Realtime Path Tracer for Bevy

bevy-hikari is an implementation of global illumination for Bevy.

After Bevy releasing 0.8, the plugin moves to deferred hybrid path tracing. For the old version (0.1.x) which uses voxel cone tracing with anisotropic mip-mapping, please check the bevy-0.6 branch.

Bevy Version Support

bevy	bevy-hikari
0.6	0.1
0.8	0.2

Progress

• Extraction and preparation of mesh assets and instances
• G-Buffer generation
• 2-bounce path tracing
• Next event estimation
• ReSTIR: Temporal sample reuse
• ReSTIR: Spatial sample reuse
• Spatiotemporal filtering
• Hardware ray tracing (upstream related)

Basic Usage

1. Add HikariPlugin to your App after PbrPlugin
2. Setup the scene with a directional light
3. Set your camera's camera_render_graph to CameraRenderGraph::new(bevy_hikari::graph::NAME)

use bevy::{pbr::PbrPlugin, prelude::*, render::camera::CameraRenderGraph};
use bevy_hikari::prelude::*;
use std::f32::consts::PI;

fn main() {
    App::new()
        .add_plugins(DefaultPlugins)
        .add_plugin(PbrPlugin)
        // Add Hikari after PBR
        .add_plugin(HikariPlugin)
        .add_startup_system(setup)
        .run();
}

fn setup(
    mut commands: Commands,
    mut meshes: ResMut<Assets<Mesh>>,
    mut materials: ResMut<Assets<StandardMaterial>>,
    _asset_server: Res<AssetServer>,
) {
    // Plane
    commands.spawn_bundle(PbrBundle {
        mesh: meshes.add(Mesh::from(shape::Plane { size: 5.0 })),
        material: materials.add(Color::rgb(0.3, 0.5, 0.3).into()),
        ..default()
    });
    // Cube
    commands.spawn_bundle(PbrBundle {
        mesh: meshes.add(Mesh::from(shape::Cube { size: 1.0 })),
        material: materials.add(Color::rgb(0.8, 0.7, 0.6).into()),
        transform: Transform::from_xyz(0.0, 0.5, 0.0),
        ..default()
    });

    // Only directional light is supported
    commands.spawn_bundle(DirectionalLightBundle {
        directional_light: DirectionalLight {
            illuminance: 10000.0,
            ..Default::default()
        },
        transform: Transform {
            translation: Vec3::new(0.0, 5.0, 0.0),
            rotation: Quat::from_euler(EulerRot::XYZ, -PI / 4.0, PI / 4.0, 0.0),
            ..Default::default()
        },
        ..Default::default()
    });

    // Camera
    commands.spawn_bundle(Camera3dBundle {
        // Set the camera's render graph to Hikari's
        camera_render_graph: CameraRenderGraph::new(bevy_hikari::graph::NAME),
        transform: Transform::from_xyz(-2.0, 2.5, 5.0).looking_at(Vec3::ZERO, Vec3::Y),
        ..Default::default()
    });
}

Effects

You can check the video here.

Screenshots

License

Just like Bevy, all code in this repository is dual-licensed under either:

• MIT License (LICENSE-MIT or http://opensource.org/licenses/MIT)
• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)

at your option.

Credits

"Fire Extinguisher" model and textures Copyright (C) 2021 by Cameron 'cron' Fraser. Released under Creative Commons Attribution-ShareAlike 4.0 International (CC-BY-SA 4.0) license.