VAO and element array buffer state

Question

I was recently writing some OpenGL 3.3 code with Vertex Array Objects (VAO) and tested it later on Intel graphics adapter where I found, to my disappointment, that element

Answer 1

I can imagine the ELEMENT buffer not being cached; if you do:

glBindBuffer(GL_ARRAY_BUFFER, n_vertex_buffer_object);
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), p_OffsetInVBO(0));

It is like saying:

gBoundBuffer_GL_ARRAY_BUFFER=n_vertex_buffer_object;
currentVAO->enable|=(1<<0);
currentVAO->vertexBuffer=IndexToPointer(gBoundBuffer_GL_ARRAY_BUFFER);

In other words, glBindBuffer() doesn't do anything but set the value of GL_ARRAY_BUFFER. It is at glVertexAttribPointer() where you modify the VAO.

So when you do:

glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, p_index_buffer_object_list[0]);
glBindVertexArray(0);

You really do:

gBoundBuffer_GL_ELEMENT_ARRAY_BUFFER=p_index_buffer_object_list[0];
currentVAO=0;

Where it makes sense that the GL_ELEMENT_ARRAY_BUFFER binding is not doing anything. I'm not sure if there is a glVertexAttribPointer()-like variant for elements though (like glElementPointer()), which would actually act on the VAO.