1. A method of image compositing directly from ray tracing samples, comprising: obtaining a plurality of ray tracing samples from a ray tracing renderer that renders a scene, each ray tracing sample of said plurality of ray tracing samples comprising a sample object identity of an object within said scene that intersects a ray associated with said ray tracing sample; a sample color; and, a sample location; applying one or more compositing operations to modify said plurality of ray tracing samples to form composited ray tracing samples; rasterizing said composited ray tracing samples into a composited image comprising a plurality of pixels after said applying said one or more compositing operations; generating a preview image from said composited ray tracing samples, wherein said generating said preview image comprises selecting a subset of said composited ray tracing samples; and, rasterizing said subset of said composited ray tracing samples into said preview image; displaying said preview image; generating a higher quality preview image from a larger subset of said composited ray tracing samples using a background process while said preview image is displayed; and, displaying said higher quality preview image when said background process is complete.