scratch

faces == the "fs"
for(unsigned int i = 0; i < faces.size(); i += 3){
        int index = faces[i];
        vec4 vertex = vertices[index - 1];
        vec4 a = vertex;
        out_vertices.push_back(vertex);

        index = faces[i + 1];
        vertex = vertices[index - 1];
        vec4 b = vertex;
        out_vertices.push_back(vertex);

        index = faces[i + 2];
        vertex = vertices[index - 1];
        vec4 c = vertex;
        out_vertices.push_back(vertex);


        vec3 norm = normalize(cross(b - a, c - b));
    
        normals.push_back(norm);
        normals.push_back(norm);
        normals.push_back(norm);
    }