]> gerrit.simantics Code Review - simantics/3d.git/blobdiff - org.simantics.g3d/src/org/simantics/g3d/math/MathTools.java
Converting variable angle turn turn to fixed angle could fail.
[simantics/3d.git] / org.simantics.g3d / src / org / simantics / g3d / math / MathTools.java
index 92d954f4b0375ce5ff855baafb13ff54bcbb5384..aa8b0551fdc845ac8db698724f6ad38d7d612b76 100644 (file)
-/*******************************************************************************\r
- * Copyright (c) 2012, 2013 Association for Decentralized Information Management in\r
- * Industry THTH ry.\r
- * All rights reserved. This program and the accompanying materials\r
- * are made available under the terms of the Eclipse Public License v1.0\r
- * which accompanies this distribution, and is available at\r
- * http://www.eclipse.org/legal/epl-v10.html\r
- *\r
- * Contributors:\r
- *     VTT Technical Research Centre of Finland - initial API and implementation\r
- *******************************************************************************/\r
-package org.simantics.g3d.math;\r
-\r
-import javax.vecmath.AxisAngle4d;\r
-import javax.vecmath.Matrix3d;\r
-import javax.vecmath.Matrix4d;\r
-import javax.vecmath.Quat4d;\r
-import javax.vecmath.Tuple3d;\r
-import javax.vecmath.Tuple4d;\r
-import javax.vecmath.Vector2f;\r
-import javax.vecmath.Vector3d;\r
-\r
-import org.simantics.g3d.math.EulerTools.Order;\r
-\r
-\r
-/**\r
- * Some useful geometry related math functions. Beware, methods may modify their input parameters!\r
- * \r
- * @author Marko Luukkainen\r
- *\r
- */\r
-public class MathTools {\r
-    \r
-    public static double NEAR_ZERO = 0.0000001;\r
-    public static double NEAR_HALF = 0.4999999;\r
-    \r
-    public static final Vector3d Z_AXIS = new Vector3d(0.0,0.0,1.0);\r
-       public static final Vector3d Y_AXIS = new Vector3d(0.0,1.0,0.0);\r
-       public static final Vector3d X_AXIS = new Vector3d(1.0,0.0,0.0);\r
-       public static final Vector3d ORIGIN = new Vector3d(0.0,0.0,0.0);\r
-       \r
-       final static double EPS = 1.0e-12;\r
-       \r
-       \r
-       public static boolean equals(double d1, double d2) {\r
-               return Math.abs(d1-d2) < EPS;\r
-       }\r
-       \r
-       public static boolean equals(Tuple3d p1, Tuple3d p2) {\r
-               return distanceSquared(p1, p2) < NEAR_ZERO;\r
-       }\r
-       \r
-       public static boolean equals(Tuple4d p1, Tuple4d p2) {\r
-               return distanceSquared(p1, p2) < NEAR_ZERO;\r
-       }\r
-       \r
-       public static double distance(Tuple3d p1, Tuple3d p2) {\r
-               double dx, dy, dz;\r
-\r
-               dx = p2.x - p1.x;\r
-               dy = p2.y - p1.y;\r
-               dz = p2.z - p1.z;\r
-               return Math.sqrt(dx*dx+dy*dy+dz*dz);\r
-       }\r
-       \r
-       public static double distance(Tuple4d p1, Tuple4d p2) {\r
-               double dx, dy, dz, dw;\r
-\r
-               dx = p2.x - p1.x;\r
-               dy = p2.y - p1.y;\r
-               dz = p2.z - p1.z;\r
-               dw = p2.w - p1.w;\r
-               return Math.sqrt(dx*dx+dy*dy+dz*dz+dw*dw);\r
-       }\r
-       \r
-       public static double distanceSquared(Tuple3d p1, Tuple3d p2) {\r
-               double dx, dy, dz;\r
-\r
-               dx = p2.x - p1.x;\r
-               dy = p2.y - p1.y;\r
-               dz = p2.z - p1.z;\r
-               return dx*dx+dy*dy+dz*dz;\r
-       }\r
-       \r
-       public static double distanceSquared(Tuple4d p1, Tuple4d p2) {\r
-               double dx, dy, dz, dw;\r
-\r
-               dx = p2.x - p1.x;\r
-               dy = p2.y - p1.y;\r
-               dz = p2.z - p1.z;\r
-               dw = p2.w - p1.w;\r
-               return dx*dx+dy*dy+dz*dz+dw*dw;\r
-       }\r
-       \r
-       public static boolean isValid(Tuple3d t) {\r
-               return !(Double.isInfinite(t.x) || Double.isNaN(t.x) ||\r
-                                Double.isInfinite(t.y) || Double.isNaN(t.y) ||\r
-                                Double.isInfinite(t.z) || Double.isNaN(t.z));\r
-       }\r
-    \r
-    public static Vector3d closestPointOnEdge(Vector3d point, Vector3d edgePoint1, Vector3d edgePoint2) {\r
-        point.sub(edgePoint1);\r
-        Vector3d v = new Vector3d(edgePoint2);\r
-        v.sub(edgePoint1);\r
-        double t = v.dot(point);\r
-        t /= v.lengthSquared();\r
-        if (t <= 0.0f)\r
-          return edgePoint1;\r
-        if (t >= 1.0f)\r
-          return edgePoint2;\r
-        v.scale(t);\r
-        v.add(edgePoint1);\r
-        return v;   \r
-    }\r
-    \r
-    public static Vector3d closestPointOnStraight(Tuple3d point, Tuple3d straightPoint, Vector3d straightDir) {\r
-        Vector3d v = new Vector3d(point);\r
-        v.sub(straightPoint);\r
-        double t = straightDir.dot(v);\r
-        t /= straightDir.lengthSquared();\r
-        v.set(straightDir);\r
-        v.scale(t);\r
-        v.add(straightPoint);\r
-        return v;   \r
-    }\r
-    \r
-    public static Vector3d closestPointOnStraight(Tuple3d point, Tuple3d straightPoint, Vector3d straightDir, double u[]) {\r
-        Vector3d v = new Vector3d(point);\r
-        v.sub(straightPoint);\r
-        u[0] = straightDir.dot(v);\r
-        u[0] /= straightDir.lengthSquared();\r
-        v.set(straightDir);\r
-        v.scale(u[0]);\r
-        v.add(straightPoint);\r
-        return v;   \r
-    }\r
-    \r
-    public static double distanceFromPlane(Vector3d point, Vector3d planeNormal, Tuple3d planePoint) {\r
-        point.sub(planePoint);\r
-        \r
-        return planeNormal.dot(point);\r
-    }\r
-      \r
-    public static double distanceFromPlane(Vector3d point, Vector3d planeNormal, float d) {\r
-        return (planeNormal.dot(point) + d);\r
-    }\r
-    \r
-    public static boolean intersectStraightPlane(Tuple3d linePoint, Vector3d lineDir, Tuple3d planePoint, Vector3d planeNormal, Tuple3d intersectPoint) {\r
-        intersectPoint.set(planePoint);\r
-        intersectPoint.sub(linePoint);\r
-        double u = planeNormal.dot(new Vector3d(intersectPoint));\r
-        double v = planeNormal.dot(lineDir);\r
-        if (Math.abs(v) < NEAR_ZERO)\r
-            return false;\r
-        u /= v;\r
-        intersectPoint.set(lineDir);\r
-        intersectPoint.scale(u);\r
-        intersectPoint.add(linePoint);\r
-        return true;\r
-    }\r
-    \r
-    public static boolean intersectStraightPlane(Tuple3d linePoint, Vector3d lineDir, Tuple3d planePoint, Vector3d planeNormal, Vector3d intersectPoint, double[] u) {\r
-        intersectPoint.set(planePoint);\r
-        intersectPoint.sub(linePoint);\r
-        u[0] = planeNormal.dot(intersectPoint);\r
-        double v = planeNormal.dot(lineDir);\r
-        if (Math.abs(v) < NEAR_ZERO)\r
-            return false;\r
-        u[0] /= v;\r
-        intersectPoint.set(lineDir);\r
-        intersectPoint.scale(u[0]);\r
-        intersectPoint.add(linePoint);\r
-        return true;\r
-    }\r
-    \r
-    public static boolean intersectLineLine(Tuple3d l1_start,Tuple3d l1_end,Tuple3d l2_start,Tuple3d l2_end,Tuple3d l1_pos, Tuple3d l2_pos) {\r
-            Vector3d p13 = new Vector3d();\r
-            Vector3d p43 = new Vector3d();\r
-            Vector3d p21 = new Vector3d();\r
-            double d1343,d4321,d1321,d4343,d2121;\r
-            double numer,denom;\r
-            p13.sub(l1_start, l2_start);\r
-            p43.sub(l2_end,l2_start);\r
-            if (Math.abs(p43.x)  < NEAR_ZERO && Math.abs(p43.y)  < NEAR_ZERO && Math.abs(p43.z)  < NEAR_ZERO)\r
-               return false;\r
-            p21.sub(l1_end,l1_start);\r
-            if (Math.abs(p21.x)  < NEAR_ZERO && Math.abs(p21.y)  < NEAR_ZERO && Math.abs(p21.z)  < NEAR_ZERO)\r
-               return false;\r
-\r
-            d1343 = p13.dot(p43);\r
-            d4321 = p43.dot(p21);\r
-            d1321 = p13.dot(p21);\r
-            d4343 = p43.lengthSquared();\r
-            d2121 = p21.lengthSquared();\r
-\r
-            denom = d2121 * d4343 - d4321 * d4321;\r
-            if (Math.abs(denom) < NEAR_ZERO)\r
-               return false;\r
-            numer = d1343 * d4321 - d1321 * d4343;\r
-\r
-            double mua = numer / denom;\r
-            double mub = (d1343 + d4321 * mua) / d4343;\r
\r
-            l1_pos.x = l1_start.x + mua * p21.x;\r
-            l1_pos.y = l1_start.y + mua * p21.y;\r
-            l1_pos.z = l1_start.z + mua * p21.z;\r
-            l2_pos.x = l2_start.x + mub * p43.x;\r
-            l2_pos.y = l2_start.y + mub * p43.y;\r
-            l2_pos.z = l2_start.z + mub * p43.z;\r
-\r
-            return true;\r
-    }\r
-    \r
-    public static boolean intersectStraightStraight(Tuple3d p1,Vector3d p21,Tuple3d p3,Vector3d p43,Tuple3d pa,Tuple3d pb) {\r
-        Vector3d p13 = new Vector3d();\r
-\r
-        double d1343,d4321,d1321,d4343,d2121;\r
