code: public Matrix4 setToOrtho (
          double left, double right, double bottom, double top,
          double near, double far, IVector3 nearFarNormal) {
          double rlr = 1f / (left - right);
          double rbt = 1f / (bottom - top);
          double rnf = 1f / (near - far);
          double s = 2f / (near*nearFarNormal.z() - far*nearFarNormal.z());
          return set(-2f * rlr, 0f, 0f, (right + left) * rlr,
                     0f, -2f * rbt, 0f, (top + bottom) * rbt,
                     s * nearFarNormal.x(), s * nearFarNormal.y(), 2f * rnf, (far + near) * rnf,
                     0f, 0f, 0f, 1f);
      }
docs: Sets this to an orthographic projection matrix.
  
  @return a reference to this matrix, for chaining.