Difference between revisions of "4/Threading"

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(One True Event Loop)
 
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{{ParentArticle|[[4]]}}
 
{{ParentArticle|[[4]]}}
  
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=== Arguments ===
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=== Threading ===
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* Having the game engine run in its own thread is a huge plus by itself. Game lag won't have to also mean UI lag.
 
* Having the game engine run in its own thread is a huge plus by itself. Game lag won't have to also mean UI lag.
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* Having logic and user interface run in separate threads allows simple usage of modal dialogs, e.g. message boxes (you don't have to specify class-level callbacks, but rather call a function and check the return value, like with the Windows MessageBox API)
 
 
* Combining SDL and network event loops in a single thread would be complicated.
 
* Combining SDL and network event loops in a single thread would be complicated.
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=== Notes ===
 
 
* Fibers would solve synchronization and modality problems, unfortunately they are not very portable and not currently implemented in D. (It's still possible to use them using OS primitives.)
 
* Fibers would solve synchronization and modality problems, unfortunately they are not very portable and not currently implemented in D. (It's still possible to use them using OS primitives.)
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* Using modal dialogs does not allow more than one independent modal dialog per thread, because dialogs must be closed in the reverse order they're opened due to the order of the thread's call stack. This implies that modal dialogs ''must'' be modal for the entire thread. Thus:
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{{gap}}
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** Every window which wants to display modal dialogs must have its own thread, or
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* Use a single thread for event handling. Long-running synchronous tasks (such as the game engine) will run in separate threads.
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** Modal dialogs are app-modal, or
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* SDL and network event loops run in separate threads, sending messages to event handling thread?
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** Modal dialogs are not used.
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** How does the network thread handle ''sent'' data?
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*** Not using modal dialogs isn't so bad in D, considering that it supports anonymous functions (lambdas). The code could look something like: <br><code>MessageBox("Are you sure you want to overwrite this file?", (MessageBoxResult r) { if (r == MessageBoxResult.OK) saveFile(); } );</code>
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** Is this a good idea for single-core CPUs?
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=== Modality ===
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''Here, "modal" means "the call to show this dialog is blocking, and the calling code will resume running only after said dialog is closed". Confirmation message boxes are an example.''
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* Modal dialogs will not be used.
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** Not using modal dialogs isn't so bad in D, considering that it supports anonymous functions (lambdas). The code could look something like: <br><code>MessageBox("Are you sure you want to overwrite "~fileName~"?", (MessageBoxResult r) { if (r == MessageBoxResult.OK) saveFile(fileName); } );</code>
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=== Display list ===
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* Constructing the display list is a fairly cheap operation. The game engine should construct its display list (or meta-display list, since some visual elements do not depend on game logic) after every logic frame.
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** Tweened rendering..?
  
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=== Questions ===
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== External links ==
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* Level of separation of individual UI windows?
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* [http://gamedev.stackexchange.com/questions/8765/one-true-event-loop One True Event Loop] on Game Development StackExchange
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* When, and in which thread does the game's display list (scene) get constructed?
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** Retained mode, for better hardware-accelerated performance?
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*** OpenGL doesn't seem to support retained mode rendering, but Direct3D does
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* How much will threading / message passing affect performance, compared to a single-threaded solution?
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Latest revision as of 17:30, 8 March 2011

(Up to 4)

Threading

  • Having the game engine run in its own thread is a huge plus by itself. Game lag won't have to also mean UI lag.
  • Combining SDL and network event loops in a single thread would be complicated.
  • Fibers would solve synchronization and modality problems, unfortunately they are not very portable and not currently implemented in D. (It's still possible to use them using OS primitives.)

 

  • Use a single thread for event handling. Long-running synchronous tasks (such as the game engine) will run in separate threads.
  • SDL and network event loops run in separate threads, sending messages to event handling thread?
    • How does the network thread handle sent data?
    • Is this a good idea for single-core CPUs?

Modality

Here, "modal" means "the call to show this dialog is blocking, and the calling code will resume running only after said dialog is closed". Confirmation message boxes are an example.

  • Modal dialogs will not be used.
    • Not using modal dialogs isn't so bad in D, considering that it supports anonymous functions (lambdas). The code could look something like:
      MessageBox("Are you sure you want to overwrite "~fileName~"?", (MessageBoxResult r) { if (r == MessageBoxResult.OK) saveFile(fileName); } );

Display list

  • Constructing the display list is a fairly cheap operation. The game engine should construct its display list (or meta-display list, since some visual elements do not depend on game logic) after every logic frame.
    • Tweened rendering..?

External links

Retrieved from "https://worms2d.info/?title=4/Threading&oldid=18581"
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