I've mostly been working on memory optimizations. Last time i tried running the planet with 2048x2048 textures, i got a crash at 2 Gb. What ? Two Gigabytes for high-resolution textures ? Something had to be wrong. But at the time i didn't investigate. Turns up i had forgotten to clean up "a few" buffers. In addition, i was calculating the 6 faces of the planet and only then uploading them to textures. Now i interleave this process, so that i only have to keep in memory a single planet face at a given time. I reach 200 Mb (vs 2 Gb) during the generation process.
I also implemented texture compression, and it seems to run well.
I zoomed a bit over the planet at a few hundred kilometers altitude: