World Events

Built-in authoring reference for Mercury 1.0.1. All events.

Arrived

Runs when a Walk To order finishes — the walker reached the clicked/ordered cell (or the closest open cell beside a solid target). A blocked or cancelled walk never fires it.

Reference key: arrived.

Editor category: World > Navigation and Portals.

Example: Use Arrived to open the door the player clicked on once the walker actually gets there.

Object inputs: self.

Event context is a read-only snapshot for this invocation. It is available in the Event’s Action fields; store a required value in a declared Variable before using it in another Event.

This Event exposes no additional context fields. Configure its filter and Object inputs where offered; a missing field is not an implicit zero-valued output.

Collision

Runs when this instance overlaps or collides with the selected object.

Reference key: collision.

Editor category: World > Collisions.

Example: Use Collision to damage the player when they touch an enemy.

Object inputs: self, other.

Filter (Object): Select the Object definition relevant to this Event. Collision filters select the other participant; the Event Object input identifies its live occurrence.

Event context is a read-only snapshot for this invocation. It is available in the Event’s Action fields; store a required value in a declared Variable before using it in another Event.

Event context

Field	Type	Description
otherName	thing:object	Object resource of the other colliding participant. The Event Object input targets the live instance; this field identifies its reusable definition.
otherInstance	instance	Live instance supplied by this Event. Use this typed handle to target the participant or store it in an Instance Variable; an Object resource name identifies its reusable definition instead. The handle can be empty when no participant is supplied.
otherId	text	Runtime instance identifier of the other participant. Distinguishes placements of the same Object; blank when no participant is supplied.

Collision Enter

Runs once when this instance starts colliding or overlapping with the selected object.

Reference key: collisionEnter.

Editor category: World > Collisions.

Example: Use Collision Enter to open a door once when the player reaches its trigger.

Object inputs: self, other.

Filter (Object): Select the Object definition relevant to this Event. Collision filters select the other participant; the Event Object input identifies its live occurrence.

Event context is a read-only snapshot for this invocation. It is available in the Event’s Action fields; store a required value in a declared Variable before using it in another Event.

Event context

Field	Type	Description
otherName	thing:object	Object resource of the other colliding participant. The Event Object input targets the live instance; this field identifies its reusable definition.
otherInstance	instance	Live instance supplied by this Event. Use this typed handle to target the participant or store it in an Instance Variable; an Object resource name identifies its reusable definition instead. The handle can be empty when no participant is supplied.
otherId	text	Runtime instance identifier of the other participant. Distinguishes placements of the same Object; blank when no participant is supplied.

Collision Leave

Runs once when this instance stops colliding or overlapping with the selected object.

Reference key: collisionLeave.

Editor category: World > Collisions.

Example: Use Collision Leave to close a sensor or stop an effect when contact ends.

Object inputs: self, other.

Filter (Object): Select the Object definition relevant to this Event. Collision filters select the other participant; the Event Object input identifies its live occurrence.

Event context is a read-only snapshot for this invocation. It is available in the Event’s Action fields; store a required value in a declared Variable before using it in another Event.

Event context

Field	Type	Description
otherName	thing:object	Object resource of the other colliding participant. The Event Object input targets the live instance; this field identifies its reusable definition.
otherInstance	instance	Live instance supplied by this Event. Use this typed handle to target the participant or store it in an Instance Variable; an Object resource name identifies its reusable definition instead. The handle can be empty when no participant is supplied.
otherId	text	Runtime instance identifier of the other participant. Distinguishes placements of the same Object; blank when no participant is supplied.

End of Path

Runs when this instance reaches the end of a path whose End setting is Stop.

Reference key: endOfPath.

Editor category: World > Navigation and Portals.

Object inputs: self.

Event context is a read-only snapshot for this invocation. It is available in the Event’s Action fields; store a required value in a declared Variable before using it in another Event.

This Event exposes no additional context fields. Configure its filter and Object inputs where offered; a missing field is not an implicit zero-valued output.

Enter View

Runs once when this instance enters any active camera view, including when it is created inside the view during play. A hidden instance still counts by its position. Instances placed in the view when the Scene starts are already in view, so it does not run for them.

Reference key: enterView.

Editor category: World > Views.

Example: Use Enter View to wake enemies as they scroll onto the screen.

Object inputs: self.

Event context is a read-only snapshot for this invocation. It is available in the Event’s Action fields; store a required value in a declared Variable before using it in another Event.

This Event exposes no additional context fields. Configure its filter and Object inputs where offered; a missing field is not an implicit zero-valued output.

Leave View

Runs once when this instance leaves all active camera views.

Reference key: leaveView.

Editor category: World > Views.

Example: Use Leave View to pause expensive logic when an object leaves the camera.

Object inputs: self.

Event context is a read-only snapshot for this invocation. It is available in the Event’s Action fields; store a required value in a declared Variable before using it in another Event.

