where are my objects???

[Francesco Gallarotti]

I have a class Model that contains a private

vector<Vertex*> vertices

Each Vertex object has some info in it, and among those there is a

Vector *normal

In a piece of code (inside a parser that reads data from a file and builds a
data structure) I have this loop:

void Model::computeVerticesNormals(void) {
for(int i=0; i<vertices.size(); i++) {

// for each vertex....
Vertex *v = vertices[i];
int numOfTriangles = v->getNumberOfTriangles();
float x=0.0f, y=0.0f, z=0.0f;

// ....goes through the list of incident triangles
// (i.e. triangles that share the same vertex)
for(int j=0; j<numOfTriangles; j++) {
Triangle *t = v->getTriangle(j);
Vertex *n = t->getNormal();
x = x+n->getX();
y = y+n->getY();
z = z+n->getZ();
}

// averages the normals of each triangle
// to get the normal at the vertex
x = x/numOfTriangles;
y = y/numOfTriangles;
z = z/numOfTriangles;

Vertex *result = new Vertex(x,y,z);
result->normalize();

// set the vertex normal
v->setNormal(result);

// reads back the vertex normal from the vertex itself
// to see if the correct value has been saved
Vertex *test = v->getNormal();
cout<< i << ") " << *test << endl;
}
}
This is the ouput produced:

Computing normals at vertices...
0) (0,0,1)
1) (0.467037,-0.494024,0.73336)
2) (-0.611279,-0.146755,0.77769)
3) (0.184617,0.627597,0.756332)
4) (0.220298,-0.969669,-0.105883)
5) (-0.947068,0.281957,0.153498)
6) (0.720865,0.691571,-0.0456409)
7) (0.215026,-0.96971,-0.115873)
8) (-0.93456,0.277214,0.223049)
9) (0.71061,0.695713,-0.104963)
10) (0.176013,-0.961244,-0.212202)
11) (-0.901334,0.272784,0.336431)
12) (0.702211,0.703715,-0.108096)
13) (0.132502,-0.956589,-0.259579)
14) (-0.835799,0.253162,0.487185)
15) (0.660714,0.724194,-0.197484)
16) (0.0889998,-0.951882,-0.293258)
17) (-0.775485,0.236146,0.585541)
18) (0.624514,0.743401,-0.239451)
.................
.................

which shows that the normals have been successfully saved in the Vertex
objects.

When this part of code ends, the code goes into some other code (different
..cpp file) that is in charge of displaying the geometry on the screen using
openGL. The part of code that surprises me is the following:

// for each vertex
int numOfVertices = my_model->getNumOfVertices();
cout << "vertices = " << numOfVertices <<endl;
for(int j=0; j<numOfVertices; j++) {

// prints out the content of the vertex (x,y,z coords)
Vertex* v=my_model->getVertex(j);
cout << "vertex["<<j<<"]" <<*v << endl;
// and the address of the normal (which should be a valid address)
Vertex* n=v->getNormal();
cout << "normal["<<j<<"]" <<n << endl;
}

instead the output that I am getting is:

vertices = 234
vertex[0](-1.01545,-0.479097,-17.894)
normal[0]CDCDCDCD
vertex[1](-1.17015,0.165296,-17.894)
normal[1]CDCDCDCD
vertex[2](-0.380034,-0.667315,-17.894)
normal[2]CDCDCDCD
vertex[3](-1.49616,-0.935275,-17.894)
normal[3]CDCDCDCD
vertex[4](-0.616068,0.00116807,-11.7246)
normal[4]CDCDCDCD
vertex[5](0.17405,-0.831445,-11.7246)
normal[5]CDCDCDCD
vertex[6](-0.942071,-1.09939,-11.7246)
normal[6]CDCDCDCD
vertex[7](0.32804,-0.27849,-7.19337)
normal[7]CDCDCDCD
vertex[8](1.11816,-1.1111,-7.19337)
normal[8]CDCDCDCD
vertex[9](0.00204068,-1.37905,-7.19337)
normal[9]CDCDCDCD
vertex[10](1.4273,-0.604105,-2.42307)
normal[10]CDCDCDCD
.............
.............

where CDCDCDCD is a way for VC6 to say that the address is not valid

Where are my normals? They were there a fraction of a second before... where
are they now???
Any suggestions???
I am totally lost on this one. Maybe some of you had similar problems before
and you can suggest a debugging plan or something....

thanks

Francesco

[Jonathan Mcdougall]

> Where are my normals?

Should ask them, they know better than anyone.

Please post some real code describing your problem
and every function which interacts with the problematic
code along with object declarations.
Jonathan

[Moonlit]

Hi,

It is hard to tell from this code. Just a gamble and probably wrong but are
you trying to read a 3DS file with andrea's ingegneri's code?

