Pacenote Generator

Simplified corner detection system that generates pacenotes from driveline points. Analyzes road geometry using circle-fitting to identify direction changes, then groups consecutive nodes into corners with simplification passes.

Public API

Default Parameters

M.defaultParams = {
  lookAheadContext = 7,          -- Nodes to look ahead/behind for direction
  straightThreshold = 5.0,       -- Degrees below which is "straight"
  mergeDistanceThreshold = 0.2,  -- Meters threshold for merging straights
  maxSimplifyIterations = 10     -- Max simplification passes
}

Internals

Key Local Functions

Corner Detection Pipeline

1. Convert: Input points → route array with pos and id
2. Annotate: For each node, look ±context nodes, fit circle, compute:
   • direction: "" (straight), " right", or " left" (via cross product sign)
   • angle: arc angle (0 if below straightThreshold)
   • radius: distance from point to fitted circle center
3. Split: Create new corner segment whenever direction changes
4. Simplify: Iteratively merge straights that extend along a line + consecutive same-direction corners

Output Format

{
  {
    pos = vec3,        -- first node position (corner start)
    posEnd = vec3,     -- last node position (corner end)
    direction = string, -- "" | " right" | " left"
    angle = number,    -- total arc angle in degrees
    length = number,   -- total corner length in meters
    nodes = table      -- array of annotated route nodes
  },
  ...
}

Direction Detection

Uses 2D cross product (Z component) of consecutive segments:

local cross = (p3z - p2z):cross(p2z - p1z).z
-- cross > 0 → right, cross < 0 → left

How It Works

1. Caller provides array of driveline points (with .pos property or as vec3)
2. Points are converted to route nodes and annotated with geometry data
3. Route is split into corners at each direction change
4. Simplification merges inline straights and consecutive same-direction corners
5. Returns array of corner descriptors used by notebook to create pacenotes

Adapted from geometry.lua but simplified to focus only on corner detection without velocity/severity calculations.

Usage Example

local generator = require('gameplay/rally/notebook/pacenoteGenerator')

-- Detect corners from driveline points
local corners = generator.detectCorners(drivelinePoints)

-- With custom parameters
local corners = generator.detectCorners(drivelinePoints, {
  lookAheadContext = 5,
  straightThreshold = 3.0,
  mergeDistanceThreshold = 0.5,
  maxSimplifyIterations = 15
})

-- Use results to generate pacenotes
for _, corner in ipairs(corners) do
  if corner.direction ~= "" then
    -- Create pacenote for this corner
  end
end

See Also

• Rally Codriver - Related reference
• Rally Mission Settings - Related reference
• Rally Pacenote - Related reference
• Gameplay Systems Guide - Guide