C++ Vectors and OpenGL - c++

Question

I have a strange error with the OpenGL code I am writing. As a test, I'm creating a vector of spheres and using push_back(s1). I'm adding multiple spheres to the vector. However, when I run the program it only draws the sphere that was most recently pushed into the vector.
#include "Sphere.h";
#include <iostream>;
#include <vector>;
using namespae std;
vector<Sphere> spheres;
Sphere s1 = Sphere(1.0, "One");
Sphere s2 = Sphere(2.0, "Two");
Sphere s3 = Sphere(3.0, "Three");
void init(void) {
spheres.push_back(s1);
spheres.push_back(s2);
spheres.push_back(s3);
for each(Sphere s in spheres) {
cout << s.getName() << "\n";
}
}
// OTHER CODE OMMITED
void display(void) {
glClear(GL_COLOR_BUFFER_BIT);
glColor3f(1.0, 1.0, 0.0);
glPushMatrix();
for each(Sphere in s) {
s.draw();
}
glPopMatrix();
}
Obviously there is a main method in there where all the GL stuff is setup and I know that there is no issue there.
So the sphere has its own draw method. Now the interesting part is that in the console it outputs:
Three
Three
Three
and proceeds to draw s3, three times to the screen.
So my question is: why is it only drawing the last item in the vector three times? I have also tried using an iterator and a normal for loop but they all produce the same result.
Anyone have an idea?
EDITS
getName() function:
string Sphere::getName() {
return name;
}
iterator for vector:
vector<Sphere>::iterator it;
void display() {
for(it = planets.begin(); it != planets.end(); ++it) {
it->draw();
}
}
draw code in Sphere:
GLdouble r = 0.0;
GLfloat X = 0.0f;
string name = " ";
Sphere::Sphere(GLdouble ra, GLfloat x, string n)
{
r = ra;
X = pos;
name = n;
}
Sphere::~Sphere(void)
{
}
void Sphere::draw(void)
{
glutSolidSphere(r, 10, 8);
glTranslatef(X, 0.0, 0.0);
}
string Sphere::getName(void)
{
return name;
}

Answer 1

The problem appears to be that you have defined 3 global variables in Sphere.cpp, instead of class member variables. So every time the constructor runs, it overwrites the previous values, and you only see the last object constructed.
The solution is to declare them as members.
In Sphere.h, inside the class definition for Sphere, put
class Sphere {
// constructors, your current functions, and so on...
private:
GLdouble r;
GLfloat X;
string name;
}
Finally, questions like this are an example of why it's important that you provide a small example that demonstrates the problem. The first reason is it makes it easier for us to determine the source of the problem. The second is that is that it makes you examine your code in small parts. Once you've isolated the problem, it is more likely you'll be able to recognize the problem on your own.