Regards, Ron AF Greve.
"Francesco Gallarotti" <ga********@hotmail.com> wrote in message
news:Xz*********************@news4.srv.hcvlny.cv.n et...

I have a class Model that contains a private

vector<Vertex*> vertices

Each Vertex object has some info in it, and among those there is a

Vector *normal

In a piece of code (inside a parser that reads data from a file and builds a data structure) I have this loop:

void Model::computeVerticesNormals(void) {
for(int i=0; i<vertices.size(); i++) {

// for each vertex....
Vertex *v = vertices[i];
int numOfTriangles = v->getNumberOfTriangles();
float x=0.0f, y=0.0f, z=0.0f;

// ....goes through the list of incident triangles
// (i.e. triangles that share the same vertex)
for(int j=0; j<numOfTriangles; j++) {
Triangle *t = v->getTriangle(j);
Vertex *n = t->getNormal();
x = x+n->getX();
y = y+n->getY();
z = z+n->getZ();
}

// averages the normals of each triangle
// to get the normal at the vertex
x = x/numOfTriangles;
y = y/numOfTriangles;
z = z/numOfTriangles;

Vertex *result = new Vertex(x,y,z);
result->normalize();

// set the vertex normal
v->setNormal(result);

// reads back the vertex normal from the vertex itself
// to see if the correct value has been saved
Vertex *test = v->getNormal();
cout<< i << ") " << *test << endl;
}
}
This is the ouput produced:

Computing normals at vertices...
0) (0,0,1)
1) (0.467037,-0.494024,0.73336)
2) (-0.611279,-0.146755,0.77769)
3) (0.184617,0.627597,0.756332)
4) (0.220298,-0.969669,-0.105883)
5) (-0.947068,0.281957,0.153498)
6) (0.720865,0.691571,-0.0456409)
7) (0.215026,-0.96971,-0.115873)
8) (-0.93456,0.277214,0.223049)
9) (0.71061,0.695713,-0.104963)
10) (0.176013,-0.961244,-0.212202)
11) (-0.901334,0.272784,0.336431)
12) (0.702211,0.703715,-0.108096)
13) (0.132502,-0.956589,-0.259579)
14) (-0.835799,0.253162,0.487185)
15) (0.660714,0.724194,-0.197484)
16) (0.0889998,-0.951882,-0.293258)
17) (-0.775485,0.236146,0.585541)
18) (0.624514,0.743401,-0.239451)
................
................

which shows that the normals have been successfully saved in the Vertex
objects.

When this part of code ends, the code goes into some other code (different
.cpp file) that is in charge of displaying the geometry on the screen using openGL. The part of code that surprises me is the following:

// for each vertex
int numOfVertices = my_model->getNumOfVertices();
cout << "vertices = " << numOfVertices <<endl;
for(int j=0; j<numOfVertices; j++) {

// prints out the content of the vertex (x,y,z coords)
Vertex* v=my_model->getVertex(j);
cout << "vertex["<<j<<"]" <<*v << endl;
// and the address of the normal (which should be a valid address) Vertex* n=v->getNormal();
cout << "normal["<<j<<"]" <<n << endl;
}

instead the output that I am getting is:

vertices = 234
vertex[0](-1.01545,-0.479097,-17.894)
normal[0]CDCDCDCD
vertex[1](-1.17015,0.165296,-17.894)
normal[1]CDCDCDCD
vertex[2](-0.380034,-0.667315,-17.894)
normal[2]CDCDCDCD
vertex[3](-1.49616,-0.935275,-17.894)
normal[3]CDCDCDCD
vertex[4](-0.616068,0.00116807,-11.7246)
normal[4]CDCDCDCD
vertex[5](0.17405,-0.831445,-11.7246)
normal[5]CDCDCDCD
vertex[6](-0.942071,-1.09939,-11.7246)
normal[6]CDCDCDCD
vertex[7](0.32804,-0.27849,-7.19337)
normal[7]CDCDCDCD
vertex[8](1.11816,-1.1111,-7.19337)
normal[8]CDCDCDCD
vertex[9](0.00204068,-1.37905,-7.19337)
normal[9]CDCDCDCD
vertex[10](1.4273,-0.604105,-2.42307)
normal[10]CDCDCDCD
............
............

where CDCDCDCD is a way for VC6 to say that the address is not valid

Where are my normals? They were there a fraction of a second before... where are they now???
Any suggestions???
I am totally lost on this one. Maybe some of you had similar problems before and you can suggest a debugging plan or something....

