Subpixel Reconstruction antialiasing for ray tracing

We introduce a practical antialiasing approach for interactive ray tracing and path tracing. Our method is inspired by the Subpixel Reconstruction Antialiasing (SRAA) method which separates the shading from visibility and geometry sampling to produce antialiased images at reduced cost. While SRAA is designed for GPU-based deferred shading renderer, we extend the concept to ray-tracing based applications. We take a hybrid rendering approach in which we add a GPU rasterization step to produce the depth and normal buffers with subpixel resolution. By utilizing those extra buffers, we are able to produce antialiased ray traced images without incurring performance penalty of tracing additional primary rays. Furthermore, we go beyond the primary rays and achieve antialiasing for shadow rays and reflective rays as well.