This decouples the opinionated "core pipeline" from the new (less opinionated) bevy_render crate. The "core pipeline" is intended to be used by crates like bevy_sprites, bevy_pbr, bevy_ui, and 3rd party crates that extends core rendering functionality.
Makes the "Render App World" directly available to Extract step systems as a `RenderWorld` resource. Prior to this, there was no way to directly read / write render world state during the Extract step. The only way to make changes was through Commands (which were applied at the end of the stage).
```rust
// `thing` is an "app world resource".
fn extract_thing(thing: Res<Thing>, mut render_world: ResMut<RenderWorld>) {
render_world.insert_resource(ExtractedThing::from(thing));
}
```
RenderWorld makes a number of scenarios possible:
* When an extract system does big allocations, it is now possible to reuse them across frames by retrieving old values from RenderWorld (at the cost of reduced parallelism from unique RenderWorld borrows).
* Enables inserting into the same resource across multiple extract systems
* Enables using past RenderWorld state to inform future extract state (this should generally be avoided)
Ultimately this is just a subset of the functionality we want. In the future, it would be great to have "multi-world schedules" to enable fine grained parallelism on the render world during the extract step. But that is a research project that almost certainly won't make it into 0.6. This is a good interim solution that should easily port over to multi-world schedules if/when they land.
* 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>
