Blender exporter with animation

Hi and happy new year! I have written a blender exporter that writes out .gpmesh, .gpskel and .gpanim(s) These are the custom file formats in the book from chapter 12 on. When loading the files in the engine (I used chapter 12) the gpmesh comes in fine, the tpose is correct but the other animations are messed up. You can still see the animation matches somewhat the one created in blender but something is wrong there. I was not able to figure out where the mistake happens. To my best knowledge the skeleton and animation files contain the local transforms of the bones using matrix_local in Blender's python API.

I included the script and the example Blend file (Blender 3.0.0) for testing in my fork: https://github.com/michaeleggers/code/tree/blender-exporter-update/Exporter/Blender

Maybe someone is interested in looking into it.

As I am relatively new to Blender, I used this tutorial to model, rig and animate and also used the texture provided by Imphenzia: https://youtu.be/yjjLD3h3yRc