Resolved: OpenGL VBO doesn’t show anything when it is put in a class

Question:

I have an OpenGL project where I wanted to wrap all the objects in classes. I started with the VBO. Before wrapping, the code looked something like this:

// includes
int main()
{
    // init OpenGL
    GLfloat vertices[] = {
        // vertices
    };
    GLint VBO;
    glGenBuffers(1, &VBO);
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
    // more stuff
    // create VAO
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    // more stuff
}

This works as intended. I made a class that looks like this:

// vbo.h
#ifndef VBO_H
#define VBO_H

// includes

class VBO
{
public:
    VBO(GLfloat *, GLenum);
    ~VBO();

    void bind();
    void unbind();

    GLuint id;
};

#endif

// vbo.cpp
#include "vbo.h"

VBO::VBO(GLfloat *vertices, GLenum type)
{
    glGenBuffers(1, &id);
    glBindBuffer(GL_ARRAY_BUFFER, id);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, type);
}

VBO::~VBO()
{
    glDeleteBuffers(1, &id);
}

void VBO::bind()
{
    glBindBuffer(GL_ARRAY_BUFFER, id);
}

void VBO::unbind()
{
    glBindBuffer(GL_ARRAY_BUFFER, 0);
}

and changed main to look like this:

// includes
#include "vbo.h"

int main()
{
    // init OpenGL
    GLfloat vertices[] = {
        // vertices
    };
    VBO vbo(vertices, GL_STATIC_DRAW);
    // more stuff
    // create VAO
    vbo.bind();
    // more stuff
}

And now it doesn’t render anything. I am using OpenGL version 3.3 core profile, what am I doing wrong?

Answer:

Use std::vector &vertices instead of float*

VBO::VBO(std::vector<float> &vertices, GLenum type)
{
    glGenBuffers(1, &id);
    glBindBuffer(GL_ARRAY_BUFFER, id);
    glBufferData(GL_ARRAY_BUFFER, vertices.size() * sizeof(float), &vertices[0], type);
}

Also would be a good idea to create custom Constructor and assignment operator , incase you build multiple copies all of them will share the same VAO and VBO and if one gets deleted all of them will hold invalid VAO’s and VBO’s

If you have better answer, please add a comment about this, thank you!

Source: Stackoverflow.com