[osg-users] Get Animation current time

[Robert Osfield]

HI Diego,

I can point you in the right direction but I can't sit beside you and
walk through your code in a debugger.  When figuring out a crash this
is what is needed.

The only thing I can add is that using raw C pointer is generally a
red flag and one should be very cautious about doing so.  The OSG uses
a combination of ref_ptr<> that using ref counting to retain ownership
and observer_ptr<> to hold a pointer where no ownership is intended
(it's a form of weak_ptr<>,)   For you app it might be that either
might be appropriate, it's your application I can't make these
judgements for you.

Robert.

On Mon, 7 Jan 2019 at 19:30, Diego Mancilla <dmancillac at gmail.com> wrote:
>
> Hello Robert,
>
> Thank you very much for you complete response.
>
>  I'm trying to do what you suggest and have my on AnimationPath/AnimationPathCallback classes that handle my data. But I stumble into a problem.
>
>  When I subclass AnimationPath and AnimationPathCallback I have no problems. But when I wrote my own classes, from scratch my application crashes.
>
>  In order to achieve what I want, I pass a pointer to a custom data container class to my AnimationPath class (I called it MobilesAnimationPath) from my main application. I tried to keep most part of the architecture of AnimationPath, but I eliminate the TimeControlPointMap container. So, now my class generates the control points from the data pointed from custom data pointer class.
>
>
> So, for instance, my custom Path class looks like this:
>
>
> Code:
> #include "MobileObject.h"
> #include <osg/AnimationPath>
> #include <osg/Object>
>
> using namespace osg;
>
> class MobilesAnimationPath: public virtual osg::Object
> {
> public:
>         MobilesAnimationPath();
>         MobilesAnimationPath(const MobilesAnimationPath &, const osg::CopyOp & copyop = osg::CopyOp::SHALLOW_COPY);
>         MobilesAnimationPath(MobileObject & mobile);
>
>         META_Object(osg, MobilesAnimationPath); //Visual Studio complains about this line, but compiles... : "function definition for META_Object not found"
>
>         enum LoopMode
>         {
>                 SWING,
>                 LOOP,
>                 NO_LOOPING
>         };
>
>         void setLoopMode(LoopMode loopMode);
>         LoopMode getLoopMode() const;
>
>         virtual bool getInterpolatedControlPoint(double time, osg::AnimationPath::ControlPoint & cp) const;
>
>         double getFirstTime() const;
>         double getLastTime() const;
>         double getPeriod() const;
>
> protected:
>         ~MobilesAnimationPath(){};
>
> private:
>         MobileObject * _mobile;
>         LoopMode _loopMode;
>
> };
>
>
>
> And the implementation.
>
>
> Code:
> #include "MobilesAnimationPath.h"
>
> MobilesAnimationPath::MobilesAnimationPath()
>         :_loopMode(NO_LOOPING)
>         ,_mobile(nullptr)
> {
> }
>
>
> MobilesAnimationPath::MobilesAnimationPath(const MobilesAnimationPath& ap, const osg::CopyOp& copyop)
>         :osg::Object(ap, copyop)
>         ,_loopMode(ap._loopMode)
>         ,_mobile(ap._mobile)
> {
> }
>
> MobilesAnimationPath::MobilesAnimationPath(MobileObject & mobile)
>         :_loopMode(NO_LOOPING)
> {
>         _mobile = &mobile;
> }
>
> void MobilesAnimationPath::setLoopMode(LoopMode loopMode)
> {
>         _loopMode = loopMode;
> }
>
> MobilesAnimationPath::LoopMode MobilesAnimationPath::getLoopMode() const
> {
>         return _loopMode;
> }
>
> double MobilesAnimationPath::getFirstTime() const
> {
>         if (_mobile != nullptr)
>         {
>                 if (_mobile->dataLoaded())
>                 {
>                         return _mobile->getFirstTime();
>                 }
>         }
>         return 0.0;
> }
>
> double MobilesAnimationPath::getLastTime() const
> {
>         if (_mobile != nullptr)
>         {
>                 if (_mobile->dataLoaded())
>                 {
>                         return _mobile->getLastTime();
>                 }
>         }
>         return 0.0;
> }
>
> double MobilesAnimationPath::getPeriod() const
> {
>         if (_mobile != nullptr)
>         {
>                 if (_mobile->dataLoaded())
>                 {
>                         return _mobile->getFirstTime() - _mobile->getLastTime();
>                 }
>         }
>         return 0.0;
> }
>
> bool MobilesAnimationPath::getInterpolatedControlPoint(double time, osg::AnimationPath::ControlPoint & cp) const
> {
>         if (_mobile == nullptr) return false;
>         if (!_mobile->dataLoaded()) return false;
>
>         // at this point _mobile points something thats not nullptr but returns garbage...
>
>         switch (_loopMode)
>         {
>         case(SWING):
>         {
>                 double modulated_time = (time - getFirstTime()) / (getPeriod()*2.0);
>                 double fraction_part = modulated_time - floor(modulated_time);
>                 if (fraction_part > 0.5) fraction_part = 1.0 - fraction_part;
>
>                 time = getFirstTime() + (fraction_part*2.0) * getPeriod();
>                 break;
>         }
>         case(LOOP):
>         {
>                 double modulated_time = (time - getFirstTime()) / getPeriod();
>                 double fraction_part = modulated_time - floor(modulated_time);
>                 time = getFirstTime() + fraction_part * getPeriod();
>                 break;
>         }
>         case(NO_LOOPING):
>                 // no need to modulate the time.
>                 break;
>         }
>
>         //... here I fill the control point through the data on _mobile.
>
>         return true;
>
>
> }
>
>
>
> but at the first call to "getInterpolatedControlPoint" the application crashes. Moreover, the _mobile pointer is "corrupted", i.e., when I try to access its data it returns garbage (but it not nullptr). Also the "time" value passed is random (sometimes huge, sometimes negative, etc...)
>
> As I pointed on the code snippet, MSVS complains about my META_Object call, but the code compiles.
>
> Am I missing something?
>
> Cheers,
>
> ------------------
> Read this topic online here:
> http://forum.openscenegraph.org/viewtopic.php?p=75403#75403
>
>
>
>
>
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