Визуализация трехмерных объектов с использованием аналитического задания освещенности окружающей среды

Abstract

The realism of the formation of graphic scenes is largely determined by the illumination of the environment. Illumination in the real scenes is a physically complex phenomenon that includes various sources, such as local illumination areas and large continuous lighting distributions. Current graphics hardware supports only point or directional light sources. One of reasons is the lack of simple procedural formulas for common illumination distributions. The purpose of the work is to use an analytical quantitative formula for radiation, which formalizes observations and allows fundamental approximation. This work focuses on the Lambert component of bidirectional radiation. The radiation environment map is used for diffuse reflection. The map is indexed along the surface normal, each pixel stores the illumination for a certain orientation of the surface. An effective presentation of the illumination the environment maps is proposed. We consider the visualization of objects with the use of the illumination the environment maps. Using the analytical task to emit the components of the spherical harmonics of the illumination harmonics allows us to calculate and apply nine coefficients corresponding to low-frequency types of illumination in order to minimize mistakes. The radiation is insensitive to high frequencies in illumination, and is well approximated using only nine parameters. The radiation can be represented procedurally as a quadratic polynomial in the Cartesian components of the surface normal and can be expressed explicitly. This leads to a simple and effective procedural rendering algorithm, using graphics processors hardware. The method allows to use of arbitrary illumination distribution for the components of bidirectional reflection. This removes the limitations of current graphics equipment for point and directional light sources. The method allows you to effectively calculate the texture maps of the illumination the environment and can be used in systems of highly realistic graphics.