Maths - Quaternion Code

individual methods

• conjugate
• normalise
• scale
• mul
• add

complete sfrotation class

This class can represent a 3D rotation. The class has 4 double numbers which represent the rotation as either quaternion, axis-angle or euler number depending on the cde int/enum

The class has methods to combine with other rotations. Also many other methods, including the ability to load and save to from VRML and x3d

There are 3 versions available depending on language:

• sfrotation Java
• sfrotation C#
• sfrotation C++

See also the following related classes

• sfvec2f
• sfvec3f
• sfrotation
• sftranslation
• sfmulti3d

The full source code is available on Sourceforge here:

• Full source code for program

Conjugate

public final void conjugate(Quat4d q1) {
    x = -q1.x;
    y = -q1.y;
    z = -q1.z;
    w = q1.w;
  }

Normalising Quaternions

public final void normalise() {
    double n = Math.sqrt(x*x + y*y + z*z + w*w);
    x /= n;
    y /= n;
    z /= n;
    w /= n;
}

Quaternion Scalar Multiplication

public final void scale(double s){
    x *= s;
    y *= s;
    z *= s;
    w *= s;
}
  

public final void mul(Quat4d q1,Quat4d q2) {
    x =  q1.x * q2.w + q1.y * q2.z - q1.z * q2.y + q1.w * q2.x;
    y = -q1.x * q2.z + q1.y * q2.w + q1.z * q2.x + q1.w * q2.y;
    z =  q1.x * q2.y - q1.y * q2.x + q1.z * q2.w + q1.w * q2.z;
    w = -q1.x * q2.x - q1.y * q2.y - q1.z * q2.z + q1.w * q2.w;
}

public final void add(Quat4d q1,Quat4d q2) {
    x = q1.x + q2.x;
    y = q1.y + q2.y;
    z = q1.z + q2.z;
    w = q1.w + q2.w;
}

EuclideanSpace

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