An apparatus, such as a head mounted device (HMD), includes one or more processors configured to implement a graphics pipeline that renders pixels in window space with a nonuniform pixel spacing. The apparatus also includes a first distortion function that maps the non-uniformly spaced pixels in window space to uniformly spaced pixels in raster space. The apparatus further includes a scan converter configured to sample the pixels in window space through the first distortion function. The scan converter is configured to render display pixels used to generate an image for display to a user based on the uniformly spaced pixels in raster space. In some cases, the pixels in the window space are rendered such that a pixel density per subtended area is constant across the user's field of view.