-        double numer,denom;\r
-        \r
-        p13.sub(p1, p3);\r
-        if (Math.abs(p43.x)  < NEAR_ZERO && Math.abs(p43.y)  < NEAR_ZERO && Math.abs(p43.z)  < NEAR_ZERO)\r
-           return false;\r
-        if (Math.abs(p21.x)  < NEAR_ZERO && Math.abs(p21.y)  < NEAR_ZERO && Math.abs(p21.z)  < NEAR_ZERO)\r
-           return false;\r
-\r
-        d1343 = p13.dot(p43);\r
-        d4321 = p43.dot(p21);\r
-        d1321 = p13.dot(p21);\r
-        d4343 = p43.lengthSquared();\r
-        d2121 = p21.lengthSquared();\r
-\r
-        denom = d2121 * d4343 - d4321 * d4321;\r
-        if (Math.abs(denom) < NEAR_ZERO)\r
-           return false;\r
-        numer = d1343 * d4321 - d1321 * d4343;\r
-\r
-        double mua = numer / denom;\r
-        double mub = (d1343 + d4321 * mua) / d4343;\r
-\r
-        pa.x = p1.x + mua * p21.x;\r
-        pa.y = p1.y + mua * p21.y;\r
-        pa.z = p1.z + mua * p21.z;\r
-        pb.x = p3.x + mub * p43.x;\r
-        pb.y = p3.y + mub * p43.y;\r
-        pb.z = p3.z + mub * p43.z;\r
-\r
-        return true;\r
-   }\r
-    \r
-    /**\r
-     * Calculate the line segment PaPb that is the shortest route between\r
-     *  two lines P1P2 and P3P4. Calculate also the values of mua and mub where\r
-     *  Pa = P1 + mua (P2 - P1)\r
-     *  Pb = P3 + mub (P4 - P3)\r
-     * @param p1\r
-     * @param p21\r
-     * @param p3\r
-     * @param p43\r
-     * @param pa\r
-     * @param pb\r
-     * @param mu\r
-     * @return\r
-     */\r
-    public static boolean intersectStraightStraight(Tuple3d p1,Vector3d p21,Tuple3d p3,Vector3d p43,Tuple3d pa,Tuple3d pb, double mu[]) {\r
-        Vector3d p13 = new Vector3d();\r
-\r
-        double d1343,d4321,d1321,d4343,d2121;\r
-        double numer,denom;\r
-        double EPS = 0.001;\r
-        p13.sub(p1, p3);\r
-        if (Math.abs(p43.x)  < EPS && Math.abs(p43.y)  < EPS && Math.abs(p43.z)  < EPS)\r
-           return false;\r
-        if (Math.abs(p21.x)  < EPS && Math.abs(p21.y)  < EPS && Math.abs(p21.z)  < EPS)\r
-           return false;\r
-\r
-        d1343 = p13.dot(p43);\r
-        d4321 = p43.dot(p21);\r
-        d1321 = p13.dot(p21);\r
-        d4343 = p43.lengthSquared();\r
-        d2121 = p21.lengthSquared();\r
-\r
-        denom = d2121 * d4343 - d4321 * d4321;\r
-        if (Math.abs(denom) < EPS)\r
-           return false;\r
-        numer = d1343 * d4321 - d1321 * d4343;\r
-\r
-        mu[0] = numer / denom;\r
-        mu[1] = (d1343 + d4321 * mu[0]) / d4343;\r
-\r
-        pa.x = p1.x + mu[0] * p21.x;\r
-        pa.y = p1.y + mu[0] * p21.y;\r
-        pa.z = p1.z + mu[0] * p21.z;\r
-        pb.x = p3.x + mu[1] * p43.x;\r
-        pb.y = p3.y + mu[1] * p43.y;\r
-        pb.z = p3.z + mu[1] * p43.z;\r
-\r
-        return true;\r
-   }\r
-   \r
-  \r
-   \r
-   public static void rotate(Quat4d q, Tuple3d in, Tuple3d out) {\r
-       // p' = q * p * q'\r
-       double tw =           - q.x*in.x - q.y*in.y - q.z*in.z;\r
-       double tx =  q.w*in.x            + q.y*in.z - q.z*in.y;\r
-       double ty =  q.w*in.y - q.x*in.z            + q.z*in.x;\r
-       double tz =  q.w*in.z + q.x*in.y - q.y*in.x           ;\r
-       \r
-       //temp * q' -> x = -x, y = -y z = -z\r
-       //out.w = tw*q.w + tx*q.x + ty*q.y + tz*q.z;\r
-       out.x =  -tw*q.x + tx*q.w - ty*q.z + tz*q.y;\r
-       out.y =  -tw*q.y + tx*q.z + ty*q.w - tz*q.x;\r
-       out.z =  -tw*q.z - tx*q.y + ty*q.x + tz*q.w;  \r
-   }\r
-   \r
-   public static void getMatrix(Quat4d quat, Matrix3d m) {\r
-                  m.m00 = 1.0f - 2.0 * (quat.y * quat.y + quat.z * quat.z);\r
-                  m.m01 = 2.0 * (quat.x * quat.y + quat.w * quat.z);\r
-                  m.m02 = 2.0 * (quat.x * quat.z - quat.w * quat.y);\r
-                  m.m10 = 2.0 * (quat.x * quat.y - quat.w * quat.z);\r
-                  m.m11 = 1.0 - 2.0f * (quat.x * quat.x + quat.z * quat.z);\r
-                  m.m12 = 2.0 * (quat.y * quat.z + quat.w * quat.x);\r
-                  m.m20 = 2.0 * (quat.x * quat.z + quat.w * quat.y);\r
-                  m.m21 = 2.0 * (quat.y * quat.z - quat.w * quat.x);\r
-                  m.m22 = 1.0 - 2.0f * (quat.x * quat.x + quat.y * quat.y);\r
-\r
-   }\r
-   \r
-   \r
-   private static double q[] = new double[3];\r
-   private static int nxt[] = { 1, 2, 0 };\r
-   /**\r
-    * Converts Matrix to Quaternion\r
-    * \r
-    * Note: non-thread safe.\r
-    * \r
-    * @param mat\r
-    * @param quat\r
-    */\r
-   public static void getQuat(Matrix3d mat, Quat4d quat) {\r
-          double tr = mat.m00 + mat.m11 + mat.m22;\r
-               if (tr > 0.0) {\r
-                       double s = Math.sqrt(tr + 1.0);\r
-                       quat.w = 0.5 * s;\r
-                       s = 0.5 / s;\r
-                       quat.x = (mat.m21 - mat.m12) * s;\r
-                       quat.y = (mat.m02 - mat.m20) * s;\r
-                       quat.z = (mat.m10 - mat.m01) * s;\r
-               } else {\r
-                       int i = 0, j, k;\r
-                       if (mat.m11 > mat.m00)\r
-                               i = 1;\r
-                       if (mat.m22 > mat.getElement(i, i))\r
-                               i = 2;\r
-                       \r
-\r
-                       j = nxt[i];\r
-                       k = nxt[j];\r
-\r
-                       double s = Math.sqrt((mat.getElement(i, i) - (mat.getElement(j, j) + mat.getElement(k, k))) + 1.0);\r
-\r
-                       q[i] = s * 0.5;\r
-\r
-                       if (Math.abs(s) > 0.001)\r
-                               s = 0.5 / s;\r
-\r
-                       quat.w = (mat.getElement(k, j) - mat.getElement(j, k)) * s;\r
-                       q[j] = (mat.getElement(j, i) + mat.getElement(i, j)) * s;\r
-                       q[k] = (mat.getElement(k, i) + mat.getElement(i, k)) * s;\r
-\r
-                       quat.x = q[0];\r
-                       quat.y = q[1];\r
-                       quat.z = q[2];\r
-               }\r
-       }\r
-   \r
-   public static Quat4d getQuat(Matrix3d mat) {\r
-          Quat4d q = new Quat4d();\r
-          getQuat(mat, q);\r
-          return q;\r
-   }\r
-   \r
-   public static AxisAngle4d getFromPseudoEuler(Vector3d euler) {\r
-       AxisAngle4d aa = new AxisAngle4d();\r
-       aa.angle = euler.length();\r
-       Vector3d normal = new Vector3d(euler);\r
-       if (aa.angle > NEAR_ZERO) {\r
-           normal.normalize();\r
-           aa.x = normal.x;\r
-           aa.y = normal.y;\r
-           aa.z = normal.z;\r
-       } else {\r
-           aa.x = 1.0;\r
-           aa.y = 0.0;\r
-           aa.z = 0.0;\r
-       }\r
-       \r
-       return aa;\r
-   }\r
-   \r
-   public static Vector3d getPseudoEuler(AxisAngle4d aa) {\r
-       Vector3d euler = new Vector3d(aa.x,aa.y,aa.z);\r
-       euler.scale(aa.angle);\r
-       return euler;\r
-   }\r
-   \r
-   \r
-   public static void getQuat(Vector3d euler, Quat4d quat)  {\r
-          Quat4d q = EulerTools.getQuatFromEuler(Order.YXZ, euler.y,euler.x,euler.z);\r
-          quat.set(q);\r
-       // http://en.wikipedia.org/wiki/Rotation_formalisms_in_three_dimensions#Conversion_formulae_between_formalisms\r
-       // Using the x-convention, the 3-1-3 Euler angles phi, theta and psi (around the Z, X and again the Z-axis)   \r
-//        quat.x = -Math.cos((euler.x - euler.z)*0.5)*Math.sin(euler.y*0.5);\r
-//        quat.y = -Math.sin((euler.x - euler.z)*0.5)*Math.sin(euler.y*0.5);\r
-//        quat.z = -Math.sin((euler.x + euler.z)*0.5)*Math.cos(euler.y*0.5);\r
-//        quat.w = Math.sin((euler.x + euler.z)*0.5)*Math.cos(euler.y*0.5);\r
-          \r
-          // http://www.euclideanspace.com/maths/geometry/rotations/conversions/eulerToQuaternion/index.htm\r
-          // Y, Z, X order\r
-//         double c1 = Math.cos(euler.y*0.5);\r
-//         double s1 = Math.sin(euler.y*0.5);\r
-//         double c2 = Math.cos(euler.z*0.5);\r
-//         double s2 = Math.sin(euler.z*0.5);\r
-//         double c3 = Math.cos(euler.x*0.5);\r
-//         double s3 = Math.sin(euler.x*0.5);\r
-//         double c1c2 = c1*c2;\r
-//         double s1s2 = s1*s2;\r
-//         quat.w =c1c2*c3 - s1s2*s3;\r
-//         quat.x =c1c2*s3 + s1s2*c3;\r
-//         quat.y =s1*c2*c3 + c1*s2*s3;\r
-//         quat.z =c1*s2*c3 - s1*c2*s3;\r
-\r
-//         Quat4d q2 = EulerTools.getQuatFromEuler(Order.YZX, euler.y,euler.z,euler.x);\r
-//         System.out.println("Q " + quat + " Q2 " + q2);\r
-//        double c1 = Math.cos(euler.y);\r
-//         double s1 = Math.sin(euler.y);\r
-//         double c2 = Math.cos(euler.z);\r
-//         double s2 = Math.sin(euler.z);\r
-//         double c3 = Math.cos(euler.x);\r
-//         double s3 = Math.sin(euler.x);\r
-//         quat.w = Math.sqrt(1.0 + c1 * c2 + c1*c3 - s1 * s2 * s3 + c2*c3) / 2.0;\r
-//         double w4 = (4.0 * quat.w);\r
