jMonkeyEngine 3.0 Beginner's Guide

Time for action – rotate it again, Sam

Think of a quaternion as a Java object capable of storing rotations, which you can then apply to a geometry. Don't worry, the 3D engine does the tough calculation work for you!

As an exercise, let's create a Quaternion object that accepts a 45-degree rotation around the x axis:

1. Create a Quaternion object:

   Quaternion roll045 = new Quaternion();
   

2. Supply the angle and the axis as arguments. The angle is 45*FastMath.DEG_TO_RAD. The constant for the x axis is Vector3f.UNIT_X. This gives us:

   roll045.fromAngleAxis( 45*FastMath.DEG_TO_RAD , Vector3f.UNIT_X );
   

3. Replace the relative rotate() method from the previous exercises and apply this absolute rotation instead:

   geom2.setLocalRotation( roll045 );
   

4. Clean and build the ...