Practical game animation?

开发者_StackOverflow中文版I understand that game development involves a 'game loop', in which the scene is drawn. This game loop either runs as fast as possible (no timer, frame animation) or is called based on a timer (timer animation). I'm curious as to how advanced animation (something beyond just simple geometry) is actually done, considering how many frames might take place in say, a character walking. Obviously the programmer has not hard-coded in the position of the character's foot at every frame of the animation, so I'm wondering how this would actually be done?

If any clarification of the question is necessary, I'll be happy to fill more in.