# `QuakeServer.Animation`
[🔗](https://github.com/jaman/quake_server/blob/v0.1.0/lib/quake_server/animation.ex#L1)

The animation of the entities a program sends itself, carried to each watching player
as GoldSrc's engine carries `entity_state_t`'s `sequence`, `frame`, `animtime` and
`framerate` for every entity it sends (`delta.lst`).

    server = QuakeServer.Animation.sample(server)
    {states, server} = QuakeServer.Animation.take(server, 1)
    states #=> %{374 => %{sequence: 0.0, time: 3.0, framerate: 1.0, animtime: 3.97}}

`sample/1` runs once a server frame, at the server's `time`. For each live entity with
a `SendEntity`, its state is `sequence`, the program's `frame` (the studio sequence);
`time`, the program's `frame1time` (seconds into the sequence); `animtime`, the
server's time; and `framerate`, how many seconds `frame1time` moved for each second
the server's time moved since the entity's last sample in the same sequence. When the
sequence changes or `frame1time` goes back, the framerate stays the last one
measured; an entity sampled the first time has framerate 0. A program without a
`frame1time` field has no animation.

`take/2` gives the states of the entities the player holds
(`QuakeServer.Network.held/2`) that the player was not sent yet, or whose state is not
the one the player can work out from the state last sent: its sequence or framerate
differs, or its `time` differs by more than a thousandth of a second from the last
`time` moved on at the last framerate to the new `animtime`. GoldSrc's client shows
the sequence at `time + (now - animtime) * framerate` seconds, and with no time passed
since `animtime` at `time`.

# `state`

```elixir
@type state() :: %{
  sequence: float(),
  time: float(),
  framerate: float(),
  animtime: float()
}
```

An entity's animation as sent to a player.

# `sample`

```elixir
@spec sample(QuakeServer.Server.t()) :: QuakeServer.Server.t()
```

Sample the animation of every live entity with a `SendEntity` at the server's time.

# `take`

```elixir
@spec take(QuakeServer.Server.t(), non_neg_integer()) ::
  {%{required(pos_integer()) => state()}, QuakeServer.Server.t()}
```

The states player `viewer` lacks of the entities it holds, kept as sent.

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*Consult [api-reference.md](api-reference.md) for complete listing*