Sensors / Triggers

Detects overlaps and contacts without physical collision response.

A sensor remains a normal collision shape for broad-phase filtering, contact events, and raycasts, but Jolt does not use it to push or block other bodies.

High-Level API#

body.set_sensor(enabled)
body.is_sensor()

Creation option#

var trigger_layer = jolt_layer_create("Triggers");
var trigger = jolt_box_create_dynamic(0, 0, 2, 4, 4, 4, {
    sensor: true,
    layer: trigger_layer
});
trigger.set_user_data({kind:"DamageZone", damage:10});

The shared body option sensor defaults to false. set_sensor() changes the state at runtime and activates non-Static bodies. is_sensor() returns a Boolean; native errors are captured by the high-level wrapper.

What a sensor does#

Reading trigger events#

jolt_update();

var events = trigger.get_collisions();
for (var i = 0; i < array_length(events); ++i) {
    var event = events[i];
    if (event.type == JOLT_COLLISION_ENTER) {
        show_debug_message("Entered trigger");
    }
}

Per-body events set sensor=true when either participant is a sensor. World events expose body_a_sensor and body_b_sensor separately.

Filtering and visualization#

A sensor pair still needs an enabled collision-layer combination. Raycasts do not automatically exclude sensors. Debug draw shows sensors only when JOLT_DEBUG_SENSORS is enabled; JOLT_DEBUG_SHAPES alone draws non-sensor bodies.

jolt_debug_enable(true);
jolt_debug_set(JOLT_DEBUG_SENSORS, true);
jolt_debug_draw();

Low-Level / Advanced API#

Both functions use numeric world/body handles. The setter returns 1/0; the getter returns 1/0 and reports invalid handles through native error state.

Current project integrations#

• Sensors›

Verified operation contracts#

These contracts distinguish units, return values, errors and lifetime according to the current implementation. Check results: false, 0 and undefined can mean different things for different methods.