Multi-Threading XNA GameComponents

1
votes

I am developing an XNA project, where there are two DrawableGameComponents A and B, with the following constraints:

  • Either A is visible, or B is visible. So only one of their "Draw" methods has to be called.
  • Both A and B need to be enabled - always. So the "Update" method of each has to be called under all circumstances.

Currently both A and B are executed in the same thread. However, the "Update" methods of them are very CPU-Intensive. Since both GameComponents do not need to talk to each other, and both GameComponents do not need to share any data, it is easily possible to parallelize them.

What I would like to know is how to do that in XNA. The "Update" and "Draw" methods are called by the XNA Framework, so I do not know where to put the Threads. Is there a standard way of doing this?

2
multithreadingxna
multi threading is mildly different on the xbox360 than a PC. it would have to be coded a little differently depending. Is this targeting either one or the other or both? Also, if it is for PC, you have no garrantee that the user has a multi core CPU. If they have a single core CPU, multi threading will probably cost time, not save it. - Steve H
the target machine is a PC only. The project is not a game and there will only be one machine with a lot of cores executing it, so there is no problem with multi-threading in general. - Christian

2 Answers

1
votes

Usually this is done through game state managment, where the Game1 class (default class) is used to call the Update() and/or Draw() of other classes (game components)

Take a look at the xnadevelopment game state managment tutorial, their they describe how to call diffrent updates and draws of different classes, and hopefully u'll see that multi-threading can be implemented in the Game1 class (default auto-created XNA class)

p.s. if you dont mind doing a lot of reading take a look at this article on XNA multi threading, its accompanied by some diagrams that explain how it works very well.

0
votes

You haven't specified if you need both Update's to run simultaneously so I'm going off the assumption that one component is the only that needs to be drawn.

Using DrawableGameComponents they are automatically synced with your Game object, but, if you store a reference to each component instead of instantiating them without a stored reference, such as:

componentOne = new FirstComponenet(this);
Components.Add(componentOne);
componentTwo = new SecondComponent(this);
Components.Add(componentTwo);
// Immediately disable componetTwo
componentTwo.Enabled = false; // Prevents Update from firing
componentTwo.Visible = false; // Prevents Draw from firing (for Drawable components only)

Then you can let XNA manage the Update/Draw loops as per normal. componentOne and componentTwo being class level variables, you can manage when each are active.

Again, this is based on the assumption that you don't need one to update at the same time the other does.