Difference between revisions of "Viewer Architecture"

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{{OSWikiLearnBox}}
{{OSWikiLearnBox}}
[[Category:Viewer Architecture]]
[[Category:Viewer Architecture]]
[[Category: AW Groupies]]


The Second Life client (also known as the "viewer") is a complex piece of software. It can be visualized as a streaming media client like RealPlayer, a game engine like Quake 3, or a web browser.
The Second Life client (also known as the "viewer") is a complex piece of software. It can be visualized as a streaming media client like RealPlayer, a game engine like Quake 3, or a web browser.
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* [[Adding a menu item]]
* [[Adding a menu item]]
* [[Adding a dialog]]
* [[Adding a dialog]]
* [[Adding a cursor]]
* [[How movement works]]
* [[How movement works]]
* [[How the camera works]]
* [[How the camera works]]
* [[How login works]]
* [[Login_Protocol|How login works]]
* [[Hegemons Login Analysis]]
* [[Hegemons Login Analysis]]
* [[How keyboard processing works]]
* [[How keyboard processing works]]
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== Major Systems ==
== Major Systems ==
* [[Animation]] - avatar motions
* [[Asset System]] - transport for animations, sounds, notecards, scripts, etc.
* [[Asset System]] - transport for animations, sounds, notecards, scripts, etc.
* [[Avatar Appearance]] - appearance is constructed from a mesh, parameters to deform the mesh, and textures to describe clothing
* [[Avatar Appearance]] - appearance is constructed from a mesh, parameters to deform the mesh, and textures to describe clothing
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* [[Image System]] - prioritizes and decodes JPEG2000 images into OpenGL textures
* [[Image System]] - prioritizes and decodes JPEG2000 images into OpenGL textures
** [[Texture cache]] - used for reading and writing texture data to the local disk cache  
** [[Texture cache]] - used for reading and writing texture data to the local disk cache  
* [[Inventory]] - server-side storage of assets for each user
** [[Image Pipeline]] - fetches textures from the servers and decodes them
* [[Inventory OS|Inventory]] - server-side storage of assets for each user
* [[L$ System]]
* [[L$ System]]
* [[LLMedia API]] - arbitrary media on object surfaces
* [[Message System]] - reliable and unreliable transport over UDP
* [[Message System]] - reliable and unreliable transport over UDP
* [[Movie System]] - QuickTime-based video on object surfaces
* [[Muting Objects and Agents]] - How the viewer manages the muted object list  
* [[Muting Objects and Agents]] - How the viewer manages the muted object list  
* [[Rendering System]] - from viewer object to drawable to face to vertices to graphics card
* [[Rendering System]] - from viewer object to drawable to face to vertices to graphics card
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# Shutdown
# Shutdown
One way to see what goes on in the main loop is to bring up the debug menus (Ctrl-Alt-D) then Client->Consoles->Fast Timers (or Ctrl-Shift-9) and expand the entries in the caption.
One way to see what goes on in the main loop is to bring up the debug menus (Ctrl-Alt-D) then Client->Consoles->Fast Timers (or Ctrl-Shift-9) and expand the entries in the caption.
:see also: [[AW_Groupies#Communications| AW Groupies protocol and login documentation links]]
=== Startup and initalisation ===
(updated for 1.20.14 code)
The main() function for the viewer exists in either llappviewerlinux.cpp, llappviewerwin32.cpp or llappviewermac.cpp depending on your platform. This creates the instance of LLAppViewerLinux, LLAppViewerWin32 or LLAppViewerMac which all are derrived from LlAppViewer. The initial platform dependent code sets up the various error handlers to handle a viewer exception (crash condition). The reset of the platform dependent appviewer classes are related to crash handlers.
The initialization then occurs in LLAppViewer::init() this is the real low level setup and class creation and does things including :-
* Sets up application directory locations
* Sets up logging
* loads configuration
* sets up Curl
* Creates worker threads
* Creates the LLUI system
* loads saved/default settings
* initalises the cache system
* sets up the viewer window
* Checks the CPU type and features
* checks memory and graphics card
* Initalises joystick
Then the LLAppViewer::mainloop() is started


== Sources of Input ==
== Sources of Input ==
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* Known [[defines]]
* Known [[defines]]
* [[Godmode]] - what Lindens can do
* [[Godmode]] - what Lindens can do
== See also ==
*  [[Viewer Roadmap]] - how everything you read here could be changing or might have already changed.
*  [[Viewer Software Overview]] - where to find things in the source code
*  [http://developer.dimentox.com/ Viewer 2 Doxygen]

Latest revision as of 20:03, 26 March 2011

The Second Life client (also known as the "viewer") is a complex piece of software. It can be visualized as a streaming media client like RealPlayer, a game engine like Quake 3, or a web browser.

First you'll need to learn some terminology like "agent", "sim", and "region" in the glossary.

Learn by Example

Major Systems

Threads

The viewer is a single process with a few threads:

  • Main thread -- The input/output main program function (including rendering).
  • VFS thread -- Thread responsible for reading/writing to the local virtual file system.
  • LFS thread -- Thread responsible for some reading/writing to the local native file system.
  • Image thread -- Thread responsible for requesting and decoding image data
  • Error Thread -- Thread responsible for catching exceptions, calling the (currently unused?) error handler, and retiring
  • Worker Threads -- Threads designed to do cpu intensive background tasks
    • These threads may be paused during rendering so as not to reduce performance (design in-progress)

Program Flow

  1. Initialize - newview/viewer.cpp :: main()
  2. Loop - newview/viewer.cpp :: main_loop()
    • Gathers keyboard and mouse input
    • Pumps the TCP i/o
    • idle()
    • Render the frame
    • let filesystem and worker threads process
  3. Shutdown

One way to see what goes on in the main loop is to bring up the debug menus (Ctrl-Alt-D) then Client->Consoles->Fast Timers (or Ctrl-Shift-9) and expand the entries in the caption.

see also: AW Groupies protocol and login documentation links

Startup and initalisation

(updated for 1.20.14 code)

The main() function for the viewer exists in either llappviewerlinux.cpp, llappviewerwin32.cpp or llappviewermac.cpp depending on your platform. This creates the instance of LLAppViewerLinux, LLAppViewerWin32 or LLAppViewerMac which all are derrived from LlAppViewer. The initial platform dependent code sets up the various error handlers to handle a viewer exception (crash condition). The reset of the platform dependent appviewer classes are related to crash handlers.

The initialization then occurs in LLAppViewer::init() this is the real low level setup and class creation and does things including :-

  • Sets up application directory locations
  • Sets up logging
  • loads configuration
  • sets up Curl
  • Creates worker threads
  • Creates the LLUI system
  • loads saved/default settings
  • initalises the cache system
  • sets up the viewer window
  • Checks the CPU type and features
  • checks memory and graphics card
  • Initalises joystick

Then the LLAppViewer::mainloop() is started

Sources of Input

User Guides

See also