2 files changed, 34 insertions, 14 deletions
diff --git a/src/jogl/classes/com/jogamp/math/DoubleUtil.java b/src/jogl/classes/com/jogamp/math/DoubleUtil.java
index e9ccceb10..8f1e44cd0 100644
--- a/src/jogl/classes/com/jogamp/math/DoubleUtil.java
+++ b/src/jogl/classes/com/jogamp/math/DoubleUtil.java
@@ -149,7 +149,11 @@ public final class DoubleUtil {
   }
 
   /**
-   * Return true if both values are equal, i.e. their absolute delta < <code>epsilon</code>.
+   * Returns true if both values are equal, i.e. their absolute delta < {@code epsilon} if 0 != {@code epsilon},
+   * otherwise == {@code 0}.
+   * <p>
+   * {@code epsilon} is allowed to be {@code 0}.
+   * </p>
    * <p>
    * Implementation considers following corner cases:
    * <ul>
@@ -161,7 +165,8 @@ public final class DoubleUtil {
    * @see #EPSILON
    */
   public static boolean isEqual(final double a, final double b, final double epsilon) {
-      if ( Math.abs(a - b) < epsilon ) {
+      if( 0 == epsilon && Math.abs(a - b) == 0 ||
+          0 != epsilon && Math.abs(a - b) < epsilon ) {
           return true;
       } else {
           // Values are equal (Inf, Nan .. )
@@ -170,7 +175,7 @@ public final class DoubleUtil {
   }
 
   /**
-   * Return true if both values are equal, i.e. their absolute delta < {@link #EPSILON}.
+   * Returns true if both values are equal, i.e. their absolute delta < {@link #EPSILON}.
    * <p>
    * Implementation considers following corner cases:
    * <ul>
@@ -191,7 +196,7 @@ public final class DoubleUtil {
   }
 
   /**
-   * Return true if both values are equal, i.e. their absolute delta < {@link #EPSILON}.
+   * Returns true if both values are equal, i.e. their absolute delta < {@link #EPSILON}.
    * <p>
    * Implementation does not consider corner cases like {@link #isEqual(float, float, float)}.
    * </p>
@@ -202,7 +207,7 @@ public final class DoubleUtil {
   }
 
   /**
-   * Return true if both values are equal w/o regarding an epsilon.
+   * Returns true if both values are equal w/o regarding an epsilon.
    * <p>
    * Implementation considers following corner cases:
    * <ul>
@@ -234,7 +239,11 @@ public final class DoubleUtil {
   }
 
   /**
-   * Return true if both values are equal, i.e. their absolute delta < <code>epsilon</code>.
+   * Returns {@code -1}, {@code 0} or {@code 1} if {@code a} is less, equal or greater than {@code b},
+   * taking {@code epsilon} into account for equality.
+   * <p>
+   * {@code epsilon} is allowed to be {@code 0}.
+   * </p>
    * <p>
    * Implementation considers following corner cases:
    * <ul>
@@ -248,7 +257,8 @@ public final class DoubleUtil {
    * @see #EPSILON
    */
   public static int compare(final double a, final double b, final double epsilon) {
-      if ( Math.abs(a - b) < epsilon ) {
+      if( 0 == epsilon && Math.abs(a - b) == 0 ||
+          0 != epsilon && Math.abs(a - b) < epsilon ) {
           return 0;
       } else {
           return compare(a, b);
@@ -256,15 +266,25 @@ public final class DoubleUtil {
   }
 
   /**
-   * Return true if value is zero, i.e. it's absolute value < <code>epsilon</code>.
+   * Returns true if value is zero, i.e. it's absolute value < {@code epsilon} if 0 != {@code epsilon},
+   * otherwise {@code 0 == a}.
+   * <p>
+   * {@code epsilon} is allowed to be {@code 0}.
+   * </p>
+   * <pre>
+   *    return 0 == epsilon && 0 == a || 0 != epsilon && Math.abs(a) < epsilon
+   * </pre>
+   * @param a value to test
+   * @param epsilon optional positive epsilon value, maybe {@code 0}
    * @see #EPSILON
    */
   public static boolean isZero(final double a, final double epsilon) {
-      return Math.abs(a) < epsilon;
+      return 0 == epsilon && a == 0 ||
+             0 != epsilon && Math.abs(a) < epsilon;
   }
 
   /**
-   * Return true if value is zero, i.e. it's absolute value < {@link #EPSILON}.
+   * Returns true if value is zero, i.e. it's absolute value < {@link #EPSILON}.
    * @see #EPSILON
    */
   public static boolean isZero(final double a) {
diff --git a/src/jogl/classes/com/jogamp/math/FloatUtil.java b/src/jogl/classes/com/jogamp/math/FloatUtil.java
index 94182baec..4ca706457 100644
--- a/src/jogl/classes/com/jogamp/math/FloatUtil.java
+++ b/src/jogl/classes/com/jogamp/math/FloatUtil.java
@@ -1454,7 +1454,7 @@ public final class FloatUtil {
   }
 
   /**
-   * Return true if both values are equal, i.e. their absolute delta < {@link #EPSILON}.
+   * Returns true if both values are equal, i.e. their absolute delta < {@link #EPSILON}.
    * <p>
    * Implementation considers following corner cases:
    * <ul>
@@ -1475,7 +1475,7 @@ public final class FloatUtil {
   }
 
   /**
-   * Return true if both values are equal, i.e. their absolute delta < {@link #EPSILON}.
+   * Returns true if both values are equal, i.e. their absolute delta < {@link #EPSILON}.
    * <p>
    * Implementation does not consider corner cases like {@link #isEqual(float, float, float)}.
    * </p>
@@ -1486,7 +1486,7 @@ public final class FloatUtil {
   }
 
   /**
-   * Return true if both values are equal w/o regarding an epsilon.
+   * Returns true if both values are equal w/o regarding an epsilon.
    * <p>
    * Implementation considers following corner cases:
    * <ul>
@@ -1563,7 +1563,7 @@ public final class FloatUtil {
   }
 
   /**
-   * Return true if value is zero, i.e. it's absolute value < {@link #EPSILON}.
+   * Returns true if value is zero, i.e. it's absolute value < {@link #EPSILON}.
    * @see #EPSILON
    */
   public static boolean isZero(final float a) {