bevy_debug_lines

A prototype plugin providing a simple line drawing api for bevy.

About

This plugin uses a shader and sends individual points to the GPU, which then moves geometry to make a line. This is quite fast with a significant number of lines, and there is no added cost to moving lines around.

Usage

Add the plugin in your App::build() phase:

use bevy::prelude::*;
use bevy_prototype_debug_lines::*;

fn main() {
    App::build()
        .add_plugins(DefaultPlugins)
        .add_plugin(DebugLinesPlugin)
        ...
        .run();
}

Draw a line in whatever system you have using the DebugLines resource:

fn some_system(
    ...
    mut lines: ResMut<DebugLines>
) {
    let id = 0;
    let start = Vec3::splat(-1.0);
    let end = Vec3::splat(1.0);
    lines.add_or_update_line(id, start, end);
}

See the examples for a more complete usage example.

Notes and Missing Stuff

This plugin is in alpha, so there are things missing and general annoyances:

• Each separate line needs a separate ID... to separate it from the others. This can probably be handled automatically instead.
• There is a defined maximum number of lines that is kinda low (MAX_LINES = 128). I have some ideas to resolve this.
• Thickness is hardcoded (see line.vert), this is also easy to resolve.
• Color is hardcoded (see line.frag).
• Missing documentation, but there's only really one function you should use; add_or_update_line(id, start, end).