draw cube using VBO

I’m trying to draw a cube using VBO.
I’m using freeglut & glew.
Here is my code


#include <GL/glew.h>
#include <GL/glut.h>
#include <stdio.h>

const int g_width = 800;
const int g_height = 800;

#pragma comment(lib, "glew32.lib")

static const GLsizeiptr PositionSize = 8 * 3 * sizeof(GLfloat);
static const GLfloat PositionData[] =
{
	0.0f, 0.0f, 0.0f,
	1.0f, 0.0f, 0.0f,
	1.0f, 1.0f, 0.0f,
	0.0f, 1.0f, 0.0f,
	0.0f, 0.0f, -1.0f,
	1.0f, 0.0f, -1.0f,
	1.0f, 1.0f, -1.0f,
	0.0f, 1.0f, -1.0f
};

static const GLsizeiptr ColorSize = 8 * 3 * sizeof(GLubyte);
static const GLubyte ColorData[] =
{
	255,   0,   0,
	255, 255,   0,
	  0, 255,   0,
	  0, 255,   0,
	  0,   0, 255,
	255,   0,   0,
	255, 255,   0,
	  0, 255,   0
};

static const GLsizei VertexCount = 8; 

GLuint vertexId;
GLuint colorId;

void initBuffers()
{
	glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
    glShadeModel(GL_SMOOTH);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    
		gluPerspective(45.0f, 640.0f / 480.0f, 0.5f, 100.0f);

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();

    glGenBuffers(1, &vertexId);
	glBindBuffer(GL_ARRAY_BUFFER, vertexId);
	glBufferData(GL_ARRAY_BUFFER, PositionSize, &PositionData[0], GL_STATIC_DRAW);

	glBindBuffer(GL_ARRAY_BUFFER, 0);

	glGenBuffers(1, &colorId);
	glBindBuffer(GL_ARRAY_BUFFER, vertexId);
	glBufferData(GL_ARRAY_BUFFER, ColorSize , &ColorData[0], GL_STATIC_DRAW);

}

void freeBuffers()
{
	glDeleteBuffers(1, &vertexId);
	glDeleteBuffers(1, &colorId);
}

void drawBuffers()
{
	
	glEnableClientState(GL_VERTEX_ARRAY);
    glEnableClientState(GL_COLOR_ARRAY);
		glBindBuffer(GL_ARRAY_BUFFER, colorId);
		glColorPointer(3, GL_UNSIGNED_BYTE, 0, NULL);
		glBindBuffer(GL_ARRAY_BUFFER, vertexId);
		glVertexPointer(3, GL_FLOAT, 0, NULL);
	    glDrawArrays(GL_TRIANGLES, 0, VertexCount);
    glDisableClientState(GL_COLOR_ARRAY);
    glDisableClientState(GL_VERTEX_ARRAY);
	

glEnd();
}

void draw()
{
	glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
	glLoadIdentity();

	glEnable(GL_COLOR_MATERIAL);
		drawBuffers();
	glDisable(GL_COLOR_MATERIAL);

	glFlush();
	glutSwapBuffers();
}

int main(int argc, char **argv)
{
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA);
	glutInitWindowSize(g_width, g_height);
	glutCreateWindow("VBO ASSIMP STARTER");

	glewExperimental = true;
	if (glewInit() != GLEW_OK)
	{
		fprintf(stderr, "Failed to initilaize GLEW
");
		return -1;
	}

	initBuffers();
	glEnable(GL_DEPTH_TEST);
	glutDisplayFunc(draw);
	glutMainLoop();
	freeBuffers();

	return 0;
}

The problem is that window is black and it doesn’t show any cube.
What is the problem?

hi ChuckE
Don’t take advise from a newbie like me too serious! The opengl seems to be parted in old and new ways (pre, post 3.0 - fixedFunction pipeline & shaders + buffers). You should investigate the boundary between the two. I can use modern buffers and glut but not paint anything without involving shaders. You seem to have omitted the shaders. If you are all new it might pose a bit of an obstacle ;o/ But it’s no small feat to be where you are now. Doing the shadeing-thing is a confined part and can be worked on separately.

Extending on what CarstenT said, this is a good tutorial for modern OpenGL (v. 3.3+): it teaches you plenty of theory behind graphics (vectors, matrices, transformations, etc), a necessity since the matrix stacks and such were removed, at a very reasonable pace. It has a quite intuitive discussion of shaders and such.

This is good also http://ogldev.atspace.co.uk/index.html