๐งต Untitled Thread
Anonymous at Sun, 16 Mar 2025 15:49:30 UTC No. 1009432
>coworker rotates tangent space normalmap in photoshop
Anonymous at Sun, 16 Mar 2025 17:04:39 UTC No. 1009438
> picrelated
Grandpa? Anyway, based.
Anonymous at Sun, 16 Mar 2025 18:07:59 UTC No. 1009440
>>1009439
looks good to me
Anonymous at Mon, 17 Mar 2025 00:52:42 UTC No. 1009452
>>1009432
You can rotate 90 degrees in an image editor as long as you move red to green and green to red channel. Any other angle transformation you need to do in a 3D editor and re-bake down.
Anonymous at Mon, 17 Mar 2025 07:11:27 UTC No. 1009470
>>1009452
you forgot about inverting (not every) RG channels
Anonymous at Mon, 17 Mar 2025 10:20:55 UTC No. 1009484
>>1009439
would still work heh
Anonymous at Mon, 17 Mar 2025 13:41:04 UTC No. 1009492
>>1009470
Yeah, I can never remember which way, it depends if it is green up or green down etc. I always check against a unrotated normal or with a light in the editor which way I need flip what.
Anonymous at Mon, 17 Mar 2025 13:48:23 UTC No. 1009493
>>1009492
Just see normalmap of hemisphere bump as reference. In the end it has to look this same after rotation
Anonymous at Mon, 17 Mar 2025 17:48:32 UTC No. 1009509
>>1009493
He rotates it 45 degrees, you can't do that as the red and green channel needs to be aligned with the tangent and the bi-tangent of the geometry you end up using it on.
But you can swap out the data between the tangent and the bi-tangent by swapping red and green channels.
This is useful if you have a normal map of a horizontal image element you want to have appear vertical.
If it looks like his map initially or not depends what directions your shader/software wants.
It'd be cool if we all had agreed on 'green-up red-right', but much like like 'Z-up' 'Y-up' we're not as lucky as to be living in such a world.
Anonymous at Tue, 18 Mar 2025 11:39:37 UTC No. 1009547
>>1009509
just have LUT for every possible rotation angle
Anonymous at Tue, 18 Mar 2025 16:07:15 UTC No. 1009556
>>1009492
OpenGL Y up
DirectX Y down
I always remember DirectX down since it starts with a D
Proprietary? Wild west lol
Anonymous at Tue, 18 Mar 2025 17:19:18 UTC No. 1009562
>>1009492
>>1009556
It's even easier to remember
In OpenGL positive green color points up, meaning whatever points up gonna look brighter, because green seems relatively bright to human eye
Generally in most cases light sources are above us (sun, lamp posts etc). So OpenGL normal maps gonna just look more natural to us because of these two factors
DirectX is made by Microsoft, that means they fucked up and did the opposite
Positive red always points right in both cases
Anonymous at Thu, 20 Mar 2025 09:39:35 UTC No. 1009731
>>1009439
>Rotates 45 degrees
Anon the tangent and bitangent need to be perpendicular from eachother
And the normal is perpendicular to both the tangent and bitangent.