Abstract : Indirect lighting accounts for subtle but essential effects in virtual scenes, and plays a great role in our perception of geometry. It is especially wanted in video games, on fully dynamic scenes, where it greatly enhances the perceived realism. In this paper, we present a screen-space hierarchical algorithm for computing indirect lighting for animated scenes. Our algorithm is fully compatible with deferred-shading rendering engines for video games, and computes indirect lighting in less than 10 ms, leaving enough computation time for other gaming tasks, such as interaction and animation. Our algorithm works in two steps: first, we compute indirect illumination in screen-space at all possible scales, then we filter and combine together the illumination received at the different scales. We describe both the algorithm and its practical integration inside a commercial video-game rendering engine.