Orientation Problem: Roll / Pitch Axis are mixed! Pls help

TrackingState.HeadPose.ThePose is actually a Quaternion (which has x,y,z,w components that do NOT correspond to rotations around each axis), so you'll either need to change your approach to use Quaternion operations, or you'll need to first convert it to a set of Euler angles (which are x,y,z rotations around each axis).

You can get the Euler angles like this:

Posef pose = hmdState.HeadPose.ThePose;
float yaw, pitch, roll;
pose.Rotation.GetEulerAngles<Axis_Y, Axis_X, Axis_Z>(&yaw, &pitch, &roll);

"cybereality" wrote:
You can get the Euler angles like this:

That only works if the developer includes the deprecated math header.

"jherico" wrote:
That only works if the developer includes the deprecated math header.

Didn't realize that. I'll see about updating my example.

Thanks for the help

Posef pose = hmdState.HeadPose.ThePose;
float yaw, pitch, roll;
pose.Rotation.GetEulerAngles<Axis_Y, Axis_X, Axis_Z>(&yaw, &pitch, &roll);

i tried these, but it didnt worked. Guess i have to identify the header.

Bump for more help

Is there a way to get the Euler angles without the old math header, without too much effort???

I don't know if this will help, because I am going to assume that your goal is to use the euler angles to create a view matrix... If that is the case, don't use euler at all.


Matrix4f ViewHMD;
if(RenderingLeft)
{
ViewHMD = CalculateViewFromPose(EyeRenderPose[0].Orientation,EyeRenderPose[0].Position);
}
else
{
ViewHMD = CalculateViewFromPose(EyeRenderPose[1].Orientation,EyeRenderPose[1].Position);
}

:geek:


EDIT : It looks like I modified this function :

Matrix4f CalculateViewFromPose(ovrQuatf Rotation, ovrVector3f Position)
{
const Vector3f RightVector(1.0f, 0.0f, 0.0f);
const Vector3f UpVector(0.0f, 1.0f, 0.0f);
const Vector3f ForwardVector(0.0f, 0.0f, -1.0f); // -1 because HMD looks along -Z at identity orientation

OVR::Quat<float> QRotation;

QRotation.x = Rotation.x;
QRotation.y = Rotation.y;
QRotation.z = Rotation.z;
QRotation.w = Rotation.w;

Vector3f up = QRotation.Rotate(UpVector);
Vector3f forward = QRotation.Rotate(ForwardVector);

// Transform the position of the center eye in the real world (i.e. sitting in your chair)
// into the frame of the player's virtual body.

Vector3f viewPos(Position.x,Position.y,Position.z);//ForceZeroHeadMovement ? ThePlayer.BodyPos : worldPose.Translation;

Matrix4f view = Matrix4f::LookAtRH(viewPos, viewPos + forward, up);


//Matrix4f view = Matrix4f(worldPose.Rotation);
return view;
}

OVR_Math.h is still there in 0.6.0.1, and you can include it like this.

#include "Extras\OVR_Math.h"

I realize that OVR.h says it will be deprecated, but whenever that happens I assume there will be a replacement.

So it's probably safe to use for the time being.

Here is a full C++ sample that I compiled with 0.6.0.1 and can confirm is working.

#include "OVR_CAPI.h"
#include "Extras\OVR_Math.h"
#include <iostream>
#include <conio.h>
#include <windows.h>

using namespace std;
using namespace OVR;

int main()
{
	ovr_Initialize(nullptr);
	
	ovrHmd HMD;

	ovrHmd_Create(0, &HMD);

	ovrHmd_ConfigureTracking(HMD, ovrTrackingCap_Orientation | ovrTrackingCap_MagYawCorrection | ovrTrackingCap_Position, 0);

	while(true){
		ovrFrameTiming ftiming = ovrHmd_GetFrameTiming(HMD, 0);
		ovrTrackingState hmdState = ovrHmd_GetTrackingState(HMD, ftiming.DisplayMidpointSeconds);
		
		if (hmdState.StatusFlags & (ovrStatus_OrientationTracked | ovrStatus_PositionTracked)) {
			Posef pose = hmdState.HeadPose.ThePose;
			float yaw, pitch, roll;
			pose.Rotation.GetEulerAngles<Axis_Y, Axis_X, Axis_Z>(&yaw, &pitch, &roll);

			cout << "yaw: " << RadToDegree(yaw) << ", pitch: " << RadToDegree(pitch) << ", roll: "  << RadToDegree(roll)  << endl;
			
			Sleep(75);
		}

		if (_kbhit()) break;
	}
	
	ovrHmd_Destroy(HMD);

	ovr_Shutdown();
}

Hope that helps.

@matlock: Please use the code tags when pasting in code. Thanks.

"floreth" wrote:

Is there a way to get the Euler angles without the old math header, without too much effort???

If you have or can use GLM, they have an easy method for converting a quaternion into euler angles.

ovrQuatf oq;
glm::quat q(oq.x, oq.y, oq.z, oq.w);
glm::vec3 euler = glm::eulerAngles(q);

Failing that, you'll probably end up falling back on the actual implementation: