What I mean is if the program was first written for a right-handed coordinate environment,

I then converted it into Direct3D, but the fruit of it is still using a right-handed system.

For example, when it starts thinking about a left turn, it is thinking about a negative radian,

however, in Direct3D context, a left turn is an increase in radian, which is the reverse,

But the point is I don't want to change the logic of the whole program from start to end,

It would be too error-prone.

I just want to say feed it a Direct3D Vector and let it run as if it is in a right-handed system.

Is it possible?

The major point is, I don't want to change it because it is already working.

Thanks

Jack

Dear Hodgman,

Thanks for responding.

Another problem following this is that I just want to change this part (this library),

At first blush, every other stuff is already working in the "default" environment which is Direct3D.

So what I do prefer is add another layer to this library, this will convert this into the parameter into OpenGL,

and I take back from it, it will be in Direct3D context again.

But I can't think of a way to make the program think this is a right turn

D3DXVECTOR3 crs = zs + R_min * dot(D3DXVECTOR3(cos(anglstart), sin(anglstart), 0), rotZ(PI / 2));

It is a right turn in the original program, but it is talking about a left-turn in Direct3D sense.

I don't mind changing all the PI / 2 to -PI / 2, but I was a little bit careless, everything would be screwed up.

You may say, okay, let's do a find-and-replace, but it is quite a complex library, there are a lot of convoluted logics going on

inside this library, Therefore It's not easy to change everything and hoping the last thing would behave as the original.

At least, I've already tried. :)

Thanks for helping.

Both D3D and OpenGL use left handed coordinates

Are you sure about this? My understanding was that OpenGL is right-handed (x-right, y-up, z-backwards) and DirectX is left-handed (x-right, y-up, z-forward). If you apply the right hand rule (e.g. https://en.wikipedia.org/wiki/Right-hand_rule) DirectX would not satisfy this. I wonder if there is a reference?

Thanks for clearing this up. This makes a lot of sense. I always looked at this from the definition of the projection matrix.