Using PyODE (setting rotations)

Scripting Issues
1

Hi, I’m using PyODE to do some physics simulation in my application. From PyODE I can do body.getPosition , body.getRotation.
Setting position is simple -> I just call node.setPos(position) and it works.
The problem is that body.getRotation returns a row major rotation matrix for the object.

How can I use this matrix with a Panda3d object?

THanks

2

dunno if this helps you. but might be worth looking at since its a ODE sample in cobination with panda. tried it myself month ago and worked quite well.
https://discourse.panda3d.org/viewtopic.php?t=1485&highlight=ode
if not. just try to search the forum for “ode”

3

There is a setCell / getCell function on Mat4 & Mat3 matrix in panda3D.

I use following code to convert from Newton to P3D and from P33D to Newton.

Newton follow a row major convention (it’s the same convention than DirectX in fact).

I hope this may help you a little.

 def toNewtonMatrix(self,P3Dmatrix):
    nMat=nMatrix()
    offset=0
    for i in range(4):
	for j in range(4):
		nMat[offset+j]=c_float(P3Dmatrix.getCell(i,j))
	offset=offset+j+1
    return nMat
   
  def toP3DMatrix(self,NEWTONmatrix):
    pMat=Mat4(0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0)
    offset=0
    for i in range(4):
	for j in range(4):
		pMat.setCell(i,j,NEWTONmatrix[offset+j])
	offset=offset+j+1
    return pMat
4

Hi,

this is what I do:

   def set_model_pos_and_rot (self, pos = None, rot = None):
      if not pos:
         pos = self.geom.getPosition ()
      if not rot:
         q = self.geom.getQuaternion () # (w, x, y, z)
         gquat = Quat (q [0], q [1], q [2], q [3])
      else:
         gquat = Quat ()
         gquat.setFromMatrix (Mat3 (*rot))
      gpos = VBase3 (pos [0], pos [1], pos [2])
      self.model.setPosQuat (gpos, gquat)

Cheerio
Peter