Normal Maps for Rendering Vast Ocean Scenes

Anonymous

Keywords: Normal Maps, Reflectance Modeling, Ray Tracing, Environmental sciences

TL;DR: The impact of simulation-driven normal maps on rendering of height-field oceans is evaluated for a variety of ocean and sky conditions.

Abstract: Maritime scene simulations frequently use a height-field representation of the ocean surface. Many scenarios create a visible surface over large areas, with high amounts of detail for a camera close to the surface. Efficient rendering of a vast ocean like this makes use of Level of Detail (LOD) degradation of polygonal tessellation of the surface. But LOD degradation can have consequences in the rendered scene, particularly near the horizon, for both qualitative and quantitative metrics. The magnitude of these impacts depend on the specifics of the ocean surface conditions, and on the structure of sky light illuminating the surface. Here we present a method of extending the concept of normal mapping to efficiently restore full spatial resolution of the surface normals to the LOD degraded surface. The impact of this normal mapping process is evaluated for qualitative and quantitative metrics, across a collection of ocean surface random realizations and for a collection of sky illumination patterns. Specific cases are presented in detail, and a summary assessment of the impact of 93 simulations is presented.