phys debugging; see L818@ActorWithBody.kt

src/org/dyn4j/geometry/Vector2.kt

@@ -28,6 +28,7 @@
 package org.dyn4j.geometry
 
 import org.dyn4j.Epsilon
+import kotlin.math.sign
 
 /**
  * This class represents a vector or point in 2D space.
@@ -699,6 +700,9 @@ class Vector2 {
         return a
     }
 
+    val signum: Vector2
+        get() = Vector2(this.x.sign, this.y.sign)
+
     companion object {
         /** A vector representing the x-axis; this vector should not be changed at runtime; used internally  */
         internal val X_AXIS = Vector2(1.0, 0.0)