public void addLocal(Matrix4f mat) {
        m00 += mat.m00;
        m01 += mat.m01;
        m02 += mat.m02;
        m03 += mat.m03;
        m10 += mat.m10;
        m11 += mat.m11;
        m12 += mat.m12;
        m13 += mat.m13;
        m20 += mat.m20;
        m21 += mat.m21;
        m22 += mat.m22;
        m23 += mat.m23;
        m30 += mat.m30;
        m31 += mat.m31;
        m32 += mat.m32;
        m33 += mat.m33;
    }
Sum in place, with the specified matrix.

@param mat the matrix to add (not null)
jme3-core/src/main/java/com/jme3/math/Matrix4f.java