state-buffer

Captures a running buffer of player states for use in anti-cheat or statistical libraries.

No this is not an NPC-related library, it simply records a players actions into Pawn memory and provides an interface to access that data.

Installation

Simply install to your project:

sampctl package install Southclaws/state-buffer

Include in your code and begin using the library:

#include <state-buffer>

Usage

By including this library, OnScriptInit is hooked to start the frame capture timer. This timer runs every STATE_BUFFER_GRANULARITY milliseconds with a default value of 100. This means every 100ms, every connected player's state (see the E_BUFFERED_STATE enumerator for what is stored in a frame) is stored.

The amount of history stored is controlled with MAX_STATE_BUFFER_SIZE with a default value of 256. Meaning 256 * 100 / 1000 = 25.6 seconds of player state history is stored with default settings.

You can use the function GetPlayerStateFrame to get the player's state from a particular point in history, as long as it's within the buffer history.

This can be used to "re-play" a player's actions over the previous 25 seconds, very useful for administrative work.

Example - Positional Data

To get historical position data from a player:

new frames[MAX_STATE_BUFFER_SIZE][E_BUFFERED_STATE];
GetPlayerStateFrames(playerid, frames);

new next;
new Float:distance;
for(new i; i < MAX_STATE_BUFFER_SIZE - 1; ++i) {
    next = i + 1; // the next frame

    // add up distance of the past 25 seconds
    distance += GetDistance3D(
        frames[next][posPedX], frames[next][posPedY], frames[next][posPedZ],
        frames[i][posPedX], frames[i][posPedY], frames[i][posPedZ]
    );
}

printf("Over the last 25.6 seconds, player moved %fm", distance);

Development

The library is currently in an early stage and more states can be added easily to record a more accurate representation of a player's history. An administrative tool may also be released that's built on top of this library providing rewind/replay features for administrators to investigate potential rule breakers.

Testing

To test, simply run the package:

sampctl package run

And connect to localhost:7777 to see a demo.