Using preloaders
First you have to prepare your themes as it was described in the previous chapters. There is nothing specific about preloaders in theme preparation.
Installing preloaders
There is no theoretical limit to the number of preloaders you can use. All preloaders are exact copies of the same script called T-O-M Preloader shipping with the Theme-O-Matic since version 2.0.
To install a new preloader, you just have to drag one copy of the T-O-M Preloader from your inventory to your object's contents.
The preloader scripts must all have unique names in the object's inventory but the viewer normally takes care of adding an appropriate suffix so you don't have to worry about this. Dropping several copies you will get "T-O-M Preloader", "T-O-M Preloader 1", "T-O-M Preloader 2", etc. The actual script name has no importance, as long as it is unique.
Once your preloaders are installed, install the T-O-M Core script and it will automatically assign every preloader a unique ID, which is a number starting from 1. This number will be useful for client scripts to refer to preloaders.
Note: if you added or removed preloaders since you installed the T-O-M Core, it is necessary to re-assign the preloader IDs. Do do this you can either:
remove the T-O-M Core script and add it again from your own inventory, or
add the T-O-M DEV Reset script, whose job is to send a RESET signal to the T-O-M Core and remove itself from the object's inventory.
An example setup with 12 preloaders
Theme auto-loading
Principle
It is normally the job of the client script to tell each preloader which theme it should (pre)load and when to apply it.
In order to keep things as simple as possible for creators, an auto-load feature was added inside the T-O-M Preloader script. Here auto-load means that, as soon as it gets its unique ID assigned by the T-O-M Core script, the preloader looks if it can find in the prim's inventory a notecard named "AutoT #n" where n is the number equal to the preloader's ID. If it can find it then it attempts to preload this notecard as a theme immediately.
Example
For example, say you have 4 themes that you want to be ready as soon as possible through the usage of 4 preloaders. Then:
step 1: name your theme notecards AutoT #1, AutoT #2, AutoT #3, AutoT #4 ;
step 2: add four copies of the T-O-M Preloader script into your object ;
step 3: add the T-O-M Core script and an appropriate client script.
It is important that the T-O-M Core be added last since it will give the "start" signal to preloaders and coordinate the whole process. If you need to add another preloader, you can remove the T-O-M Core, add your new preloader, and add the T-O-M Core again. Alternatively, you can have your client script send a reset signal to the T-O-M.
Spelling!
Please note that:
notecard naming is case-sensitive : it's "AutoT #1", not "autot #1"
spaces and other invisible characters matter! You need one space between AutoT and the hashtag, nowhere else.