This Event exposes no additional context fields. Configure its filter and Object inputs where offered; a missing field is not an implicit zero-valued output.

Runs on this instance when Navigate To Point reaches its point, or when Chase Object comes within its Stop Distance of the target. With Avoid Others on, a walker held back by others already at the goal arrives as close as the crowd allows. Works in 2D and 3D Scenes.

Reference key: navigationArrived.

Editor category: World > Navigation and Portals.

Example: On Navigation Arrived, play the attack animation.

Object inputs: self.

Event context is a read-only snapshot for this invocation. It is available in the Event’s Action fields; store a required value in a declared Variable before using it in another Event.

This Event exposes no additional context fields. Configure its filter and Object inputs where offered; a missing field is not an implicit zero-valued output.

Runs on this instance when Navigate To Point or Chase Object finds no route, has nothing to chase, or keeps getting stuck. A Chase Object walk keeps trying; Navigate To Point stops. Works in 2D and 3D Scenes.

Reference key: navigationBlocked.

Editor category: World > Navigation and Portals.

Example: On Navigation Blocked, pick a new patrol point.

Object inputs: self.

Event context is a read-only snapshot for this invocation. It is available in the Event’s Action fields; store a required value in a declared Variable before using it in another Event.

This Event exposes no additional context fields. Configure its filter and Object inputs where offered; a missing field is not an implicit zero-valued output.

Outside View

Runs while this instance is outside every active camera view.

Reference key: outsideView.

Editor category: World > Views.

Example: Use Outside View to despawn projectiles after they leave the camera.

Object inputs: self.

Event context is a read-only snapshot for this invocation. It is available in the Event’s Action fields; store a required value in a declared Variable before using it in another Event.

This Event exposes no additional context fields. Configure its filter and Object inputs where offered; a missing field is not an implicit zero-valued output.

Portal Traversed 3D

Runs on the traveler after it crosses a linked Portal. Other is the destination endpoint; event.portalPair is the pair name. 3D Scenes on the Babylon engine only.

Reference key: portalTraversed3d.

Editor category: World > Navigation and Portals.

Example: On Portal Traversed 3D, play an arrival effect and branch on event.portalPair.

Object inputs: self, other.

Event context is a read-only snapshot for this invocation. It is available in the Event’s Action fields; store a required value in a declared Variable before using it in another Event.

Event context

Field	Type	Description
otherName	thing:object	Object resource of the other participant. This identifies the reusable definition; use the Event Object input to target the live participant.
otherInstance	instance	Live instance supplied by this Event. Use this typed handle to target the participant or store it in an Instance Variable; an Object resource name identifies its reusable definition instead. The handle can be empty when no participant is supplied.
otherId	text	Runtime instance identifier of the other participant. Distinguishes placements of the same Object; blank when no participant is supplied.
portalPair	text	Pair name of the traversed portals. Matches the Portal components’ Pair setting.

Stepped on Cell

Runs each time this grid walker lands on a cell — filtered by the zone painted there (blank = every cell). event.zone and event.tileType describe the landing spot. Zones are painted with the Scene Editor’s Zones tool.

Reference key: steppedOnCell.

Editor category: World > Collisions.

Example: Stepped On Cell [tallgrass] rolls a random encounter each step through the painted tall grass.

Object inputs: self.

Filter (Zone (blank = any cell)): Select the named cell zone involved in this Event.

Event context is a read-only snapshot for this invocation. It is available in the Event’s Action fields; store a required value in a declared Variable before using it in another Event.

Event context

Field	Type	Description
zone	text	Zone label of the newly entered cell. Blank when that cell has no zone label.
tileType	text	Tile Type label of the tile or cell involved. This is gameplay metadata, not a Sprite frame number.

Tile Collision

Runs when this instance collides with a solid tile of the chosen type (or any typed tile). Tile types are named per tile in the Tileset editor’s Inspect panel.

Reference key: tileCollision.

Editor category: World > Collisions.

Example: Use Tile Collision [hazard] to hurt the player when they step on spikes painted from a tileset.

Object inputs: self.

Filter (Tile type): Select the gameplay Tile Type carried by the contacted tile; this is separate from its visual artwork.

Event context is a read-only snapshot for this invocation. It is available in the Event’s Action fields; store a required value in a declared Variable before using it in another Event.

Event context

Field	Type	Description
tileType	text	Tile Type label of the tile or cell involved. This is gameplay metadata, not a Sprite frame number.

Z Order Changed

Runs after this instance depth changes.

Reference key: zOrderChanged.

Editor category: World > Object Changes.

Example: Use Z Order Changed when a depth change should trigger follow-up behavior.

Object inputs: self.

Event context is a read-only snapshot for this invocation. It is available in the Event’s Action fields; store a required value in a declared Variable before using it in another Event.

This Event exposes no additional context fields. Configure its filter and Object inputs where offered; a missing field is not an implicit zero-valued output.

Myth Engine Documentation