PhysicsJointMotorForce# ( joint )

Parameters

joint - a current physics joint handle

Description

Returns the signed force actually applied by a distance or slider motor, in newtons.

It excludes spring/limit and perpendicular constraint forces. Positive force separates distance anchors or pushes body B along slider frame A's X axis. Read after StepPhysics; this is the latest cached substep impulse divided by substep duration. PhysicsJointMotorMaximum returns the configured force cap.

Invalid, stale or wrong-kind handles raise a runtime error.

Requires Extended mode.

See also: PhysicsJointSpring, PhysicsJointFrame, PhysicsJointThresholds, PhysicsJointEventJoint, StepPhysics.

Example

; PhysicsJointMotorForce Example
; ------------------------------
; Requires Extended mode.

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

Const PHYSICS_STATIC=0
Const PHYSICS_DYNAMIC=2

camera=CreateCamera()
PositionEntity camera,0,3,-7
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 static column, and a platform that slides up and down it
column=CreateCube()
ScaleEntity column,0.2,2,0.2
PositionEntity column,0,2,1.2
EntityColor column,150,150,160
column_body=CreatePhysicsBody(world,column,PHYSICS_STATIC)
column_shape=PhysicsBodyBox(column_body,0.4,4,0.4)
platform=CreateCube()
ScaleEntity platform,1,0.1,1
PositionEntity platform,0,0.5,0
EntityColor platform,255,120,70
platform_body=CreatePhysicsBody(world,platform,PHYSICS_DYNAMIC)
platform_shape=PhysicsBodyBox(platform_body,2,0.2,2,5)
slider=CreatePhysicsSliderJoint(column_body,platform_body,0,0.5,0,0,1,0)
PhysicsJointLimits slider,True,0,3

; A crate rides on the platform
crate=CreateCube()
ScaleEntity crate,0.3,0.3,0.3
PositionEntity crate,0,1,0
EntityColor crate,120,200,140
crate_body=CreatePhysicsBody(world,crate,PHYSICS_DYNAMIC)
crate_shape=PhysicsBodyBox(crate_body,0.6,0.6,0.6)

; The motor drives the platform along the slider's axis
direction=1

While Not KeyDown(1)

    ; Space reverses the lift
    If KeyHit(57) Then direction=-direction
    PhysicsJointMotor slider,True,direction*1,200
    StepPhysics world,1.0/60.0,4

    ; 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   Space: up / down   Esc: exit"
    Text 0,20,"PhysicsJointMotorForce(slider) = "+PhysicsJointMotorForce(slider)+" N"
    Text 0,40,"The motor holds up the platform and the crate against gravity"

    Flip

Wend

FreePhysicsWorld world
End

Index

Blitz3D+ Command Reference

PhysicsJointMotorForce# ( joint )

Parameters

Description

Example