Blender_bevy_components_workflow/examples/basic/README.md

# Workflow with blender / demo information

This example, is actually closer to a boilerplate + tooling showcases how to use a minimalistic [Blender](https://www.blender.org/) (gltf) centric workflow for [Bevy](https://bevyengine.org/), ie defining entites & their components
inside Blender using Blender's objects **custom properties**.
Aka "Blender as editor for Bevy"

It also allows you to setup 'blueprints' in Blender by using collections (the recomended way to go most of the time), or directly on single use objects .

## Features

* Useful if you want to use Blender (or any editor allowing to export gltf with configurable gltf_extras) as your Editor
* define Bevy components as custom properties in Blender (RON, though an older JSON version is also available)
* no plugin or extra tools needed in Blender (but I provide a little Blender plugin to auto-export to gltf on save if you want !)
* define components in Blender Collections & override any of them in your collection instances if you want
* code to auto add additional required components in Bevy (if B is needed with A but B is not present, it adds it:  optional & configurable)
* minimal setup & code,  you can have something basic running fast
* opensource 

There is a [video tutorial/explanation](https://youtu.be/-lcScjQCA3c) if you want, or you can skip to the text version ahead


## Running this example

```
cargo run --example general  --features bevy/dynamic_linking
```

## Workflow

The workflow goes as follows (once you got your Bevy code setup)

### All core/helper modules

see the [example](./examples/general/) for more information on how to set things up


### Then...

- create & register all your components you want to be able to set from the Blender side (this is basic Bevy, no specific work needed)

![component registration](./docs/component_registration.png)


- Create a mesh/ collection (for reuse) in Blender
- Go to object properties => add a property, and add your component data
    - unit structs, enums, and more complex strucs / components are all supported, (if the fields are basic data types at least,
    have not tried more complex ones yet, but should also work)
        - for structs with no params (unit structs): use a **STRING** property & an empty value 
        - for structs with params: use a RON representation of your fields (see below) 
        - for tupple strucs you can use any of the built in Blender custom property types: Strings, Booleans, floats, Vectors, etc

        ![unit struct components in Blender](./docs/components_blender.png)

        In rust:

        ![unit struct components in Bevy](./docs/demo_simple_components.png)

        (the Rust struct for these components for reference is [here](./examples/general/game.rs#34) )


        ![complex components in Blender](./docs/components_blender_parameters.png)

        In rust:

        ![complex components in Blender](./docs/camera_tracking_component.png)

        (the Rust struct for this component for reference is [here](./examples/general/core/camera/camera_tracking.rs#21) )

        There is an other examples of using various Component types: Enums, Tupple structs,  strucs with fields etc [here](./examples/general/test_components.rs),
        even colors, Vecs (arrays), Vec2, Vec3 etc are all supported

        ![complex components in Blender](./docs/components_blender_parameters2.png)

- for collections & their instances: 
    * I usually create a library scene with nested collections
        * the leaf collections are the assets you use in your level
        * add an empty called xxxx_components
        * add the components as explained in the previous part
        ![blender collection asset](./docs/blender_collections.png)

    * In the Level/world itself, just create an instance of the collection (standard Blender, ie Shift+A -> collection instance -> pick the collection)


- export your level as a glb/gltf file :
    !!**IMPORTANT** you need to check the following:
    - custom properties
    - cameras & lights if you want a complete level (as in this example)

    ![gltf_export](./docs/gltf_export.png)


- load it in Bevy (see the demo main file for this)
- you should see the components attached to your entities in Bevy

![components in bevy](./docs/components_bevy.png)
![components in bevy](./docs/components_bevy2.png)
![components in bevy](./docs/components_bevy3.png)


> note: you get a warning if there are any unregistered components in your gltf file (they get ignored)
you will get a warning **per entity**
![missing components warnings](./docs/component_warnings.png)


### Additional notes

* You usually define either the Components directly or use ```Proxy components``` that get replaced in Bevy systems with the actual Components that you want (usually when for some reason, ie external crates with unregistered components etc) you cannot use the components directly.

Included are the following modules / tools
 * [```process_gltf```](./src/process_gltfs.rs) the most important module: this is the one extracting ```component``` information from the gltf files
 * [```insert_dependant_component```](./examples/general/core/relationships/relationships_insert_dependant_components.rs)  a small utility to automatically inject 
    components that are dependant on an other component
    for example an Entity with a Player component should also always have a ShouldBeWithPlayer component
    you get a warning if you use this though, as I consider this to be stop-gap solution (usually you should have either a bundle, or directly define all needed components)
 * [```camera```](./examples/general/core/camera/) an example post process/replace proxies plugin, for Camera that also adds CameraTracking functions (to enable a camera to follow an object, ie the player)
 * [```lighting```](./examples/general/core/lighting/) an other example post process/replace proxies plugin for lighting, that toggles shadows, lighting config, etc so that things look closer to the original Blender data
 * [```physics```](./examples/general/core/physics/) an other example post process/replace proxies plugin for physics, that add [Rapier](https://rapier.rs/docs/user_guides/bevy_plugin/getting_started_bevy) Colliders, Rigidbodies etc . Most of these do not need proxies these days, as the most Rapier components are in the Registry & can be used directly

Feel free to use as you want, rip it appart, use any/all parts that you need !

This tooling and workflow has enabled me to go from a blank Bevy + Blender setup to a working barebones level in very little time (30 minutes or so ?) !
You can then add your own components & systems for your own gameplay very easilly

## Information
- the Bevy/ Rust code is [here](./examples/general/main.rs)
- the Blender file is [here](./assets/models/level.blend)
- I added [bevy_editor_pls](https://github.com/jakobhellermann/bevy_editor_pls) as a dependency for convenience so you can inspect your level/components