# Objective
- Fixes#4234
- Fixes#4473
- Built on top of #3989
- Improve performance of `assign_lights_to_clusters`
## Solution
- Remove the OBB-based cluster light assignment algorithm and calculation of view space AABBs
- Implement the 'iterative sphere refinement' algorithm used in Just Cause 3 by Emil Persson as documented in the Siggraph 2015 Practical Clustered Shading talk by Persson, on pages 42-44 http://newq.net/dl/pub/s2015_practical.pdf
- Adapt to also support orthographic projections
- Add `many_lights -- orthographic` for testing many lights using an orthographic projection
## Results
- `assign_lights_to_clusters` in `many_lights` before this PR on an M1 Max over 1500 frames had a median execution time of 1.71ms. With this PR it is 1.51ms, a reduction of 0.2ms or 11.7% for this system.
---
## Changelog
- Changed: Improved cluster light assignment performance
Co-authored-by: robtfm <50659922+robtfm@users.noreply.github.com>
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
- Reduce time spent in the `check_visibility` system
## Solution
- Use `Vec3A` for all bounding volume types to leverage SIMD optimisations and to avoid repeated runtime conversions from `Vec3` to `Vec3A`
- Inline all bounding volume intersection methods
- Add on-the-fly calculated `Aabb` -> `Sphere` and do `Sphere`-`Frustum` intersection tests before `Aabb`-`Frustum` tests. This is faster for `many_cubes` but could be slower in other cases where the sphere test gives a false-positive that the `Aabb` test discards. Also, I tested precalculating the `Sphere`s and inserting them alongside the `Aabb` but this was slower.
- Do not test meshes against the far plane. Apparently games don't do this anymore with infinite projections, and it's one fewer plane to test against. I made it optional and still do the test for culling lights but that is up for discussion.
- These collectively reduce `check_visibility` execution time in `many_cubes -- sphere` from 2.76ms to 1.48ms and increase frame rate from ~42fps to ~44fps
# Objective
Fixes#3744
## Solution
The old code used the formula `normal . center + d + radius <= 0` to determine if the sphere with center `center` and radius `radius` is outside the plane with normal `normal` and distance from origin `d`. This only works if `normal` is normalized, which is not necessarily the case. Instead, `normal` and `d` are both multiplied by some factor that `radius` isn't multiplied by. So the additional code multiplied `radius` by that factor.
# Objective
- Add support for loading lights from glTF 2.0 files
## Solution
- This adds support for the KHR_punctual_lights extension which supports point, directional, and spot lights, though we don't yet support spot lights.
- Inserting light bundles when creating scenes required registering some more light bundle component types.
This makes the [New Bevy Renderer](#2535) the default (and only) renderer. The new renderer isn't _quite_ ready for the final release yet, but I want as many people as possible to start testing it so we can identify bugs and address feedback prior to release.
The examples are all ported over and operational with a few exceptions:
* I removed a good portion of the examples in the `shader` folder. We still have some work to do in order to make these examples possible / ergonomic / worthwhile: #3120 and "high level shader material plugins" are the big ones. This is a temporary measure.
* Temporarily removed the multiple_windows example: doing this properly in the new renderer will require the upcoming "render targets" changes. Same goes for the render_to_texture example.
* Removed z_sort_debug: entity visibility sort info is no longer available in app logic. we could do this on the "render app" side, but i dont consider it a priority.
