We propose an extension of the Desertscapes Simulation model capable of simulating dune formation, propagation and aeolian erosion of bedrock. The original method as well as an existing GPU implementation are improved by introducing bilinear interpolation and removing the random event-driven nature of the original method, increasing accuracy and removing noise. The convergence of avalanching is improved using a new sand propagation scheme and we propose and evaluate a new method for reptation which increases realism in the generated dune shapes when compared to previous work. Problems caused by divergent wind fields generated by the previous method are addressed by removing divergence efficiently in the frequency domain. Under a bidirectional wind scheme, our results are a closer match to a reference offline method than previous work. Despite multiple extensions to the method, our implementation is significantly faster than the previous GPU implementation. Our method can generate detailed, physically plausible desert environments very quickly, with possible applications in both computer graphics as well as geomorphology. Supported dune types include transverse, barchan, star, nabhka, parabolic, linear and echo dunes.