Blender_bevy_components_workflow/tools/blenvy/README-components.md

# Components

## Supported components

- normally (minus any bugs, please report those!) all components using **registered** types should be useable and editable
- this includes (non exhaustive list):
  * enums (even complex ones !)  
  * complex structs, with various types of fields (including nested ones)
  * lists/ vecs
  * hashmaps
  * etc !

![suported types](./docs/components_suported_types.png)

## Supported items for components

you can add components to 
  - objects 
  - collections/ blueprints
  - meshes
  - materials

These will be all applied correctly to the resulting entities on the Bevy side

### Blueprints & components:

- to add components to a blueprint, select your blueprint's collection and add the desired component

![blueprint components](./docs/components_blueprints.png)

- when you select a blueprint/collection **instance** you can view both the **blueprint** level components (for all instances) ...

![blueprint components](./docs/components_blueprints_blueprint.png)


- and the components specific to that **instance**

![blueprint components](./docs/components_blueprints_instance.png)


> if the instance and blueprint have the same component, the component value of the **instance** takes precedence & overwrites that of the blueprint ! In the case above, the component will have the value ```Metal``` for that instance.

## adding components

- to add a component, select any object, collection, mesh or material and then select the component from the components list: (the full type information will be displayed as tooltip)

- click on the dropdown to get the full list of available components

![components list](./docs/components_list.png)

- the list of components is searchable !

![filter components](./docs/components_search.png)

- add a component by clicking on the "add component" button once you have selected your desired component

![add component](./docs/components_add.png)

  it will appear in the component list for that object

![add component](./docs/components_add2.png)


## editing components

- to edit a component's value just use the UI: 

![edit component](./docs/components_edit.png)


## copy & pasting 

- you can also copy & paste components between objects/collections/meshes/materials

- click on the "copy component button" of the component you want to copy

![copy component](./docs/components_copy.png)

- then select the item you want to copy the component (& its value) to, and click on the paste button.

It will add the component to the select item

![paste component](./docs/components_paste.png)

> if the target item already has the same component, its values will be overwritten


## Toggling component details

- for large/ complex components you can toggle the details of that component:

![toggle details](./docs/components_details.png)


## Error handling & unregistered types

- if you have a component made up of unregistered structs/enums etc, you will get visual feedback & the component will be deactivated

    ![invalid component](./docs/components_invalid.png)

  > see [here](#renamingupgradingfixing-components) for ways to convert invalid / unregistered components to other types.


- if you are encountering this type of view: don't panic your component data is not gone ! It just means you need to reload the registry data by clicking on the relevant button

    ![missing registry data](./docs/components_missing_registry_data.png)

- non registered types can be viewed in this panel : (can be practical to see if you have any missing registrations too!)

    ![unregistered types](./docs/components_unregistered_types.png)


## Renaming/upgrading/fixing components

![rename and fix](./docs/components_rename_fix.png)

### Single item actions

this panel shows you the list of components that either 
 * are not in the registry anymore
 * are invalid (there is some error in the component that makes it unavailable in Blenvy)
 * need upgrading (ie they where stored as a custom property instead of Blenvy metadata for example)

> The last case is also for components that where created before Blenvy , using the legacy **bevy_components** Blender add-on

> The objects & components in this panel are not related to your current selection

- select the target component for a given source item/component:

![rename and fix](./docs/components_rename_fix2.png)

- click on the apply button

![rename and fix](./docs/components_rename_fix3.png)

- you will get a notification depending on how the process went, and if all went well, the entry will be deleted from the list of items that need fixing/upgrades

![rename and fix](./docs/components_rename_fix4.png)


### Bulk actions:

- you can rename/convert/upgrade or delete a given type of component to another for ALL of your objects, collections, meshes and materials in one go
by choosing an original and a target component & clicking on apply or delete


## Known issues & limitations:

* **Range** data (ie ```Range<f32>``` etc) are not handled at this time
* **Entity** structs are always set to 0 (setting entity values on the Blender side at this time does not make much sense anyway) 



## Technical details

- Blenvy's component system uses the data from the exported **type registry** in the registry.json file to add **metadata** to objects/collection/meshes/etc containing information about what components it uses + some extra information
- uses Blender's **PropertyGroups** to generate custom UIs & connects those groups with the custom properties so that no matter the complexity
of your Bevy components you get a nicely packed custom_property
- in order to avoid name clashes, it uses the full paths of components & stores the data in the ```bevy_components``` custom property
- changing the values of a component in the UI  will automatically update the value of the underlying entry in the ```bevy_components``` custom property
- different item types in Blender result in different types of GltfExtra components in Bevy (this all happens under the hood):
  - objects : GltfExtras
  - collections/ blueprints: SceneGltfExtras (as the Blueprints get exported as seperate scenes)
  - meshes: MeshGltfExtras
  - materials: MaterialGltfExtras