Add equals operator to matrixX

Includes tests

lib/src/vector_math/matrix2.dart

@@ -136,12 +136,23 @@ class Matrix2 {
   /// Dimension of the matrix.
   int get dimension => 2;
 
+  /// Access the element of the matrix at the index [i].
   double operator [](int i) => _m2storage[i];
 
+  /// Set the element of the matrix at the index [i].
   void operator []=(int i, double v) {
     _m2storage[i] = v;
   }
 
+  /// Check if two matrices are the same.
+  bool operator ==(other) {
+    return (other is Matrix2) &&
+        (_m2storage[0] == other._m2storage[0]) &&
+        (_m2storage[1] == other._m2storage[1]) &&
+        (_m2storage[2] == other._m2storage[2]) &&
+        (_m2storage[3] == other._m2storage[3]);
+  }
+
   /// Returns row 0
   Vector2 get row0 => getRow(0);
 

lib/src/vector_math/matrix3.dart

@@ -234,6 +234,20 @@ class Matrix3 {
     _m3storage[i] = v;
   }
 
+  /// Check if two matrices are the same.
+  bool operator ==(other) {
+    return (other is Matrix3) &&
+        (_m3storage[0] == other._m3storage[0]) &&
+        (_m3storage[1] == other._m3storage[1]) &&
+        (_m3storage[2] == other._m3storage[2]) &&
+        (_m3storage[3] == other._m3storage[3]) &&
+        (_m3storage[4] == other._m3storage[4]) &&
+        (_m3storage[5] == other._m3storage[5]) &&
+        (_m3storage[6] == other._m3storage[6]) &&
+        (_m3storage[7] == other._m3storage[7]) &&
+        (_m3storage[8] == other._m3storage[8]);
+  }
+
   /// Returns row 0
   Vector3 get row0 => getRow(0);
 

lib/src/vector_math/matrix4.dart

@@ -429,12 +429,35 @@ class Matrix4 {
   /// Dimension of the matrix.
   int get dimension => 4;
 
+  /// Access the element of the matrix at the index [i].
   double operator [](int i) => _m4storage[i];
 
+  /// Set the element of the matrix at the index [i].
   void operator []=(int i, double v) {
     _m4storage[i] = v;
   }
 
+  /// Check if two matrices are the same.
+  bool operator ==(other) {
+    return (other is Matrix4) &&
+        (_m4storage[0] == other._m4storage[0]) &&
+        (_m4storage[1] == other._m4storage[1]) &&
+        (_m4storage[2] == other._m4storage[2]) &&
+        (_m4storage[3] == other._m4storage[3]) &&
+        (_m4storage[4] == other._m4storage[4]) &&
+        (_m4storage[5] == other._m4storage[5]) &&
+        (_m4storage[6] == other._m4storage[6]) &&
+        (_m4storage[7] == other._m4storage[7]) &&
+        (_m4storage[8] == other._m4storage[8]) &&
+        (_m4storage[9] == other._m4storage[9]) &&
+        (_m4storage[10] == other._m4storage[10]) &&
+        (_m4storage[11] == other._m4storage[11]) &&
+        (_m4storage[12] == other._m4storage[12]) &&
+        (_m4storage[13] == other._m4storage[13]) &&
+        (_m4storage[14] == other._m4storage[14]) &&
+        (_m4storage[15] == other._m4storage[15]);
+  }
+
   /// Returns row 0
   Vector4 get row0 => getRow(0);
 

test/matrix2_test.dart

@@ -112,6 +112,12 @@ void testMatrix2Solving() {
   expect(backwards.y, equals(b.y));
 }
 
+void testMatrix2Equals() {
+  expect(new Matrix2.identity(), equals(new Matrix2.identity()));
+  expect(new Matrix2.zero(), isNot(equals(new Matrix2.identity())));
+  expect(new Matrix2.zero(), isNot(equals(5)));
+}
+
 void main() {
   group('Matrix2', () {
     test('Determinant', testMatrix2Determinant);
@@ -121,5 +127,6 @@ void main() {
     test('dot product', testMatrix2Dot);
     test('Scale', testMatrix2Scale);
     test('solving', testMatrix2Solving);
+    test('equals', testMatrix2Equals);
   });
 }

test/matrix3_test.dart

@@ -310,6 +310,12 @@ void testMatrix3Solving() {
   expect(backwards2.y, equals(b2.y));
 }
 
+void testMatrix3Equals() {
+  expect(new Matrix3.identity(), equals(new Matrix3.identity()));
+  expect(new Matrix3.zero(), isNot(equals(new Matrix3.identity())));
+  expect(new Matrix3.zero(), isNot(equals(5)));
+}
+
 void main() {
   group('Matrix3', () {
     test('Determinant', testMatrix3Determinant);
@@ -325,5 +331,6 @@ void main() {
     test('dot product', testMatrix3Dot);
     test('Scale', testMatrix3Scale);
     test('solving', testMatrix3Solving);
+    test('equals', testMatrix3Equals);
   });
 }

test/matrix4_test.dart

@@ -589,6 +589,12 @@ void testMatrix4Compose() {
   }
 }
 
+void testMatrix4Equals() {
+  expect(new Matrix4.identity(), equals(new Matrix4.identity()));
+  expect(new Matrix4.zero(), isNot(equals(new Matrix4.identity())));
+  expect(new Matrix4.zero(), isNot(equals(5)));
+}
+
 void main() {
   group('Matrix4', () {
     test('instancing from Float32List', testMatrix4InstacingFromFloat32List);
@@ -611,5 +617,6 @@ void main() {
     test('perspective transform', testMatrix4PerspectiveTransform);
     test('solving', testMatrix4Solving);
     test('compose/decompose', testMatrix4Compose);
+    test('equals', testMatrix4Equals);
   });
 }