Online Chapter on Articulated Models

[Andrew Davison]

Dear All,

I've just added an introductory chapter on building simple articulated models out of boxes and cylinders. The example model performs a basic form of collision detection and recovery.

It's chapter N4 "The Colliding Grabbers" in the Java 3D section of the Killer Game Programming in Java website, http://fivedots.coe.psu.ac.th/~ad/jg/.

Comments are appreciated.

- Andrew

[Breakfast]

I'm not sure if I'm understanding the code that performs rotations in 7.5:

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// global reusable objects for calculations private Transform3D t3d = new Transform3D(); private Transform3D toRot = new Transform3D(); private void doRotate(TransformGroup tg, int rotType, double angle) // rotate the tg joint by angle radians {   tg.getTransform(t3d);   if (rotType == X_JOINT)     toRot.rotZ(angle); // left/right == rotation around z-axis  else if (rotType == Y_JOINT)     toRot.rotX(angle); // up/down == rotation around x-axis  else // must be Z_JOINT    toRot.rotY(angle); // spin == rotation around y-axis  t3d.mul(toRot); // t3d = t3d * toRot, which adds the rotation  tg.setTransform(t3d); }

I don't quite understand where "toRot" is getting it's initial value from.

[Andrew Davison]

The Transform3D constructor initializes the transform to be an identity matrix, which you can think of as a rotation of 0 degrees for the x-, y-, and z- axes.

- Andrew

Games published by our own members! Check 'em out!

[Breakfast]

You know what, I did know that. I have no idea why it didn't make sense before...

[jiyanliang]

Hello,Mr
  your book is very good! In your book of "killer game programing in java" , you have Tour3D example,In this example
you use  BoundingSphere as  a sphere,  I want to use BoundingBox , but can't take effect, i think it is same as BoundingSphere.
can you help me
 thank you!
best reguards!!!!!!!!!!!!!!!!!!!
   sunnyan