Simple volumetric laser-beam renderer. The demo uses the Qt framework.

To render a laser beam, first set the glow color by calling glColor and then call LaserEffect::draw on the instance you created:

LaserEffect effect;
glColor3f(0.f, 1.f, 0.f);
effect.draw(Vector3(-1.f, 5.f, 1.f), Vector3(1.f, 5.f, -1.f), 0.4f, 0.35f);

the result of which looks like this:

This will render a laser "beam segment" with a green glow. If your application has a rendering loop that gets constantly updated, repeatedly constructing a LaserEffect instance will be inefficient. You should ideally create a LaserEffect instance when the OpenGL context is constructed and ready (in a Qt application, this would be in QGLWidget::initializeGL()) and reuse it.