[osg-users] [Performance] Update dynamic vertices in drawable by external incoming data

[OpenSceneGraph Users]

Hello everyone,

I am not experienced at osg and want to post my question here (please bear 
me if my question is stupid). 

Here is the backround of my question:
I get 400 ~ 800 incoming points of simulated road marks by one programm 
every 20 ~ 30 ms. My Programm is fed by these points continuously on the 
main thread. My goal is to visualise them by connecting them into lines:

After reading many releated posts on this forum, I got some ideas and 
implemented them:

this is basic setup:
    osg::ref_ptr<osg::Geode> road_mark_geode; // hold the vertices inside 
my program
    ...
    osg::ref_ptr<osg::Geometry> geom(new osg::Geometry());

    geom->setUseVertexBufferObjects(true);
    geom->setUseDisplayList(false);
    geom->setUpdateCallback(new DynamicRoadMarkCallback); //  I customized 
a osg::Drawable::UpdateCallback to run vertices->dirty(), to update inside 
road mark vertices 
    osg::Vec3Array* vertices(new osg::Vec3Array());
    geom->setVertexArray(vertices);
    geom->addPrimitiveSet(new osg::DrawArrays(GL_LINE_STRIP, 0, 
DEFAULT_VERTEX_SIZE));
    road_mark_geode->addDrawable(geom.get());
    ...

Given that data reception is on main thread, i did this (points_in is 
incoming data from another program):

Loop on main thread:
    receive points and store them -> call function "*update_pos_of_vertices* " 
to set the pos (x, y, z) for vertices by new points.
   
    Blow is the interested code snippet:
   
    getdata(points_in, points_save); // save incoming data into "
*points_save"* of my own data type
 
    update_pos_of_vertices (points_save) {
        osg::Geometry* geo_drawable = 
static_cast<osg::Geometry*>(road_mark_geode->getDrawable(0));
geo_drawable->setDataVariance(osg::Object::DYNAMIC);
osg::DrawArrays* drawArrays = 
static_cast<osg::DrawArrays*>(geo_drawable->getPrimitiveSet(0));
osg::Vec3Array* vertices = 
static_cast<osg::Vec3Array*>(geo_drawable->getVertexArray());
int num_vertices = points_save.size();
drawArrays->setCount(num_vertices);
vertices->resize(num_vertices);
for (... ) { 
vertices->at(i).set(points_save[i]); // set new pos of each vertex
}
    }

My program ran and i got visualized lines which are linked by points (see 
pic in attachment). But my program becomes very slow: average time for one 
single loop is 50ms. So my question is:
How can I improve the performance?
Did I do anything wrong regarding the my implementation above?

Look  forward to any help, tips and remarks!
Thank you

Yuan

   



    

    







 



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