-//         quat.x = (c2 * s3 + c1 * s3 + s1 * s2 * c3) / w4 ;\r
-//         quat.y = (s1 * c2 + s1 * c3 + c1 * s2 * s3) / w4 ;\r
-//         quat.z = (-s1 * s3 + c1 * s2 * c3 +s2) / w4 ;\r
-   }\r
-   \r
-   \r
-  \r
-   \r
-   public static void getEuler(Quat4d quat,Vector3d euler)  {\r
-          Vector3d e = EulerTools.getEulerFromQuat(Order.YXZ, quat);\r
-          euler.x = e.y;\r
-          euler.y = e.x;\r
-          euler.z = e.z;\r
-          \r
-          // http://en.wikipedia.org/wiki/Rotation_formalisms_in_three_dimensions#Conversion_formulae_between_formalisms\r
-//        euler.x = Math.atan2(quat.x * quat.z + quat.y* quat.w, quat.y*quat.z - quat.x * quat.w);\r
-//        euler.y = Math.acos(-square(quat.x) - square(quat.y) + square(quat.z) + square(quat.w));\r
-//        euler.z = -Math.atan2(quat.x * quat.z - quat.y* quat.w, quat.y*quat.z + quat.x * quat.w);\r
-          \r
-          // http://www.euclideanspace.com/maths/geometry/rotations/conversions/quaternionToEuler/index.htm\r
-         // Y, Z, X order\r
-//        double test = quat.x * quat.y + quat.z * quat.w;\r
-//        if (test > NEAR_HALF) {\r
-//                euler.y = 2.0 * Math.atan2(quat.x,quat.w);\r
-//                euler.z = Math.PI * 0.5;\r
-//                euler.x = 0.0;\r
-//        } else if (test < -NEAR_HALF) {\r
-//                euler.y = -2.0 * Math.atan2(quat.x,quat.w);\r
-//                euler.z = -Math.PI * 0.5;\r
-//                euler.x = 0.0;\r
-//        } else {\r
-//                double sqx = square(quat.x);\r
-//                double sqy = square(quat.y);\r
-//                double sqz = square(quat.z);\r
-//                euler.y = Math.atan2(2.0*(quat.y*quat.w-quat.x*quat.z), 1.0 - 2.0*(sqy-sqz));\r
-//                euler.z = Math.asin(2.0*test);\r
-//                euler.x = Math.atan2(2.0*(quat.x*quat.w-quat.y*quat.z), 1.0 - 2.0*(sqx-sqz));\r
-//                System.out.println(euler + " " + EulerTools.getEulerFromQuat(Order.YXZ, quat) +  " " + quat);\r
-//        }\r
-//        double sqw = quat.w*quat.w;\r
-//         double sqx = quat.x*quat.x;\r
-//         double sqy = quat.y*quat.y;\r
-//         double sqz = quat.z*quat.z;\r
-//             double unit = sqx + sqy + sqz + sqw; // if normalised is one, otherwise is correction factor\r
-//             double test = quat.x*quat.y + quat.z*quat.w;\r
-//             if (test > 0.499*unit) { // singularity at north pole\r
-//                     euler.y = 2 * Math.atan2(quat.x,quat.w);\r
-//                     euler.z = Math.PI/2;\r
-//                     euler.x = 0;\r
-//                     return;\r
-//             }\r
-//             if (test < -0.499*unit) { // singularity at south pole\r
-//                     euler.y = -2 * Math.atan2(quat.x,quat.w);\r
-//                     euler.z = -Math.PI/2;\r
-//                     euler.x = 0;\r
-//                     return;\r
-//             }\r
-//             euler.y = Math.atan2(2*quat.y*quat.w-2*quat.x*quat.z , sqx - sqy - sqz + sqw);\r
-//             euler.z = Math.asin(2*test/unit);\r
-//             euler.x = Math.atan2(2*quat.x*quat.w-2*quat.y*quat.z , -sqx + sqy - sqz + sqw);\r
-   }\r
-   \r
-   public static Quat4d getQuat(Vector3d euler) {\r
-          Quat4d q = new Quat4d();\r
-          getQuat(euler,q);\r
-          return q;\r
-   }\r
-   \r
-   \r
-   public static Vector3d getEuler(Quat4d quat) {\r
-          Vector3d v = new Vector3d();\r
-          getEuler(quat, v);\r
-          return v;\r
-   }\r
-   \r
-   public static Quat4d getQuat(AxisAngle4d aa) {\r
-          Quat4d q = new Quat4d();\r
-          getQuat(aa, q);\r
-          return q;\r
-   }\r
-   \r
-   public static AxisAngle4d getAxisAngle(Quat4d q) {\r
-          AxisAngle4d aa = new AxisAngle4d();\r
-          aa.set(q);\r
-          return aa;\r
-   }\r
-   \r
-   public static Quat4d getIdentityQuat() {\r
-          return new Quat4d(0, 0, 0, 1);\r
-   }\r
-   \r
-   public static void getQuat(AxisAngle4d aa, Quat4d q) {\r
-          double mag,amag;\r
-               // Quat = cos(theta/2) + sin(theta/2)(roation_axis) \r
-               \r
-               amag = Math.sqrt( aa.x*aa.x + aa.y*aa.y + aa.z*aa.z);\r
-               if( amag < NEAR_ZERO ) {\r
-                   q.w = 1.0;\r
-                   q.x = 0.0;\r
-                   q.y = 0.0;\r
-                   q.z = 0.0;\r
-               } else {  \r
-                  amag = 1.0/amag; \r
-                  double a2 = aa.angle * 0.5;\r
-                  mag = Math.sin(a2);\r
-                  q.w = Math.cos(a2);\r
-              q.x = aa.x*amag*mag;\r
-              q.y = aa.y*amag*mag;\r
-              q.z = aa.z*amag*mag;\r
-               }\r
-   }\r
-   \r
-   \r
-       /*\r
-        * Cohen-Sutherland\r
-        */\r
-       \r
-       private static final int IN = 0;\r
-       private static final int LEFT = 1;\r
-       private static final int RIGHT = 2;\r
-       private static final int BOTTOM = 4;\r
-       private static final int TOP = 8;\r
-       \r
-       \r
-       private static int bitcode(Vector2f p1, Vector2f min, Vector2f max) {\r
-               int code = IN;\r
-               if (p1.x < min.x)\r
-                       code |= LEFT;\r
-               else if (p1.x > max.x)\r
-                       code |= RIGHT;\r
-               if (p1.y < min.y)\r
-                       code |= BOTTOM;\r
-               else if (p1.y > max.y)\r
-                       code |= TOP;\r
-               return code;\r
-       }\r
-       \r
-       public static boolean clipLineRectangle(Vector2f p1,Vector2f p2, Vector2f min, Vector2f max, Vector2f r1, Vector2f r2) {\r
-               while (true) {\r
-                       int o1 = bitcode(p1, min, max);\r
-                       int o2 = bitcode(p2, min, max);\r
-                       int and = o1 & o2;\r
-                       int or = o1 | o2;\r
-                       if (and != IN) {\r
-                               return false;\r
-                       }\r
-                       if (or == IN) {\r
-                               r1.set(p1);\r
-                               r2.set(p2);\r
-                               return true;\r
-                       }\r
-                       if (o1 == IN) {\r
-                               Vector2f t = p1;\r
-                               p1 = p2;\r
-                               p2 = t;\r
-                               int t2 = o1;\r
-                               o1 = o2;\r
-                               o2 = t2;\r
-                       }\r
-                       if ((o1 & TOP) != IN) {\r
-                               float t = (max.y - p1.y) / (p2.y - p1.y);\r
-                               p1.x += t * (p2.x - p1.x);\r
-                               p1.y = max.y;\r
-                       } else if ((o1 & BOTTOM) != IN) {\r
-                               float t = (min.y - p1.y) / (p2.y - p1.y);\r
-                               p1.x += t * (p2.x - p1.x);\r
-                               p1.y = min.y;\r
-                       } else if ((o1 & LEFT) != IN) {\r
-                               float t = (min.x - p1.x) / (p2.x - p1.x);\r
-                               p1.y += t * (p2.y - p1.y);\r
-                               p1.x = min.x;\r
-                       } else if ((o1 & RIGHT) != IN) {\r
-                               float t = (max.x - p1.x) / (p2.x - p1.x);\r
-                               p1.y += t * (p2.y - p1.y);\r
-                               p1.x = max.x;\r
-                       } else {\r
-                               throw new RuntimeException("Error in clipping code");\r
-                       }\r
-               }\r
-               \r
-       }\r
-       \r
-       public static double square(double d) {\r
-               return d * d;\r
-       }\r
-       \r
-       \r
-        public static void multiplyOrientation(AxisAngle4d aa, AxisAngle4d rot)  {\r
-               Quat4d q1 = new Quat4d();\r
-               getQuat(aa, q1);\r
-               Quat4d q2 = new Quat4d();\r
-               getQuat(rot, q2);\r
-               q2.mul(q1);\r
-               rot.set(q2);\r
-        }\r
-        \r
-        public static double radToDeg(double rad) {\r
-                return (rad / Math.PI) * 180.0;\r
-        }\r
-        \r
-        public static double degToRad(double deg) {\r
-                return (deg / 180.0) * Math.PI;\r
-        }\r
-        \r
-        public static double clamp(double min, double max,double v) {\r
-                if (v < min)\r
-                        return min;\r
-                if (v > max)\r
-                        return max;\r
-                return v;\r
-        }\r
-        \r
-        public static AxisAngle4d createRotation(Vector3d original, Vector3d rotated) { \r
-               AxisAngle4d result = new AxisAngle4d();\r
