Track Builder - Basic Borders

Generates left and right border mesh geometry for track segments in the track builder system.

Overview

util_trackBuilder_basicBorders provides border cross-section shapes (regular, bevel, racetrack, rail, etc.) and compiles them into 3D mesh data (vertices, normals, UVs, faces) for track segment borders. Each side of the track gets an independent mesh with configurable shape and material.

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

Exports (M)

Internals

Available Shapes

Shape Structure

Each shape defines:

• crossPoints - array of {point = vec3, uv = number, sharp = bool} defining the 2D profile.
• cap - triangle indices for start/end caps.
• faces - groups of vertex indices forming face strips.
• faceInfo - precomputed face/normal/cap data (computed on module load).

Mesh Compilation (compileMeshInfo)

For each track point that passes the quality filter:

1. Cross-section vertices are transformed into world space using the point's orientation, width, and position.
2. Normals are rotated similarly.
3. UVs use the cross-section uv for U and point.uvY * uvHeight for V.
4. Faces connect consecutive cross-sections into quads.
5. Optional start/end caps are added based on segment meshInfo.

Quality Levels

At quality level 4, borders degrade to the none shape (invisible).

Output Format

{
  verts = {{x,y,z}, ...},
  uvs = {{u,v}, ...},
  normals = {{x,y,z}, ...},
  faces = {{v, n, u}, ...},
  material = "track_editor_A_border",
  tag = "side 1" or "side -1"
}

How It Works

1. Track builder assigns leftMesh and rightMesh shape names to each segment.
2. getMeshes(segment) compiles both sides into mesh data.
3. The mesh data is passed to the ProceduralMesh system for rendering.

Lua Examples

-- Used internally by the track builder pipeline:
local borderMeshes = extensions.util_trackBuilder_basicBorders.getMeshes(segment)
-- Returns array: {leftMeshData, rightMeshData}

Additional Exports

• M.getMeshes - (undocumented)