** I'm not a 3D programmer, and if I use the wrong technical terms - sue me.
It's how this bear of very little brain wraps his mind around a bunch of new -
and therefore strange - concepts.
Alberto: Yes it does help - quite a bit. Because what you say is what I
want to do: rotate the tank so it's normal is parallel with the terrain normal.
And the code presented by the original author:
terrainHeight = heightTestResults.getWorldIntersectPoint();
terrainNormal = heightTestResults.getWorldIntersectNormal();
tankXform->setPosition(osg::Vec3(tankPosition.x(),
tankPosition.y(),terrainHeight.z()));
osg::Quat rotate;
rotate.makeRotate(terrainNormal, osg::Vec3f(0,0,1));
tankXform->setAttitude(rotate);
doesn't do that. I couldn't get it to work for me.
rotate.makeRotate(terrainNormal, osg::Vec3f(0,0,1)); - gives the solution to
"What rotation need I apply to the terrain normal to make it parrallel to
vertical?" Vertical being the implied normal of the tank-model.
rotate.makeRotate(osg::Vec3f(0,0,1), terrainNormal); - is the line that gives
the solution to "What rotation need I apply to the vertical to make it parallel
to the terrain normal." The two vectors need to be reversed from the original
code.
To all the other newbies: I hear the snorts of derision in the background.
"It's only a detail." "Rookie." "Newbie." "Everyone knows that." Just
ignore them, and keep plugging away. If "they" are so smart then why didn't
anyone else point out the disconnect between conception and execution?
Oh I get it now, "they" intentionally leave those kinds of tiny problems
lying around. What else can the newbies tackle with any hope of success to
boost their self-confidence? Very clever.
> El Lunes, 15 de Enero de 2007 23:59, Steve Schneider escribió:
> > >osg::Quat rotate;
> > >rotate.makeRotate(terrainNormal, osg::Vec3f(0,0,1));
> void makeRotate (const Vec3d &vec1, const Vec3d &vec2)
> "Make a rotation Quat which will rotate vec1 to vec2. "
> In other words: you create a quaternion with the value of the angle between
> the vertical axis (Z) and the terrain normal, which is in fact the sloping
> angle of the tank (the amount of degrees the Z vector of the tank must
> be rotated to match the terrain normal).
> HTH,
> Alberto
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