-               if (createRotation(original, rotated, result))\r
-                       return result;\r
-               return null;\r
-        }\r
-        \r
-        \r
-        public static void setIdentity(Quat4d q) {\r
-               q.w = 1.0;\r
-               q.x = 0.0;\r
-               q.y = 0.0;\r
-               q.z = 0.0;\r
-        }\r
-        \r
-       public static void setIdentity(AxisAngle4d aa) {\r
-               aa.angle = 0.0;\r
-               aa.x = 0.0;\r
-               aa.y = 1.0;\r
-               aa.z = 0.0;\r
-       }\r
-       \r
-       public static void set(Matrix3d mat, double m00, double m01, double m02,\r
-                       double m10, double m11, double m12, double m20, double m21,\r
-                       double m22) {\r
-               mat.m00 = m00;\r
-               mat.m01 = m01;\r
-               mat.m02 = m02;\r
-\r
-               mat.m10 = m10;\r
-               mat.m11 = m11;\r
-               mat.m12 = m12;\r
-\r
-               mat.m20 = m20;\r
-               mat.m21 = m21;\r
-               mat.m22 = m22;\r
-       }\r
-       \r
-       public static void set(Matrix4d mat, double[] v) {\r
-               mat.m00 = v[0];\r
-               mat.m01 = v[1];\r
-               mat.m02 = v[2];\r
-               mat.m03 = v[3];\r
-\r
-               mat.m10 = v[4];\r
-               mat.m11 = v[5];\r
-               mat.m12 = v[6];\r
-               mat.m13 = v[7];\r
-\r
-               mat.m20 = v[8];\r
-               mat.m21 = v[9];\r
-               mat.m22 = v[10];\r
-               mat.m23 = v[11];\r
-\r
-               mat.m30 = v[12];\r
-               mat.m31 = v[13];\r
-               mat.m32 = v[14];\r
-               mat.m33 = v[15];\r
-\r
-       }\r
-        \r
-        public static boolean createRotation(Vector3d original, Vector3d rotated, AxisAngle4d result) {\r
-                \r
-                       if (rotated.lengthSquared() > 0.01)\r
-                               rotated.normalize();\r
-                       else\r
-                               return false;\r
-                       double d = original.dot(rotated);\r
-                       if (d > 0.9999) {\r
-                               // original and rotated are parallel, pointing at the same direction\r
-                               result.angle = 0.0;\r
-                               result.x = 0.0;\r
-                               result.y = 1.0;\r
-                               result.z = 0.0;\r
-                       } else if (d < -0.9999) {\r
-                               // original and rotated are parallel, pointing at the opposite direction \r
-                               Vector3d a = Z_AXIS;\r
-                               if (Math.abs(a.dot(original)) > 0.8 )\r
-                                       a = Y_AXIS;\r
-                               result.set(a, Math.PI);\r
-                       } else {\r
-                               double angle = original.angle(rotated);\r
-                               Vector3d axis = new Vector3d();\r
-                               axis.cross(original, rotated);\r
-                               result.set(axis,angle);\r
-                       }\r
-                       return true;\r
-                }\r
-        \r
-        public static boolean createRotation(Vector3d original, Vector3d rotated, Quat4d result) {\r
-                \r
-                       if (rotated.lengthSquared() > 0.01)\r
-                               rotated.normalize();\r
-                       else\r
-                               return false;\r
-                       double d = original.dot(rotated);\r
-                       if (d > 0.9999) {\r
-                               // original and rotated are parallel, pointing at the same direction\r
-                               result.w = 1.0;\r
-                               result.x = 0.0;\r
-                               result.y = 0.0;\r
-                               result.z = 0.0;\r
-                       } else if (d < -0.9999) {\r
-                               // original and rotated are parallel, pointing at the opposite direction \r
-                               Vector3d a = Z_AXIS;\r
-                               if (Math.abs(a.dot(original)) > 0.8 )\r
-                                       a = Y_AXIS;\r
-                               getQuat(a, Math.PI, result);\r
-                               \r
-                       } else {\r
-                               double angle = original.angle(rotated);\r
-                               Vector3d axis = new Vector3d();\r
-                               axis.cross(original, rotated);\r
-                               getQuat(axis, angle, result);\r
-                       }\r
-                       return true;\r
-                }\r
-        \r
-        public static void getQuat(Vector3d axis, double angle, Quat4d q)\r
-    {\r
-               double mag,amag;\r
-               // Quat = cos(theta/2) + sin(theta/2)(roation_axis) \r
-               \r
-               amag = Math.sqrt( axis.x*axis.x + axis.y*axis.y + axis.z*axis.z);\r
-               if( amag < EPS ) {\r
-                   q.w = 1.0;\r
-                   q.x = 0.0;\r
-                   q.y = 0.0;\r
-                   q.z = 0.0;\r
-               } else {  \r
-                   amag = 1.0/amag; \r
-                   double a2 = angle*0.5;\r
-                   mag = Math.sin(a2);\r
-                   q.w = Math.cos(a2);\r
-                   q.x = axis.x*amag*mag;\r
-                   q.y = axis.y*amag*mag;\r
-                   q.z = axis.z*amag*mag;\r
-               }\r
-       \r
-    }\r
-        \r
-        /**\r
-         * Linear interpolation of quaternions. Result IS set to q1.\r
-         * @param q1\r
-         * @param q2\r
-         * @param alpha\r
-         */\r
-        public static void lip(Quat4d q1, Quat4d q2, double alpha) {\r
-                double s1 = 1.0 - alpha;\r
-                double s2 = alpha;\r
-                q1.scale(s1);\r
-                mad(q1,q2,s2);\r
-                q1.normalize();\r
-        }\r
-        \r
-        public static double dot(Quat4d q1, Quat4d q2) {\r
-                return q1.x * q2.x + q1.y * q2.y + q1.z * q2.z + q1.w * q2.w;\r
-        }\r
-        \r
-        public static void mad(Tuple3d q1, Tuple3d q2, double s2) {\r
-                q1.x += q2.x * s2;\r
-                q1.y += q2.y * s2;\r
-                q1.z += q2.z * s2;\r
-        }\r
-        \r
-        public static void mad(Quat4d q1, Quat4d q2, double s2) {\r
-                q1.x += q2.x * s2;\r
-                q1.y += q2.y * s2;\r
-                q1.z += q2.z * s2;\r
-                q1.w += q2.w * s2;\r
-        }\r
-        \r
-        /**\r
-         * Slerp\r
-         * \r
-         * Sets results to q1. Modifies q2.\r
-         * \r
-         * @param q1\r
-         * @param q2\r
-         * @param alpha\r
-         */\r
-        public static void sip(Quat4d q1, Quat4d q2, double alpha) {\r
-                double cosom = dot(q1,q2);\r
-                if (cosom < 0.0) {\r
-                        cosom = -cosom;\r
-                        q2.negate();\r
-                }\r
-                \r
-                if (cosom > 0.9999) {\r
-                        q2.sub(q1);\r
-                        q2.scale(alpha);\r
-                        q1.add(q2);\r
-                        q1.normalize();\r
-                        return;\r
-                }\r
-                double theta_0 = Math.acos(cosom);\r
-                double theta = theta_0 * alpha;\r
-                Quat4d t = new Quat4d(q1);\r
-                t.scale(-cosom);\r
-                t.add(q2);\r
-                t.normalize();\r
-                t.scale(Math.sin(theta));\r
-                q1.scale(Math.cos(theta));\r
-                q1.add(t);\r
-        }\r
-}\r
+/*******************************************************************************
+ * Copyright (c) 2012, 2013 Association for Decentralized Information Management in
+ * Industry THTH ry.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     VTT Technical Research Centre of Finland - initial API and implementation
+ *******************************************************************************/
+package org.simantics.g3d.math;
+
+import javax.vecmath.AxisAngle4d;
+import javax.vecmath.Matrix3d;
+import javax.vecmath.Matrix4d;
+import javax.vecmath.Quat4d;
+import javax.vecmath.Tuple2d;
+import javax.vecmath.Tuple3d;
+import javax.vecmath.Tuple4d;
+import javax.vecmath.Vector2d;
+import javax.vecmath.Vector2f;
+import javax.vecmath.Vector3d;
+
+import org.simantics.g3d.math.EulerTools.Order;
+
+
+/**
+ * Some useful geometry related math functions. Beware, methods may modify their input parameters!
