This paper presents the formulation of a constrained 6-degree-of-freedom (6-DoF) powered descent guidance problem. The goal of this work is to design algorithms that obtain locally optimal solutions to such problems, and that are amenable to real-time implementation. Using unit dual quaternions to parameterize the equations of motion, we devise a free final time continuous optimal control problem that is subject to state and control constraints. A novel feature of this formulation is the use of state-triggered constraints, which are constraints enforced only when a certain state-dependent criterion is met. We use these constraints to model a line of sight pointing constraint that is enforced conditionally based on the distance from the landing site. A numerical example highlights how the inclusion of this constraint alters control commands and the resulting descent trajectory.