Hi Bill, Is there any reason why you could retain a ref_ptr<> to the Operation and modify it in your frame loop, or get the list of operations and use a dynamic_cast<MotionBlurOperation*>() to determine which one is the one you need to modify?
Robert. On 16 May 2013 23:15, William Hart <[email protected]> wrote: > Hi, > > I've been using the Accumulation buffer to apply motion blur to point > cloud animations, directly taken from the osgMotionBlur example, where the > motion blur is applied to each window as an osg::Operation. What I'd like > to be able to do is dynamically change the amount of blur by varying the > persistence parameter. I've poked around the API and found that I can > remove the motion blur operation with a removeAllOperations call then > reapply the motion blur with a different persistence value, but this causes > the accumulation buffer to be cleared. I can't see any other way to access > the Operator once its been applied. > > Below is the code, > > #include <osgViewer/ViewerBase> > #include <osgViewer/Viewer> > #include <iostream> > > class MotionBlurOperation: public osg::Operation > { > public: > MotionBlurOperation(double persistence): > osg::Operation("MotionBlur",true), > cleared_(false), > persistence_(persistence) > { > } > > virtual void operator () (osg::Object* object) > { > osg::GraphicsContext* gc = > dynamic_cast<osg::GraphicsContext*>(object); > if (!gc) return; > > double t = gc->getState()->getFrameStamp()->getSimulationTime(); > > if (!cleared_) > { > // clear the accumulation buffer > glClearColor(0, 0, 0, 0); > glClear(GL_ACCUM_BUFFER_BIT); > cleared_ = true; > t0_ = t; > } > > double dt = fabs(t - t0_); > t0_ = t; > > // compute the blur factor > double s = powf(0.2, dt / persistence_); > > // scale, accumulate and return > glAccum(GL_MULT, s); > glAccum(GL_ACCUM, 1 - s); > glAccum(GL_RETURN, 1.0f); > } > > private: > bool cleared_; > double t0_; > double persistence_; > }; > > void motionblur(osgViewer::GraphicsWindow* w, double persistence) { > w->add(new MotionBlurOperation(persistence)); > } > > any ideas ? > > thanks in advance > > Bill > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >
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