Modern OpenGL: VBO, GLM and Matrix Stacks

Question

After searching and reading about Modern OpenGL in order to upgrade my existing project, I\'m a bit confused, since my 3D framework based on OpenGL 2.1.

so, as far a

Answer 1

If your rendering already happens hierarchically using, for example, function recursion then you already have matrix stack!

void renderMesh(Matrix transform, Mesh mesh)
{
    // here call glDrawElements/glDrawArrays and send transform matrix to MVP uniform
    mesh->draw(transform);

    // now render all the sub-meshes, then will be transformed relative to current mesh
    for (int i=0; isubMeshCount(); i++)
    {
        Matrix subMeshTransform = mesh->getSubMeshTransform(i);
        Mesh subMesh = mesh->getSubMesh();

        renderMesh(subMeshTransform * transform, subMesh);
    }
}

// somwhere in main function
...
Matrix projection = Matrix::perspective(...);
Matrix view = camera->getViewMatrix();

Matrix transform = view * projectIon;
renderMesh(transform, rootMesh);