Dynamic Split Screen

Introduction :

The classic technique of local multiplayer games is to split the screen into 4 parts so that each player can move away from the others freely.
But in some games, players stay together most of the time.
This wastes 75% of the screen.

One solution to this problem is to cut the screen dynamically.
In this system, a single camera captures all the players when they are gathered together, but when a player moves away a new camera will capture that player specifically by cutting out the screen.
That way we never have more cameras than we need.

When all players are close enough, only one camera is used.

If the players are far from each other, you use as many cameras as there are players.

The cameras render each image separately using the stencil buffer to select what is rendered to the screen.

We then combine the images rendered by each camera.

The screen is divided so that the players can easily find each other, always knowing in which direction to go to join the others.