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#ActualD.V.D

Posted 11 March 2013 - 06:58 PM

Im trying to make my own mesh class without copying the code from a tutorial and I ran into some trouble. As of now, Im not actually importing any info, I have all the vertices stored in a c++ vector class and I have a render function to render the model. The problem is that once I call the render function, my GLuint VBO gets a value of 0 and apperantly the size of my vertices drops from 5 or whatever value it was before to 0. Im not sure why, I figured it might be something to do with how OpenGL handles buffers since I can't modify these values outside of my class (theyre private). Does anyone have an idea as to why these values get modified and become 0? I call CreateMesh just before GlutMainLoop is called which is were my tutorial creates theyre model. The // after cout functions simply state the values the cout functions display.

Mesh.h

 

#include <vector>
#include <assert.h>
#include "Vector.h"
#include "glew.h"
#include <iostream>
 
using namespace std;
 
struct Vertex {
    Vector3f pos;
 
    Vertex () {};
 
    Vertex (const Vector3f &_pos) {
        pos = _pos;
    }
};
 
struct Mesh {
public:
 
    Mesh ();
    Mesh (vector<Vertex>);
 
    void Render ();
 
private:
 
    GLuint VBO; // Vertex Buffer Object
    vector<Vertex> vertices;
 
};

 

Mesh.cpp

 

#include "Mesh.h"
 
Mesh::Mesh () {}
 
Mesh::Mesh (vector<Vertex> _vertices) {
    vertices.resize(_vertices.size());
    vertices = _vertices;
 
    //cout << vertices.size() << endl; // 5
    //cout << VBO << endl; // 3435973836
 
    glGenBuffers(1, &VBO);
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(Vertex) * vertices.size(), &vertices[0], GL_STATIC_DRAW);
 
    //cout << vertices.size() << endl; // 5
    //cout << VBO << endl; // 1
}
 
void Mesh::Render () {
    //cout << vertices.size() << endl; // 0
    //cout << VBO << endl; // 0
    glEnableVertexAttribArray(0);
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, 0);
    glDrawArrays(GL_POINTS, 0, vertices.size());
    glDisableVertexAttribArray(0);
}

 

Render Function:

 

Mesh CreateMesh () {
    vector<Vertex> Vertices (5, Vector3f());
    Vertices[0].pos = Vector3f(0.0f, 0.0f, 0.0f);
    Vertices[1].pos = Vector3f(0.0f, 0.0f, 0.0f);
 
    return Mesh(Vertices);
}
 
static void RenderScene () {
    // VBO = 0 here too
    glClear(GL_COLOR_BUFFER_BIT);
    Model.Render();
    glutSwapBuffers();
}

#2D.V.D

Posted 11 March 2013 - 05:37 PM

Im trying to make my own mesh class without copying the code from a tutorial and I ran into some trouble. As of now, Im not actually importing any info, I have all the vertices stored in a c++ vector class and I have a render function to render the model. The problem is that once I call the render function, my GLuint VBO gets a value of 0 and apperantly the size of my vertices drops from 5 or whatever value it was before to 0. Im not sure why, I figured it might be something to do with how OpenGL handles buffers since I can't modify these values outside of my class (theyre private). Does anyone have an idea as to why these values get modified and become 0? I call CreateMesh just before GlutMainLoop is called which is were my tutorial creates theyre model. The // after cout functions simply state the values the cout functions display.

