@@ -19,11 +19,11 @@
 
 /**
  * @brief A 4x4 matrix of floats.
  */
 OF_SUBCLASSING_RESTRICTED
-@interface OF4x4Matrix: OFObject
+@interface OF4x4Matrix: OFObject <OFCopying>
 {
 	float _values[16];
 }
 
 #ifdef OF_HAVE_CLASS_PROPERTIES
@@ -60,8 +60,16 @@
 
 /**
  * @brief Transposes the matrix.
  */
 - (void)transpose;
+
+/**
+ * @brief Mulitplies the receiver with the specified matrix on the left side
+ *	  and the receiver on the right side.
+ *
+ * @param matrix The matrix to multiply the receiver with
+ */
+- (void)multiplyWithMatrix: (OF4x4Matrix *)matrix;
 @end
 
 OF_ASSUME_NONNULL_END