+ * 
+ * @author Marko Luukkainen
+ *
+ */
+public class MathTools {
+       
+       public static double NEAR_ZERO = 0.000000001;
+       public static double NEAR_HALF = 0.499999999;
+       
+       public static final Vector3d Z_AXIS = new Vector3d(0.0,0.0,1.0);
+       public static final Vector3d Y_AXIS = new Vector3d(0.0,1.0,0.0);
+       public static final Vector3d X_AXIS = new Vector3d(1.0,0.0,0.0);
+       public static final Vector3d ORIGIN = new Vector3d(0.0,0.0,0.0);
+       
+       final static double EPS = 1.0e-12;
+       
+       
+       public static boolean equals(double d1, double d2) {
+               return Math.abs(d1-d2) < EPS;
+       }
+       
+       public static boolean equals(Tuple3d p1, Tuple3d p2) {
+               return distanceSquared(p1, p2) < NEAR_ZERO;
+       }
+       
+       public static boolean equals(Tuple4d p1, Tuple4d p2) {
+               return distanceSquared(p1, p2) < NEAR_ZERO;
+       }
+       
+       public static double distance(Tuple3d p1, Tuple3d p2) {
+               double dx, dy, dz;
+
+               dx = p2.x - p1.x;
+               dy = p2.y - p1.y;
+               dz = p2.z - p1.z;
+               return Math.sqrt(dx*dx+dy*dy+dz*dz);
+       }
+       
+       public static double distance(Tuple4d p1, Tuple4d p2) {
+               double dx, dy, dz, dw;
+
+               dx = p2.x - p1.x;
+               dy = p2.y - p1.y;
+               dz = p2.z - p1.z;
+               dw = p2.w - p1.w;
+               return Math.sqrt(dx*dx+dy*dy+dz*dz+dw*dw);
+       }
+       
+       public static double distanceSquared(Tuple3d p1, Tuple3d p2) {
+               double dx, dy, dz;
+
+               dx = p2.x - p1.x;
+               dy = p2.y - p1.y;
+               dz = p2.z - p1.z;
+               return dx*dx+dy*dy+dz*dz;
+       }
+       
+       public static double distanceSquared(Tuple4d p1, Tuple4d p2) {
+               double dx, dy, dz, dw;
+
+               dx = p2.x - p1.x;
+               dy = p2.y - p1.y;
+               dz = p2.z - p1.z;
+               dw = p2.w - p1.w;
+               return dx*dx+dy*dy+dz*dz+dw*dw;
+       }
+       
+       public static boolean isValid(Tuple3d t) {
+               return !(Double.isInfinite(t.x) || Double.isNaN(t.x) ||
+                        Double.isInfinite(t.y) || Double.isNaN(t.y) ||
+                        Double.isInfinite(t.z) || Double.isNaN(t.z));
+       }
+       
+       public static Vector3d closestPointOnEdge(Vector3d point, Vector3d edgePoint1, Vector3d edgePoint2) {
+               point.sub(edgePoint1);
+               Vector3d v = new Vector3d(edgePoint2);
+               v.sub(edgePoint1);
+               double t = v.dot(point);
+               t /= v.lengthSquared();
+               if (t <= 0.0f)
+                       return edgePoint1;
+               if (t >= 1.0f)
+                       return edgePoint2;
+               v.scale(t);
+               v.add(edgePoint1);
+               return v;   
+       }
+       
+       public static Vector3d closestPointOnStraight(Tuple3d point, Tuple3d straightPoint, Vector3d straightDir) {
+               Vector3d v = new Vector3d(point);
+               v.sub(straightPoint);
+               double t = straightDir.dot(v);
+               t /= straightDir.lengthSquared();
+               v.set(straightDir);
+               v.scale(t);
+               v.add(straightPoint);
+               return v;   
+       }
+       
+       public static Vector3d closestPointOnStraight(Tuple3d point, Tuple3d straightPoint, Vector3d straightDir, double u[]) {
+               Vector3d v = new Vector3d(point);
+               v.sub(straightPoint);
+               u[0] = straightDir.dot(v);
+               u[0] /= straightDir.lengthSquared();
+               v.set(straightDir);
+               v.scale(u[0]);
+               v.add(straightPoint);
+               return v;   
+       }
+       
+       public static double distanceFromPlane(Vector3d point, Vector3d planeNormal, Tuple3d planePoint) {
+               point.sub(planePoint);
+               
+               return planeNormal.dot(point);
+       }
+       
+       public static double distanceFromPlane(Vector3d point, Vector3d planeNormal, float d) {
+               return (planeNormal.dot(point) + d);
+       }
+       
+       public static Vector3d projectToPlane(Vector3d v, Vector3d planeNormal) {
+           //v.normalize();
+           //planeNormal.normalize();
+           Vector3d t = new Vector3d();
+           t.cross(v,planeNormal);
+           t.cross(planeNormal, t);
+           return t;
+           
+       }
+       
+       public static boolean intersectStraightPlane(Tuple3d linePoint, Vector3d lineDir, Tuple3d planePoint, Vector3d planeNormal, Tuple3d intersectPoint) {
+               intersectPoint.set(planePoint);
+               intersectPoint.sub(linePoint);
+               double u = planeNormal.dot(new Vector3d(intersectPoint));
+               double v = planeNormal.dot(lineDir);
+               if (Math.abs(v) < NEAR_ZERO)
+                       return false;
+               u /= v;
+               intersectPoint.set(lineDir);
+               intersectPoint.scale(u);
+               intersectPoint.add(linePoint);
+               return true;
+       }
+       
+       public static boolean intersectStraightPlane(Tuple3d linePoint, Vector3d lineDir, Tuple3d planePoint, Vector3d planeNormal, Vector3d intersectPoint, double[] u) {
+               intersectPoint.set(planePoint);
+               intersectPoint.sub(linePoint);
+               u[0] = planeNormal.dot(intersectPoint);
+               double v = planeNormal.dot(lineDir);
+               if (Math.abs(v) < NEAR_ZERO)
+                       return false;
+               u[0] /= v;
+               intersectPoint.set(lineDir);
+               intersectPoint.scale(u[0]);
+               intersectPoint.add(linePoint);
+               return true;
+       }
+       
+       public static boolean intersectLineLine(Tuple3d l1_start,Tuple3d l1_end,Tuple3d l2_start,Tuple3d l2_end,Tuple3d l1_pos, Tuple3d l2_pos) {
+                       Vector3d p13 = new Vector3d();
+                       Vector3d p43 = new Vector3d();
+                       Vector3d p21 = new Vector3d();
+                       double d1343,d4321,d1321,d4343,d2121;
+                       double numer,denom;
+                       p13.sub(l1_start, l2_start);
+                       p43.sub(l2_end,l2_start);
+                       if (Math.abs(p43.x)  < NEAR_ZERO && Math.abs(p43.y)  < NEAR_ZERO && Math.abs(p43.z)  < NEAR_ZERO)
+                               return false;
+                       p21.sub(l1_end,l1_start);
+                       if (Math.abs(p21.x)  < NEAR_ZERO && Math.abs(p21.y)  < NEAR_ZERO && Math.abs(p21.z)  < NEAR_ZERO)
+                               return false;
+
+                       d1343 = p13.dot(p43);
+                       d4321 = p43.dot(p21);
+                       d1321 = p13.dot(p21);
+                       d4343 = p43.lengthSquared();
+                       d2121 = p21.lengthSquared();
+
+                       denom = d2121 * d4343 - d4321 * d4321;
+                       if (Math.abs(denom) < NEAR_ZERO)
+                               return false;
+                       numer = d1343 * d4321 - d1321 * d4343;
+
+                       double mua = numer / denom;
+                       double mub = (d1343 + d4321 * mua) / d4343;
+
+                       l1_pos.x = l1_start.x + mua * p21.x;
+                       l1_pos.y = l1_start.y + mua * p21.y;
+                       l1_pos.z = l1_start.z + mua * p21.z;
+                       l2_pos.x = l2_start.x + mub * p43.x;
+                       l2_pos.y = l2_start.y + mub * p43.y;
+                       l2_pos.z = l2_start.z + mub * p43.z;
+
+                       return true;
+       }
+       
+       public static boolean intersectStraightStraight(Tuple3d p1,Vector3d p21,Tuple3d p3,Vector3d p43,Tuple3d pa,Tuple3d pb) {
+               Vector3d p13 = new Vector3d();
+
+               double d1343,d4321,d1321,d4343,d2121;
+               double numer,denom;
+               
+               p13.sub(p1, p3);
+               if (Math.abs(p43.x)  < NEAR_ZERO && Math.abs(p43.y)  < NEAR_ZERO && Math.abs(p43.z)  < NEAR_ZERO)
+                       return false;
+               if (Math.abs(p21.x)  < NEAR_ZERO && Math.abs(p21.y)  < NEAR_ZERO && Math.abs(p21.z)  < NEAR_ZERO)
+                       return false;
+
+               d1343 = p13.dot(p43);
+               d4321 = p43.dot(p21);
+               d1321 = p13.dot(p21);
+               d4343 = p43.lengthSquared();
+               d2121 = p21.lengthSquared();
+
+               denom = d2121 * d4343 - d4321 * d4321;
+               if (Math.abs(denom) < NEAR_ZERO)
+                       return false;
+               numer = d1343 * d4321 - d1321 * d4343;
+
+               double mua = numer / denom;
+               double mub = (d1343 + d4321 * mua) / d4343;
+
+               pa.x = p1.x + mua * p21.x;
+               pa.y = p1.y + mua * p21.y;
+               pa.z = p1.z + mua * p21.z;
+               pb.x = p3.x + mub * p43.x;
+               pb.y = p3.y + mub * p43.y;
+               pb.z = p3.z + mub * p43.z;
+
+               return true;
+       }
+       
+       /**
+        * Calculate the line segment PaPb that is the shortest route between
+        *  two lines P1P2 and P3P4. Calculate also the values of mua and mub where
+        *  Pa = P1 + mua (P2 - P1)
+        *  Pb = P3 + mub (P4 - P3)
+        * @param p1
+        * @param p21
+        * @param p3
+        * @param p43
+        * @param pa
