Minimap Roads

Renders navgraph road segments on the minimap with spatial culling.

Overview

ui_apps_minimap_roads draws navgraph road links as colored line segments on the minimap. It builds a kd-tree spatial index on first call, then queries visible roads each frame for efficient rendering.

Extension path: lua/ge/extensions/ui/apps/minimap/roads.lua

Exports (M)

Internals

First-Call Initialization

On the first call to drawRoads, the module:

1. Iterates all map.getMap().nodes and their links
2. Skips links with hiddenInNavi = true
3. Stores link data in a flat array: [x1, y1, x2, y2, color] per link
4. Builds a kdtreebox2d spatial index with bounding boxes per link
5. Colors roads by drivability:
   • ≥ 0.9 → main road color
   • > 0.25 → low drivability color
   • ≤ 0.25 → lowest drivability color

Per-Frame Rendering

After initialization, each frame:

for lIdx in kdNodes:queryNotNested(camPos.x-radius, camPos.y-radius, camPos.x+radius, camPos.y+radius) do
  local s1X, s1Y = worldToMapXY(links[lIdx], links[lIdx+1])
  local s2X, s2Y = worldToMapXY(links[lIdx+2], links[lIdx+3])
  -- Draw background stroke (dark outline)
  td:lineRoundEnd(s1X, s1Y, s2X, s2Y, bgWidth, bgWidth, 0, bgColor, bgColor, 0, 0, 0, layers.ROADS_BG)
  -- Draw foreground (colored road)
  td:lineRoundEnd(s1X, s1Y, s2X, s2Y, fgWidth, fgWidth, 0, color, color, 0, 0, 0, layers.ROADS_FG)
end

Road Styling

Roads use constant-width rendering (not scaled to road radius):

• Background width: 2 * scaleInverse * dpi + 2 * dpi - dark outline
• Foreground width: 2 * scaleInverse * dpi - colored fill

Color sets come from ui_apps_minimap_utils.getStyleColorSet().

Fallback Grid

If no roads exist and grid drawing is disabled, the module calls ui_apps_minimap_utils.drawGrid() as a fallback visual reference.

How It Works

1. First drawRoads call builds a kd-tree from all navgraph links
2. Each frame, queries the kd-tree for links within the visible radius
3. Draws each visible link as a two-layer line (outline + fill)
4. reset() clears the cache for map transitions

Additional Exports

The following exports are available but not yet documented in detail:

• M.drawRoads
• M.reset

See Also

• Minimap Additional Info - Related reference
• Minimap Layers - Related reference
• Minimap (Main) - Related reference
• UI System Guide - Guide