Scripted camera motions

[Brennan Peter Sellner]

Is there any way to smoothly reposition the camera programatically?  I've
been able to use EnvironmentBase::SetCamera() to set the camera position,
but that can be quite disorienting: I would prefer to set a desired
position and the time needed to get there.  It doesn't look like it's
possible to set trajectories for the camera; am I missing something?

Thanks,

-Brennan

[Rosen Diankov-2]

Hi Brennan,

There are no functions to take in camera trajectories and smoothly
interpolate. That being said, it would be easy to use the Trajectory
class to specify waypoints (use DOF=0) and increment the timer
manually through your plugin. When you want to set the camera position
at time t, call

Trajectory::SampleTrajectory(t, point);
EnviornmentBase::SetCamera(point.trans.trans, point.rot);

SampleTrajectory uses SLERP to smoothly interpolate the quaternions.

However, There currently is no way to set the camera through scripting
without making your own plugin.

Rosen,

2008/8/10 Brennan Peter Sellner <[hidden email]>:

> Is there any way to smoothly reposition the camera programatically?  I've
> been able to use EnvironmentBase::SetCamera() to set the camera position,
> but that can be quite disorienting: I would prefer to set a desired
> position and the time needed to get there.  It doesn't look like it's
> possible to set trajectories for the camera; am I missing something?
>
> Thanks,
>
> -Brennan
>
>
>
> -------------------------------------------------------------------------
> This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
> Build the coolest Linux based applications with Moblin SDK & win great prizes
> Grand prize is a trip for two to an Open Source event anywhere in the world
> http://moblin-contest.org/redirect.php?banner_id=100&url=/
> _______________________________________________
> Openrave-users mailing list
> [hidden email]
> https://lists.sourceforge.net/lists/listinfo/openrave-users
>

[Brennan Peter Sellner]

Thanks, Rosen, that worked well!

In case anyone else needs to do this at some point, the relevant
code from my Problem plugin is below.

Thanks!

-Brennan

-------------------------------------------------------------

/*************************
  * Header
  *************************/

class IpcRemoteControlProblem : public ProblemInstance
{
   <snip>
   // Iterate a camera move in progress; if no move is in progress, pop
   // one from the queue.  Called once per simulation step.
   void moveCamera();

   // Queue of camera movements: camera movement commands are
   // transmitted to the plugin and queued.
   //
   // OpenRaveSetCamera is one of my structures, with
   // 8 elements: x, y, z, q1, q2, q3, q4, and t (time)
   list<OpenRaveSetCamera> cameraQueue;
   bool cameraMoveInProgress;
   Trajectory cameraTrajectory;
   // A simple timer class that can return the time
   // (in fractional seconds) since it was last reset.
   StopWatch cameraTimer;
   <snip>
}


/*************************
  * Implementation
  *************************/

bool IpcRemoteControlProblem::SimulationStep(float fElapsedTime) {
   <snip>
   // Always update the camera position.
   moveCamera();
   <snip>
}

void IpcRemoteControlProblem::moveCamera() {

   if(cameraMoveInProgress) {
     Trajectory::TPOINT point;
     float t = (float) cameraTimer.elapsedTime();
     // SampleTrajectory uses SLERP to smoothly interpolate the
     // quaternions.
     cameraTrajectory.SampleTrajectory(t, point);
     // base is an EnvironmentBase*
     base->SetCamera(point.trans.trans, point.trans.rot);

     // If enough time has passed, stop the move.
     if(t >= cameraTrajectory.GetTotalDuration()) {
       cameraMoveInProgress = false;
     }
   }
   else if(cameraQueue.size() > 0) {
     cameraTrajectory = Trajectory(0);
     // Start from the current position.
     Trajectory::TPOINT curP;
     curP.time = 0;
     curP.trans = base->GetCameraTransform();
     cameraTrajectory.AddPoint(curP);

     // And move to the target position.
     Trajectory::TPOINT targetP;
     OpenRaveSetCamera camera = cameraQueue.front();
     targetP.time = camera.t;
     Vector pos(camera.x, camera.y, camera.z);
     Vector quat(camera.q1, camera.q2, camera.q3, camera.q4);
     targetP.trans = Transform(quat, pos);
     cameraTrajectory.AddPoint(targetP);

     RAVEPRINT(L"Moving camera to new position; taking %f seconds.\n", camera.t);

     cameraTrajectory.CalcTrajTiming(NULL, Trajectory::LINEAR, false, false);

     cameraMoveInProgress = true;
     cameraQueue.pop_front();
     cameraTimer.restart();
   }
}