Mattie,
You might have confused between transform(Vector3f normal) and
transform(Point3f point). For transform(Vector3f normal), the forth element
of the normal is assumed to be zero.
/**
* Transforms the normal parameter by this transform and places the value
* back into normal. The fourth element of the normal is assumed to be
* zero.
* Note: For correct lighting results, if a transform has uneven scaling
* surface normals should transformed by the inverse transpose of
* the transform. This the responsibility of the application and is not
* done automatically by this method.
* @param normal the input normal to be transformed
*/
public final void transform(Vector3f normal)
/**
* Transforms the point parameter with this transform and
* places the result back into point. The fourth element of the
* point input paramter is assumed to be one.
* @param point the input point to be transformed
*/
public final void transform(Point3f point)
- Chien Yang
Java 3D Team.
> Delivered-To: [EMAIL PROTECTED]
> X-Priority: 3 (Normal)
> Mime-Version: 1.0
> Date: Wed, 22 Aug 2001 18:01:05 +0200
> From: matthias sweertvaegher <[EMAIL PROTECTED]>
> Subject: [JAVA3D] bug in Transform3D.transform(Vector3f) ?!
> To: [EMAIL PROTECTED]
>
> hello
>
> I believe I have discovered a bug in the Transform3D class
>
> the documentation says the following about Transform3D.transform(Vector3f) :
> Transforms the point parameter with this transform and places the result back
into point. The fourth element of the point input paramter is assumed to be one.
>
> However when I pass a vector3f to the transform method , the vector stays
(0,0,0)
> My transform works, because when I transform a vector4f initialised to
(0,0,0,1) the vector is correctly transformed
> So I believe the transformmethod doesn't use a w-value=1
> Or am I interpreting the meaning of "....assumed to be one" wrong?
>
> 1) transform of vector3f , pos stays (0,0,0)
> Vector3f pos = new Vector3f(); //initialises pos to (0,0,0)
> transform3d.transform(pos);
>
> 2) transform of vector4f , pos is correctly transformed
> Vector4f pos = new Vector4f(0,0,0,1);
> transform3d.transform(pos);
>
> regards,
> mattie
>
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