Crate cloudiful_bevy_outline 

cloudiful-bevy-outline

Small reusable Bevy outline helper crate for geometry-shell outlines.

What it provides

• GpmoOutlinePlugin: initializes default outline assets
• GpmoOutlinePlugin::with_default_style(...): installs a custom default outline style
• OutlineStyle: configurable color, emissive strength, and shell scale
• OutlineAssets: default cached material/style resource
• OutlineShell: marker component for spawned outline meshes
• create_outline_material(...): build a custom outline material from an OutlineStyle
• outline_shell_transform(...): build the transform used for shell scaling
• spawn_outline_mesh(...): attach an outline mesh with a custom material/style
• spawn_default_outline_mesh(...): attach an outline mesh using the plugin’s default style

What it does not provide

• screen-space outlines
• stencil-based outline passes
• automatic mesh duplication for arbitrary scenes

This crate intentionally stays simple: it supports the common “draw a slightly enlarged backface-only shell” outline technique.

Usage

Add the plugin:

use bevy::prelude::*;
use cloudiful_bevy_outline::{GpmoOutlinePlugin, OutlineAssets};

let mut app = App::new();
app.init_resource::<Assets<StandardMaterial>>()
    .add_plugins(GpmoOutlinePlugin::default());
app.update();

assert!(app.world().contains_resource::<OutlineAssets>());

Spawn an outline child with the default material/style resource:

use bevy::prelude::*;
use cloudiful_bevy_outline::{OutlineAssets, spawn_default_outline_mesh};

fn attach_outline(
    parent: &mut ChildSpawnerCommands,
    outline_assets: &OutlineAssets,
    mesh: Handle<Mesh>,
) {
    spawn_default_outline_mesh(parent, outline_assets, mesh, Visibility::Hidden);
}

Then toggle the outline child’s Visibility.

The full runnable example lives at examples/basic.rs.

Default Style Flow

GpmoOutlinePlugin creates one default material at startup and stores it in OutlineAssets.

• use OutlineAssets when many outline shells can share one default look
• use GpmoOutlinePlugin::with_default_style(...) when the whole app should start with a different default style
• use create_outline_material(...) when one outline needs its own material
• use outline_shell_transform(...) when you need the shell scale without spawning through the helper

Custom style example:

use bevy::prelude::*;
use cloudiful_bevy_outline::{GpmoOutlinePlugin, OutlineAssets, OutlineStyle};

let mut app = App::new();
app.init_resource::<Assets<StandardMaterial>>()
    .add_plugins(GpmoOutlinePlugin::with_default_style(OutlineStyle {
        color: Color::srgb(1.0, 0.6, 0.2),
        emissive_strength: 3.0,
        scale: Vec3::splat(1.12),
    }));
app.update();

let outline_assets = app.world().resource::<OutlineAssets>();
assert_eq!(outline_assets.default_style().emissive_strength, 3.0);

Technique

This crate uses a geometry-shell outline:

1. draw the normal mesh
2. draw a second mesh with front-face culling
3. scale that second mesh slightly larger
4. only the outside silhouette remains visible

Structs

GpmoOutlinePlugin

Plugin that creates the default outline material and OutlineAssets.

OutlineAssets

Shared default outline material and style created by GpmoOutlinePlugin.

OutlineShell

Marker component for spawned outline shell meshes.

OutlineStyle

Visual parameters for a geometry-shell outline.

Functions

create_outline_material

Creates a custom material for one outline style.

outline_shell_transform

Returns the shell transform derived from an OutlineStyle.

spawn_default_outline_mesh

Spawns one outline shell child using the shared OutlineAssets.

spawn_outline_mesh

Spawns one outline shell child using an explicit material and style.