Hi!

For a project, I made a visualisation of a vector calculation (with draw_line3d() etc.). Now I want to port the calculation to a micro controller. So I have to code all vec_...() functions for my own.
The problem is, that the vec_rotate() algorithm wasn't added to the manual. Does anybody know how to write a function that does something similar? I searched the internet, but it seems to be very difficult => a micro controller isn't that fast, so it should be something with less instructions.

Thanks for your help!

i guess multiplying the vector with a rotation matrix would be easiest.

The rotation matrices would indeed be the easiest, and almost only way to do it.
and most microcontrollers have at least 1 MHz, so speed doesn't have to be a serious problem.

Using quaternions is faster and more stable (no singularities known as gimbal lock) because even with the transformation overhead you need less operations (mul, add) compared to a full matrix multiplication with a vector!

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?



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

Are you doing arbitrary rotations or just on the XY, XZ or YZ plane?

I'm only doing rotations by using the tilt. Does that answer your question?

for 2d rotations you only need something like that:

x' = x cos f - y sin f
y' = y cos f + x sin f

Got it working Thanks for the hint!