I see...well, that won't work. Compilation happens based on the textures. You can't change the texture of some inbetween polygons without triggering a complete recompilation again...if IIRC, this isn't supported anyway. A solution is to put all textures into one and just change u/v-mapping. That requires no new compilation, "just" a new fill of the native buffers, which isn't particularly fast either, but depending on the frequency in which this happens, it might be fast enough.