crystal.Sensor

Component allowing an entity to detect collision with others without blocking them. Freshly created sensors have no category and are activated by nothing.

In a typical platforming game, collectable coins and power-ups would use sensor components.

Constructor

Like all other components, Sensor components are created by calling Entity:add_component. The constructor expects one argument: a love.Shape. The entity must have a Body component added prior to adding any sensors.

entity:add_component(crystal.Body);
entity:add_component(crystal.Sensor, love.physics.newCircleShape(4));

Methods

Name	Description
activations	Returns all components currently overlapping this sensor.
disable_activation_by	Prevents this sensor from being activated by colliders or sensors of specific categories.
disable_activation_by_everything	Prevents this sensor from being activated by colliders or sensors of any category.
disable_sensor	Prevents this sensor from being activated.
enable_activation_by	Allows this sensor to be activated by colliders or sensors of specific categories.
enable_activation_by_everything	Allows this sensor to be activated by colliders or sensors of any category.
enable_sensor	Allows this sensor to be activated.
set_categories	Sets which physics categories describe this sensor.
shape	Returns the shape of this sensor.

Callbacks

Name	Description
on_activate	Called when a collider or sensor starts overlapping this sensor.
on_deactivate	Called when a collider or sensor stops overlapping this sensor.

Examples

local ecs = crystal.ECS:new();
ecs:add_system(crystal.PhysicsSystem);

local pressure_plate = ecs:spawn(crystal.Entity);
pressure_plate:add_component(crystal.Body);

local sensor = pressure_plate:add_component(crystal.Sensor, love.physics.newRectangleShape(20, 20));
sensor:set_categories("trigger");
sensor:enable_activation_by("characters");
sensor.on_activate = function()
  print("Pressure plate activated!");
end