void main(){
    FragPos = vec3(view * model * vec4(aPos, 1.0));
    TexCoords = aTexCoord;
    Normal = transpose(inverse(mat3(view * model))) * aNormal;
    vec3 T = normalize(vec3(view * model * vec4(aTangent, 0.0)));
    vec3 N = normalize(vec3(view * model * vec4(aNormal, 0.0)));
    // re-orthogonalize T with respect to N
    T = normalize(T - dot(T, N) * N);
    // then retrieve perpendicular vector B with the cross product of T and N
    vec3 B = cross(N, T);

    mat3 TBN = transpose(mat3(T, B, N));
    for(int i = 0; i < 2; i++){
    lightpos[i] = vec3(view * vec4(vec3(pointLight[i].position), 1.0));
    }
    TangentLightPos = TBN * lightpos[0];
    //TangentViewPos  = TBN * viewPos;
    TangentFragPos  = TBN * FragPos;
    gl_Position = projection * view * model * vec4(aPos, 1.0f);
}