bevy/crates
Patrick Walton f398674e51
Implement opt-in sharp screen-space reflections for the deferred renderer, with improved raymarching code. (#13418)
This commit, a revamp of #12959, implements screen-space reflections
(SSR), which approximate real-time reflections based on raymarching
through the depth buffer and copying samples from the final rendered
frame. This patch is a relatively minimal implementation of SSR, so as
to provide a flexible base on which to customize and build in the
future. However, it's based on the production-quality [raymarching code
by Tomasz
Stachowiak](https://gist.github.com/h3r2tic/9c8356bdaefbe80b1a22ae0aaee192db).

For a general basic overview of screen-space reflections, see
[1](https://lettier.github.io/3d-game-shaders-for-beginners/screen-space-reflection.html).
The raymarching shader uses the basic algorithm of tracing forward in
large steps, refining that trace in smaller increments via binary
search, and then using the secant method. No temporal filtering or
roughness blurring, is performed at all; for this reason, SSR currently
only operates on very shiny surfaces. No acceleration via the
hierarchical Z-buffer is implemented (though note that
https://github.com/bevyengine/bevy/pull/12899 will add the
infrastructure for this). Reflections are traced at full resolution,
which is often considered slow. All of these improvements and more can
be follow-ups.

SSR is built on top of the deferred renderer and is currently only
supported in that mode. Forward screen-space reflections are possible
albeit uncommon (though e.g. *Doom Eternal* uses them); however, they
require tracing from the previous frame, which would add complexity.
This patch leaves the door open to implementing SSR in the forward
rendering path but doesn't itself have such an implementation.
Screen-space reflections aren't supported in WebGL 2, because they
require sampling from the depth buffer, which Naga can't do because of a
bug (`sampler2DShadow` is incorrectly generated instead of `sampler2D`;
this is the same reason why depth of field is disabled on that
platform).

To add screen-space reflections to a camera, use the
`ScreenSpaceReflectionsBundle` bundle or the
`ScreenSpaceReflectionsSettings` component. In addition to
`ScreenSpaceReflectionsSettings`, `DepthPrepass` and `DeferredPrepass`
must also be present for the reflections to show up. The
`ScreenSpaceReflectionsSettings` component contains several settings
that artists can tweak, and also comes with sensible defaults.

A new example, `ssr`, has been added. It's loosely based on the
[three.js ocean
sample](https://threejs.org/examples/webgl_shaders_ocean.html), but all
the assets are original. Note that the three.js demo has no screen-space
reflections and instead renders a mirror world. In contrast to #12959,
this demo tests not only a cube but also a more complex model (the
flight helmet).

## Changelog

### Added

* Screen-space reflections can be enabled for very smooth surfaces by
adding the `ScreenSpaceReflections` component to a camera. Deferred
rendering must be enabled for the reflections to appear.

![Screenshot 2024-05-18
143555](https://github.com/bevyengine/bevy/assets/157897/b8675b39-8a89-433e-a34e-1b9ee1233267)