+        * @param pb
+        * @param mu
+        * @return
+        */
+       public static boolean intersectStraightStraight(Tuple3d p1,Vector3d p21,Tuple3d p3,Vector3d p43,Tuple3d pa,Tuple3d pb, double mu[]) {
+               Vector3d p13 = new Vector3d();
+
+               double d1343,d4321,d1321,d4343,d2121;
+               double numer,denom;
+               double EPS = 0.001;
+               p13.sub(p1, p3);
+               if (Math.abs(p43.x)  < EPS && Math.abs(p43.y)  < EPS && Math.abs(p43.z)  < EPS)
+                       return false;
+               if (Math.abs(p21.x)  < EPS && Math.abs(p21.y)  < EPS && Math.abs(p21.z)  < EPS)
+                       return false;
+
+               d1343 = p13.dot(p43);
+               d4321 = p43.dot(p21);
+               d1321 = p13.dot(p21);
+               d4343 = p43.lengthSquared();
+               d2121 = p21.lengthSquared();
+
+               denom = d2121 * d4343 - d4321 * d4321;
+               if (Math.abs(denom) < EPS)
+                       return false;
+               numer = d1343 * d4321 - d1321 * d4343;
+
+               mu[0] = numer / denom;
+               mu[1] = (d1343 + d4321 * mu[0]) / d4343;
+
+               pa.x = p1.x + mu[0] * p21.x;
+               pa.y = p1.y + mu[0] * p21.y;
+               pa.z = p1.z + mu[0] * p21.z;
+               pb.x = p3.x + mu[1] * p43.x;
+               pb.y = p3.y + mu[1] * p43.y;
+               pb.z = p3.z + mu[1] * p43.z;
+
+               return true;
+       }
+       
+
+       
+       public static void rotate(Quat4d q, Tuple3d in, Tuple3d out) {
+               // p' = q * p * q'
+               double tw =             - q.x*in.x - q.y*in.y - q.z*in.z;
+               double tx =  q.w*in.x            + q.y*in.z - q.z*in.y;
+               double ty =  q.w*in.y - q.x*in.z            + q.z*in.x;
+               double tz =  q.w*in.z + q.x*in.y - q.y*in.x           ;
+               
+               //temp * q' -> x = -x, y = -y z = -z
+               //out.w = tw*q.w + tx*q.x + ty*q.y + tz*q.z;
+               out.x =  -tw*q.x + tx*q.w - ty*q.z + tz*q.y;
+               out.y =  -tw*q.y + tx*q.z + ty*q.w - tz*q.x;
+               out.z =  -tw*q.z - tx*q.y + ty*q.x + tz*q.w;  
+       }
+       
+       public static void getMatrix(Quat4d quat, Matrix3d m) {
+                       m.m00 = 1.0f - 2.0 * (quat.y * quat.y + quat.z * quat.z);
+                       m.m01 = 2.0 * (quat.x * quat.y + quat.w * quat.z);
+                       m.m02 = 2.0 * (quat.x * quat.z - quat.w * quat.y);
+                       m.m10 = 2.0 * (quat.x * quat.y - quat.w * quat.z);
+                       m.m11 = 1.0 - 2.0f * (quat.x * quat.x + quat.z * quat.z);
+                       m.m12 = 2.0 * (quat.y * quat.z + quat.w * quat.x);
+                       m.m20 = 2.0 * (quat.x * quat.z + quat.w * quat.y);
+                       m.m21 = 2.0 * (quat.y * quat.z - quat.w * quat.x);
+                       m.m22 = 1.0 - 2.0f * (quat.x * quat.x + quat.y * quat.y);
+
+       }
+       
+       public static void getMatrix(Quat4d quat, Matrix4d m) {
+               m.setZero();
+               m.m00 = 1.0f - 2.0 * (quat.y * quat.y + quat.z * quat.z);
+               m.m01 = 2.0 * (quat.x * quat.y + quat.w * quat.z);
+               m.m02 = 2.0 * (quat.x * quat.z - quat.w * quat.y);
+               m.m10 = 2.0 * (quat.x * quat.y - quat.w * quat.z);
+               m.m11 = 1.0 - 2.0f * (quat.x * quat.x + quat.z * quat.z);
+               m.m12 = 2.0 * (quat.y * quat.z + quat.w * quat.x);
+               m.m20 = 2.0 * (quat.x * quat.z + quat.w * quat.y);
+               m.m21 = 2.0 * (quat.y * quat.z - quat.w * quat.x);
+               m.m22 = 1.0 - 2.0f * (quat.x * quat.x + quat.y * quat.y);
+               m.m33 = 1.0;
+       }
+       
+       private static double q[] = new double[3];
+       private static int nxt[] = { 1, 2, 0 };
+       /**
+        * Converts Matrix to Quaternion
+        * 
+        * Note: non-thread safe.
+        * 
+        * @param mat
+        * @param quat
+        */
+       public static void getQuat(Matrix3d mat, Quat4d quat) {
+               double tr = mat.m00 + mat.m11 + mat.m22;
+               if (tr > 0.0) {
+                       double s = Math.sqrt(tr + 1.0);
+                       quat.w = 0.5 * s;
+                       s = 0.5 / s;
+                       quat.x = (mat.m21 - mat.m12) * s;
+                       quat.y = (mat.m02 - mat.m20) * s;
+                       quat.z = (mat.m10 - mat.m01) * s;
+               } else {
+                       int i = 0, j, k;
+                       if (mat.m11 > mat.m00)
+                               i = 1;
+                       if (mat.m22 > mat.getElement(i, i))
+                               i = 2;
+                       
+
+                       j = nxt[i];
+                       k = nxt[j];
+
+                       double s = Math.sqrt((mat.getElement(i, i) - (mat.getElement(j, j) + mat.getElement(k, k))) + 1.0);
+
+                       q[i] = s * 0.5;
+
+                       if (Math.abs(s) > 0.001)
+                               s = 0.5 / s;
+
+                       quat.w = (mat.getElement(k, j) - mat.getElement(j, k)) * s;
+                       q[j] = (mat.getElement(j, i) + mat.getElement(i, j)) * s;
+                       q[k] = (mat.getElement(k, i) + mat.getElement(i, k)) * s;
+
+                       quat.x = q[0];
+                       quat.y = q[1];
+                       quat.z = q[2];
+               }
+       }
+       
+       public static Quat4d getQuat(Matrix3d mat) {
+               Quat4d q = new Quat4d();
+               getQuat(mat, q);
+               return q;
+       }
+       
+       public static AxisAngle4d getFromPseudoEuler(Vector3d euler) {
+               AxisAngle4d aa = new AxisAngle4d();
+               aa.angle = euler.length();
+               Vector3d normal = new Vector3d(euler);
+               if (aa.angle > NEAR_ZERO) {
+                       normal.normalize();
+                       aa.x = normal.x;
+                       aa.y = normal.y;
+                       aa.z = normal.z;
+               } else {
+                       aa.x = 1.0;
+                       aa.y = 0.0;
+                       aa.z = 0.0;
+               }
+               
+               return aa;
+       }
+       
+       public static Vector3d getPseudoEuler(AxisAngle4d aa) {
+               Vector3d euler = new Vector3d(aa.x,aa.y,aa.z);
+               euler.scale(aa.angle);
+               return euler;
+       }
+       
+       
+       public static void getQuat(Vector3d euler, Quat4d quat)  {
+               Quat4d q = EulerTools.getQuatFromEuler(Order.YXZ, euler.y,euler.x,euler.z);
+               quat.set(q);
+       // http://en.wikipedia.org/wiki/Rotation_formalisms_in_three_dimensions#Conversion_formulae_between_formalisms
+       // Using the x-convention, the 3-1-3 Euler angles phi, theta and psi (around the Z, X and again the Z-axis)   
+//        quat.x = -Math.cos((euler.x - euler.z)*0.5)*Math.sin(euler.y*0.5);
+//        quat.y = -Math.sin((euler.x - euler.z)*0.5)*Math.sin(euler.y*0.5);
+//        quat.z = -Math.sin((euler.x + euler.z)*0.5)*Math.cos(euler.y*0.5);
+//        quat.w = Math.sin((euler.x + euler.z)*0.5)*Math.cos(euler.y*0.5);
+               
+               // http://www.euclideanspace.com/maths/geometry/rotations/conversions/eulerToQuaternion/index.htm
+               // Y, Z, X order
+//         double c1 = Math.cos(euler.y*0.5);
+//         double s1 = Math.sin(euler.y*0.5);
+//         double c2 = Math.cos(euler.z*0.5);
+//         double s2 = Math.sin(euler.z*0.5);
+//         double c3 = Math.cos(euler.x*0.5);
+//         double s3 = Math.sin(euler.x*0.5);
+//         double c1c2 = c1*c2;
+//         double s1s2 = s1*s2;
+//         quat.w =c1c2*c3 - s1s2*s3;
+//         quat.x =c1c2*s3 + s1s2*c3;
+//         quat.y =s1*c2*c3 + c1*s2*s3;
+//         quat.z =c1*s2*c3 - s1*c2*s3;
+
+//         Quat4d q2 = EulerTools.getQuatFromEuler(Order.YZX, euler.y,euler.z,euler.x);
+//         System.out.println("Q " + quat + " Q2 " + q2);
+//        double c1 = Math.cos(euler.y);
+//         double s1 = Math.sin(euler.y);
+//         double c2 = Math.cos(euler.z);
+//         double s2 = Math.sin(euler.z);
+//         double c3 = Math.cos(euler.x);
+//         double s3 = Math.sin(euler.x);
+//         quat.w = Math.sqrt(1.0 + c1 * c2 + c1*c3 - s1 * s2 * s3 + c2*c3) / 2.0;
+//         double w4 = (4.0 * quat.w);
+//         quat.x = (c2 * s3 + c1 * s3 + s1 * s2 * c3) / w4 ;
+//         quat.y = (s1 * c2 + s1 * c3 + c1 * s2 * s3) / w4 ;
+//         quat.z = (-s1 * s3 + c1 * s2 * c3 +s2) / w4 ;
+       }
+       
+       
+
+       
+       public static void getEuler(Quat4d quat,Vector3d euler)  {
+               Vector3d e = EulerTools.getEulerFromQuat(Order.YXZ, quat);
+               euler.x = e.y;
+               euler.y = e.x;
+               euler.z = e.z;
+               
+               // http://en.wikipedia.org/wiki/Rotation_formalisms_in_three_dimensions#Conversion_formulae_between_formalisms
+//        euler.x = Math.atan2(quat.x * quat.z + quat.y* quat.w, quat.y*quat.z - quat.x * quat.w);
+//        euler.y = Math.acos(-square(quat.x) - square(quat.y) + square(quat.z) + square(quat.w));
+//        euler.z = -Math.atan2(quat.x * quat.z - quat.y* quat.w, quat.y*quat.z + quat.x * quat.w);
+               
+               // http://www.euclideanspace.com/maths/geometry/rotations/conversions/quaternionToEuler/index.htm
+       // Y, Z, X order
+//        double test = quat.x * quat.y + quat.z * quat.w;
+//        if (test > NEAR_HALF) {
+//                euler.y = 2.0 * Math.atan2(quat.x,quat.w);
