Playing Multiplayer Tag in FlexSim! TagServer.fsm TagClient.fsm This is a side project to show off some fun things FlexSim can do using sockets. Sockets are just one possible way that one instance of FlexSim can communicate with another. In its simplest sense, a socket is just a port number and an IP address that computers use to send information to each other. For example, whenever a computer visits a website, it uses sockets to create a connection to the webserver's IP address on port 80 (HTTP) or port 443 (HTTPS). All of this occurs within the framework of the TCP/IP network. Similarly, FlexSim can establish socket connections to communicate with another FlexSim as long as you know the IP address and choose a port for both instances to connect on. Establish Socket Connection In this game of tag, the model that acts as the server uses these commands to set up socket connection with the client: socketinit(); servercreatemain(8002); serveraccept(0); Note: All of the commands in this article can be found in the documentation The client then runs the following to connect to the server. The HostIP should be the IP address of the device running the server model (or 127.0.0.1 if running both client and server on the same machine). socketinit(); int a = clientcreate(); int a_con = clientconnect(a, HostIP, 8002); On both the client model and server model, these commands are in the OnRunStart trigger and the server creates 5 socket connections for each player. 4 for inputs (up, down, left, right) and 1 for passing in their player name from the client. The server model will freeze and wait for all sockets to be set up. For example, if there are 3 players, the server model will wait until 3 clients have successfully ran the client model and connected. After all clients have connected to the server, we can use clientsend() and serverreceive() to send information from client to server. An example of this is sending movement inputs from client to server. This is what that looks like: Client // MOVE if (iskeydown(87)){ clientsend(2, "up"); } if (iskeydown(83)){ clientsend(3, "down"); } if (iskeydown(65)){ clientsend(4, "left"); } if (iskeydown(68)){ clientsend(5, "right"); } Server string up1 = serverreceive(token.Rank * 5 - 3, NULL, 100, 1); string down1 = serverreceive(token.Rank * 5 - 2, NULL, 100, 1); string left1 = serverreceive(token.Rank * 5 - 1, NULL, 100, 1); string right1 = serverreceive(token.Rank * 5, NULL, 100, 1); // token.Rank is the number of the player (1,2,3 etc.) and is used to reference the right // socket for each player's inputs //reset coordinates te.X = 0; te.Y = 0; te.Stop = 0; if (up1 != ""){ // up W meaning the server received an input on this socket te.Y = 1; // this accounts for getting multiple messages from client like "upupup" } if (down1 != ""){ // down S te.Y = -1; // this label is later used in a travel activity } if (left1 != ""){ // left A te.X = -1; } if (right1 != ""){ // right D te.X = 1; } Note: In a typical game environment, the server is also sending information back to the clients, but in this example, all visuals and logic occur on the server. Game Logic All game logic is found on the server process flow. Setup and Order of Models To play Tag, follow these steps: Note: If there are certain firewalls or security groups on your network that doesn't allow traffic into FlexSim outside local networks you may be limited on who can connect to play tag 1. Open TagServer model and change NumPlayers parameter to the desired number of players 2. Open TagClient model and change both global variables (HostIP and EnterNameHere). Again, if everything is running on the same device, use 127.0.0.1 as the HostIP global variable value. 3. Reset and Run the TagServer model first 4. Reset and Run the TagClient model. You should get this output if connection was successful 5. Run clients one at a time for each player until all players have connected and the server will run automatically. This is the output on the server upon successful connection 6. Enjoy!

Introducing FlexSim Galaga! GALAGA.fsm This is an example of how a game could be made in FlexSim. Feel free to download the model and try it out (FlexSim Version is 23.1). Or if you are interested, see below for how the game works. How it works FlexSim Galaga uses Process Flow to perform all logic that occurs in the game. It also takes advantage of Global Variables to keep track of game data as the game is played. This allows one token to set a variable, for example WaveCounter, and that same value can be referenced anywhere in the model. Player Movement and Inputs I used the function iskeydown() for all player inputs. A token loops through a Custom Code activity that continuously checks for which keys are being pressed and makes the corresponding changes in the model. An example of this for player movement looks like this: if (iskeydown(65) && te.location.x > -90){ // left A te.location.x = te.location.x - 10; } if (iskeydown(68) && te.location.x < 90){ // right D te.location.x = te.location.x + 1 For shooting, similar code is written and assigns a label to the player. This label is used for the token to act differently depending on what the player has bought from the shop. The shop inputs are similar and check if the player has enough money for the selected item in the shop. (See the process flow activities 'Shoot Inputs' and 'Shop Inputs' for how this is done.) Wave Health and Speed As the game plays out, waves get more difficult and arrive faster. Each enemy ship has a certain health value and money value that the player earns when destroying it. These values come from the Global Table WaveHealth. After 50 waves, this table is repeated to spawn new waves. This can go on forever in Endless Mode or this table can be modified during the Model run by buying Extreme Mode. The game starts with Waves that last 20 seconds. To make the waves arrive faster over time, this code lowers the WaveDuration from 20 to 15 to 10 etc. every 12 waves. 5 seconds is the fastest wave time and doesn't get any faster. if (WaveCounter % 12 == 0){ if (WaveDuration > 5){ WaveDuration = WaveDuration - 5; } } Enemy Ships and "Collision" Logic When enemy ships are created, they are added to a Global Map called ColShipMap. The key is the column number the ship is in (1-20) and the value is an array of all ships in that column. This makes it easy to check if a shot has hit a ship. While shots are moving the token they are associated with constantly checks the distance between the shot and any ships in that column (thanks to ColShipMap). The column the shot belongs to is calculated based on the x location of where it is created. When the distance between the shot and a ship in that column is close enough, labels are changed on the token so the game knows which ship was hit and to decrease the health or destroy the object entirely. double x = token.shot.getLocation(1, 0, 0).x; // inverse of token.item.location.x = ((index - 1) * 10) - 95; int index = (x + 95) / 10 + 2; token.Index = index; Array spaceships = ColShipMap[index]; Vec3 shotPos = token.shot.as(Object).getLocation(0.5, 0.5, 0); for (int i = 1; i <= spaceships.length; i++){ double spaceshipY = spaceships.location.y; if (Math.fabs(spaceshipY - newY) < 2) { token.Hit = 1; token.target = spaceships; token.SpliceIndex = i; break; } } Display There are several Billboard objects in the model that toggle depending on the state of the game. (switch_hideshape() is used to make them appear like they are flashing) Feel free to look in the process flow for when these occur, but the overall purpose is to inform the player of what is happening in the game. Note: If you zoom out and want to re-center the model for an optimal display. Open properties and click on the view called 'Menu.' Then close the properties window. All other windows like the Toolbox are closed to make game visuals better. Feel free to look into the Process Flow or Model Triggers for anything I didn't mention. Enjoy!