PhysicsBodyEvents world,enabled

Parameters

world - world handle

enabled - True to capture events, False to disable

Description

Enables/disables copied body movement/sleep event capture for a world.

Disabled by default. Changing the setting clears the current batch and releases its buffer; setting the existing value leaves the batch intact. Enabling starts capture on the next StepPhysics. Storage is reserved for at most the world's body count before stepping; allocation failure reports an error without advancing physics. Body event capture is opt-in per world. The copied batch is replaced after each StepPhysics; it is independent of held query snapshots. Awake dynamic and kinematic bodies can emit entries, including zero-motion awake bodies; static bodies do not. A fell-asleep entry marks that transition, and sleeping bodies normally leave the stream. Entries are sorted by wrapper body handle, not creation order. Tags and final native world poses are copied after continuous-collision correction; after deletion live body/entity getters return zero. Event indices belong to one step. A kinematic native pose can differ from its authored entity target while integration approaches it.

Invalid/stale/wrong-kind handles, invalid indices or unavailable payload fields raise runtime errors.


See also: QueryPhysicsBodyContacts, QueryPhysicsShapeContacts, QueryPhysicsSensor, CountPhysicsQueryManifolds.

Example

; PhysicsBodyEvents Example
; -------------------------

Graphics3D 640,480,0,2
SetBuffer BackBuffer()

Const PHYSICS_STATIC=0
Const PHYSICS_DYNAMIC=2
Const CRATE_COUNT=12

SeedRnd MilliSecs()

camera=CreateCamera()
PositionEntity camera,0,6,-12
RotateEntity camera,20,0,0

light=CreateLight()
RotateEntity light,45,-30,0
AmbientLight 60,60,60

; An independent Box3D world with standard gravity
world=CreatePhysicsWorld()

; Blue static floor
ground=CreateCube()
ScaleEntity ground,6,0.5,6
PositionEntity ground,0,-0.5,0
EntityColor ground,80,160,255
ground_body=CreatePhysicsBody(world,ground,PHYSICS_STATIC)
ground_shape=PhysicsBodyBox(ground_body,12,1,12)

; A pile of crates, dropped from random heights
Dim crates(CRATE_COUNT)
Dim crate_bodies(CRATE_COUNT)
For i=1 To CRATE_COUNT
    crates(i)=CreateCube()
    ScaleEntity crates(i),0.5,0.5,0.5
    crate_bodies(i)=CreatePhysicsBody(world,crates(i),PHYSICS_DYNAMIC)
    crate_shape=PhysicsBodyBox(crate_bodies(i),1,1,1)
Next
DropPile()

; Copy body movement and sleep events after every step
PhysicsBodyEvents world,True
events=True

While Not KeyDown(1)

    ; R drops the pile again
    If KeyHit(19) Then DropPile()

    If KeyHit(57)
        events=Not events
        PhysicsBodyEvents world,events
    EndIf

    StepPhysics world,1.0/60.0,4

    ; Orange crates are awake, grey crates are asleep
    For i=1 To CRATE_COUNT
        If PhysicsBodyIsAwake(crate_bodies(i))
            EntityColor crates(i),255,120,70
        Else
            EntityColor crates(i),150,150,150
        EndIf
    Next

    ; Arrow keys move the camera
    If KeyDown(200) Then MoveEntity camera,0,0,0.1
    If KeyDown(208) Then MoveEntity camera,0,0,-0.1
    If KeyDown(203) Then TurnEntity camera,0,1,0
    If KeyDown(205) Then TurnEntity camera,0,-1,0

    RenderWorld

    Text 0,0,"Arrow keys: move camera   R: drop again   Space: switch events   Esc: exit"
    Text 0,20,"PhysicsBodyEvents world,"+events
    Text 0,40,"Body events from the last step: "+CountPhysicsBodyEvents(world)

    Flip

Wend

FreePhysicsWorld world
End

Function DropPile()
    For i=1 To CRATE_COUNT
        ResetPhysicsBody crate_bodies(i),Rnd(-1.5,1.5),2+i*0.8,Rnd(-1.5,1.5),0,Rnd(Pi),0
    Next
End Function

Index