4. Starting the engine

Great! Now that we are set up, let's actually make a game.

Before we start, if you want to follow the tutorial make sure again, that you added all sprites, all scripts and the object obj_htme to an empty project.

The menu

Let's create a very basic menu.

First create a new room called htme_rom_menu. For this tutorial we are keeping things very basic and we are not using any views. Set the background color to be black and the dimensions of the room to be *800600**px.

Add obj_htme to the room. This object should be created in the first room of every game you create. It is persistent and will exist even when you change the rooms.

Now create an object called htme_obj_menu. This will control our basic menu. Add it to the room we just created.

In the Draw-Event put the following code, that will simply display a message on how to proceed when starting the game:

draw_text(20,20,"Press N for new server and B to connect.");

Add two more events to it. One B-key event and a N-key event. B will join a server and N create a new one.

Starting the server

In the N-key event add the following code:

///START SERVER

//Ask player for port
var port = real(get_string("On which port should the server listen?","6510"));

//Setup server, on success start game, on failure end the game.
if (htme_serverStart(port,32)) {
    room_goto(htme_rom_demo);
} else {
    show_message("Could not start server! Check your network configuration!");
    game_end();
}

This will first ask the player on which port the server should run (of course you can also decide to specify a fixed port number).

After that it starts the server using htme_serverStart(port,maxplayers) on that port and allows a maximum of 32 players. It checks if the server is running, and if it is, it goes to the game room that we will create in a second.

Starting the client

In the B-key event add the following code:

///CONECT TO A SERVER

//Ask player for ip & port
var ip = get_string("To which server should we connect?","127.0.0.1");
var port = real(get_string("And on which port is the server running?","6510"));

//Setup client, on success go to waiting room, otherwise end game
if (htme_clientStart(ip, port)) {
    room_goto(htme_rom_connecting); //NOTE THAT WE ARE GOING TO ANOTHER ROOM HERE THAN THE SERVER ABOVE
} else {
    show_message("Could not start client! Check your network configuration!");
    game_end();
}

Now that is slightly more complicated. It asks for both ip and port and then tries to connect using htme_clientStart(ip, port).
Now instead of going to the game room when we are done, we actually want the client to go to htme_rom_connecting which is a room we are now going to create. Why? This room will display a message saying "Connecting..." and there will be an object in it that waits for the client to be connected. After that we want to go to the game room. It's like the waiting room at the doctor.

The waiting room htme_rom_connecting

Create a room called htme_rom_connecting that is just like the first one (but without the objects in it). Now create the object htme_obj_waitforclient and place it into the room.

In the Draw event put the following code:

draw_text(20,20,"Connecting...");

This will display the message "Connecting..." after the player decided to start the client.

In the Step-Event put the following:

///Check if client is connected
if (htme_clientIsConnected()) {
    room_goto(htme_rom_demo);
}
if (htme_clientConnectionFailed()) {
    show_message("Connection with server failed!");
    game_restart();
}

The first statement used the htme_clientIsConnected() function to check if the client is... well connected. If so, we can finally go to the game room.
If the global timeout has been reached, the engine gives up to conect. In this case the second if-Statement is activated which uses htme_clientConnectionFailed() to check if the connection failed. In our example it will simply restart the game.

This waiting room is just an example and you can use different techniques to display a waiting... message.

Connection done!

Theoretically, we could now play the game. Of course, there is no game. The game will crash if we try to start a server because our game room htme_rom_demo does not exist.

For now, create an empty room just like you did before and call it htme_rom_demo.

Now, when you fire up your game twice, you should be able to start a server on one game, which should lead you to the empty room.

On the other game you should be able to connect to this server by connecting to the ip 127.0.0.1. If it was successfull, the "Connecting..." message should disappear, and you'll find yourself in the same empty room as the server. Yay!

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