does Chimpunk physics using flipped X rotation?

[Vovchik]

I'm working on Go-Chimpunk library https://github.com/vova616/chipmunk
And also on a game engine, but when I'm passing position to physic engine I always need to do the following
body.SetAngle(180-p.GameObject().Transform().WorldRotation().Z)
is the chipmunk physics flipped?
I also looked on the demo application and when I use angle of 75 the box is flipped as well
that picture demonstrate my question



I calculate my matrix like this

mat.Scale(s.X, s.Y, s.Z)
mat.Rotate(r.X, 1, 0, 0)
mat.Rotate(r.Y, 0, 1, 0)
mat.Rotate(r.Z, 0, 0, 1)
mat.Translate(p.X, p.Y, p.Z)

camera view matrix the same but with Invert after the Translate

so is it problem with my engine or chipmunk uses flipped rotation?

[slembcke]

Chipmunk angles are always in radians and always measured in a counterclockwise direction like in trigonometry and most other math. The direction of rotation also depends on if your y-axis is up or down. Again, I went with the traditional route and the y-axis points up.

There isn't really a correct direction, so I chose what I was more comfortable with.

[Vovchik]

my y-axis is up..
so what are you suggesting?
how is it possible to change that in the chipmunk library?

[slembcke]

It's not possible to change it. You just need to be aware of it when you interpret the angles. If it goes the wrong way, multiply it by -1. If you need it to be in degrees, multiply it by 180/pi.