vao_example.cpp

#define BUFFER_OFFSET(offset)  ((GLvoid*) NULL + offset)
#define NumberOf(array)        (sizeof(array)/sizeof(array[0]))

void main()
{
    // Temporary vertex data
    GLfloat  cubeVerts[][3] = {
        { -1.0, -1.0, -1.0 },
        { -1.0, -1.0,  1.0 },
        { -1.0,  1.0, -1.0 },
        { -1.0,  1.0,  1.0 },
        {  1.0, -1.0, -1.0 },
        {  1.0, -1.0,  1.0 },
        {  1.0,  1.0, -1.0 },
        {  1.0,  1.0,  1.0 },
    };

    // Temporary colour data
    GLfloat  cubeColors[][3] = {
        {  0.0,  0.0,  0.0 },
        {  0.0,  0.0,  1.0 },
        {  0.0,  1.0,  0.0 },
        {  0.0,  1.0,  1.0 },
        {  1.0,  0.0,  0.0 },
        {  1.0,  0.0,  1.0 },
        {  1.0,  1.0,  0.0 },
        {  1.0,  1.0,  1.0 },
    };

    // Temporary index data
    GLubyte  cubeIndices[] = {
        0, 1, 3, 2,
        4, 6, 7, 5,
        2, 3, 7, 6,
        0, 4, 5, 1,
        0, 2, 6, 4,
        1, 5, 7, 3
    };


    enum { 
        Vertices = 0, 
        Colors   = 1, 
        Elements = 2, 
        NumVBOs  = 3 
    };

    /* ---------------------------- Setup vertex array and buffers ---------------------------- */

    // Store our buffers
    GLuint buffers[NumVBOs];

    // Store our VAO
    GLuint VAO;

    // Create a VAO
    glGenVertexArrays(1, &VAO);
    // Make the VAO current
    glBindVertexArray(VAO);

    // Generate enough buffers to satisfy NumVBOs
    glGenBuffers(NumVBOs, buffers);

    /* ---------------------------- Pass Vertex Data ---------------------------- */

    // Set active VBO to vertex
    glBindBuffer(GL_ARRAY_BUFFER, buffers[Vertices]);
    // Pass vertex data to GPU
    glBufferData(GL_ARRAY_BUFFER, sizeof(cubeVerts), cubeVerts, GL_STATIC_DRAW);
    // Vertex data starts at the beginning of it's buffer
    glVertexPointer(3, GL_FLOAT, 0, BUFFER_OFFSET(0));
    // Enable vertex array drawing
    glEnableClientState(GL_VERTEX_ARRAY);

    /* ---------------------------- Pass Colour Data ---------------------------- */

    // Set active VBO to colours
    glBindBuffer(GL_ARRAY_BUFFER, buffers[Colors]);
    // Pass colour data to GPU
    glBufferData(GL_ARRAY_BUFFER, sizeof(cubeColors), cubeColors, GL_STATIC_DRAW);
    // Colour data starts at the beginning of it's buffer
    glColorPointer(3, GL_FLOAT, 0, BUFFER_OFFSET(0));
    // Enable colour array drawing
    glEnableClientState(GL_COLOR_ARRAY);

    /* ---------------------------- Pass Index Data ---------------------------- */    

    // Set the active VBO to the cube index data (for DrawElements)
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, buffers[Elements]);
    // Pass index data to GPU
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(cubeIndices), cubeIndices, GL_STATIC_DRAW);

    // Render loop
    while(true)
    {
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        // Make VAO active
        glBindVertexArray(VAO);

        // Draw
        glDrawElements(GL_QUADS, NumberOf(cubeIndices), GL_UNSIGNED_BYTE, BUFFER_OFFSET(0));

        // Make VAO unactive
        glBindVertexArray(0);
        
        glutSwapBuffers();
    }
}