Light

Light extends Object, adding functions and properties to it.

A Light is an object that can be placed in the scene to act as a light source.

There are currently 3 types of light: point, spot, and directional.

A code example of Light's various fields can be found in the world Lights Tests.

Constructors

Light ( )

Creates a Light with default properties.

local l = Light()

-- change light properties
l.Radius = 50
l.Color = Color(1.0, 1.0, 0.5)

-- use it as a normal object in the scene
l:SetParent(World)
l.Position = { x, y, z }

Functions

Inherited from Object

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nil AddChild ( Object child, boolean keepWorld optional )

Adds given Object as a child. Object extensions like Shape or MutableShape are naturally accepted too.

The keepWorld optional parameter, false by default, dictates whether to maintain the child's world or local position and rotation. Keeping world will ensure the object doesn't move in the scene, adjusting its local position/rotation accordingly; keeping local will have the object move in the scene in order to maintain an equivalent local position/rotation relative to its new parent.

local o = Object()
local myShape = Shape(Items.someuser.someitem)
o:AddChild(myShape)
nil RemoveChild ( Object child, boolean keepWorld optional )

Unsets parent/child relationship with child parameter. The child ends up being deleted if it has no other references.

The keepWorld optional parameter, false by default, dictates whether to maintain the child's world or local position and rotation. Keeping world will ensure the object doesn't move in the scene, adjusting its local position/rotation accordingly; keeping local will have the object move in the scene in order to maintain an equivalent local position/rotation relative to its new parent.

o:RemoveChild(someChildObject)
nil RemoveChildren ( boolean keepWorld optional )

Unsets parent/child relationship with all children. Individual children end up being deleted if they have no other references.

The keepWorld optional parameter, false by default, dictates whether to maintain the child's world or local position and rotation. Keeping world will ensure the object doesn't move in the scene, adjusting its local position/rotation accordingly; keeping local will have the object move in the scene in order to maintain an equivalent local position/rotation relative to its new parent.

o:RemoveChildren()
nil GetChild ( integer index )

Get child Object at index.

if o.ChildrenCount > 0 then
  print(o:GetChild(1)) -- prints first child
end

Get Light's parent.

print(myObject:GetParent())
nil SetParent ( Object parent, boolean keepWorld optional )

Sets parent/child relationship with parent parameter. nil can be used to remove the Object from its parent.

The keepWorld optional parameter, false by default, dictates whether to maintain the child's world or local position and rotation. Keeping world will ensure the object doesn't move in the scene, adjusting its local position/rotation accordingly; keeping local will have the object move in the scene in order to maintain an equivalent local position/rotation relative to its new parent.

It's also a good practice to set child/parent relationships before setting positions.

local o = Object()
o:SetParent(Map) -- o is now a child of the map
-- (Map is an extension of Object)
nil RemoveFromParent ( boolean keepWorld optional )

Removes the Light from its parent. Doesn't do anything if the Light has no parent.

The keepWorld optional parameter, false by default, dictates whether to maintain the child's world or local position and rotation. Keeping world will ensure the object doesn't move in the scene, adjusting its local position/rotation accordingly; keeping local will have the object move in the scene in order to maintain an equivalent local position/rotation relative to its new parent.

o:RemoveFromParent()

Converts a local position to world coordinate system.

local p = Number3(1, 2, 3)
local pInWorldCoords = myObject:PositionLocalToWorld(p)

Converts a world position to local coordinate system.

local p = Number3(1, 2, 3)
local pInLocalCoords = myObject:PositionWorldToLocal(p)

Rotates the Light in its own coordinates system.

o = Object()
-- rotate with provided Euler angle
o:RotateLocal({0, 0, math.pi / 2.0})

-- rotate along specified axis
o:RotateLocal(o.Forward, math.pi / 2.0)

Rotate the Light in the World coordinates system.

o = Object()
-- rotate with provided Euler angles
o:RotateWorld({0, 0, math.pi / 2.0})

-- rotate along specified axis
o:RotateWorld(o.Forward, math.pi / 2.0)
-- same as o:RotateLocal({0, 0, 1}, math.pi / 2.0)

Converts a rotation from local to world relative to this object.

Converts a rotation from world to local relative to this object.

Returns true if the two Objects may collide with each other.

nil ApplyForce ( Object self, Number3 value )

Apply a force to Object, taking into account its Mass.

Resets to Light's original collision box. For example, Player and Shape objects will revert to fitting their model bounding box.

