This paper presents a new technique, which we call depth-preserving reflection mapping, to render mirror-like reflections on planar surfaces in constant time. It is a hybrid solution which combines geometry-based rendering and image-based rendering into a two-pass mirror reflection rendering approach. The technique extends the traditional reflection mapping to preserve depth per texel and uses forward warping to approximate the mirror-like reflections on planar surfaces. For clarity, to distinguish these texels from the ones of traditional reflection mapping, we call them zexels.