Trying out Newton Dynamics...

BlitzMax Forums/MiniB3D Module/Trying out Newton Dynamics...

SLotman

(Posted 2011) [#1]

I'm trying my hand with Newtown on miniB3D - but haven't got very far :(

The thing is - I have everything set up, and apparently working; I can move objects with "NewtonBodySetVelocity" - they move, rotate and collide with each other.

But no matter what I do, I can't get objects to fall using gravity. It's like they're floating in space or something! Trying "NewtonBodySetForce" does absolutely nothing...

Anyway, here is the code I'm using:

removed, look code below which is working better

To test it, you're going to need these files (the newton.a files were taken from Warner's engine, as the inc/newton.bmx):

http://www.icongames.com.br/temp/newton-minib3d.zip

Can anyone tell me what I'm doing wrong here?

Last edited 2011

Last edited 2011

SLotman

(Posted 2011) [#2]

Hmmm... manage to get it working adding a callback.

Still have some problems to iron out - I'm trying to move the cube changing it's velocity, but somehow while I'm moving it, it doesn't fall again :(

SLotman

(Posted 2011) [#3]

So... this is the best I could come up with:

SuperStrict

Import ig.minib3d

?win32
Import "libnewtonwin.a"
?linux
Import "libnewtonlin.a"
?MacOS
Import "libnewtonmac.a"
?
Include "inc/Newton.bmx"


Graphics3D 800,600,0,2
Global camera:TCamera=CreateCamera()
MoveEntity camera, 0,10,-20

'// the moving cube
Global cube:TMesh=CreateCube()
PositionEntity cube, 0, 6, 0
EntityColor cube, 255,0,0

Local cube2:TMesh=CreateCube()
PositionEntity cube2, 1.5,2,0
EntityColor cube2, 0,255,0

'// Create plane
Local plane:TMesh = CreateCube()
ScaleEntity plane, 10,1,10
EntityColor plane,150,170,255
EntityAlpha plane,.8

'// create the newton world
Global World:Byte Ptr = NewtonCreate(Null , Null)

'// parameters simulation
NewtonSetPlatformArchitecture (World, 0)
NewtonSetSolverModel(World,0)
NewtonSetFrictionModel(World,0)

'// set world size
Local V1:TVector=TVector.Create(-1000,-1000,-1000)
Local V2:TVector=TVector.Create( 1000, 1000, 1000)
NewtonSetWorldSize(World,V1,V2)

'// add static Floor Physics
Local floorCollision:Byte Ptr = NewtonCreateBox (World, 20,2,20, Null)
Local rigidFloorBox :Byte Ptr = NewtonCreateBody(World, floorCollision)
'NewtonReleaseCollision(World, floorCollision)

'// add static "cube2" Physics
Local c2Box  :Byte Ptr = NewtonCreateBox (World, 2,2,2, Null)
Local c2Body :Byte Ptr = NewtonCreateBody(World, c2Box)
NewtonBodySetMatrix (c2Body, cube2.mat.grid)

'// add a rigid cube
Local cubeCollision:Byte Ptr = NewtonCreateBox(World, 2,2,2, Null) 'cube.mat.grid)
Global rigidCube    :Byte Ptr = NewtonCreateBody(World, cubeCollision)

'// set the body mass And inertia (making it dynamic, not static)
Global mass#=10.0
NewtonBodySetMassMatrix (rigidCube, mass, 1.0, 1.0, 1.0)

'// set the body matrix (fix it's position)
NewtonBodySetMatrix (rigidCube, cube.mat.grid)

'// for later...
NewtonBodySetUserData (rigidCube, cube)

NewtonBodySetAutoFreeze(rigidCube, 0)

NewtonBodySetForceAndTorqueCallback(rigidCube, PhysicsApplyForceAndTorque)
 
Local light:TLight=CreateLight()
Global moveForce:TVector
Global fx#=0, fy#=0, fz#=0

While Not KeyHit(KEY_ESCAPE)

   Local frameTime%=MilliSecs()
   Cls
   PointEntity camera, plane

   UpdateWorld

   RenderWorld

   BeginMax2D()
    DrawText "Pos:" + EntityX(cube,1) + "," + EntityY(cube,1) + "," + EntityZ(cube,1), 10,10
    DrawText "Rot:" + EntityPitch(cube,1) + "," + EntityYaw(cube,1) + "," + EntityRoll(cube,1), 10,30
   EndMax2D()
   Flip
   
   frameTime = MilliSecs()-frameTime

   NewtonBodyGetVelocity(rigidCube, moveforce)

   Local fx#=0, fy#=0, fz#=0
   If KeyDown(KEY_RIGHT) Then fx=10
   If KeyDown(KEY_LEFT) Then fx=-10
   If KeyHit(KEY_SPACE) Then fy=20 
   If KeyDown(KEY_UP) Then fz=10
   If KeyDown(KEY_DOWN) Then fz=-10

   If Abs(moveForce.x) > 10 Then fx=0
   If Abs(moveForce.y) > 0.5 Then fy=0
   If Abs(moveForce.z) > 10 Then fz=0

   moveForce=TVector.Create(fx * 100.0, fy * 400.0,-fz * 100.0)

   NewtonUpdate(World,frameTime) 
   NewtonBodyGetMatrix(rigidCube, cube.mat.grid)


Wend

'// Get rid of everything
NewtonDestroyAllBodies(World)
NewtonDestroy(World)



Function PhysicsApplyForceAndTorque()

   Local gravity#[3]
   gravity[0] = 0.0
   gravity[1] = -9.8 * mass * 5.0
   gravity[2] = 0.0

   NewtonBodyAddForce(rigidCube, gravity) 
   NewtonBodyAddForce(rigidCube, moveForce) 

End Function

It seems to be working... but when I just move the red cube left/right it turns itself with no apparent reason. Is this right? Do I have to set somehow some friction value so it won't spin?

Also, I would love some other way to move the body - specially without acceleration. I was using NewtonSetVelocity in the main loop, but that would just remove the gravity every time I hit any key to move around...

Anyone can help? Give any insight?

Kryzon

(Posted 2011) [#4]

Klepto2 has made a functional Newton module: http://code.google.com/p/minib3dextended/ - you can use it as reference.