# Objective
- Closes#9384.
## Solution
- Make the movement speed of the `CameraController` adjustable with the
scroll wheel as mentioned
[here](https://github.com/bevyengine/bevy/issues/9384#issuecomment-1668957931).
The speed use an exponential progression (10% increase per scroll tick
by default) to allow adapting the speed to different scales.
- For the `scene_viewer` example, make the default speed proportional to
the size of the scene using what's computed for the default camera
placement. This gives a good enough default to fly over the scene from
the outside. I don't think there's a good way to get a default speed
fitting for all scenes since some are meant to be viewed from outside
while other are traversable environments.
# Objective
Drawing a `Gizmos::circle` whose normal is derived from a Transform's
local axes now requires converting a Vec3 to a Direction3d and
unwrapping the result, and I think we shold move the conversion into
Bevy.
## Solution
We can make
`Transform::{left,right,up,down,forward,back,local_x,local_y,local_z}`
return a Direction3d, because they know that their results will be of
finite non-zero length (roughly 1.0).
---
## Changelog
`Transform::up()` and similar functions now return `Direction3d` instead
of `Vec3`.
## Migration Guide
Callers of `Transform::up()` and similar functions may have to
dereference the returned `Direction3d` to get to the inner `Vec3`.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Joona Aalto <jondolf.dev@gmail.com>
# Objective
Unify flycam-style camera controller from the examples.
`parallax_mapping` controller was kept as is.
## Solution
Fixed some mouse movement & cursor grabbing related issues too.
