Thanks for your fast replies!
I have no experience with quaternions or matrices... Could somebody give me an example that would be equal to that lite-c code, please?

Code:
ANGLE angTemp;
angTemp.pan = 0;
angTemp.tilt = -48;
angTemp.roll = 0;
vec_rotate(vecTemp, angTemp); //rotate vecTemp 48 degrees down


I also looked into some snippets about ratation matrices and it looks very slow (a lot of multiplication and angular functions)...

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