Mesh.h

 

#include <vector>
#include <assert.h>
#include "Vector.h"
#include "glew.h"
#include <iostream>
 
using namespace std;
 
struct Vertex {
    Vector3f pos;
 
    Vertex () {};
 
    Vertex (const Vector3f &_pos) {
        pos = _pos;
    }
};
 
struct Mesh {
public:
 
    Mesh ();
    Mesh (vector<Vertex>);
 
    void Render ();
 
private:
 
    GLuint VBO; // Vertex Buffer Object
    vector<Vertex> vertices;
 
};

 

Mesh.cpp

 

#include "Mesh.h"
 
Mesh::Mesh () {}
 
Mesh::Mesh (vector<Vertex> _vertices) {
    vertices.resize(_vertices.size());
    vertices = _vertices;
 
    //cout << vertices.size() << endl; // 5
    //cout << VBO << endl; // 3435973836
 
    glGenBuffers(1, &VBO);
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(Vertex) * vertices.size(), &vertices[0], GL_STATIC_DRAW);
 
    //cout << vertices.size() << endl; // 5
    //cout << VBO << endl; // 1
}
 
void Mesh::Render () {
    //cout << vertices.size() << endl; // 0
    //cout << VBO << endl; // 0
    glEnableVertexAttribArray(0);
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, 0);
    glDrawArrays(GL_POINTS, 0, vertices.size());
    glDisableVertexAttribArray(0);
}

 

Render Function:

 

Mesh CreateMesh () {
    vector<Vertex> Vertices (5, Vector3f());
    Vertices[0].pos = Vector3f(0.0f, 0.0f, 0.0f);
    Vertices[1].pos = Vector3f(0.0f, 0.0f, 0.0f);
 
    return Mesh(Vertices);
}
 
static void RenderScene () {
    glClear(GL_COLOR_BUFFER_BIT);
    Model.Render();
    glutSwapBuffers();
}

#1D.V.D

Posted 11 March 2013 - 05:34 PM

Im trying to make my own mesh class without copying the code from a tutorial and I ran into some trouble. As of now, Im not actually importing any info, I have all the vertices stored in a c++ vector class and I have a render function to render the model. The problem is that once I call the render function, my GLuint VBO gets a value of 0 and apperantly the size of my vertices drops from 5 or whatever value it was before to 0. Im not sure why, I figured it might be something to do with how OpenGL handles buffers since I can't modify these values outside of my class (theyre private). Does anyone have an idea as to why these values get modified and become 0? I call CreateMesh just before GlutMainLoop is called which is were my tutorial creates theyre model. The // after cout functions simply state the values the cout functions display.

Mesh.h

 

#include <vector>
#include <assert.h>
#include "Vector.h"
#include "glew.h"
#include <iostream>
 
using namespace std;
 
struct Vertex {
    Vector3f pos;
 
    Vertex () {};
 
    Vertex (const Vector3f &_pos) {
        pos = _pos;
    }
};
 
struct Mesh {
public:
 
    Mesh ();
    Mesh (vector<Vertex>);
 
    void Render ();
 
private:
 
    GLuint VBO; // Vertex Buffer Object
    vector<Vertex> vertices;
 
};

Mesh.cpp

#include "Mesh.h"
 
Mesh::Mesh () {}
 
Mesh::Mesh (vector<Vertex> _vertices) {
    vertices.resize(_vertices.size());
    vertices = _vertices;
 
    //cout << vertices.size() << endl; // 5
    //cout << VBO << endl; // 3435973836
 
    glGenBuffers(1, &VBO);
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(Vertex) * vertices.size(), &vertices[0], GL_STATIC_DRAW);
 
    //cout << vertices.size() << endl; // 5
    //cout << VBO << endl; // 1
}
 
void Mesh::Render () {
    //cout << vertices.size() << endl; // 0
    //cout << VBO << endl; // 0
    glEnableVertexAttribArray(0);
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, 0);
    glDrawArrays(GL_POINTS, 0, vertices.size());
    glDisableVertexAttribArray(0);
}

Render Function:

Mesh CreateMesh () {
    vector<Vertex> Vertices (5, Vector3f());
    Vertices[0].pos = Vector3f(0.0f, 0.0f, 0.0f);
    Vertices[1].pos = Vector3f(0.0f, 0.0f, 0.0f);
 
    return Mesh(Vertices);
}
 
static void RenderScene () {
    glClear(GL_COLOR_BUFFER_BIT);
    Model.Render();
    glutSwapBuffers();
}

 


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