Active illumination systems which perform disparity gating, or the ability to selectively image photons that arrive from a specified surface geometry some distance away, have recently shown usefulness for robotics, autonomous vehicles, and surveillance applications. In this paper, we present a new technique for sloped disparity gating, capturing a particular set of sloped planar surfaces in a scene, implemented using the synchronization between a raster-scanning projector and the rolling shutter of a camera. We demonstrate how to control the slope and thickness of these planar surfaces using hardware parameters of pixel clock, synchronization delay, and exposure. Finally, we perform applications including real-time image masking and imaging in scattering media with a real hardware prototype in the lab. This work showcases the potential for energy-efficient, geometry-aware disparity gating in the future.