Properties

A collection of general lighting and color properties. This can only be accessed on global Light object.

Angle of the cone of a spot light, default is 0.7 radians. Has no effect on other light types.

Enables the light source as a shadow caster. Cubzh may limit the number of light shadow casters in a scene based on each player's device.

Color of the light, white by default.

The hardness of a light source represents the core intensity of the emitted light.

At the minimum value of 0, the lit area will appear diffuse with smooth edges. At its maximum value of 1, it will appear bright with clear sharp edges.

Default hardness is 0.5.

Intensity of the light, default is 1.8. A value between 0.0 and 1.0 dims illumination of the scene, whereas values higher than 1.0 adds light color over the scene.

This can be set on global Light object to control all lights' intensity at once, or on a light instance to override its individual intensity.

Integer or table of integers between 1 and 12. The light will affect other objects in matching layers.

Toggles the light source on and off.

PriorityGroup is a way to create light groups in order of importance from 0 to 255 (default group).

If your world is played on a mobile or lower-end device, the maximum number of simultaneaous lights on screen may vary based on hardware capabilities.

If you want to ensure a smooth gameplay on your world for all users, a good practice is to prioritize all gameplay-essential lights.
For example, if your game features a light torch that the player carries, you could place it in PriorityGroup 0 to ensure it is always rendered first and leave other lights that are part of the environment in a lower group.

You can assign as many lights as you want per group, however only groups order is garanteed, lights within a given group are rendered unordered.

Radius of a point light. Alias to Light.Range for convenience.

Range of the light, 30 by default. Has no effect for directional lights.

The light type can be one of LightType.Point (by default), LightType.Spot, or LightType.Directional.

Note that it can be changed at any time.

Inherited from Object

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Light's constant acceleration in world coordinates per second squared.

⚠️ Acceleration will only affect Light's position while Light.Physics is true.

-- Acceleration can be used to compensate gravity: 
myObject.Acceleration = -Config.ConstantAcceleration
-- myObject's acceleration is now the invert of 
-- Config.ConstantAcceleration, cancelling it.

Collision groups the Light belongs to.

⚠️ It doesn't mean the Light will collide with other Objects in these groups.

If the Light belongs to group number 3 for example, it means all Objects that have group number 3 in their Object.CollidesWithGroups property will collide with it.

By default:
- Objects collide with the Map and other Objects
- Players collide with the Map only

That can all be configured differently depening on your needs.

local object1 = Object()
local object2 = Object()
-- It's not mandatory to set Physics to true
-- An object with Physics set to false contributes to the
-- physics simulation as a static item (can't be moved)
object1.Physics = true
object2.Physics = true

-- making sure 2 objects collide with each other
-- NOTE: by default:
-- Map.CollisionGroups == {1},
-- Player.CollisionGroups == {2},
-- Object.CollisionGroups == {3}
object1.CollisionGroups = {5}
object2.CollisionGroups = {5}
object1.CollidesWithGroups = {1, 5} -- collides with Map + objects in group 5
object2.CollidesWithGroups = {1, 5} -- collides with Map + objects in group 5

-- would also work this way if you don't 
-- remember Map's group (which can be changed too by the way)
object1.CollidesWithGroups = Map.CollisionGroups + {5}

-- making an object collides with the Map and Players
local object = Object()
object.CollidesWithGroups = Map.CollisionGroups + Player.CollisionGroups

-- for Player (local player) to collide with other players and the Map
Player.CollidesWithGroups = Map.CollisionGroups + Player.CollisionGroups

Collision groups the Light collides with.

By default:
- Objects collide with the Map and other Objects
- Players collide with the Map and the Objects

That can all be configured differently depending on your needs.

local object = Object()

-- It's not mandatory to change Physics value.
-- (default value is PhysicsMode.Static)
-- An object with Physics set to PhysicsMode.Static contributes 
-- to the physics simulation as a static item (can't be moved)
object.Physics = PhysicsMode.Dynamic

-- making an object collide with the Map and Players
object.CollidesWithGroups = Map.CollisionGroups + Player.CollisionGroups

-- for an Object to collide with other objects only
-- (won't collide with the map)
object.CollidesWithGroups = object.CollisionGroups

-- for Player (local player) to collide with other players and the Map
Player.CollidesWithGroups = Map.CollisionGroups + Player.CollisionGroups

