Left 4 Voting 2

Left 4 Dead 2 has a VGUI voting system controller by a bunch of Events and UserMessages. You can use either a string from the resource file, or L4D_TargetID_Player which will let you create any vote you want.

How voting works

1. A client issues a callvote with the vote type and argument.
2. The VoteStart User Message is sent.
3. Clients use the "Vote" command to register their votes ("Yes" or "No"), after which the server sends a VoteRegistered UserMessage to that player to acknowledge their vote. A vote_changed event is sent to all players with updated numbers.
4. When the vote is complete, the server sends either a VotePass or VoteFail UserMessage.

Console Commands

Vote

Note: This command is only valid when a vote is ongoing.

Name:	Vote
Structure:	string option "Yes" or "No"

User Messages

Note: These user messages use unsigned bytes for the team number. Since Valve represents no team as -1, no team is instead represented as its two's complement, 255.

VoteStart

Note: Sent to all players in the vote group, corresponding with teams. The default implementation also sends it to bots.

Name:	VoteStart
Structure:	byte team Team index or 255 for all byte initiator Client index (NOT USERID) of person who started the vote, or 99 for the server. string issue Vote issue translation string string param1 Vote issue text string param1 Name of person who started the vote

VoteRegistered

Note: Only sent to player who voted

Name:	VoteRegistered
Structure:	byte vote 0 for No, 1 for Yes

VotePass

Note: Sent to all players after a vote passes.

Name:	VotePass
Structure:	byte team Team index or 255 for all string details Vote success translation string string param1 Vote winner

VoteFail

Note: Sent to all players after a vote fails.

Name:	VoteFail
Structure:	byte team Team index or 255 for all

Events

Note: team is -1 when sent to all players)

vote_changed

Name:	vote_changed
Structure:	byte yesVotes byte noVotes byte potentialVotes

Example voting plugin

This is a basic plugin that starts a vote, "Is gaben fat?". It does not ensure the same client does not vote multiple times, nor does it actually kick the user.

#include <sourcemod>

#define L4D2_TEAM_ALL -1

new yesvotes;
new novotes;
#define MAX_VOTES 4

public OnPluginStart()
{
	RegConsoleCmd("testvote",Callvote_Handler);
	RegConsoleCmd("Vote",vote);
}
public Action:Callvote_Handler(client, args)
{
	new Handle:bf = StartMessageAll("VoteStart", USERMSG_RELIABLE);

	BfWriteByte(bf, L4D2_TEAM_ALL);
	BfWriteByte(bf, 0);
	BfWriteString(bf, "#L4D_TargetID_Player");
	BfWriteString(bf, "Is gaben fat?");
	BfWriteString(bf, "Server");
	EndMessage();
	
	yesvotes = 0;
	novotes = 0;
	UpdateVotes();
	
	return Plugin_Handled;
}
public UpdateVotes()
{
	new Handle:msg = CreateEvent("vote_changed");
	SetEventInt(msg,"yesVotes",yesvotes);
	SetEventInt(msg,"noVotes",novotes);
	SetEventInt(msg,"potentialVotes",MAX_VOTES);
	FireEvent(msg);
	
	if (yesvotes+novotes == MAX_VOTES)
	{
		PrintToServer("voting complete!");
		if (yesvotes > novotes)
		{
			new Handle:bf = StartMessageAll("VotePass");
			BfWriteByte(bf, L4D2_TEAM_ALL);
			BfWriteString(bf, "#L4D_TargetID_Player");
			BfWriteString(bf, "Gaben is fat");
			EndMessage();
		}
		else
		{
			new Handle:bf = StartMessageAll("VoteFailed");
			BfWriteByte(bf, L4D2_TEAM_ALL);
			EndMessage();
		}
	}
}
public Action:vote(client, args)
{
	new String:arg[8];
	GetCmdArg(1,arg,8);
	PrintToServer("Got vote %s from %i",arg,client);
	if (strcmp(arg,"Yes",true) == 0)
	{
		yesvotes++;
	}
	else if (strcmp(arg,"No",true) == 0)
	{
		novotes++;
	}
	
	UpdateVotes();
	return Plugin_Continue;
}

See Also

• Left 4 Voting
• TF2 Voting
• BuiltinVotes, a SourceMod extension that exposes a voting API that uses this voting system.