opengl – Generate vertices of a sphere by using spherical coordinates

I’m trying to generate points for a sphere by subdividing the space of spherical coordinate in res sector and res slices.

At first I did my own implementation, but it wasn’t working. After a while I looked online and I copied Songho implementation and others as well.

But I still have the same issue:
strip made of points

The points are not evenly spaced in the sphere, creating a strip.

This is the code I’m using to generate the sphere:

   float sectorStep = 2 * PI / res;
    float stackStep = PI / res;
    float sectorAngle, stackAngle;
    for(int i = 0; i <= res; ++i){
        stackAngle = PI / 2 - i * stackStep;
        float xy = r * sinf(stackAngle);
        float z = r * cosf(stackAngle);
        for(int j = 0; j <= res; ++j){
            sectorAngle = j * sectorStep;
            float x = xy * sinf(sectorAngle);
            float y = xy * cosf(sectorAngle);
    glGenVertexArrays(1, &VAO);
    glGenBuffers(1, &verticesVBO);
    glBindBuffer(GL_ARRAY_BUFFER, verticesVBO);
    glBufferData(GL_ARRAY_BUFFER, vertices.size(),, GL_STATIC_DRAW);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, 0);

And here it’s how I draw it:

    glm::mat4 projection = glm::perspective(glm::radians(camera.getFOV()), (float) SCR_WIDTH / (float) SCR_HEIGHT, 0.1f, 100.0f);
    glm::mat4 view = camera.getViewMatrix();

    glm::mat4 model = glm::mat4(1.0f);
    shader.setUniform("projection_view", projection*view);
    shader.setUniform("model", model);
    glDrawArrays(GL_POINTS, 0, sphere.vertices.size());

I wanted to draw the vertices first and then move to drawing the triangles.

Sorry if this is a stupid question.