QuatArg: add the isRotationIdentity() method

stephengold · Feb 24, 2025 · 522d2b3 · 522d2b3
1 parent 8ad8279
commit 522d2b3
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diff --git a/src/main/java/com/github/stephengold/joltjni/Quat.java b/src/main/java/com/github/stephengold/joltjni/Quat.java
@@ -364,6 +364,22 @@ public boolean isNormalized(float tolerance) {
         }
     }
 
+    /**
+     * Test whether the quaternion represents an identity rotation. The
+     * quaternion is unaffected.
+     *
+     * @return {@code true} if the real component is a non-zero number and the
+     * imaginary components are all zero, otherwise {@code false}
+     */
+    @Override
+    public boolean isRotationIdentity() {
+        if (w != 0f && !Float.isNaN(w) && x == 0f && y == 0f && z == 0f) {
+            return true;
+        } else {
+            return false;
+        }
+    }
+
     /**
      * Test whether the quaternion is zero. The quaternion is unaffected.
      *

diff --git a/src/main/java/com/github/stephengold/joltjni/readonly/QuatArg.java b/src/main/java/com/github/stephengold/joltjni/readonly/QuatArg.java
@@ -90,6 +90,15 @@ public interface QuatArg {
      */
     boolean isNormalized(float tolerance);
 
+    /**
+     * Test whether the quaternion represents an identity rotation. The
+     * quaternion is unaffected.
+     *
+     * @return {@code true} if the real component is a non-zero number and the
+     * imaginary components are all zero, otherwise {@code false}
+     */
+    boolean isRotationIdentity();
+
     /**
      * Test whether the quaternion is zero. The quaternion is unaffected.
      *