OpenGL VAO not working as intended - c++

Question

From what I understand VAOs should store the states needed for rendering like the buffers and the attribute pointers.
But the problem I am having is, I need to set-up the VAO and load the data to the buffers every time before rendering or else the things being drawn is wrong.
I am using a class called mesh that hold the VAO and VBO handles as protected GLuint variables to initialize and load the vertex data into the GPU.
I searched for hours but it seams no one else is having the same problem.
So if I initialize like this and render like this :
mesh coneMesh, sphereMesh, boxMesh;
coneMesh.setup(coneVertex, GL_STATIC_DRAW, 1, ShaderA);
sphereMesh.setup(*sphereVertex, GL_STATIC_DRAW,1, ShaderA);
boxMesh.setup(boxVertex, GL_STATIC_DRAW, 1, ShaderA);
and in the rendering loop:
//sphereMesh.setup(*sphereVertex, GL_STATIC_DRAW,1, ShaderA);
sphereMesh.render(GL_TRIANGLE_STRIP,0,sphereVertex->size(),0);
sphereMesh.render(GL_TRIANGLE_STRIP,0,sphereVertex->size(),1);
//coneMesh.setup(coneVertex, GL_STATIC_DRAW, 1, ShaderA);
glPolygonMode( GL_FRONT_AND_BACK, GL_LINE);
coneMesh.render(GL_TRIANGLE_STRIP,0,coneVertex.size(),2);
glPolygonMode( GL_FRONT_AND_BACK, GL_FILL);
//boxMesh.setup(boxVertex, GL_STATIC_DRAW, 1, ShaderA);
boxMesh.render(GL_LINE_LOOP, 0, boxVertex.size());
glfwSwapBuffers(window);
If I take out he comments and reinitialize the VAO and reload the data every thing works perfectly, can someone please tell me what I am doing wrong and how to fix it? Thank You
int mesh::setup(std::vector<vertex> &vert, GLenum BufferDataUsage, GLuint nuberOfAttribute, shader &shad)
{
this->nuberOfAttribute = nuberOfAttribute;
this->shad = &shad;
std::vector<glm::vec3> position;
std::vector<glm::vec2> textureCoord;
position.reserve(vert.size());
textureCoord.reserve(vert.size());
for(unsigned int i; i<vert.size(); i++)
{
position.push_back(vert[i].pos());
textureCoord.push_back((vert[i].textureCoordinate));
}
glGenVertexArrays(1, &vao);
glBindVertexArray(vao);
glGenBuffers(1,&vbo[0]);
glBindBuffer(GL_ARRAY_BUFFER,vbo[0]);
glBufferData(GL_ARRAY_BUFFER,(GLsizeiptr)vert.size() * sizeof (position[0]), &position[0], BufferDataUsage);
glEnableVertexAttribArray(0);
glVertexAttribPointer ( ( GLuint ) 0, 3, GL_FLOAT, GL_FALSE,0,0);
glBindBuffer(GL_ARRAY_BUFFER,0);
glBindVertexArray(0);
std::cout <<vbo[0]<<std::endl;
return 0;
}
And the rendering function:
void mesh::render(GLenum DrawHint, GLint first,GLsizei count)
{
shad->bind();//glUseProgram(id)
//set up transform matrix and set up uniform
glBindVertexArray(vao);
glDrawArrays(DrawHint, first, count);
glBindVertexArray(0);
Edit
1.)I have ran the code in another machine and the problem didn't go away. So it's probably not a driver bug.
2.)I can confirm that the different VAO and VBO are not overwriting each other since the handles on each of them is unique.
3.) Now I have no idea what could possibly course this problem.

Answer 1

glBindBuffer(GL_ARRAY_BUFFER,0);
glBindVertexArray(0);
Unbinding the VBO has to go after unbinding the VAO, as otherwise VAO will remember your VBO not being bound.
EDIT
As pointed out in comments, it's OK to unbind GL_ARRAY_BUFFER before unbinding the VAO. It wouldn't be OK for GL_ELEMENT_ARRAY_BUFFER, which is not used in this example though.
Therefore, the problem must lie elsewhere.