![Screenshot 2024-05-18
143606](https://github.com/bevyengine/bevy/assets/157897/cc9e1cd0-9951-464a-9a08-e589210e5606)
2024-05-27 13:43:40 +00:00
..
bevy_a11y Add README.md to all crates (#13184) 2024-05-02 18:56:00 +00:00
bevy_animation Remove ClampColor (#13307) 2024-05-10 13:15:56 +00:00
bevy_app Deprecate dynamic plugins (#13080) 2024-05-20 20:01:28 +00:00
bevy_asset Allow AssetServer::load to acquire a guard item. (#13051) 2024-05-23 13:28:29 +00:00
bevy_audio Add README.md to all crates (#13184) 2024-05-02 18:56:00 +00:00
bevy_color Added a Grey trait, and implementations on baked-in colors. Fixes #13206 (#13237) 2024-05-26 12:53:50 +00:00
bevy_core Determine msrv for every standalone bevy_* crate. (#13211) 2024-05-13 18:26:41 +00:00
bevy_core_pipeline Implement opt-in sharp screen-space reflections for the deferred renderer, with improved raymarching code. (#13418) 2024-05-27 13:43:40 +00:00
bevy_derive Deprecate dynamic plugins (#13080) 2024-05-20 20:01:28 +00:00
bevy_dev_tools Refactor ci_testing and separate it from DevToolsPlugin (#13513) 2024-05-26 22:32:36 +00:00
bevy_diagnostic Add README.md to all crates (#13184) 2024-05-02 18:56:00 +00:00
bevy_dylib Add README.md to all crates (#13184) 2024-05-02 18:56:00 +00:00
bevy_dynamic_plugin Deprecate dynamic plugins (#13080) 2024-05-20 20:01:28 +00:00
bevy_ecs simple Debug impls for query iterators (#13476) 2024-05-22 18:56:09 +00:00
bevy_encase_derive Add README.md to all crates (#13184) 2024-05-02 18:56:00 +00:00
bevy_gilrs Add README.md to all crates (#13184) 2024-05-02 18:56:00 +00:00
bevy_gizmos Implement Rhombus 2D primitive. (#13501) 2024-05-26 15:27:57 +00:00
bevy_gltf Emissive is now LinearRgba on StandardMaterial (#13352) 2024-05-24 17:23:35 +00:00
bevy_hierarchy Add README.md to all crates (#13184) 2024-05-02 18:56:00 +00:00
bevy_input Separate state crate (#13216) 2024-05-09 18:06:05 +00:00
bevy_internal Refactor ci_testing and separate it from DevToolsPlugin (#13513) 2024-05-26 22:32:36 +00:00
bevy_log Improve tracing layer customization (#13159) 2024-05-12 21:16:56 +00:00
bevy_macro_utils Add README.md to all crates (#13184) 2024-05-02 18:56:00 +00:00
bevy_math Implement Rhombus 2D primitive. (#13501) 2024-05-26 15:27:57 +00:00
bevy_mikktspace Determine msrv for every standalone bevy_* crate. (#13211) 2024-05-13 18:26:41 +00:00
bevy_pbr Implement opt-in sharp screen-space reflections for the deferred renderer, with improved raymarching code. (#13418) 2024-05-27 13:43:40 +00:00
bevy_ptr add Debug for ptr types (#13498) 2024-05-24 21:25:11 +00:00
bevy_reflect Implement Rhombus 2D primitive. (#13501) 2024-05-26 15:27:57 +00:00
bevy_render Implement Rhombus 2D primitive. (#13501) 2024-05-26 15:27:57 +00:00
bevy_scene Add README.md to all crates (#13184) 2024-05-02 18:56:00 +00:00
bevy_sprite Make render phases render world resources instead of components. (#13277) 2024-05-21 18:23:04 +00:00
bevy_state Revert "Add on_unimplemented Diagnostics to Most Public Traits" (#13413) 2024-05-17 17:00:43 +00:00
bevy_tasks multi_threaded feature rename (#12997) 2024-05-06 20:49:32 +00:00
bevy_text Add doc comments explaining the different behaviours of alignment and Anchor with text_2d (#8022) 2024-05-12 21:42:04 +00:00
bevy_time Adds doc note that Timer and Stopwatch must be progressed manually (#13441) 2024-05-20 19:46:25 +00:00
bevy_transform Use Dir3 for local axis methods in GlobalTransform (#13264) 2024-05-06 20:52:05 +00:00
bevy_ui Fix UI elements randomly not appearing after #13277. (#13462) 2024-05-21 22:06:25 +00:00
bevy_utils Add README.md to all crates (#13184) 2024-05-02 18:56:00 +00:00
bevy_window Ensure clean exit (#13236) 2024-05-12 15:56:01 +00:00
bevy_winit Ensure clean exit (#13236) 2024-05-12 15:56:01 +00:00