# \[Solved\] Debugging Normal Mapping
**URL:** https://discourse.libcinder.org/t/solved-debugging-normal-mapping/2132
**Category:** Using Cinder
**Created:** [July 26, 2025, 2:37pm UTC](https://discourse.libcinder.org/t/solved-debugging-normal-mapping/2132 "2025-07-26T14:37:32Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@Gazoo](https://discourse.libcinder.org/u/Gazoo)
#### Post date: [July 26, 2025, 2:37pm UTC](https://discourse.libcinder.org/t/solved-debugging-normal-mapping/2132/1 "2025-07-26T14:37:32Z")
Hey 'Embers,
I’m trying to render a normal mapped sphere with a moon texture obtained from here:
> **[Computer rendering of the Earth and Moon |](https://richardandersson.net/?p=331)**
But for reasons that aren’t entirely clear to me, the render looks quite off and even super dark in spots. I’m using the vert/frag shader provided in the LibCinder `NormalMappingBasic` application with the specular highlight turned off.
I’m seeing two - possibly related issues:
- The craters are clearly not lit correctly, they have the shadow on the ‘opposite side’.
- There are multiple strong dark patches that makes very little sense to me.
What I can confirm is that the normals and tangents look decent:
I’ve tried flipping the tangent (\* -1) without seeing the intended result, and I’m messed a fair bit with how the light source is placed but I feel like I’m kind of fumbling in the dark.
I’d much appreciate any concrete steps I could take to simplify the bug hunt I’m on, or - of course - a direct finger pointed at the likely culprit.
Cheers,
Gazoo
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### Author:  [@Gazoo](https://discourse.libcinder.org/u/Gazoo)
#### Post date: [August 6, 2025, 3:27pm UTC](https://discourse.libcinder.org/t/solved-debugging-normal-mapping/2132/2 "2025-08-06T15:27:53Z")
Turns out I’d forgotten to pass the bound texture IDs into the GLSL shader. I did bind the texture resources to texture ID’s, but then didn’t pass them properly.