Function Preload

It does two things:

1. Try to read the file, if "Allow Local Files" is enabled then also searches in the game folder
2. Append filename to preload buffer

Note

The game only reads these files, does not load them. The reading is done in a separate thread and does not freeze the game. One file is not read twice, no matter how often you call Preload().

Note

Trick: It does not escape double-quotes " on purpose (approved not a bug, it's a feature). It is possible to inject custom code in Preload files this way (Lua):

PreloadGenClear()
PreloadGenStart()
Preload(' ")\ncall otherFunction("123")\n//')
PreloadGenEnd("its-a-feature.txt")
Copy

Results in the following preload file code (Jass):

function PreloadFiles takes nothing returns nothing
 
        call PreloadStart()
        call Preload( " ")
call otherFunction("123")
//" )
        call PreloadEnd( 754.6 )
 
endfunction
Copy

Note

Game folder: Reforged: Warcraft III\_retail_\somefile.txt, instead of _retail_ there's also a _ptr_ game version currently. Classic: ?

Note

Mini tutorial:

What are Preload files?

Preload files instruct the game to pre-read a file/resources to avoid freezes/stutter during gameplay. It's done to move the file into OS cache. Blizzard used preload files to load all required files at map init. See blizzard.j or campaign maps.

Create a preload file (Lua)

PreloadGenClear()
PreloadGenStart()
-- call Preload("filename.ext") as often as you need, one call per file you add
Preload("Textures\\Knight.blp")
PreloadGenEnd("MyPreloadFile.txt")
Copy

How to run a preload file

This must be done manually:

Preloader("MyPreloadFile.txt")
Copy

Lua code in preload files?

It is possible although in a very hacky way, described here. You need to use "//! beginusercode" to start a section containing Lua code and end it using "//! endusercode". It works because the code is compiled on the fly with Jass2Lua.

Note

See: PreloadEnd, PreloadStart, PreloadRefresh, PreloadEndEx, PreloadGenClear, PreloadGenStart, PreloadGenEnd, Preloader.

Note

Also see the documentation for Preloader for more info on the generated files.