This work proposes an automatic real time lighting technique for procedurally generated isometric maps. The scenario is generated from a string seed and the proposed lighting system estimates the geometrical shape of the 2D objects as if they were 3D for further light interaction, therefore producing a 2.5D effect. We employ opacity maps to overcome an issue generated by the geometrical shape estimation. The solution is a coupled approach between the CPU and GPU. The produced visuals, gameplay and performance were evaluated by gamers, programmers and designers. Furthermore, the performance, in terms of frames per second, was evaluated over distinct graphics cards and processors and was satisfactory.