Tooling to support precomputed global illumination for the Bevy game engine.
This crate, bevy-baked-gi, provides a workflow for baked global illumination
in Bevy, using three well-established techniques: lightmapping, irradiance
volumes, and reflection probes. Global illumination enhances the realism of
rendered scenes by modeling the effects of multiple light bounces; as a simple
example, GI allows objects next to a red wall to appear red. Generally, GI is
expensive to simulate, so a popular technique is to precompute the lighting for
static elements of a scene to allow for fast approximation of global
illumination at runtime. This crate provides straightforward Bevy tooling to
support these three common methods.
It's important to note that neither this crate nor Bevy itself provides any
built-in lightmapper. You'll need to precompute the lightmaps for your scenes
using a tool external to Bevy. Fortunately, bevy-baked-gi provides a
convenient tool, export-blender-gi, that allows for the use of Blender
(optionally with The Lightmapper addon) to bake global illumination.
The following tools may be useful for baking global illumination.
bevy-baked-gi comes with a command-line tool called export-blender-gi that
you can apply to a Blender .blend file to convert baked irradiance volumes and
cube reflection probes from Blender's native format into a native Bevy .scn.ron
asset. For cubemap reflection probes, the tool uses a fork of the glTF IBL
Sampler to preprocess the cubemap images into diffuse and specular parts, so
they can be used just as environment maps are used in Bevy.
Note that you must bake the light probes before the tool is able to export them. In the Eevee renderer, use the button "Render → Indirect Lighting → Bake Indirect Lighting".
An artist-friendly UI wrapping the above export-blender-gi tool is available
as a Blender add-on. To install it, navigate to "Preferences → Add-ons →
Install…" and open the BlenderAddons/export-bevy-gi/export-bevy-gi.py script.
In the add-on preferences, locate the pre-built export-blender-gi or
export-blender-gi.exe. You can then export baked irradiance volumes and cube
reflection probes with the "File → Export → Bevy Global Illumination (.scn.ron)"
menu item. You'll need to bake the light probes (in Eevee, "Render → Indirect
Lighting → Bake Indirect Lighting") and save the .blend file first.
Within the UnityAssets directory there is an experimental Unity plugin to allow for using Unity's Progressive Lightmapper (or another tool, like Bakery) to bake the lighting for scenes. Please note that this plugin is highly experimental.
In case you want to bake the lightmaps using a tool other than Blender and Unity, a detailed description of the lightmap and irradiance volume format is available in the Bevy documentation.
Dual-licensed under the MIT and Apache 2.0 license. See the LICENSE-MIT and
LICENSE-APACHE2 files.
bevy-baked-gi follows the same code of conduct as Rust itself. Reports can be
made to the project authors.