+//                euler.z = Math.PI * 0.5;
+//                euler.x = 0.0;
+//        } else if (test < -NEAR_HALF) {
+//                euler.y = -2.0 * Math.atan2(quat.x,quat.w);
+//                euler.z = -Math.PI * 0.5;
+//                euler.x = 0.0;
+//        } else {
+//                double sqx = square(quat.x);
+//                double sqy = square(quat.y);
+//                double sqz = square(quat.z);
+//                euler.y = Math.atan2(2.0*(quat.y*quat.w-quat.x*quat.z), 1.0 - 2.0*(sqy-sqz));
+//                euler.z = Math.asin(2.0*test);
+//                euler.x = Math.atan2(2.0*(quat.x*quat.w-quat.y*quat.z), 1.0 - 2.0*(sqx-sqz));
+//                System.out.println(euler + " " + EulerTools.getEulerFromQuat(Order.YXZ, quat) +  " " + quat);
+//        }
+//        double sqw = quat.w*quat.w;
+//         double sqx = quat.x*quat.x;
+//         double sqy = quat.y*quat.y;
+//         double sqz = quat.z*quat.z;
+//             double unit = sqx + sqy + sqz + sqw; // if normalised is one, otherwise is correction factor
+//             double test = quat.x*quat.y + quat.z*quat.w;
+//             if (test > 0.499*unit) { // singularity at north pole
+//                     euler.y = 2 * Math.atan2(quat.x,quat.w);
+//                     euler.z = Math.PI/2;
+//                     euler.x = 0;
+//                     return;
+//             }
+//             if (test < -0.499*unit) { // singularity at south pole
+//                     euler.y = -2 * Math.atan2(quat.x,quat.w);
+//                     euler.z = -Math.PI/2;
+//                     euler.x = 0;
+//                     return;
+//             }
+//             euler.y = Math.atan2(2*quat.y*quat.w-2*quat.x*quat.z , sqx - sqy - sqz + sqw);
+//             euler.z = Math.asin(2*test/unit);
+//             euler.x = Math.atan2(2*quat.x*quat.w-2*quat.y*quat.z , -sqx + sqy - sqz + sqw);
+       }
+       
+       public static Quat4d getQuat(Vector3d euler) {
+               Quat4d q = new Quat4d();
+               getQuat(euler,q);
+               return q;
+       }
+       
+       
+       public static Vector3d getEuler(Quat4d quat) {
+               Vector3d v = new Vector3d();
+               getEuler(quat, v);
+               return v;
+       }
+       
+       public static Quat4d getQuat(AxisAngle4d aa) {
+               Quat4d q = new Quat4d();
+               getQuat(aa, q);
+               return q;
+       }
+       
+       public static AxisAngle4d getAxisAngle(Quat4d q) {
+               AxisAngle4d aa = new AxisAngle4d();
+               double mag = q.x * q.x + q.y * q.y + q.z * q.z;
+
+               if (mag > EPS) {
+                       mag = Math.sqrt(mag);
+                       aa.angle = 2.0 * Math.atan2(mag, q.w);
+                       mag = 1.0 / mag;
+                       aa.x = q.x * mag;
+                       aa.y = q.y * mag;
+                       aa.z = q.z * mag;
+                       
+               } else {
+                       aa.x = 0.0;
+                       aa.y = 1.0;
+                       aa.z = 0.0;
+                       aa.angle = 0.0;
+               }
+               // aa.set(q);
+               return aa;
+       }
+       
+       public static Quat4d getIdentityQuat() {
+               return new Quat4d(0, 0, 0, 1);
+       }
+       
+       public static void getQuat(AxisAngle4d aa, Quat4d q) {
+               double mag,amag;
+               // Quat = cos(theta/2) + sin(theta/2)(roation_axis) 
+               
+               amag = Math.sqrt( aa.x*aa.x + aa.y*aa.y + aa.z*aa.z);
+               if( amag < NEAR_ZERO ) {
+                       q.w = 1.0;
+                       q.x = 0.0;
+                       q.y = 0.0;
+                       q.z = 0.0;
+               } else {  
+                       amag = 1.0/amag; 
+                       double a2 = aa.angle * 0.5;
+                       mag = Math.sin(a2);
+                       q.w = Math.cos(a2);
+                       q.x = aa.x*amag*mag;
+                       q.y = aa.y*amag*mag;
+                       q.z = aa.z*amag*mag;
+               }
+       }
+       
+       
+       /*
+        * Cohen-Sutherland
+        */
+       
+       private static final int IN = 0;
+       private static final int LEFT = 1;
+       private static final int RIGHT = 2;
+       private static final int BOTTOM = 4;
+       private static final int TOP = 8;
+       
+       
+       private static int bitcode(Vector2f p1, Vector2f min, Vector2f max) {
+               int code = IN;
+               if (p1.x < min.x)
+                       code |= LEFT;
+               else if (p1.x > max.x)
+                       code |= RIGHT;
+               if (p1.y < min.y)
+                       code |= BOTTOM;
+               else if (p1.y > max.y)
+                       code |= TOP;
+               return code;
+       }
+       
+       public static boolean clipLineRectangle(Vector2f p1,Vector2f p2, Vector2f min, Vector2f max, Vector2f r1, Vector2f r2) {
+               while (true) {
+                       int o1 = bitcode(p1, min, max);
+                       int o2 = bitcode(p2, min, max);
+                       int and = o1 & o2;
+                       int or = o1 | o2;
+                       if (and != IN) {
+                               return false;
+                       }
+                       if (or == IN) {
+                               r1.set(p1);
+                               r2.set(p2);
+                               return true;
+                       }
+                       if (o1 == IN) {
+                               Vector2f t = p1;
+                               p1 = p2;
+                               p2 = t;
+                               int t2 = o1;
+                               o1 = o2;
+                               o2 = t2;
+                       }
+                       if ((o1 & TOP) != IN) {
+                               float t = (max.y - p1.y) / (p2.y - p1.y);
+                               p1.x += t * (p2.x - p1.x);
+                               p1.y = max.y;
+                       } else if ((o1 & BOTTOM) != IN) {
+                               float t = (min.y - p1.y) / (p2.y - p1.y);
+                               p1.x += t * (p2.x - p1.x);
+                               p1.y = min.y;
+                       } else if ((o1 & LEFT) != IN) {
+                               float t = (min.x - p1.x) / (p2.x - p1.x);
+                               p1.y += t * (p2.y - p1.y);
+                               p1.x = min.x;
+                       } else if ((o1 & RIGHT) != IN) {
+                               float t = (max.x - p1.x) / (p2.x - p1.x);
+                               p1.y += t * (p2.y - p1.y);
+                               p1.x = max.x;
+                       } else {
+                               throw new RuntimeException("Error in clipping code");
+                       }
+               }
+               
+       }
+       
+       public static double square(double d) {
+               return d * d;
+       }
+       
+       
+       public static void multiplyOrientation(AxisAngle4d aa, AxisAngle4d rot)  {
+               Quat4d q1 = new Quat4d();
+               getQuat(aa, q1);
+               Quat4d q2 = new Quat4d();
+               getQuat(rot, q2);
+               q2.mul(q1);
+               rot.set(q2);
+       }
+       
+       public static double radToDeg(double rad) {
+               return (rad / Math.PI) * 180.0;
+       }
+       
+       public static double degToRad(double deg) {
+               return (deg / 180.0) * Math.PI;
+       }
+       
+       public static double clamp(double min, double max,double v) {
+               if (v < min)
+                       return min;
+               if (v > max)
+                       return max;
+               return v;
+       }
+       
+       public static AxisAngle4d createRotation(Vector3d original, Vector3d rotated) { 
+               AxisAngle4d result = new AxisAngle4d();
+               if (createRotation(original, rotated, result))
+                       return result;
+               return null;
+       }
+       
+       
+       public static void setIdentity(Quat4d q) {
+               q.w = 1.0;
+               q.x = 0.0;
+               q.y = 0.0;
+               q.z = 0.0;
+       }
+       
+       public static void setIdentity(AxisAngle4d aa) {
+               aa.angle = 0.0;
+               aa.x = 0.0;
+               aa.y = 1.0;
+               aa.z = 0.0;
+       }
+       
+       public static void set(Matrix3d mat, double m00, double m01, double m02,
+                       double m10, double m11, double m12, double m20, double m21,
+                       double m22) {
+               mat.m00 = m00;
+               mat.m01 = m01;
+               mat.m02 = m02;
+
+               mat.m10 = m10;
+               mat.m11 = m11;
+               mat.m12 = m12;
+
+               mat.m20 = m20;
+               mat.m21 = m21;
+               mat.m22 = m22;
+       }
+       
+       public static void set(Matrix4d mat, double[] v) {
+               mat.m00 = v[0];
+               mat.m01 = v[1];
+               mat.m02 = v[2];
+               mat.m03 = v[3];
+
+               mat.m10 = v[4];
+               mat.m11 = v[5];
+               mat.m12 = v[6];
+               mat.m13 = v[7];
+
+               mat.m20 = v[8];
+               mat.m21 = v[9];
+               mat.m22 = v[10];
+               mat.m23 = v[11];
+
+               mat.m30 = v[12];
+               mat.m31 = v[13];
+               mat.m32 = v[14];