-- making sure 2 objects collide with each others
-- NOTE: by default:
-- Map.CollisionGroups == {1},
-- Player.CollisionGroups == {2},
-- Object.CollisionGroups == {3}
local object1 = Object()
local object2 = Object()
object1.CollisionGroups = {5}
object2.CollisionGroups = {5}
object1.CollidesWithGroups = {1, 5} -- collides with Map + objects in group 5
object2.CollidesWithGroups = {1, 5} -- collides with Map + objects in group 5

-- would also work this way if you don't 
-- remember Map's group (which can be changed too by the way)
object1.CollidesWithGroups = Map.CollisionGroups + {5}

Sets the simulation mode for this object, it can be one of the following:
- PhysicsMode.Disabled: excluded from all physics features.
- PhysicsMode.Trigger: Light's collision box is available for casts and collision callbacks, and is passed through by other dynamic objects.
- PhysicsMode.TriggerPerBlock: if Light is a Shape, its model blocks are available for casts and collision callbacks, and is passed through by other dynamic objects.
- PhysicsMode.Static: Light's collision box is available for casts, collision callbacks, and acts as an obstacle for other dynamic objects.
- PhysicsMode.StaticPerBlock: if Light is a Shape, its model blocks are available for casts, collision callbacks, and act as obstacles for other dynamic objects.
- PhysicsMode.Dynamic: Light's world-aligned collision box is available for casts, collision callbacks, may act as obstacles for other dynamic objects, and is itself fully simulated.

By default, objects are set to PhysicsMode.Static.

You may use Dev.DisplayColliders to visualize each object's collision settings.

⚠️ When set to PhysicsMode.Disabled, Light.Velocity & Light.Motion are set to {0,0,0}.

nil by default. Can be set to a function that will be triggered when this object begins a collision with another object.

The function is called with 3 parameters:
- the object the callback was set for,
- the other actor in the collision,
- the world normal of the hit surface.

Note: it's not necessary to use all 3 parameters.

object.OnCollisionBegin = function(self, other, normal)
  print("collision began between", self, " and ", other, " with world normal ", normal)
end

nil by default. Can be set to a function that will be triggered every frame where this object remains in contact with another object.

Like OnCollisionBegin, this function has 3 arguments: self, other, normal.

nil by default. Can be set to a function that will be triggered when the Light ends colliding with another Object.

The function is called with 2 parameters: the object the callback was set for and the other actor in the collision.

object.OnCollisionEnd = function(self, other)
  print("collision ended between", self, "and", other)
end

Executed when the Pointer is dragged (moved while down). Receives a PointerEvent parameter, just like Pointer.Drag.

(nil by default)

myObject.OnPointerDrag = function(pointerEvent)
  print("dx:", pointerEvent.DX, "dy:", pointerEvent.DY)
end

Position of the Light in the world.

local o = Object()
-- places the object where the local player is
o.Position = Player.Position
boolean IsOnGround read-only

true when the Light is not falling.

⚠️ IsOnGround only makes sense when Light.Physics is true.

Can be set to true for the Light to be hidden recursively, meaning Light and all of its children are hidden.

Nothing else changes, the Light remains in the scene and it keeps being affected by the simulation (collisions, etc.).

Can be set to true for the Light to be hidden individually.

Nothing else changes, the Light remains in the scene and it keeps being affected by the simulation (collisions, etc.).

Size in world units of the shadow cookie projected under the Light, default is 0.0 (disabled).
The shadow cookie, also called blob shadow, is a square texture acting as a cheap alternative to projected shadows.

If this value is strictly positive, shadow cookies will be displayed when:
- the scene has no light source,
- the scene has light sources, but they are disabled because the client is using lower quality settings

Shadow cookies can be used as a fallback to your scene shadows for players with low quality settings, of course, you can also use them instead of shadows as a design choice.

Local position of the Light relative to its parent.

All of Light's ancestors local transformations are combined to obtain the Light "world position" (Object.Position), the Object's final position.

Rotation of the Light in the world (as seen on screen).

While it usually works for simple operations (like Rotation.X = Rotation.X + someAngle), we advise you to use Number3.Rotate to rotate an object around X, Y & Z axis.

You can also set unit vectors like Light.Up, Light.Right or Light.Forward to orient your object.

local o = Object()
o.Rotation = {0, math.pi, 0}
-- o revolved half a turn on Y axis

-- another way to rotate the object:
o.Forward:Rotate({0, 0, math.pi / 2})
o.Forward = Camera.Forward

Tick is a function executed ~30 times per second when set (nil by default). Provides the Light and elapsed time in seconds as parameters.

