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diff --git a/src/gleem/linalg/Mat4f.java b/src/gleem/linalg/Mat4f.java
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+/*
+ * gleem -- OpenGL Extremely Easy-To-Use Manipulators.
+ * Copyright (C) 1998-2003 Kenneth B. Russell ([email protected])
+ *
+ * Copying, distribution and use of this software in source and binary
+ * forms, with or without modification, is permitted provided that the
+ * following conditions are met:
+ *
+ * Distributions of source code must reproduce the copyright notice,
+ * this list of conditions and the following disclaimer in the source
+ * code header files; and Distributions of binary code must reproduce
+ * the copyright notice, this list of conditions and the following
+ * disclaimer in the documentation, Read me file, license file and/or
+ * other materials provided with the software distribution.
+ *
+ * The names of Sun Microsystems, Inc. ("Sun") and/or the copyright
+ * holder may not be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED "AS IS," WITHOUT A WARRANTY OF ANY
+ * KIND. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND
+ * WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, NON-INTERFERENCE, ACCURACY OF
+ * INFORMATIONAL CONTENT OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. THE
+ * COPYRIGHT HOLDER, SUN AND SUN'S LICENSORS SHALL NOT BE LIABLE FOR
+ * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
+ * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL THE
+ * COPYRIGHT HOLDER, SUN OR SUN'S LICENSORS BE LIABLE FOR ANY LOST
+ * REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL,
+ * CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND
+ * REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF OR
+ * INABILITY TO USE THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGES. YOU ACKNOWLEDGE THAT THIS SOFTWARE IS NOT
+ * DESIGNED, LICENSED OR INTENDED FOR USE IN THE DESIGN, CONSTRUCTION,
+ * OPERATION OR MAINTENANCE OF ANY NUCLEAR FACILITY. THE COPYRIGHT
+ * HOLDER, SUN AND SUN'S LICENSORS DISCLAIM ANY EXPRESS OR IMPLIED
+ * WARRANTY OF FITNESS FOR SUCH USES.
+ */
+
+package gleem.linalg;
+
+/** A (very incomplete) 4x4 matrix class. Representation assumes
+    multiplication by column vectors on the right. */
+
+public class Mat4f {
+  private float[] data;
+
+  /** Creates new matrix initialized to the zero matrix */
+  public Mat4f() {
+    data = new float[16];
+  }
+
+  /** Creates new matrix initialized to argument's contents */
+  public Mat4f(Mat4f arg) {
+    this();
+    set(arg);
+  }
+
+  /** Sets this matrix to the identity matrix */
+  public void makeIdent() {
+    for (int i = 0; i < 4; i++) {
+      for (int j = 0; j < 4; j++) {
+        if (i == j) {
+          set(i, j, 1.0f);
+        } else {
+          set(i, j, 0.0f);
+        }
+      }
+    }
+  }
+
+  /** Sets this matrix to be equivalent to the given one */
+  public void set(Mat4f arg) {
+    float[] mine = data;
+    float[] yours = arg.data;
+    for (int i = 0; i < mine.length; i++) {
+      mine[i] = yours[i];
+    }
+  }
+
+  /** Gets the (i,j)th element of this matrix, where i is the row
+      index and j is the column index */
+  public float get(int i, int j) {
+    return data[4 * i + j];
+  }
+
+  /** Sets the (i,j)th element of this matrix, where i is the row
+      index and j is the column index */
+  public void set(int i, int j, float val) {
+    data[4 * i + j] = val;
+  }
+
+  /** Sets the translation component of this matrix (i.e., the three
+      top elements of the third column) without touching any of the
+      other parts of the matrix */
+  public void setTranslation(Vec3f trans) {
+    set(0, 3, trans.x());
+    set(1, 3, trans.y());
+    set(2, 3, trans.z());
+  }
+
+  /** Sets the rotation component of this matrix (i.e., the upper left
+      3x3) without touching any of the other parts of the matrix */
+  public void setRotation(Rotf rot) {
+    rot.toMatrix(this);
+  }
+
+  /** Sets the upper-left 3x3 of this matrix assuming that the given
+      x, y, and z vectors form an orthonormal basis */
+  public void setRotation(Vec3f x, Vec3f y, Vec3f z) {
+    set(0, 0, x.x());
+    set(1, 0, x.y());
+    set(2, 0, x.z());
+
+    set(0, 1, y.x());
+    set(1, 1, y.y());
+    set(2, 1, y.z());
+
+    set(0, 2, z.x());
+    set(1, 2, z.y());
+    set(2, 2, z.z());
