The player can be just one component, until you split things to reuse them.
But imagine a simple 2d game: whag are you reusing on a lot of entities?
- collision size
- sprite to render and render properties
- position on grid
- maybe also a velocity, maybe an acceleration
With ECS it becomes trivial to make a system that iterates over all entities with a sprite and a position, and draws them. Another system can adjust the position with the velocity.
Notice how we can create non-moving entities by not having the velocity component at all. Also notice how we can easily add a rendered sprite to any entity without changing any code.
I know this scales well as it gets more and more popular also for larger games.
Bonus: This data is all located together so iterating over Sprite+Position is very cache friendly. And if a system only reads and writes data to the entity jt can also be parallelized.
But imagine a simple 2d game: whag are you reusing on a lot of entities? - collision size - sprite to render and render properties - position on grid - maybe also a velocity, maybe an acceleration
With ECS it becomes trivial to make a system that iterates over all entities with a sprite and a position, and draws them. Another system can adjust the position with the velocity. Notice how we can create non-moving entities by not having the velocity component at all. Also notice how we can easily add a rendered sprite to any entity without changing any code.
I know this scales well as it gets more and more popular also for larger games.
Bonus: This data is all located together so iterating over Sprite+Position is very cache friendly. And if a system only reads and writes data to the entity jt can also be parallelized.