This is the scenario – you are playing a massive 64 player map, you are running around and you suddenly see another player camping under the wreckage of a car. You are like – boom, I got this sucker. So you look down your cross-hair, aiming for that head-shot, and then you realise that this dude is looking straight back at you.
What you are observing you are rendering
What you are seeing is rendered by the game engine installed on your computer. Every game you play has a game engine and it’s responsible for rendering, for creating the universe in which the game resides. The game universe can be the green table for solitaire to San Andreas for GTA. Coming back our analogy, what you are seeing: the player, the cross-hair, the wreckage, the ground, the clouds, the sky – all of that is being rendered from your computer. Everything beyond your field of vision is not being rendered, it’s completely omitted by the game engine. Even nothing is not rendered (even if the room is empty, you still need to render the empty, in this case, even the empty is not rendered). The engine doesn’t need to render anything you are not seeing with your eyes – it would be a complete waste of processing power. For example, if you are running around the map, everything that disappears behind you is actually ceasing to exist, as far as the game’s visual engine is concerned.
The game engine creates separate realities which are then stitched together to give the illusion of a single, unified, reality
Now let’s take that the other player who is scoped on you. What he/she sees, isn’t rendered by your computer, its rendered by that player’s computer. So again, their world exists only on their computer, not yours. The other 62 players running around this map, have 62 separate game engines, rendering 62 separate worlds for each player. Each engine renders what is observed by their player. It creates 62 separate realities which are stitched together to give the illusion of one reality
What you are sensing you are rendering
If we are talking about a first/third person game, the visual perception is as part of reality as all the other four senses. You are seeing and hearing what your character is experiencing. Your character is also defined by the laws of physics as set out in the game engine. There is collision, there is gravity and everything else to give the impression that what the character is experiencing, is ‘real’. Once you take ownership of that character, you become that character. You start experiencing the game world as if it was ‘your’ world, you become aware of your characters death, it’s pain, it’s goals, it’s desires. All these senses are rendered relative to what you observe.
The sky in Skyrim is only there when your character looks up at it. Until that happens, it’s in a state of probability, its just code that can be executed.
So if you as the observer ceases to observe ie. turn the game off — the world ceases to exist with it and visa versa if the world was to cease to exist the observer will no longer be in the game.