using System.Numerics;

namespace AcDream.App.Rendering;

/// <summary>
/// Factory for the OUTDOOR render root — the cell the render roots at when the camera eye is outdoors.
/// Retail roots every in-world frame at <c>viewer_cell</c> (SmartBox::RenderNormalMode →
/// DrawInside(viewer_cell), decomp:92635); when outdoors that is a <c>CLandCell</c>. acdream models it
/// as a portal-less <see cref="LoadedCell"/> carrying only <see cref="LoadedCell.IsOutdoorNode"/> (so
/// <see cref="PortalVisibilityBuilder.Build"/> seeds OutsideView FULL-SCREEN → terrain/sky/scenery draw
/// as the root's shell) and <see cref="LoadedCell.SeenOutside"/>.
///
/// <para>R-A2 (2026-06-08): the node no longer carries reverse portals into nearby buildings. Retail
/// does NOT flood buildings from the land root — buildings flood SEPARATELY, per-building, during the
/// landscape draw (terrain BSP → DrawPortal → ConstructView(CBldPortal), decomp:326881/433895/433827).
/// acdream issues those via <see cref="PortalVisibilityBuilder.ConstructViewBuilding"/> per nearby
/// building inside <see cref="RetailPViewRenderer.DrawInside"/>. The pre-R-A2 design flooded all
/// buildings from one root through reverse portals, coupling their interior membership to a single
/// root-level portal-side test that oscillated as the chase eye grazed a doorway — the indoor flap.</para>
/// </summary>
public static class OutdoorCellNode
{
    public static LoadedCell Build(uint outdoorCellId) => new LoadedCell
    {
        CellId = outdoorCellId,
        SeenOutside = true,
        IsOutdoorNode = true,
        WorldTransform = Matrix4x4.Identity,
        InverseWorldTransform = Matrix4x4.Identity,
    };
}