OK, switching to highp does not help either, unfortunately.
Removing the rough retroreflecting part is like switching off the flickering tube in a two-tube fluorescent lamp. It does not flicker any longer, but the lamp looks different (has less light in total). Same for the lunar rim here. The O-N reflection model is the right one to use for the lunar surface. Just that some bad effect is going on here. What's the difference between GCC and MSVC here? Still no flicker in MinGW.
OK, switching to highp does not help either, unfortunately.
Removing the rough retroreflecting part is like switching off the flickering tube in a two-tube fluorescent lamp. It does not flicker any longer, but the lamp looks different (has less light in total). Same for the lunar rim here. The O-N reflection model is the right one to use for the lunar surface. Just that some bad effect is going on here. What's the difference between GCC and MSVC here? Still no flicker in MinGW.