bevy_procedural_tree

Procedural 3D trees for bevy - ported from the javascript ez-tree repository with some adjustments to better fit bevy and some changes to the semantics of the parameters due to personal opinion.

Features

• Mesh generation based on given TreeMeshSettings (a standard Mesh3d)
• Generation by global TreeMeshSettings or per instance (chosen per entity)
• User can provide a material for the branches and leafs separately
• Auto regeneration of the meshes when the settings change
• Optional use of u32_indices for the mesh (default is u16; see u32_indices feature in Cargo.toml)

Usage

See the showroom example: cargo run --example showroom --features "inspector perf_ui"

In the showroom are two trees: The tree in the middle uses the global TreeMeshSettings resource. The tree to the side uses the TreeMeshSettings component, which can be modified on the entity itself via the inspector.

Quick start (with TreeProceduralGenerationPlugin)

1. To enable auto generation: add the TreeProceduralGenerationPlugin to your app
2. (Optional) Modify the TreeMeshSettings and TreeDefaultMaterials to your liking
3. Spawn an entity and add the Treecomponent

Internally this will generate the Mesh3d for the entity and a child entity for the mesh of the leaves. It will apply the materials from the TreeDefaultMaterials resource, or from a provided override.

Quick start (without TreeProceduralGenerationPlugin)

1. use bevy_procedural_tree::meshgen::generate_tree_meshes() to generate two meshes (branches/trunk mesh and leaves mesh)
2. use the meshes for anything you like

Explanation of the most important structs

TreeMeshSettings resource

Defines the general structure of the generated 3d mesh. Every parameter is documented.

TreeDefaultTextures resource

Defines the default materials used by trees which do not use the override.

Tree component

Added to an entity to generate a new tree. It has 4 parameters:

• a seed to make this tree unique (using the same seed, with the same TreeMeshSettings produces the same tree mesh)
• an optional override for the TreeMeshSettings resource
• an optional override for the TreeDefaultMaterials bark material
• an optional override for the TreeDefaultMaterials leaf material

Possible ToDos

• Do not regenerate the whole tree each time the settings change (but do partial updates)
• Provide an example vertex shader for wind
• Implement "growing"
• Caching of already generated trees (i.e. with the lru crate)
• Multiple LODs
• Different "normal" modes (currently just orthogonal to the surface; i.e. inspiration: Reddit: Fluffy trees)

Future research

• How to generalize materials to not force the user to provide a StandardMaterial

Supported Bevy Versions

Acknowledgements

• https://github.com/dgreenheck/ez-tree
• https://ambientcg.com
• https://polyhaven.com