Hello,

I am having issues using fltXmRotate. I can set the fltXmRotateCenter and fltXmRotateAngle, but the fltXmRotateAxis doesn't take. Here is my code:

struct Point
{
    double x;
    double y;
    double z;
};

void AddXForms (mgrec *node,Point translate,Vector3* axis, Float angle )
{
    cout<<mgGetName(node)<<endl;
    node = mgGetChild(node);
    cout<<mgGetName(node)<<endl;

    //Rotate
    mgrec* xformRotate = mgNewRec (fltXmRotate);
    mgSetCoord3d (xformRotate, fltXmRotateCenter,    0, 0, 0);
    mgSetAttList (xformRotate,
    fltVectorI, axis->x,
    fltVectorJ, axis->y,
    fltVectorK, axis->z,
    mgNULL);
    mgSetAttList (xformRotate, fltXmRotateAngle, angle, mgNULL);
    mgAttach (node, xformRotate);

    //Test
    float i, j, k;
    double x, y, z;
    mgrec* xrec = mgGetXform(node);
    mgGetCoord3d (xrec, fltXmRotateCenter, &x, &y, &z);
    printf ("RotateCenter: %f, %f, %f\n", x, y, z);
    mgGetAttList (xrec,
    fltVectorI, &i,
    fltVectorJ, &j,
    fltVectorK, &k,
    mgNULL);
    printf ("RotateAxis: %f, %f, %f\n", i, j, k);
        printf ("RotateAxis should be this: %f, %f, %f\n", axis->x, axis->y, axis->z);
    mgGetAttList (xrec, fltXmRotateAngle, &angle;, mgNULL);
    printf ("RotateAngle: %f\n", angle);

    //Translate
    mgrec* xformTranslate = mgNewRec(fltXmTranslate);
    mgSetCoord3d(xformTranslate,fltXmTranslateFrom,0,0,0);
    mgSetCoord3d(xformTranslate,fltXmTranslateDelta,translate.x,translate.y,translate.z);
    //Puts the translation xform before the rotation xform
    mgAttach(node,xformTranslate);
    //Test
    xrec = mgGetXform(node);
    mgGetCoord3d (xrec, fltXmTranslateFrom, &x, &y, &z);
    printf ("TranslateFrom xyz: %f, %f, %f\n", x, y, z);
    mgGetCoord3d (xrec, fltXmTranslateDelta, &x, &y, &z);
    printf ("TranslateDelta xyz: %f, %f, %f\n", x, y, z);

}

int main(int argc, char* argv[])
{
    float u = 30*PI/180;
    float i = 84*PI/180;

    Matrix3x3* m = new Matrix3x3();
    m->row[0].set(-sin(u)*cos(i),-sin(u)*-sin(i),cos(u));
    m->row[1].set(-sin(i),cos(i),0);
    m->row[2].set(-cos(u)*cos(i),-cos(u)*sin(i),-sin(u));
    Quat* q = new Quat((Matrix3x3*) m);
    //look at w,v
    Vector3* axis = new Vector3();
    Float angle = 0;
    m->getAxisAngle(axis,angle);

    //Quat* q1 = new Quat();
    //q1->set(axis,angle);
    //look at w,v

    Point result;
    mgrec* db;
    char idname[80];
    char *id = idname;

    mgInit(&argc;, argv);

    if (!(db = mgOpenDb(argv[1]))) 
    {
        printf("\nError in mgOpenDb(%s)\n", argv[1]); 
        exit(1);
    }
    
    result = GeodeticToGeocentric(u,i,0);
    cout<<"Calculated coordinates (x,y,z): " << result.x << "," << result.y << "," << result.z << endl;
    
    AddXForms(db,result,axis,angle);

    return 0;
}

This is the output I get:

db

g1

RotateCenter: 0.000000, 0.000000, 0.000000

RotateAxis: 0.000000, 0.000000, 0.000000

RotateAxis should be this: -0.208057, 0.693214, -0.360366

RotateAngle: 3.902997

TranslateFrom xyz: 0.000000, 0.000000, 0.000000

TranslateDelta xyz: 577859.941915, 5497972.248549, 3170373.815528

As you can see my RotateAxis gets set to (0,0,0) and it should be (-0.208047,0.693214,-0.360366). What am I doing wrong? I am following the code from the User's Guide. Thanks in advance.

Ok I figured it out. I am posting the code for posterity:

void AddXForms (mgrec *node,Point translate,Vector3* axis, Float angle )
{
    cout<<mgGetName(node)<<endl;
    node = mgGetChild(node);
    cout<<mgGetName(node)<<endl;

    //Rotate
    mgrec* xformRotate = mgNewRec (fltXmRotate);
    mgSetCoord3d (xformRotate, fltXmRotateCenter,    0, 0, 0);
    mgSetAttList (xformRotate, fltXmRotateAngle, angle, mgNULL);
    mgrec* nestedAttrib = mgGetAttRec(xformRotate,fltXmRotateAxis,MG_NULL);
    mgSetAttList (nestedAttrib,
    fltVectorI, axis->x,
    fltVectorJ, axis->y,
    fltVectorK, axis->z,
    mgNULL);
    mgAttach (node, xformRotate);

    //Test
    float i, j, k;
    double x, y, z;
    mgrec* xrec = mgGetXform(node);
    mgGetCoord3d (xrec, fltXmRotateCenter, &x, &y, &z);
    printf ("RotateCenter: %f, %f, %f\n", x, y, z);
    mgGetAttList (xrec,
    fltVectorI, &i,
    fltVectorJ, &j,
    fltVectorK, &k,
    mgNULL);
    printf ("RotateAxis: %f, %f, %f\n", i, j, k);
    printf ("RotateAxis should be this: %f, %f, %f\n", axis->x, axis->y, axis->z);
    mgGetAttList (xrec, fltXmRotateAngle, &angle;, mgNULL);
    printf ("RotateAngle: %f\n", angle);

    //Translate
    mgrec* xformTranslate = mgNewRec(fltXmTranslate);
    mgSetCoord3d(xformTranslate,fltXmTranslateFrom,0,0,0);
    mgSetCoord3d(xformTranslate,fltXmTranslateDelta,translate.x,translate.y,translate.z);
    //Puts the translation xform before the rotation xform
    mgAttach(node,xformTranslate);
    //Test
    xrec = mgGetXform(node);
    mgGetCoord3d (xrec, fltXmTranslateFrom, &x, &y, &z);
    printf ("TranslateFrom xyz: %f, %f, %f\n", x, y, z);
    mgGetCoord3d (xrec, fltXmTranslateDelta, &x, &y, &z);
    printf ("TranslateDelta xyz: %f, %f, %f\n", x, y, z);
}

FYI, I found the answer in the API Ref manual in the FAQ section. "How do I access a value in a record nested inside another record?"

Alternatively, it may be more convenient to use mgSetVector and mgGetVector to set and get the record fltXmRotateAxis.