rotationMatrix in landscape mode changing? Augmented reallity on iPhone - augmented-reality

Question

I'm building au augmented reality app that shows buildings in the places given by some points of interest. When you point to that point with your iPhone (in Portrait mode), an OpenGL 3D model appears just in the position indicated by the latitud and the longitude (it converts from that GPS coordinates to screen coordinates using the rotationMatrix from CMDeviceMotion and getting the values x and y).
My problem is that I want it to work in landscape mode too. I've done all the job rotating the views, adapting the heading depending on the current device orientation...but when you point to the building in landscape mode, the model isn't fixed to that coordinates but it moves over the screen. I think the problem is that the rotationMatrix must change when you change the orientation of the device, but I cannot find the way to solve this problem. Any help?
- (void)onDisplayLink:(id)sender {
//Obtenemos los datos de movimiento del dispositivo
CMDeviceMotion *d = motionManager.deviceMotion;
//Si no son nulos (la localizacion esta activada y el magnetometro calibrado)
if (d != nil) {
//Obtenemos la matriz de rotacion
CMRotationMatrix r = d.attitude.rotationMatrix;
transformFromCMRotationMatrix(cameraTransform, &r);
//Indicamos a la vista que necesita ser renderizada de nuevo
[self setNeedsDisplay];
}
}
- (void)drawRect:(CGRect)rect {
//vistaGPS.transform = CGAffineTransformMakeRotation([gestorOrientacion >devolverAnguloSegunOrientacion]);
//Si aun no tenemos puntos de interes, salimos
if (placesOfInterestCoordinates == nil) {
return;
}
//Multiplica la matriz de proyeccion y la de rotacion ¿¿¿para obtener la rotacion en >coordenadas openGL
mat4f_t projectionCameraTransform;
multiplyMatrixAndMatrix(projectionCameraTransform, projectionTransform, >cameraTransform);
//Inicializamos el contador
int i = 0;
CLHeading *heading = locationManager.heading;
CLLocationDirection gradosDiferenciaNorteSinCorregir = heading.trueHeading;
//NSLog(#"%f , %f", gradosDiferenciaNorteSinCorregir, >gradosDiferenciaNorteSinCorregir+90);
CLLocationDirection gradosDiferenciaNorte = [gestorOrientacion >devolverHeadingCorregidoSegunOrientacion:gradosDiferenciaNorteSinCorregir];
////float bearing = [self getHeadingForDirectionFromCoordinate:newLocation.coordinate >toCoordinate: poi.coordenadas.coordinate];
labelHeading.text = [NSString stringWithFormat:#"Heading: %f", gradosDiferenciaNorte];
NSArray *subvistas = [self subviews];
for (PuntoInteres *poi in [puntosDeInteres objectEnumerator]) {
if ([subvistas containsObject:poi.vistaGL]) {
vec4f_t v;
//Multiplicamos la matriz por el vector de coordenadas del punto de interes
multiplyMatrixAndVector(v, projectionCameraTransform, >placesOfInterestCoordinates[i]);
float x = (v[0] / v[3] + 1.0f) * 0.5f;
float y = (v[1] / v[3] + 1.0f) * 0.5f;
[vistaGPS cambiarTextoLabelLatitud:x LabelLongitud:y LabelPrecision:88];
//Si la coordenada Z del vector es negativa, el modelo debe verse
if (v[2] < 0.0f) {
//Centramos la vista en el punto adecuado
poi.vistaGL.center = CGPointMake(x*self.bounds.size.width, >self.bounds.size.height-y*self.bounds.size.height);
//Indicamos que deje de estar oculta
poi.vistaGL.hidden = NO;
[poi.vistaGL.modeloAPintar establecerRotacionEnX:0.0 Y:gradosDiferenciaNorte >Z:0.0];
//Le decimos que comience a dibujarse
[poi.vistaGL startAnimation];
} else {
//Indicamos que este oculta
poi.vistaGL.hidden = YES;
//Le decimos que deje de dibujarse
[poi.vistaGL stopAnimation];
}
}
i++;
}
}
void transformFromCMRotationMatrix(vec4f_t mout, const CMRotationMatrix *m) {
mout[0] = (float)m->m11;
mout[1] = (float)m->m21;
mout[2] = (float)m->m31;
mout[3] = 0.0f;
mout[4] = (float)m->m12;
mout[5] = (float)m->m22;
mout[6] = (float)m->m32;
mout[7] = 0.0f;
mout[8] = (float)m->m13;
mout[9] = (float)m->m23;
mout[10] = (float)m->m33;
mout[11] = 0.0f;
mout[12] = 0.0f;
mout[13] = 0.0f;
mout[14] = 0.0f;
mout[15] = 1.0f;
}

Answer 1

This is a copy of my answer On stackoverflow
The rotation matrix doesn't rotate around the Z axis when the screen orientation changes. The angle properties do correct for this, but I'd rather use just the rotation matrix. Here's the code I have for that:
GLKMatrix4 deviceMotionAttitudeMatrix;
if (_cmMotionmanager.deviceMotionActive) {
CMDeviceMotion *deviceMotion = _cmMotionmanager.deviceMotion;
// Correct for the rotation matrix not including the screen orientation:
// TODO: Let the device notify me when the orientation changes instead of querying on each update.
UIDeviceOrientation orientation = [[UIDevice currentDevice] orientation];
float deviceOrientationRadians = 0.0f;
if (orientation == UIDeviceOrientationLandscapeLeft) {
deviceOrientationRadians = M_PI_2;
}
if (orientation == UIDeviceOrientationLandscapeRight) {
deviceOrientationRadians = -M_PI_2;
}
if (orientation == UIDeviceOrientationPortraitUpsideDown) {
deviceOrientationRadians = M_PI;
}
GLKMatrix4 baseRotation = GLKMatrix4MakeRotation(deviceOrientationRadians, 0.0f, 0.0f, 1.0f);
CMRotationMatrix a = deviceMotion.attitude.rotationMatrix;
deviceMotionAttitudeMatrix
= GLKMatrix4Make(a.m11, a.m21, a.m31, 0.0f,
a.m12, a.m22, a.m32, 0.0f,
a.m13, a.m23, a.m33, 0.0f,
0.0f, 0.0f, 0.0f, 1.0f);
deviceMotionAttitudeMatrix = GLKMatrix4Multiply(baseRotation, deviceMotionAttitudeMatrix);
}
else
{
// Look straight forward (we're probably in the simulator, or a device without a gyro)
deviceMotionAttitudeMatrix = GLKMatrix4MakeRotation(-M_PI_2, 1.0f, 0.0f, 0.0f);
}