Set osg::Point size

[Warren-Whitfield]

I'm creating points like this,

m_pHistoryGeometry = new osg::Geometry();
m_pHistoryVerticesArray = new osg::Vec3Array();
m_pHistoryColourArray = new osg::Vec4Array();
m_pHistoryGeometry->setVertexArray(m_pHistoryVerticesArray);
m_pHistoryGeometry->setColorArray(m_pHistoryColourArray, osg::Array::BIND_PER_VERTEX);
m_pHistoryGeometry->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::POINTS, 0, 0));
m_pHistoryGeode = new osg::Geode();
m_pHistoryGeode->addDrawable(m_pHistoryGeometry);
auto hss = m_pHistoryGeode->getOrCreateStateSet();
hss->setAttribute(new osg::Point(20.0f));

Later on I add vertex's to the array to have history tracks of targets like this,

m_pHistoryVerticesArray->push_back(worldPos);
m_pHistoryColourArray->push_back(osg::Vec4(1.0, 1.0, 0.0, 1.0));
auto draw = dynamic_cast<osg::DrawArrays*>(m_pHistoryGeometry->getPrimitiveSet(0));
draw->setCount(m_pHistoryVerticesArray->size());
m_pHistoryVerticesArray->dirty();
m_pHistoryColourArray->dirty();
m_pHistoryGeometry->dirtyBound();

I am unable to set the size of the point and it seems to be fixed at 1. What do I need to do?

[gwaldron]

osgEarth is all shader-based so some of the old FFP OpenGL stuff does not apply/work.

I recommend using the osgEarth::PointDrawable class. The example osgearth_drawables.cpp shows how to use it.

[Warren-Whitfield]

Ok cool, that works, thanks Glenn. I just need to find a workaround to what I was doing to remove older points. I did something to this effect...

if(m_pHistoryVerticesArray->size() > m_historyCount)
        {
        m_pHistoryVerticesArray->erase(m_pHistoryVerticesArray->begin());
        m_pHistoryColourArray->erase(m_pHistoryColourArray->begin());

        m_pHistoryVerticesArray->dirty();
        m_pHistoryColourArray->dirty();
        m_pHistoryGeometry->dirtyBound();
    }

So obviously I can't do this now because the arrays are private. I could of course derive my own class from yours and add similar functionality, but the jury is still out on that approach. ;-)

Edit...
Managed a workaround like this for the older points removal,

if(m_pHistoryVertsArray->size() > m_historyCount)
    {
        m_pHistoryVertsArray->erase(m_pHistoryVertsArray->begin());
        m_pHistoryPoints->importVertexArray(m_pHistoryVertsArray);
    }

[gwaldron]

The local pointers to the arrays are private, but the arrays themselves are part of the base osg::Geometry class.
So you can still say

auto* verts = dynamic_cast<osg::Vec3Array*>(pointDrawable->getVertexArray());
auto* colors = dynamic_cast<osg::Vec4Array*>(pointDrawable->getColorArray());

And operate on it directly. Just to sure to keep the colors array in sync.

[Warren-Whitfield]

Awesome thanks!