Question

I have problems getting OpenGL to work, basically I am getting alternate black and grey screens. I have it working fine using the fixed function pipeline (glBegin(), glEnd() and glTexCoord…) I think I am doing something very wrong, pretty new to this stuff. Any help would be appreciated.

struct Quad
{
    float x0, y0, z0;   // top left corner
    float x1, y1, z1;   // top right corner
    float x2, y2, z2;   // bottom left corner
    float x3, y3, z3;   // bottom right corner
    float s0, t0;
    float s1, t1;
    float s2, t2;
    float s3, t3;
    char r, g, b, a;    // tint
    float depth;        // depth value of the Quad
};

void draw{
    glEnable(GL_TEXTURE_2D);
    glEnableClientState(GL_VERTEX_ARRAY);
    glEnableClientState(GL_TEXTURE_COORD_ARRAY);
    // Note: glVertexPointer is deprecated, change to glVertexAttribPointer
    glVertexPointer(3, GL_FLOAT, sizeof(Quad), &(vertexBuffer_[0].x0));
    glTexCoordPointer(2, GL_FLOAT, sizeof(Quad), &(vertexBuffer_[0].s0));
    glBindBuffer(GL_ARRAY_BUFFER, VBOs_[activeVBO_]);
    glBufferData(GL_ARRAY_BUFFER, vertexBuffer_.size() * sizeof(Quad), &(vertexBuffer_[0]), GL_STATIC_DRAW);
    glDrawArrays(GL_QUADS, 0, vertexBuffer_.size());
    glBindBuffer(GL_ARRAY_BUFFER, 0);
    SDL_GL_SwapBuffers();
    activeVBO_ = (++activeVBO_)%NUM_VBO;
    glError();
}

Answer 1

You seem to be trying to use some odd combination of vertex arrays and VBOs. Try this walkthrough.

Strange things:

• gl*Pointer() calls should use zero-based “pointers” instead of real pointers if you’re using VBOs.

• Your Quad struct is kinda weird. I’m not quite sure you can write
  usable stride values for it. Try an array of these:

struct Vertex
{
    float x, y, z;
    float s, t;
    char r, g, b, a;
};