Qt3D and QGeometryData

[roeber]

Hi,
I'm new in programming with Qt3D. I have sucessfully added a QGLSceneNode build from the QGLBuilder class. But now I'm trying to create such a node without using the QGlBuilder class, because I need some simple lines (coordinate axis) which are not supported by the builder class, or? So I wrote the following:
@ QGeometryData geom;
geom.appendVertex(QVector3D(0, 0, 0), QVector3D(10, 0, 0));
geom.appendVertex(QVector3D(0, 0, 0), QVector3D(0, 10, 0));
geom.appendVertex(QVector3D(0, 0, 0), QVector3D(0, 0, 10));
QGLMaterial *m = new QGLMaterial;
m->setColor(Qt::red);
m_coordinateAxis = new QGLSceneNode(geom);
m_coordinateAxis->setMaterial(m);
@
But nothing appears on the screen. What's wrong?

[ceora]

use instead this:

it' a part of my code to draw a 3d grid with axis( x,y,z)

@QVector3DArray grid;
QVector3DArray xAxis,yAxis,zAxis;
painter->clearAttributes();
//glLineWidth(0);
painter->setStandardEffect(QGL::FlatColor);

painter->setColor(QColor(125,125,125));

for(int i=-8;i<=8;i++)
{
if (i==0)
{
xAxis.append(-8,i1,0);
xAxis.append(8 ,i1,0);

      yAxis.append(i*1,-8,0);
      yAxis.append(i*1,8,0);
    }
  else
    {
      grid.append(-8,i*1,0);
      grid.append(8 ,i*1,0);//distanza(lunghezza linea, spaziatura, z)

      grid.append(i*1,-8,0);
      grid.append(i*1,8,0);
    }
}

zAxis.append(0,0,0);
zAxis.append(0,0,1);

painter->setVertexAttribute(QGL::Position , grid);
painter->draw(QGL::Lines,grid.size());
//Normal Lines

//glLineWidth(2.5);//NOTE settare dimensione diversa x gli assi??
painter->setVertexAttribute(QGL::Position , xAxis);
painter->setColor(QColor(255,0,0));
painter->draw(QGL::Lines,xAxis.size());
//XAxis

painter->setVertexAttribute(QGL::Position , zAxis);
painter->setColor(QColor(0,0,255));
painter->draw(QGL::Lines,zAxis.size());
//zaxis

painter->setVertexAttribute(QGL::Position , yAxis);
painter->setColor(QColor(0,255,0));
painter->draw(QGL::Lines,yAxis.size());
painter->clearAttributes();
//yaxis@