{

private const float Epsilon = 0.000001f;

Vector3f StVec; //Saved click vector

Vector3f EnVec; //Saved drag vector

float adjustWidth; //Mouse bounds width

float adjustHeight; //Mouse bounds height

public ArcBall(float NewWidth, float NewHeight)

{

StVec = new Vector3f();

EnVec = new Vector3f();

setBounds(NewWidth, NewHeight);

}

public void mapToSphere(Point point, Vector3f vector)

{

//Copy paramter into temp point

Point2f tempPoint = new Point2f(point.X, point.Y);

//Adjust point coords and scale down to range of [-1 ... 1]

tempPoint.x = (tempPoint.x * this.adjustWidth) - 1.0f;

tempPoint.y = 1.0f - (tempPoint.y * this.adjustHeight);

//Compute the square of the length of the vector to the point from the center

float length = (tempPoint.x * tempPoint.x) + (tempPoint.y * tempPoint.y);

//If the point is mapped outside of the sphere... (length > radius squared)

if (length > 1.0f)

{

//Compute a normalizing factor (radius / sqrt(length))

float norm = (float) (1.0 / Math.Sqrt(length));

//Return the "normalized" vector, a point on the sphere

vector.x = tempPoint.x * norm;

vector.y = tempPoint.y * norm;

vector.z = 0.0f;

}

else //Else it's on the inside

{

//Return a vector to a point mapped inside the sphere sqrt(radius squared - length)

vector.x = tempPoint.x;

vector.y = tempPoint.y;

vector.z = (float) Math.Sqrt(1.0f - length);

}

}

public void setBounds(float NewWidth, float NewHeight)

{

//if(!((NewWidth > 1.0f) && (NewHeight > 1.0f)))throw new Exception("Error en set bound");

//Set adjustment factor for width/height

adjustWidth = 1.0f / ((NewWidth - 1.0f) * 0.5f);

adjustHeight = 1.0f / ((NewHeight - 1.0f) * 0.5f);

}

//Mouse down

public void click(Point NewPt)

{

mapToSphere(NewPt, this.StVec);

}

//Mouse drag, calculate rotation

public void drag(Point NewPt, Quat4f NewRot)

{

//Map the point to the sphere

this.mapToSphere(NewPt, EnVec);

//Return the quaternion equivalent to the rotation

if (NewRot != null)

{

Vector3f Perp = new Vector3f();

//Compute the vector perpendicular to the begin and end vectors

Vector3f.cross(Perp, StVec, EnVec);

//Compute the length of the perpendicular vector

if (Perp.length() > Epsilon) //if its non-zero

{

//We're ok, so return the perpendicular vector as the transform after all

NewRot.x = Perp.x;

NewRot.y = Perp.y;

NewRot.z = Perp.z;

//In the quaternion values, w is cosine (theta / 2), where theta is rotation angle

NewRot.w = Vector3f.dot(StVec, EnVec);

}

else //if its zero

{

//The begin and end vectors coincide, so return an identity transform

NewRot.x = NewRot.y = NewRot.z = NewRot.w = 0.0f;

}

}

}

{

public float x, y;

public Point2f(float x, float y)

{

this.x = x;

this.y = y;

}

{

float M00;

float M10;

float M20;

float M30;

float M01;

float M11;

float M21;

float M31;

float M02;

float M12;

float M22;

float M32;

float M03;

float M13;

float M23;

float M33;

public Matrix4f()

{

setIdentity();

}

public void get(float[] dest)

{

dest[0] = M00;

dest[1] = M10;

dest[2] = M20;

dest[3] = M30;

dest[4] = M01;

dest[5] = M11;

dest[6] = M21;

dest[7] = M31;

dest[8] = M02;

dest[9] = M12;

dest[10] = M22;

dest[11] = M32;

dest[12] = M03;

dest[13] = M13;

dest[14] = M23;

dest[15] = M33;

}

public void setZero()

{

M00 = M01 = M02 = M03 = M10 = M11 = M12 = M13 = M20 = M21 = M22 = M23 = M30 = M31 = M32 = M33 = 0.0f;

}

public void setIdentity()

{

setZero();

M00 = M11 = M22 = M33 = 1.0f;

}

public void setRotation(Quat4f q1)

{

float n, s;

float xs, ys, zs;

float wx, wy, wz;

float xx, xy, xz;

float yy, yz, zz;

n = (q1.x * q1.x) + (q1.y * q1.y) + (q1.z * q1.z) + (q1.w * q1.w);

s = (n > 0.0f) ? (2.0f / n) : 0.0f;

xs = q1.x * s;

ys = q1.y * s;

zs = q1.z * s;

wx = q1.w * xs;

wy = q1.w * ys;

wz = q1.w * zs;

xx = q1.x * xs;

xy = q1.x * ys;

xz = q1.x * zs;

yy = q1.y * ys;

yz = q1.y * zs;

zz = q1.z * zs;

