Hi Roman, 100,000 points is nothing for a modern graphics card, they can happily handle 10 times that are 60Hz. Given this I would say just create you geometry efficiently and your done, no need to complicate things further.
Robert. On Fri, Jun 11, 2010 at 3:27 PM, Roman Grigoriev <[email protected]> wrote: > Hi, > I have to make in my app dynamic lines. As far as I know display lists are > deprecated for now on GLES2 platform I try to make it using VBO+EBO, like in > osgparametric,so now it works fine. But I have to draw up to 1000 lines > with 100 points so it can be so hard to GPU. So I decided to recalculate EBO > using LOD strategy. So I'll calculate distance to my point and remove odd > indices. Could you please give me some snippet how to work with EBO in update > or draw callback? > Also my lines are trajectories and I have to draw them respectively to > simulation time. But I found that I can't change size of element buffer. > Because I found in PrimitiveSet.cpp > this lines > > Code: > > void DrawElementsUInt::draw(State& state, bool useVertexBufferObjects) const > { > ....... > if (ebo) > { > if (_numInstances>=1) state.glDrawElementsInstanced(mode, size(), > GL_UNSIGNED_INT, (const GLvoid *)(ebo->getOffset(getBufferIndex())), > _numInstances); > else glDrawElements(mode, size(), GL_UNSIGNED_INT, (const GLvoid > *)(ebo->getOffset(getBufferIndex()))); > } > } > > > > so here size() - total size of element buffer and I create for example EBO > with 200 indices total and want draw only first 100 indices - how can I make > it? > > for the reference here is my code > > Code: > > osg::Node* createModel( bool dynamic, bool useVBO) > { > osg::Geode* geode = new osg::Geode; > osg::Geometry* geom = new osg::Geometry; > geode->addDrawable(geom); > osg::Vec3 row(0.0f,0.0f,0.0); > unsigned int num_x = 200; > unsigned int num_y = 20; > unsigned int vert_no = 0; > osg::Vec3Array* vertices = new osg::Vec3Array( num_x ); > > unsigned int iy; > for(iy=0; iy<num_x; iy++) > { > (*vertices)[vert_no++] = row; > row.y()=1000.0f*iy; > row.z()+=100; > } > geom->setVertexArray(vertices); > osg::VertexBufferObject* vbo = useVBO ? new osg::VertexBufferObject : 0; > if (vbo) vertices->setVertexBufferObject(vbo); > osg::ElementBufferObject* ebo = useVBO ? new osg::ElementBufferObject : 0; > osg::DrawElementsUInt* elements = new > osg::DrawElementsUInt(GL_LINE_STRIP_ADJACENCY_EXT, num_x); > unsigned int element_no = 0; > for(unsigned int ix = 0; ix<num_x; ix++) > { > (*elements)[element_no++] = ix; > } > > geom->addPrimitiveSet(elements); > geom ->setDataVariance(osg::Object::DYNAMIC); > geom->setDrawCallback(new DrawCallback()); > if (ebo) elements->setElementBufferObject(ebo); > geom->setUseVertexBufferObjects(useVBO); > return geode; > } > > > > ... > > Thank you! > > Cheers, > Roman[/code] > > ------------------ > Read this topic online here: > http://forum.openscenegraph.org/viewtopic.php?p=28826#28826 > > > > > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
