OpenGL VBO doesn't show anything when it is put in a class-CodePudding

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?

CodePudding user response：

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