3D Programming - day/night cycle inside my 3D engine

You can jump to the main points in the video using the following timecodes: 00:00 - fist basic introduction of the problem from a simplified test scene, seen from space 05:53 - implication of the different sun conditions on the earth surface seen from above 08:09 - consideration of sun exposure for snow accumulation 11:48 - sun trajectory seen from the earth surface at different times of year and different latitudes Finally implemented day night cycle inside my 3D engine. Now the engine can vary sun position according to hour and day of the year, and also according to the latitude, with a good approximation.