+  }
+
+  /** Gets the upper left 3x3 of this matrix as a rotation. Currently
+      does not work if there are scales. Ignores translation
+      component. */
+  public void getRotation(Rotf rot) {
+    rot.fromMatrix(this);
+  }
+
+  /** Sets the elements (0, 0), (1, 1), and (2, 2) with the
+      appropriate elements of the given three-dimensional scale
+      vector. Does not perform a full multiplication of the upper-left
+      3x3; use this with an identity matrix in conjunction with
+      <code>mul</code> for that. */
+  public void setScale(Vec3f scale) {
+    set(0, 0, scale.x());
+    set(1, 1, scale.y());
+    set(2, 2, scale.z());
+  }
+
+  /** Inverts this matrix assuming that it represents a rigid
+      transform (i.e., some combination of rotations and
+      translations). Assumes column vectors. Algorithm: transposes
+      upper left 3x3; negates translation in rightmost column and
+      transforms by inverted rotation. */
+  public void invertRigid() {
+    float t;
+    // Transpose upper left 3x3
+    t = get(0, 1);
+    set(0, 1, get(1, 0));
+    set(1, 0, t);
+    t = get(0, 2);
+    set(0, 2, get(2, 0));
+    set(2, 0, t);
+    t = get(1, 2);
+    set(1, 2, get(2, 1));
+    set(2, 1, t);
+    // Transform negative translation by this
+    Vec3f negTrans = new Vec3f(-get(0, 3), -get(1, 3), -get(2, 3));
+    Vec3f trans = new Vec3f();
+    xformDir(negTrans, trans);
+    set(0, 3, trans.x());
+    set(1, 3, trans.y());
+    set(2, 3, trans.z());
+  }
+
+  /** Returns this * b; creates new matrix */
+  public Mat4f mul(Mat4f b) {
+    Mat4f tmp = new Mat4f();
+    tmp.mul(this, b);
+    return tmp;
+  }
+
+  /** this = a * b */
+  public void mul(Mat4f a, Mat4f b) {
+    for (int rc = 0; rc < 4; rc++)
+      for (int cc = 0; cc < 4; cc++) {
+        float tmp = 0.0f;
+        for (int i = 0; i < 4; i++)
+          tmp += a.get(rc, i) * b.get(i, cc);
+        set(rc, cc, tmp);
+      }
+  }
+  
+  /** Transpose this matrix in place. */
+  public void transpose() {
+    float t;
+    for (int i = 0; i < 4; i++) {
+      for (int j = 0; j < i; j++) {
+        t = get(i, j);
+        set(i, j, get(j, i));
+        set(j, i, t);
+      }
+    }
+  }
+
+  /** Multiply a 4D vector by this matrix. NOTE: src and dest must be
+      different vectors. */
+  public void xformVec(Vec4f src, Vec4f dest) {
+    for (int rc = 0; rc < 4; rc++) {
+      float tmp = 0.0f;
+      for (int cc = 0; cc < 4; cc++) {
+        tmp += get(rc, cc) * src.get(cc);
+      }
+      dest.set(rc, tmp);
+    }
+  }
+
+  /** Transforms a 3D vector as though it had a homogeneous coordinate
+      and assuming that this matrix represents only rigid
+      transformations; i.e., is not a full transformation. NOTE: src
+      and dest must be different vectors. */
+  public void xformPt(Vec3f src, Vec3f dest) {
+    for (int rc = 0; rc < 3; rc++) {
+      float tmp = 0.0f;
+      for (int cc = 0; cc < 3; cc++) {
+        tmp += get(rc, cc) * src.get(cc);
+      }
+      tmp += get(rc, 3);
+      dest.set(rc, tmp);
+    }
+  }
+  
+  /** Transforms src using only the upper left 3x3. NOTE: src and dest
+      must be different vectors. */
+  public void xformDir(Vec3f src, Vec3f dest) {
+    for (int rc = 0; rc < 3; rc++) {
+      float tmp = 0.0f;
+      for (int cc = 0; cc < 3; cc++) {
+        tmp += get(rc, cc) * src.get(cc);
+      }
+      dest.set(rc, tmp);
+    }
+  }
+  
+  /** Copies data in column-major (OpenGL format) order into passed
+      float array, which must have length 16 or greater. */
+  public void getColumnMajorData(float[] out) {
+    for (int i = 0; i < 4; i++) {
+      for (int j = 0; j < 4; j++) {
+        out[4 * j + i] = get(i, j);
+      }
+    }
+  }
+
+  public Matf toMatf() {
+    Matf out = new Matf(4, 4);
+    for (int i = 0; i < 4; i++) {
+      for (int j = 0; j < 4; j++) {
+        out.set(i, j, get(i, j));
+      }
+    }
+    return out;
+  }
+
+  public String toString() {
+    String endl = System.getProperty("line.separator");
+    return "(" +
+      get(0, 0) + ", " + get(0, 1) + ", " + get(0, 2) + ", " + get(0, 3) + endl +
+      get(1, 0) + ", " + get(1, 1) + ", " + get(1, 2) + ", " + get(1, 3) + endl +
+      get(2, 0) + ", " + get(2, 1) + ", " + get(2, 2) + ", " + get(2, 3) + endl +
+      get(3, 0) + ", " + get(3, 1) + ", " + get(3, 2) + ", " + get(3, 3) + ")";
+  }
+}