Item Properties
Item properties let item models change depending on runtime conditions. Modonomicon exposes a property you can use to change a book item's model depending on whether the Modonomicon UI is open for the player.
Open state
1) Custom book item requirement
This only works when using a custom book item (an item you register yourself). It does not work with the automatically generated book item.
2) Java helper / Occultism example
Occultism demonstrates a common approach: their GuideBookItem shows how to use ModonomiconCustomItemBase to obtain the same default Modonomicon behavior on your own item. ModonomiconCustomItemBase handles the DataComponents and registers the item property for you, which is why using it is recommended.
Tip: extending ModonomiconCustomItemBase is the easiest route because it wires up the required DataComponents handling and property registration automatically.
3) Registering the item
Register your custom item as you would any other item. For reference see Occultism's item registration (their OccultismItems class) — the book item is just a normal item registration.
4) Disable auto-generated book and datagen
If you normally generate a book item from datagen, disable that generation and tell Modonomicon about your custom item. In book.json set:
"generate_book_item": false,
"custom_book_item": "<your_item_id>"
Or in datagen via the BookModel helpers:
.withGenerateBookItem(false)
.withCustomBookItem(this.modLoc("<your_item_id>"))
5) Item model: changing the model when open
Modonomicon exposes the item property modonomicon:open_state. The value is 1.0 while the Modonomicon UI is open for the player and 0.0 otherwise. Use that predicate in your item model overrides to change model when the book is open. The following example shows a green book when closed and a purple book when open:
{
"parent": "minecraft:item/generated",
"textures": {
"layer0": "modonomicon:item/modonomicon_green"
},
"overrides": [
{
"predicate": {
"modonomicon:open_state": 1.0
},
"model": "modonomicon:item/modonomicon_purple"
}
]
}
This example points at the modonomicon:item/modonomicon_purple model shipped by Modonomicon. If you want to use your own open-state model make sure the model JSON is present and loaded (register the model file or force-load it). A texture alone is not enough — Minecraft loads models, not raw textures.