thanks

Francesco

[Francesco Gallarotti]

> > void Model::computeVerticesNormals(void) {

for(int i=0; i<vertices.size(); i++) {

// for each vertex....
Vertex *v = vertices[i];
int numOfTriangles = v->getNumberOfTriangles();
float x=0.0f, y=0.0f, z=0.0f;

// ....goes through the list of incident triangles
// (i.e. triangles that share the same vertex)
for(int j=0; j<numOfTriangles; j++) {
Triangle *t = v->getTriangle(j);
Vertex *n = t->getNormal();
x = x+n->getX();
y = y+n->getY();
z = z+n->getZ();
}

// averages the normals of each triangle
// to get the normal at the vertex
x = x/numOfTriangles;
y = y/numOfTriangles;
z = z/numOfTriangles;

Vertex *result = new Vertex(x,y,z); <<<<<<<<< creating Vertex result object here result->normalize();

// set the vertex normal
v->setNormal(result); <<<<<<<<< making the Vertex v point to it
Apparently the problem are dangling pointers.
What seems to be happening here is that i am creating objects of type Vertex
inside this function and then, after the function terminates, the objects
are gone and the pointers to them are not pointing to anything anymore.
I am not sure if this is completely correct but this seems to be the
problem.

// reads back the vertex normal from the vertex itself
// to see if the correct value has been saved
Vertex *test = v->getNormal();
cout<< i << ") " << *test << endl;
}
}
This is the ouput produced:

Computing normals at vertices...
0) (0,0,1)
1) (0.467037,-0.494024,0.73336)
2) (-0.611279,-0.146755,0.77769)
3) (0.184617,0.627597,0.756332)
4) (0.220298,-0.969669,-0.105883)
5) (-0.947068,0.281957,0.153498)
6) (0.720865,0.691571,-0.0456409)
7) (0.215026,-0.96971,-0.115873)
8) (-0.93456,0.277214,0.223049)
9) (0.71061,0.695713,-0.104963)
10) (0.176013,-0.961244,-0.212202)
11) (-0.901334,0.272784,0.336431)
12) (0.702211,0.703715,-0.108096)
13) (0.132502,-0.956589,-0.259579)
14) (-0.835799,0.253162,0.487185)
15) (0.660714,0.724194,-0.197484)
16) (0.0889998,-0.951882,-0.293258)
17) (-0.775485,0.236146,0.585541)
18) (0.624514,0.743401,-0.239451)
................
................

which shows that the normals have been successfully saved in the Vertex
objects.

When this part of code ends, the code goes into some other code (different .cpp file) that is in charge of displaying the geometry on the screen

using

openGL. The part of code that surprises me is the following:

// for each vertex
int numOfVertices = my_model->getNumOfVertices();
cout << "vertices = " << numOfVertices <<endl;
for(int j=0; j<numOfVertices; j++) {

// prints out the content of the vertex (x,y,z coords)
Vertex* v=my_model->getVertex(j);
cout << "vertex["<<j<<"]" <<*v << endl;
// and the address of the normal (which should be a valid

address)

Vertex* n=v->getNormal();
cout << "normal["<<j<<"]" <<n << endl;
}

instead the output that I am getting is:

vertices = 234
vertex[0](-1.01545,-0.479097,-17.894)
normal[0]CDCDCDCD
vertex[1](-1.17015,0.165296,-17.894)
normal[1]CDCDCDCD
vertex[2](-0.380034,-0.667315,-17.894)
normal[2]CDCDCDCD
vertex[3](-1.49616,-0.935275,-17.894)
normal[3]CDCDCDCD
vertex[4](-0.616068,0.00116807,-11.7246)
normal[4]CDCDCDCD
vertex[5](0.17405,-0.831445,-11.7246)
normal[5]CDCDCDCD
vertex[6](-0.942071,-1.09939,-11.7246)
normal[6]CDCDCDCD
vertex[7](0.32804,-0.27849,-7.19337)
normal[7]CDCDCDCD
vertex[8](1.11816,-1.1111,-7.19337)
normal[8]CDCDCDCD
vertex[9](0.00204068,-1.37905,-7.19337)
normal[9]CDCDCDCD
vertex[10](1.4273,-0.604105,-2.42307)
normal[10]CDCDCDCD
............
............

where CDCDCDCD is a way for VC6 to say that the address is not valid

Where are my normals? They were there a fraction of a second before...

where

are they now???
Any suggestions???
I am totally lost on this one. Maybe some of you had similar problems

before

and you can suggest a debugging plan or something....

thanks

Francesco

anyway thanks to everybody for spending your time trying to help.
I hope I had a good idea to change my code to fix this problem.

Francesco