Newton exponent/relaxation, no Phoenix/Glynn constant, no Spider decay, no Apollonian knobs. Built-in non-Mandelbrot regions worked only because their defaults happen to render correctly (their descriptions literally say "Set X before recall").

For a family with custom params an unattended zoom would render the wrong image (missing the per-engine params). Escape-time 2D families are otherwise reconstructable from center + zoom + iterations, so once the params round-trip, they re-zoom faithfully.

P1 — shipped (#91)

  1. Capability classifier. FractalMotionClass { Zoomable2D, Raymarch3D, NonSpatial } + FractalMotionCapabilities in Abstractions/Models/FractalCapabilities.cs. SupportsVideoZoomLeg(type) = 2D-zoomable and not user-code. (Named FractalMotionCapabilities — FractalCapabilities is already the [Flags] per-pixel-data bitmask in Enums.cs.)
  2. Per-family param snapshot. RegionFractalParams on FractalRegion — a JSON-lean, nullable snapshot of the 2D scalars (Julia/Phoenix/Glynn constants, Multibrot power, Spider decay, Newton exponent/relaxation, Secant offset, Apollonian knobs). Snapshot(type, params) captures only what a family needs (null when defaults suffice); ApplyTo(params) overlays them. Omitted from JSON when null, so Mandelbrot + legacy regions stay clean. Wired into HostColorThemeService save (BuildGeometryFromLiveState) + recall (LoadRegionFractalParams).
  3. Slideshow gate replaced. VideoSlideshowLoop now admits any SupportsVideoZoomLeg region, honours region.FractalType, restores region.Params, and routes the leg pre-render through the alt calculator.

Result: Julia/Multibrot/Phoenix/Glynn/Spider/Newton/Halley/Secant/Nova/ Magnet/Tricorn/BurningShip/TearDrop/Apollonian/generated regions play real zoom legs in the video slideshow.

P1 limitations (deliberate)

  • No motion model beyond point-zoom yet (a Julia leg zooms into a point; it does not sweep the constant — that's P2).
  • NewtonPolyCoeffs custom polynomials are not snapshotted (default-exponent path only).
  • Deep-zoom on the alt path is double-precision (EscapeTimeCalculator sets the hi limbs only → ~1e13 cap). Fine for these shallow regions.
  • A zoomable-2D region with null Params inherits whatever family fields are live (no built-in non-Mandelbrot regions hit this; user regions always snapshot).

Remaining scope

  • P2 (#92) — Julia constant-path animated legs (animate c along a path). Cheapest striking win; reuses the Phase-5 leg-animator hooks.
  • P3 (#93) — 3D raymarch camera-fly legs (Mandelbulb / Mandelbox / KIFS / Quaternion / Bicomplex / Kleinian). Needs a 3D-camera snapshot on the region and a camera-path motion model. Admits Raymarch3D.
  • P4 (#94) — Non-spatial families (Plasma, Flame, DLA, Logistic, IFS, L-System, attractors, Buddhabrot) via static-hold / param-sweep legs. Admits NonSpatial.

Security

UserEquation / Sandbox / UserBulb execute user-authored code and are excluded from the slideshow pool by FractalMotionCapabilities.IsUserCode regardless of motion class; they remain gated by Server/Guard/FractalTypeAllowlist.cs on any networked path (RCE risk). Do not admit them in P3/P4.

See also

Clone this wiki locally