Difference between revisions of "Programming Guide"

Revision as of 02:55, 13 March 2018

Programming in Space Engineers is done with the Programmable Block which can be given scripts written in C# (pronounced C Sharp). This can be used to make autonomous mining drones, long-range player-killing torpedoes, automated welding arms for ship construction and much more.

Introduction

Editor access

Only one player can edit the same script at time. If someone else has an editor for the current block open and someone else tries to open that block's editor, a notification will be shown that the editor is already open.

Main method

When the editor is opened for first time, void Main() method is present inside the code editor. This is entry point that will be called when executing script. If Main method is removed / renamed, the script will not run and you will be notified in the programmable block details area. Custom methods/variables can be defined and used, but only the Main method will be called without reference.

Variables life

There are two types of variables for scripting: Local (inside the methods) – these variables will keep their value only during execution of a method. Value will be “lost” when the method ends. Global (outside the methods) - these variables will keep their values during the lifetime of script. E.g. If the variable needs to keep value between separate runs of program, it needs to be defined outside the methods. After pressing “Remember & Exit” or “Remember” buttons, the previous script will be overwritten and all Global variables will be lost. All variables, local and global except for the built-in Storage variable will lose their value or return to their default value when recompiling the code and between saved game loads. The Storage variable is unique in that that it store data as string between saved seasons and recompile.

Compiling

When the “Check code” button is pressed, the code will be compiled and the result of the compilation will be shown. There are two steps of the compilation process: First the code inside editor is compiled by c# compiler for language errors. If there are any errors during compilation the following dialog is shown: It this case “aaa” string is placed before Main method. This is the wrong language construction and the compilation failed. In the error dialog the Line number error and description of the error is shown.

After compilation, the code is checked for usage of disallowed namespaces and types. In case that check fails, the following dialog is shown: In this case System.IO.Directory was used to delete some directory. This is forbidden and error is shown that “Not allowed type was used in script”.

If compilation and checks pass, a dialog is shown, confirming the checks passed, and the code is saved.

Script execution

When “Run” button is pressed or “Run” is assigned as terminal action, script is executed. Currently “Run” needs to be called manually e.g. user need to click on “Run” button or attach it as terminal action. Script is executed only on server even if it’s triggered from client. If there is any exception during script execution, all clients will be notified in programmable block details area about failure. In case of exception during script execution, script will not run again unless User opens editor and change script. A timer can also continuesly run the script by having a run action (you may be prompt to input an argument) and then starting/triggering itself or being started/triggered via script code (if going by the letter the timer will stop if the script crash).

Counting of instructions

Every time script is executed, every instruction of script is counted. If script executes more instruction than limit, execution is stopped and user is notified that script is too complex for execution. This prevents scripts to “freeze” game.

Whitelist

The types and classes allowed in scripts are restricted. Refer to the Scripting Whitelist to see what you are allowed to use.

Available interfaces

Possible Actions

Currently only terminal actions can be triggered inside scripts. User can access terminal system for grid on which programmable block is located and trigger any terminal action on any block at grid.

• API List

Block Classes (Action List)

• Block Action List

Same block class for different SubTypeID

Some blocks have same parent (e.g. <TypeId> in cubeblocks.sbc) and differs only by subtype (e.g. <SubtypeId>). This means there is no distinction between these block in code.
Example of these blocks is the Cargo Container: there are 3 types of cargo containers in the game: small, medium and large. These three types differ only by subtype and Type is same for them e.g. large cargo container id is:
<Id>
<TypeId>CargoContainer</TypeId>
<SubtypeId>LargeBlockLargeContainer</SubtypeId>
</Id>
Medium is:
<Id>
<TypeId>CargoContainer</TypeId>
<SubtypeId>SmallBlockMediumContainer</SubtypeId>
</Id>
And small is:
<Id>
<TypeId>CargoContainer</TypeId>
<SubtypeId>LargeBlockSmallContainer</SubtypeId>
</Id>

In this case there is only one class IMyCargoContainer for all types of cargo containers.

Example programs

Hello world

The standard Hello World program in Space Engineers can be written as such:

public void Main()
{
   Echo ("Hello, world!");
}

If this program is entered into a programmable block and run, it will result in "Hello, world!" being displayed in the programmable block's interface on the lower right hand side of the screen.

Getting your position

This program will show the current GPS coordinates of your programming block's position in the world.

public void Main()
{
    var pos = Me.GetPosition();
    Echo (pos.ToString());
}

Checking a sensor

It's easy to get a sensor to open a door or trigger some other action even without any programming if you just place that action in the sensor's "Setup actions" list. However, triggering an action when a sensor does not detect something is more difficult, and cannot be done with timer blocks. This program will automatically check a sensor every 10 ticks (working out to about 6 times per second) and close a door if the sensor does not detect anything. This can easily be applied to other purposes, like turning off drills when asteroids are not in sensor range.

List<MyDetectedEntityInfo> entity_list = new List<MyDetectedEntityInfo>(); 
public Program()
{
    Runtime.UpdateFrequency = UpdateFrequency.Update10;
    //This makes the program automatically run every 10 ticks.
}
public void Main()
{
    var door_sensor = GridTerminalSystem.GetBlockWithName("Door Sensor 1") as IMySensorBlock;
    door_sensor.DetectedEntities (entity_list);
    if (entity_list.Count == 0)
    {
        var door = GridTerminalSystem.GetBlockWithName("Door 1") as IMyDoor;
        door.ApplyAction ("Open_Off");
    }
}

For this script to work, the sensor must be named "Door Sensor 1" and the door must be named "Door 1". If you configure the sensor to open the door, the door will automatically open when the player enters the sensor range and close when the player leaves the sensor range.

Compilation errors

This is a list (in progress) of known compilation errors and what causes them.

• Method name expected: The compiler found parentheses when it wasn't expecting them. You could be missing a method name before the parentheses, or you might be inappropriately using parentheses instead of square or curly brackets, depending on what you're trying to do.

External links

• [Guide] Programmable Block - C# 101 For Space Engineers - Basic intro to C# programming for Space Engineers.
• [Guide] Programmable Block - C# 102 for Space Engineers: Loops, Strings, and Other Things - Basic intro to using loops and strings in C#
• [Guide] Programmable Block - C# 103 for Space Engineers - Math Class - Basic intro to using the Math library in C#
• Programmable Block Inter-Grid Communication Guide - Using antennas to enable programming blocks to remotely communicate with each other.
• Continuous Running No Timers Needed - Configuring programming blocks to run automatically without needing to use a timer.
• Tutorial: Constructor And Save - Saving and reloading data
• C# Operators - C# language reference for all operators, such as and, or, greater than, less than, etc.
• Space Engineers API documentation