Extension Hooks#

Interfaces the shipped setups leave at their default or never call. Each has a default that leaves the shipped setups unchanged; a custom robot or plugin overrides or reads it. The API reference documents each, and Extending Open Apero shows how to write the plugin that overrides one.

Hook	Default	What a custom robot or plugin does with it
Hit regions: `Map::registerHit()`, `Map::getHitRegions()`, `Map::isStateReachable()`, `RobotModel::updateHitRegions()`, `RobotModel::isInsideHitRegions()`, `Agent::respondToHit()`	No regions; every state reachable	Record where a collision or a vetoed step happened; the map keeps the blocked regions until `resetEpisode()`, and `SimpleRobot` rejects a state for which `isInsideHitRegions()` returns `true`
`Map::getGroundHeight()`	`false` (no ground model)	Report the ground under a state, so the path markers draw its ground track
`RobotModel::isStationingPositionAdmissible()`, `StationingCheck`	Admits every position	Restrict where nodes may be placed, separately from traversability; generators exempt only the seed at the robot’s own position
`RobotModel::attachSharedGainAnchors()`	Attaches none	Give a new cluster’s nodes gain anchors they share, which an evaluator that keeps them scores once; `RRAG` calls it once per new cluster
`HistoryData::getObservedViewpoints()`, `ObservedViewpoints`	Disabled (both thresholds `0.0`)	Ask whether a pose was already looked from (History and Observed Viewpoints)
`RobotModel::getGazePitchMin()`, `getGazePitchMax()`, `getSensorMountType()`	−π/2, π/2, `fixed`	Plan the gaze pitch or the full sensor orientation; every shipped plugin plans yaw only
`RobotModel::samplePositionNear()`, `RobotModel::getSafeRadius()`, `SensorModel::pointInSensorView()`	`samplePositionNear()` returns `false` (`SimpleRobot` implements it); every point is in view (`CameraModel` implements it)	Sample candidates around a point of interest; test without occlusion whether a point is in a sensor’s view
`Backtracker::lastProbeSamples()`, `declareMetrics()`, `getVisualization()`	No samples, columns or markers	Report the samples behind a recovery decision, add `<layer>.` columns to `performance_log.csv` and draw markers
`RRAG::findNearestExpansionAnchor()`, `isSamplePositionAdmissible()`, `indexNodeCluster()`	The nearest node; every position admissible; one spatial index	A subclass keeps its own expansion anchors and indices, or rejects sample positions early
`Edge::is_backtrack`	Set on every recovery edge; the backtrackers and edge revalidation skip such edges	Exempt recovery edges from a platform’s own pre-flight checks in `sendMovement()`
`RosAgent::statusOverlayLines()`, `RosAgent::onStateAvailable()`	The active layer, distance and time; roots the graph in the first state after a reset	Add lines to the RViz overlay, or react to each arriving state

Agent::sendMovement(), which every platform implements, and the loop hooks Agent::readyToExpand() and RobotModel::refineBeforeExecute() are described in Agent and Execution and Layers.