# Objective
- Make #8015 easier to review;
## Solution
- This commit contains changes not directly related to transmission
required by #8015, in easier-to-review, one-change-per-commit form.
---
## Changelog
### Fixed
- Clear motion vector prepass using `0.0` instead of `1.0`, to avoid TAA
artifacts on transparent objects against the background;
### Added
- The `E` mathematical constant is now available for use in shaders,
exposed under `bevy_pbr::utils`;
- A new `TAA` shader def is now available, for conditionally enabling
shader logic via `#ifdef` when TAA is enabled; (e.g. for jittering
texture samples)
- A new `FallbackImageZero` resource is introduced, for when a fallback
image filled with zeroes is required;
- A new `RenderPhase<I>::render_range()` method is introduced, for
render phases that need to render their items in multiple parceled out
“steps”;
### Changed
- The `MainTargetTextures` struct now holds both `Texture` and
`TextureViews` for the main textures;
- The fog shader functions under `bevy_pbr::fog` now take the a `Fog`
structure as their first argument, instead of relying on the global
`fog` uniform;
- The main textures can now be used as copy sources;
## Migration Guide
- `ViewTarget::main_texture()` and `ViewTarget::main_texture_other()`
now return `&Texture` instead of `&TextureView`. If you were relying on
these methods, replace your usage with
`ViewTarget::main_texture_view()`and
`ViewTarget::main_texture_other_view()`, respectively;
- `ViewTarget::sampled_main_texture()` now returns `Option<&Texture>`
instead of a `Option<&TextureView>`. If you were relying on this method,
replace your usage with `ViewTarget::sampled_main_texture_view()`;
- The `apply_fog()`, `linear_fog()`, `exponential_fog()`,
`exponential_squared_fog()` and `atmospheric_fog()` functions now take a
configurable `Fog` struct. If you were relying on them, update your
usage by adding the global `fog` uniform as their first argument;
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