Question

I have been learning VBOs for a couple weeks now, and I have been told here that VBOs can render “~1 million vertices at several hundred fps”. However, my current VBO test program only gets around 50 FPS with a little of 1 million vertices to render. Are there ways to optimize VBO efficiency? Or, more likely, am I doing something incorrectly? My test program is here:

EDIT: Improved code based on feedback.

#include <windows.h>
#include <SFML/Graphics.hpp>
#include <iostream>

#include <glew.h>
#include <gl/gl.h>
#include <gl/glu.h>

using namespace std;

float cube_vertices[] = {-1, -1, 1,
                         1, -1, 1,
                         1, 1, 1,
                         -1, 1, 1,

                         -1, -1, -1,
                         -1, 1, -1,
                         1, 1, -1,
                         1, -1, -1,

                         -1, 1, -1,
                         -1, 1, 1,
                         1, 1, 1,
                         1, 1, -1,

                         -1, -1, -1,
                         1, -1, -1,
                         1, -1, 1,
                         -1, -1, 1,

                         1, -1, -1,
                         1, 1, -1,
                         1, 1, 1,
                         1, -1, 1,

                         -1, -1, -1,
                         -1, -1, 1,
                         -1, 1, 1,
                         -1, 1, -1};

float cube_normals[] = {0, 0, 1,
                        0, 0, 1,
                        0, 0, 1,
                        0, 0, 1,

                        0, 0, -1,
                        0, 0, -1,
                        0, 0, -1,
                        0, 0, -1,

                        0, 1, 0,
                        0, 1, 0,
                        0, 1, 0,
                        0, 1, 0,

                        0, -1, 0,
                        0, -1, 0,
                        0, -1, 0,
                        0, -1, 0,

                        1, 0, 0,
                        1, 0, 0,
                        1, 0, 0,
                        1, 0, 0,

                        -1, 0, 0,
                        -1, 0, 0,
                        -1, 0, 0,
                        -1, 0, 0};
class Scene {
public:
    void setup_projection( int w, int h ) {
        glViewport( 0, 0, w, h );
        glMatrixMode( GL_PROJECTION );
        glLoadIdentity();
        gluPerspective( 50, (GLdouble)w/(GLdouble)h, 1, 5000.0 );
        glMatrixMode( GL_MODELVIEW );
    }
};
int main() {
    ///Number of models to render
    int NumberOfCubes = 0;
    cout << "Enter number of cubes to render: ";
    cin >> NumberOfCubes;
    system("cls");

    ///Create vectors for mesh data
    //6 faces * 4 verts * x, y, z * number of cubes
    std::vector<float> vertices; vertices.resize(6*4*3*NumberOfCubes);
    std::vector<float> normals; normals.resize(6*4*3*NumberOfCubes);
    for(int i = 0; i < NumberOfCubes; i++)
    {
        for(int j = 0; j < 6*4*3; j++)
        {
            vertices[(i*6*4*3) + j] = cube_vertices[j] + i;
            normals[(i*6*4*3) + j] = cube_normals[j];
        }
    }

    ///Store size of the vectors
    int SizeOfVertices = vertices.size() * sizeof(float);
    int SizeOfNormals = normals.size() * sizeof(float);

    ///Window setup, lighting setup
    sf::RenderWindow window(sf::VideoMode(800, 600, 32), "Test");
    Scene scene;
    scene.setup_projection(window.getSize().x,window.getSize().y);
    glewInit();
    glEnable(GL_DEPTH_TEST);
    glEnable(GL_LIGHTING);
    glShadeModel(GL_SMOOTH);
    glEnable(GL_LIGHT0);
    float XL = .5, YL = .1, ZL = 1;
    GLfloat ambientLight[] = { 0.2f, 0.2f, 0.2f, 1.0f };
    GLfloat diffuseLight[] = { 0.8f, 0.8f, 0.8, 1.0f };
    GLfloat specularLight[] = { 0.5f, 0.5f, 0.5f, 1.0f };
    GLfloat lightpos[] = {XL, YL, ZL, 0.};
    glLightfv(GL_LIGHT0, GL_AMBIENT, ambientLight);
    glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuseLight);
    glLightfv(GL_LIGHT0, GL_SPECULAR, specularLight);
    glLightfv(GL_LIGHT0, GL_POSITION, lightpos);

    ///Generate the VBO
    GLuint VBOID;
    glGenBuffers(1, &VBOID);
    glBindBuffer(GL_ARRAY_BUFFER, VBOID);
    glBufferData(GL_ARRAY_BUFFER, SizeOfVertices + SizeOfNormals, 0, GL_STATIC_DRAW);
    glBufferSubData(GL_ARRAY_BUFFER, 0, SizeOfVertices, &vertices[0]);
    glBufferSubData(GL_ARRAY_BUFFER, SizeOfVertices, SizeOfNormals + SizeOfVertices, &normals[0]);
    glBindBuffer(GL_ARRAY_BUFFER, 0);

    ///FPS Stuff
    sf::Clock FPS;
    sf::Clock ShowFPS;
    float fps;

    ///Start loop
    cout << "Rendering " << NumberOfCubes * 8 << " vertices." << endl;
    cout << "Using graphics card: " << glGetString(GL_RENDERER) << endl;

    while( window.isOpen() ) {
        sf::Event event;
        while( window.pollEvent( event ) ) {
            if( event.type == sf::Event::Closed )
                window.close();
        }
        fps = FPS.getElapsedTime().asSeconds();
        fps = 1 / fps;
        FPS.restart();
        if(ShowFPS.getElapsedTime().asSeconds() > 1)
        {
            cout << "FPS: " << fps << "\t FrameTime: " << 1000 / fps << endl;
            ShowFPS.restart();
        }

        glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
        glMatrixMode(GL_PROJECTION);
        glLoadIdentity();
        scene.setup_projection(window.getSize().x,window.getSize().y);
        glMatrixMode(GL_MODELVIEW);
        glLoadIdentity();
        gluLookAt(-25, -25, 150, 50, 50, 50, 0, 1, 0);

        glBindBuffer(GL_ARRAY_BUFFER, VBOID);
        glEnableClientState(GL_NORMAL_ARRAY);
        glEnableClientState(GL_VERTEX_ARRAY);
        glColor3f(1, 0, 0);

        glNormalPointer(GL_FLOAT, 0, 0);
        glVertexPointer(3, GL_FLOAT, 0, 0);

        glDrawArrays(GL_QUADS, 0, 6*4*NumberOfCubes);

        glDisableClientState(GL_VERTEX_ARRAY);
        glDisableClientState(GL_NORMAL_ARRAY);
        glBindBuffer(GL_ARRAY_BUFFER, 0);

        window.display();
    }
    return 1;
}

Answer 1

After doing further research, I found out about VBO Indexing and was able to use that to get the several hundred FPS with a million vertices.