why am i forced to clear the buffers?
I suspected that i could just “overdraw” the last drawing operation. But when i tried and removed the glClear command from the source-code, the display was not updated correctly.
You dont have to clear the color buffer, if your rendering covers the whole screen. But you still need to clear the Z buffer, or the majority of the scene wont be rendered again after the 1st frame. Because it will be comparing the depth values of the last frame, not of a clean Z buffer.