code: public Matrix4x3d identity() {
          if ((properties & PROPERTY_IDENTITY) != 0)
              return this;
          m00 = 1.0;
          m01 = 0.0;
          m02 = 0.0;
          m10 = 0.0;
          m11 = 1.0;
          m12 = 0.0;
          m20 = 0.0;
          m21 = 0.0;
          m22 = 1.0;
          m30 = 0.0;
          m31 = 0.0;
          m32 = 0.0;
          properties = PROPERTY_IDENTITY | PROPERTY_TRANSLATION | PROPERTY_ORTHONORMAL;
          return this;
      }
docs: Reset this matrix to the identity.
  <p>
  Please note that if a call to {@link #identity()} is immediately followed by a call to:
  {@link #translate(double, double, double) translate},
  {@link #rotate(double, double, double, double) rotate},
  {@link #scale(double, double, double) scale},
  {@link #ortho(double, double, double, double, double, double) ortho},
  {@link #ortho2D(double, double, double, double) ortho2D},
  {@link #lookAt(double, double, double, double, double, double, double, double, double) lookAt},
  {@link #lookAlong(double, double, double, double, double, double) lookAlong},
  or any of their overloads, then the call to {@link #identity()} can be omitted and the subsequent call replaced with:
  {@link #translation(double, double, double) translation},
  {@link #rotation(double, double, double, double) rotation},
  {@link #scaling(double, double, double) scaling},
  {@link #setOrtho(double, double, double, double, double, double) setOrtho},
  {@link #setOrtho2D(double, double, double, double) setOrtho2D},
  {@link #setLookAt(double, double, double, double, double, double, double, double, double) setLookAt},
  {@link #setLookAlong(double, double, double, double, double, double) setLookAlong},
  or any of their overloads.
  
  @return this