M00 = 1.0f - (yy + zz);

M01 = xy - wz;

M02 = xz + wy;

M03 = 0f;

M10 = xy + wz;

M11 = 1.0f - (xx + zz);

M12 = yz - wx;

M13 = 0f;

M20 = xz - wy;

M21 = yz + wx;

M22 = 1.0f - (xx + yy);

M23 = 0f;

M30 = 0f;

M31 = 0f;

M32 = 0f;

M33 = 1f;

}

public void set(Matrix4f m1)

{

M00 = m1.M00; M01 = m1.M01; M02 = m1.M02; M03 = m1.M03;

M10 = m1.M10; M11 = m1.M11; M12 = m1.M12; M13 = m1.M13;

M20 = m1.M20; M21 = m1.M21; M22 = m1.M22; M23 = m1.M23;

M30 = m1.M30; M31 = m1.M31; M32 = m1.M32; M33 = m1.M33;

}

/**

* Sets the value of this matrix to the result of multiplying

* the two argument matrices together.

*

* @param m1 the first matrix

* @param m2 the second matrix

*/

public void mul(Matrix4f m1, Matrix4f m2)

{

// alias-safe way.

set(

m1.M00 * m2.M00 + m1.M01 * m2.M10 + m1.M02 * m2.M20 + m1.M03 * m2.M30,

m1.M00 * m2.M01 + m1.M01 * m2.M11 + m1.M02 * m2.M21 + m1.M03 * m2.M31,

m1.M00 * m2.M02 + m1.M01 * m2.M12 + m1.M02 * m2.M22 + m1.M03 * m2.M32,

m1.M00 * m2.M03 + m1.M01 * m2.M13 + m1.M02 * m2.M23 + m1.M03 * m2.M33,

m1.M10 * m2.M00 + m1.M11 * m2.M10 + m1.M12 * m2.M20 + m1.M13 * m2.M30,

m1.M10 * m2.M01 + m1.M11 * m2.M11 + m1.M12 * m2.M21 + m1.M13 * m2.M31,

m1.M10 * m2.M02 + m1.M11 * m2.M12 + m1.M12 * m2.M22 + m1.M13 * m2.M32,

m1.M10 * m2.M03 + m1.M11 * m2.M13 + m1.M12 * m2.M23 + m1.M13 * m2.M33,

m1.M20 * m2.M00 + m1.M21 * m2.M10 + m1.M22 * m2.M20 + m1.M23 * m2.M30,

m1.M20 * m2.M01 + m1.M21 * m2.M11 + m1.M22 * m2.M21 + m1.M23 * m2.M31,

m1.M20 * m2.M02 + m1.M21 * m2.M12 + m1.M22 * m2.M22 + m1.M23 * m2.M32,

m1.M20 * m2.M03 + m1.M21 * m2.M13 + m1.M22 * m2.M23 + m1.M23 * m2.M33,

m1.M30 * m2.M00 + m1.M31 * m2.M10 + m1.M32 * m2.M20 + m1.M33 * m2.M30,

m1.M30 * m2.M01 + m1.M31 * m2.M11 + m1.M32 * m2.M21 + m1.M33 * m2.M31,

m1.M30 * m2.M02 + m1.M31 * m2.M12 + m1.M32 * m2.M22 + m1.M33 * m2.M32,

m1.M30 * m2.M03 + m1.M31 * m2.M13 + m1.M32 * m2.M23 + m1.M33 * m2.M33

);

}

/**

* Sets 16 values

*/

private void set(float m00, float m01, float m02, float m03,

float m10, float m11, float m12, float m13,

float m20, float m21, float m22, float m23,

float m30, float m31, float m32, float m33)

{

this.M00 = m00;

this.M01 = m01;

this.M02 = m02;

this.M03 = m03;

this.M10 = m10;

this.M11 = m11;

this.M12 = m12;

this.M13 = m13;

this.M20 = m20;

this.M21 = m21;

this.M22 = m22;

this.M23 = m23;

this.M30 = m30;

this.M31 = m31;

this.M32 = m32;

this.M33 = m33;

}

{

public float x, y, z;

public static void cross(Vector3f Result, Vector3f v1, Vector3f v2)

{

Result.x = (v1.y * v2.z) - (v1.z * v2.y);

Result.y = (v1.z * v2.x) - (v1.x * v2.z);

Result.z = (v1.x * v2.y) - (v1.y * v2.x);

}

public static float dot(Vector3f v1, Vector3f v2)

{

return (v1.x * v2.x) + (v1.y * v2.y) + (v1.z + v2.z);

}

public float length()

{

return (float)Math.Sqrt(x * x + y * y + z * z);

}