Track Builder - Ceiling Mesh

Generates ceiling/tunnel mesh geometry above track segments in the track builder system.

Overview

util_trackBuilder_ceilingMesh creates a box-shaped ceiling above the track using a width-dependent LUT system (like basicCenters). The ceiling height is configurable per point via point.ceilingMeshHeight. Used for tunnels and covered track sections.

Module path: lua/ge/extensions/util/trackBuilder/ceilingMesh.lua

Exports (M)

Internals

Cross-Section Shape

A 7-point rectangular box profile:

   1───6───7(=1)
   │       │
   2       5
   │       │
   3───4───3

Points 2, 3, 5, 6 are marked sharp for hard edges. The shape forms a closed rectangular cross-section.

Width-Based LUT

Like basicCenters, precomputes vertices and normals for each width step:

• Width scaled by LUTDetail = 10 subdivisions per unit.
• X coordinates scaled by width/2.
• Normals computed with smooth/sharp handling.

Ceiling Height

Each point's ceilingMeshHeight offsets the entire cross-section upward via:

point.ceilingMeshHeight * point.orientation.nz

UV Mapping

• U: Distance along cross-section from center × uv.width.
• V: point.uvY * uv.height for along-track tiling.

Start/End Caps

Cap UVs are computed from the actual start/end point widths. Caps respect segment.meshInfo.ceilingMesh.startCap/endCap and forceStartCap/forceEndCap.

Quality and Activation

• Returns empty at quality level 4.
• Returns empty if segment.meshInfo.ceilingMesh.active is false.

Output Format

{
  verts = {{x,y,z}, ...},
  uvs = {{u,v}, ...},
  normals = {{x,y,z}, ...},
  faces = {{v, n, u}, ...},
  material = "track_editor_A_center",
  tag = "ceiling"
}

How It Works

1. Track builder marks ceilingMesh.active = true and sets ceilingMeshHeight per point.
2. getMeshes(segment) precomputes width LUT, then compiles the mesh.
3. The ceiling floats above the track surface at the specified height.

Lua Examples

-- Used internally by track builder:
local ceilingMeshes = extensions.util_trackBuilder_ceilingMesh.getMeshes(segment)
-- Returns: {ceilingMeshData} or {} if inactive/low quality

Additional Exports

• M.getMeshes - (undocumented)