-- executed ~30 times per second on each user device
myObject.Tick = function(object, dt)
  print("elapsed:", dt, "seconds")
end

Local rotation of the Light relative to its parent.

All of Light's ancestors local transformations are combined to obtain the "world rotation" (Object.Rotation), the Object's final rotation.

Velocity of the Light in world coordinates per second.

⚠️ Velocity will only affect Light's position while Light.Physics is true. Whenever it is set to false, Velocity is set to {0,0,0}.

-- makes myObject jump:
myObject.Velocity.Y = 100

Be aware, this Motion property is a hack regarding laws of physics. (sorry Isaac)

But it's very practical to move objects without worrying about forces at play.

This is what's being used by default when you're moving around with your avatar (see Client.DirectionalPad). It's the reason why you can stop moving horizontally while in the air.

Basically, Motion is an instantaneous displacement that contributes to moving Light every frame, without changing Light.Velocity directly.

Motion is expressed in world coordinates per second.

⚠️ Motion will only affect Light's position while Light.Physics is true. Whenever it is set to false, Motion is set to {0,0,0}.

local speed = 10
myObject.Motion = Camera.Forward * speed
-- myObject will move in the same direction the camera is currently facing.
-- If the Camera rotates after this, it won't change where myObject is heading.

Scale of the Object, in its parent.

Nested Object local scales are combined to obtain the "world scale" (Object.LossyScale), the Object's final scale.

myObject.LocalScale = 2 -- the Object is now 2 times bigger
topLevelObject.LocalScale = 2
local o = Object()
o.LocalScale = 0.5
topLevelObject:AddChild(o) -- o becomes a child of topLevelObject
-- o ends up being displayed with a scale of 1
number LossyScale read-only

Convenience property that attempts to match the actual world scale as much as it can. Note that Objects that have multiple levels of nested rotations and scales will return a skewed lossy scale.

The mass of the Object determines how much a given force can move it and whether or not another object can be pushed by it. It cannot be zero, a neutral mass is a mass of 1.

The combined friction of 2 Objects in contact represents how much the moving Object will be able to slide along the colliding Object.

It is a rate between 0 (full slide, no friction) and 1 (maximum friction). Values equal to or lower than 0 will keep or increase momentum, like sliding on ice. Values higher than 1 means a faster stop, up to a value of 2 to ensure a full stop on contact regardless of the colliding Object's own friction.

[Object.Friction] can be set per-face by providing a table with any combination of the following keys : right, left, front, back, top, bottom, other.
For example, to set the friction on the bottom face of an object's collider to 0 and 0.2 on every other faces, you could set, object.Friction = { bottom=0, other=0.2 }.

The combined bounciness of 2 Objects in contact represents how much of the moving Object's velocity is produced after being in contact with the colliding Object, it is a rate between 0 (no bounce) and 1 (100% of the velocity bounced). Values higher than 1 are allowed and will create an increasing momentum at each bounce (try at your own risk).

[Object.Bounciness] can be set per-face by providing a table with any combination of the following keys : right, left, front, back, top, bottom, other.
For example, to set the bounciness on the side faces of an object's collider to 0.2 and 0 on top and bottom faces, you could set, object.Bounciness = { top=0, bottom=0, other=0.2 }.

All Objects have a collision box that represents the space occupied in the scene with regards to collisions. For Shapes and Players, the collision box is updated with their bounding box. For Objects, it is a 1-cube by default after physics was enabled for the first time.

Returns number of child Objects.

Up is a unit vector (vector with a length of 1). It determines which direction is "up" for the Light.

Setting it is a way to rotate the Light.

Right is a unit vector (vector with a length of 1). It determines which direction is "right" for the Light.

Setting it is a way to rotate the Light.

Forward is a unit vector (vector with a length of 1). It determines which direction is "forward" for the Light.

Setting it is a way to rotate the Light.

Left is a unit vector (vector with a length of 1). It determines which direction is "left" for the Light.

Setting it is a way to rotate the Light.

Down is a unit vector (vector with a length of 1). It determines which direction is "down" for the Light.

Setting it is a way to rotate the Light.

Backward is a unit vector (vector with a length of 1). It determines which direction is "backward" for the Light.

Setting it is a way to rotate the Light.