# Objective
- New clippy lints with rust 1.57 are failing
## Solution
- Fixed clippy lints following suggestions
- I ignored clippy in old renderer because there was many and it will be removed soon
This is a squash-and-rebase of @Ku95's documentation of the new renderer onto the latest `pipelined-rendering` branch.
Original PR is #2884.
Co-authored-by: dataphract <dataphract@gmail.com>
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
Implement frustum culling for much better performance on more complex scenes. With the Amazon Lumberyard Bistro scene, I was getting roughly 15fps without frustum culling and 60+fps with frustum culling on a MacBook Pro 16 with i9 9980HK 8c/16t CPU and Radeon Pro 5500M.
macOS does weird things with vsync so even though vsync was off, it really looked like sometimes other applications or the desktop window compositor were interfering, but the difference could be even more as I even saw up to 90+fps sometimes.
## Solution
- Until the https://github.com/bevyengine/rfcs/pull/12 RFC is completed, I wanted to implement at least some of the bounding volume functionality we needed to be able to unblock a bunch of rendering features and optimisations such as frustum culling, fitting the directional light orthographic projection to the relevant meshes in the view, clustered forward rendering, etc.
- I have added `Aabb`, `Frustum`, and `Sphere` types with only the necessary intersection tests for the algorithms used. I also added `CubemapFrusta` which contains a `[Frustum; 6]` and can be used by cube maps such as environment maps, and point light shadow maps.
- I did do a bit of benchmarking and optimisation on the intersection tests. I compared the [rafx parallel-comparison bitmask approach](c91bd5fcfd/rafx-visibility/src/geometry/frustum.rs (L64-L92)) with a naïve loop that has an early-out in case of a bounding volume being outside of any one of the `Frustum` planes and found them to be very similar, so I chose the simpler and more readable option. I also compared using Vec3 and Vec3A and it turned out that promoting Vec3s to Vec3A improved performance of the culling significantly due to Vec3A operations using SIMD optimisations where Vec3 uses plain scalar operations.
- When loading glTF models, the vertex attribute accessors generally store the minimum and maximum values, which allows for adding AABBs to meshes loaded from glTF for free.
- For meshes without an AABB (`PbrBundle` deliberately does not have an AABB by default), a system is executed that scans over the vertex positions to find the minimum and maximum values along each axis. This is used to construct the AABB.
- The `Frustum::intersects_obb` and `Sphere::insersects_obb` algorithm is from Foundations of Game Engine Development 2: Rendering by Eric Lengyel. There is no OBB type, yet, rather an AABB and the model matrix are passed in as arguments. This calculates a 'relative radius' of the AABB with respect to the plane normal (the plane normal in the Sphere case being something I came up with as the direction pointing from the centre of the sphere to the centre of the AABB) such that it can then do a sphere-sphere intersection test in practice.
- `RenderLayers` were copied over from the current renderer.
- `VisibleEntities` was copied over from the current renderer and a `CubemapVisibleEntities` was added to support `PointLight`s for now. `VisibleEntities` are added to views (cameras and lights) and contain a `Vec<Entity>` that is populated by culling/visibility systems that run in PostUpdate of the app world, and are iterated over in the render world for, for example, queuing up meshes to be drawn by lights for shadow maps and the main pass for cameras.
- `Visibility` and `ComputedVisibility` components were added. The `Visibility` component is user-facing so that, for example, the entity can be marked as not visible in an editor. `ComputedVisibility` on the other hand is the result of the culling/visibility systems and takes `Visibility` into account. So if an entity is marked as not being visible in its `Visibility` component, that will skip culling/visibility intersection tests and just mark the `ComputedVisibility` as false.
- The `ComputedVisibility` is used to decide which meshes to extract.
- I had to add a way to get the far plane from the `CameraProjection` in order to define an explicit far frustum plane for culling. This should perhaps be optional as it is not always desired and in that case, testing 5 planes instead of 6 is a performance win.
I think that's about all. I discussed some of the design with @cart on Discord already so hopefully it's not too far from being mergeable. It works well at least. 😄
* bevy_pbr2: Add support for most of the StandardMaterial textures
Normal maps are not included here as they require tangents in a vertex attribute.
* bevy_pbr2: Ensure RenderCommandQueue is ready for PbrShaders init
* texture_pipelined: Add a light to the scene so we can see stuff
* WIP bevy_pbr2: back to front sorting hack
* bevy_pbr2: Uniform control flow for texture sampling in pbr.frag
From 'fintelia' on the Bevy Render Rework Round 2 discussion:
"My understanding is that GPUs these days never use the "execute both branches
and select the result" strategy. Rather, what they do is evaluate the branch
condition on all threads of a warp, and jump over it if all of them evaluate to
false. If even a single thread needs to execute the if statement body, however,
then the remaining threads are paused until that is completed."
* bevy_pbr2: Simplify texture and sampler names
The StandardMaterial_ prefix is no longer needed
* bevy_pbr2: Match default 'AmbientColor' of current bevy_pbr for now
* bevy_pbr2: Convert from non-linear to linear sRGB for the color uniform
* bevy_pbr2: Add pbr_pipelined example
* Fix view vector in pbr frag to work in ortho
* bevy_pbr2: Use a 90 degree y fov and light range projection for lights
* bevy_pbr2: Add AmbientLight resource
* bevy_pbr2: Convert PointLight color to linear sRGB for use in fragment shader
* bevy_pbr2: pbr.frag: Rename PointLight.projection to view_projection
The uniform contains the view_projection matrix so this was incorrect.
* bevy_pbr2: PointLight is an OmniLight as it has a radius
* bevy_pbr2: Factoring out duplicated code
* bevy_pbr2: Implement RenderAsset for StandardMaterial
* Remove unnecessary texture and sampler clones
* fix comment formatting
* remove redundant Buffer:from
* Don't extract meshes when their material textures aren't ready
* make missing textures in the queue step an error
Co-authored-by: Aevyrie <aevyrie@gmail.com>
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
