# Objective
Right now, we flip the `world_normal` in response to `double_sided &&
!is_front`, however when calculating `N` from tangents and the normal
map, we don't flip the normal read from the normal map, which produces
extremely weird results.
## Solution
- Pass `double_sided` and `is_front` flags to the
`apply_normal_mapping()` function and use them to conditionally flip
`Nt`
## Comparison
Note: These are from a custom scene running with the `transmission`
branch, (#8015) I noticed lighting got pretty weird for the back side of
translucent `double_sided` materials whenever I added a normal map.
### Before
<img width="1392" alt="Screenshot 2023-10-31 at 01 26 06"
src="https://github.com/bevyengine/bevy/assets/418473/d5f8c9c3-aca1-4c2f-854d-f0d0fd2fb19a">
### After
<img width="1392" alt="Screenshot 2023-10-31 at 01 25 42"
src="https://github.com/bevyengine/bevy/assets/418473/fa0e1aa2-19ad-4c27-bb08-37299d97971c">
---
## Changelog
- Fixed a bug where `StandardMaterial::double_sided` would interact
incorrectly with normal maps, producing broken results.
dc1f76d9a2