+               mat.m33 = v[15];
+
+       }
+       
+       public static boolean createRotation(Vector3d original, Vector3d rotated, AxisAngle4d result) {
+               
+               if (rotated.lengthSquared() > 0.01)
+                       rotated.normalize();
+               else
+                       return false;
+               double d = original.dot(rotated);
+               if (d > 0.9999) {
+                       // original and rotated are parallel, pointing at the same direction
+                       result.angle = 0.0;
+                       result.x = 0.0;
+                       result.y = 1.0;
+                       result.z = 0.0;
+               } else if (d < -0.9999) {
+                       // original and rotated are parallel, pointing at the opposite direction 
+                       Vector3d a = Z_AXIS;
+                       if (Math.abs(a.dot(original)) > 0.8 )
+                               a = Y_AXIS;
+                       result.set(a, Math.PI);
+               } else {
+                       double angle = original.angle(rotated);
+                       Vector3d axis = new Vector3d();
+                       axis.cross(original, rotated);
+                       result.set(axis,angle);
+               }
+               return true;
+       }
+       
+       public static boolean createRotation(Vector3d original, Vector3d rotated, Quat4d result) {
+               
+               if (rotated.lengthSquared() > 0.01)
+                       rotated.normalize();
+               else
+                       return false;
+               double d = original.dot(rotated);
+               if (d > 0.9999) {
+                       // original and rotated are parallel, pointing at the same direction
+                       result.w = 1.0;
+                       result.x = 0.0;
+                       result.y = 0.0;
+                       result.z = 0.0;
+               } else if (d < -0.9999) {
+                       // original and rotated are parallel, pointing at the opposite direction 
+                       Vector3d a = Z_AXIS;
+                       if (Math.abs(a.dot(original)) > 0.8 )
+                               a = Y_AXIS;
+                       getQuat(a, Math.PI, result);
+                       
+               } else {
+                       double angle = original.angle(rotated);
+                       Vector3d axis = new Vector3d();
+                       axis.cross(original, rotated);
+                       getQuat(axis, angle, result);
+               }
+               return true;
+       }
+       
+       public static boolean createRotation(Vector3d original, Vector3d rotated, Vector3d axis, AxisAngle4d result) {
+        
+        if (rotated.lengthSquared() > 0.01)
+            rotated.normalize();
+        else
+            return false;
+        if (original.lengthSquared() > 0.01)
+            original.normalize();
+        else
+            return false;
+        if (axis.lengthSquared() > 0.01)
+            axis.normalize();
+        else
+            return false;
+        double d = original.dot(rotated);
+        if (d > 0.9999) {
+            // original and rotated are parallel, pointing at the same direction
+            result.angle = 0.0;
+            result.x = axis.x;
+            result.y = axis.y;
+            result.z = axis.z;
+        } else if (d < -0.9999) {
+            // original and rotated are parallel, pointing at the opposite direction 
+            result.angle = Math.PI;
+            result.x = axis.x;
+            result.y = axis.y;
+            result.z = axis.z;
+        } else {
+            // Project vectors to Axis plane
+            Vector3d p1 = projectToPlane(original, axis);
+            Vector3d p2 = projectToPlane(rotated, axis);
+            // Create vectors where z-axis is plane normal
+            Quat4d q = getQuat(createRotation(axis, Z_AXIS));
+            Vector3d t1 = new Vector3d();
+            Vector3d t2 = new Vector3d();
+            rotate(q, p1, t1);
+            rotate(q, p2, t2);
+            // Calculate angles on z-axis plane.
+            double a1 = Math.atan2(t1.y, t1.x);
+            double a2 = Math.atan2(t2.y, t2.x);
+            result.set(axis,a2-a1);
+            
+        }
+        return true;
+    }
+       
+       public static void getQuat(Vector3d axis, double angle, Quat4d q)
+       {
+               double mag,amag;
+               // Quat = cos(theta/2) + sin(theta/2)(roation_axis) 
+               
+               amag = Math.sqrt( axis.x*axis.x + axis.y*axis.y + axis.z*axis.z);
+               if( amag < EPS ) {
+                       q.w = 1.0;
+                       q.x = 0.0;
+                       q.y = 0.0;
+                       q.z = 0.0;
+               } else {  
+                       amag = 1.0/amag; 
+                       double a2 = angle*0.5;
+                       mag = Math.sin(a2);
+                       q.w = Math.cos(a2);
+                       q.x = axis.x*amag*mag;
+                       q.y = axis.y*amag*mag;
+                       q.z = axis.z*amag*mag;
+               }
+       
+       }
+       
+       /**
+        * Linear interpolation of quaternions. Result IS set to q1.
+        * @param q1
+        * @param q2
+        * @param alpha
+        */
+       public static void lip(Quat4d q1, Quat4d q2, double alpha) {
+               double s1 = 1.0 - alpha;
+               double s2 = alpha;
+               q1.scale(s1);
+               mad(q1,q2,s2);
+               q1.normalize();
+       }
+       
+       public static double dot(Quat4d q1, Quat4d q2) {
+               return q1.x * q2.x + q1.y * q2.y + q1.z * q2.z + q1.w * q2.w;
+       }
+       
+       public static void mad(Tuple3d q1, Tuple3d q2, double s2) {
+               q1.x += q2.x * s2;
+               q1.y += q2.y * s2;
+               q1.z += q2.z * s2;
+       }
+       
+       public static void mad(Quat4d q1, Quat4d q2, double s2) {
+               q1.x += q2.x * s2;
+               q1.y += q2.y * s2;
+               q1.z += q2.z * s2;
+               q1.w += q2.w * s2;
+       }
+       
+       /**
+        * Slerp
+        * 
+        * Sets results to q1. Modifies q2.
+        * 
+        * @param q1
+        * @param q2
+        * @param alpha
+        */
+       public static void sip(Quat4d q1, Quat4d q2, double alpha) {
+               double cosom = dot(q1,q2);
+               if (cosom < 0.0) {
+                       cosom = -cosom;
+                       q2.negate();
+               }
+               
+               if (cosom > 0.9999) {
+                       q2.sub(q1);
+                       q2.scale(alpha);
+                       q1.add(q2);
+                       q1.normalize();
+                       return;
+               }
+               double theta_0 = Math.acos(cosom);
+               double theta = theta_0 * alpha;
+               Quat4d t = new Quat4d(q1);
+               t.scale(-cosom);
+               t.add(q2);
+               t.normalize();
+               t.scale(Math.sin(theta));
+               q1.scale(Math.cos(theta));
+               q1.add(t);
+       }
+       
+       
+       public static void rotate(double angle, Tuple2d v1, Tuple2d v2) {
+               // TODO : verify implementation
+               double sin = Math.sin(angle);
+               if (sin == 1.0) {
+                       v2.x = v1.y;
+                       v2.y = -v1.x;
+               } else if (sin == -1.0) {
+                       v2.x = -v1.y;
+                       v2.y = v1.x;
+               } else {
+                       double cos = Math.cos(angle);
+                       if (cos == -1.0) {
+                               v2.x = -v1.x;
+                               v2.y = -v1.y;
+                       } else if (cos != 1.0) {
+                               v2.x= v1.x * cos + v1.y * -sin;
+                               v2.y= v1.x* sin + v1.y *cos;
+                       }
+               }       
+       }
+       
+       public static Tuple3d getPosRot(double m3x2[]) {
+               Vector3d t = new Vector3d();
+               t.x = m3x2[4];
+               t.y = m3x2[5];
+               
+               
+               Vector2d v2 = new Vector2d(1,0);
+               Vector2d v = new Vector2d();
+               // use rotation of (1,0) to calculate the rotation component
+               v.x  =  m3x2[0];
+               v.y  =  m3x2[2];
+               double a1 = v2.angle(v);
+               if (v.y < 0) {
+                       t.z = a1;
+               } else {
+                       t.z = Math.PI*2.0 - a1;
+               }
+               return t;
+       }
+       
+       public static Matrix4d glFrustum(double l, double r, double b, double t, double n, double f) {
+               Matrix4d mat = new Matrix4d();
+               mat.m00 = 2.0 * n / (r - l);
+               mat.m11 = 2.0 * n / (t - b);
+               mat.m02 = (r+l) / (r-l);
+               mat.m12 = (t+b) / (t-b);
+               mat.m22 = -(f+n) / (f-n);
+               mat.m23 = -(2.0 *f * n) / (f-n);
+               mat.m32 = -1.0;
+               return mat;
+       }
+       
+       public static Matrix4d glOrtho(double l, double r, double b, double t, double n, double f) {
+               Matrix4d mat = new Matrix4d();
+               mat.m00 = 2.0 / (r - l);
+               mat.m11 = 2.0 / (t - b);
+               mat.m22 = -2.0 / (f-n);
+               mat.m33 =  1.0;
+               mat.m03 = -(r+l)/(r-l);
+               mat.m13 = -(t+b)/(t-b);
+               mat.m23 = -(f+n)/(f-n);
+               return mat;
+       }
+}