glDrawElements gives EXC_BAD_ACCESS with VBO - c++

Question

I've just started learning opengl and I was trying to implement VBOs.
this is what I'm doing:
in the main method before I iterate, for each mesh I initialize its VBOs.
The mesh->pos and mesh->norm contain the points and the normals of the triangles and the quads of the mesh.
The mesh->triangle and mesh->quad contain the indices.
for (auto mesh : scene->meshes)
{
mesh->vboPos = 0;
glGenBuffers (1, &mesh->vboPos);
glBindBuffer (GL_ARRAY_BUFFER, mesh->vboPos);
glBufferData (GL_ARRAY_BUFFER, 3 * mesh->pos.size() * sizeof(GL_FLOAT), mesh->pos.data(), GL_STATIC_DRAW);
mesh->vboNorm = 0;
glGenBuffers (1, &mesh->vboNorm);
glBindBuffer (GL_ARRAY_BUFFER, mesh->vboNorm);
glBufferData (GL_ARRAY_BUFFER, 3 * mesh->norm.size() * sizeof(GL_FLOAT), mesh->norm.data(), GL_STATIC_DRAW);
mesh->vbiTriangle = 0;
glGenBuffers (1, &mesh-> vbiTriangle);
glBindBuffer (GL_ELEMENT_ARRAY_BUFFER, mesh-> vbiTriangle);
glBufferData (GL_ELEMENT_ARRAY_BUFFER, 3 * mesh->triangle.size() * sizeof(GL_UNSIGNED_INT), mesh->triangle.data(), GL_STATIC_DRAW);
mesh->vbiQuad = 0;
glGenBuffers (1, &mesh->vbiQuad);
glBindBuffer (GL_ELEMENT_ARRAY_BUFFER, mesh->vbiQuad);
glBufferData (GL_ELEMENT_ARRAY_BUFFER, 4 * mesh->quad.size() * sizeof(GL_UNSIGNED_INT), mesh->quad.data(), GL_STATIC_DRAW);
}
while(not glfwWindowShouldClose(window))
{
...
}
After this inside the shade method I call the draw for each mesh I have. This is how the mesh code looks like:
struct Mesh {
frame3f frame = identity_frame3f; // frame
vector<vec3f> pos; // vertex position
vector<vec3f> norm; // vertex normal
vector<vec3i> triangle; // triangle
vector<vec4i> quad; // quad
Material* mat = new Material(); // material
GLuint vboPos = 0;
GLuint vboNorm = 0;
GLuint vbiTriangle =0;
GLuint vbiQuad =0;
int count = 0;
void draw()
{
glEnableVertexAttribArray(0);
glEnableVertexAttribArray(1);
glBindBuffer(GL_ARRAY_BUFFER, vboPos);
glBindBuffer(GL_ARRAY_BUFFER, vboNorm);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, vbiTriangle);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, vbiQuad);
glEnableClientState(GL_VERTEX_ARRAY);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, 0);
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 0, 0);
glDrawElements(GL_TRIANGLES, triangle.size() * 3, GL_UNSIGNED_INT, 0);
glDrawElements(GL_QUADS, quad.size() * 4, GL_UNSIGNED_INT, 0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
glDisableVertexAttribArray(0);
glDisableVertexAttribArray(1);
}
I don't really know what's the problem causing this, but I'm pretty sure I didn't understand something of how VBOs work. Can you enlighten me?

Answer 1

You are trying to do too many things at once here and I have a feeling the driver is overrunning an array trying to read the wrong element array.
Your draw function needs to be re-written:
void draw()
{
glEnableVertexAttribArray(0);
glEnableVertexAttribArray(1);
/* Setup your Position array */
glBindBuffer(GL_ARRAY_BUFFER, vboPos);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, 0);
/* Then setup your Normal array */
glBindBuffer(GL_ARRAY_BUFFER, vboNorm);
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 0, 0);
/* DO NOT DO THIS -- you are using generic vertex attributes. */
//glEnableClientState(GL_VERTEX_ARRAY);
/* First the Triangles */
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, vbiTriangle);
glDrawElements(GL_TRIANGLES, triangle.size() * 3, GL_UNSIGNED_INT, 0);
/* Now the Quads */
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, vbiQuad);
glDrawElements(GL_QUADS, quad.size() * 4, GL_UNSIGNED_INT, 0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
glDisableVertexAttribArray(0);
glDisableVertexAttribArray(1);
}