A new application for real-time shadow and sun's position in virtual environment

Abstract

This paper introduced new real-time application for outdoor computer graphic programming to control the amount of shadow with effect of sun's position. The position of sun plays an important rule for outdoor games. Calculation of sun's position, as a result, position and length of shadows require a lot of attention and preciseness. Julian dating is used to calculate the sun's position in the virtual dome. In addition, of computer graphics, building design is another field that this paper contributes on it. To create shadow, projection shadow is proposed. By calculating the sun's position in the specific date, time and location on the earth, shadow is generated. Length and angle of shadow are two parameters measured for building designers and both of them are calculated in this proposed real-time application. Therefore, it can be used for teachers to teach some part of physics about earth orbit and effect of sun on shadow and it can be used in building design and commercial games in virtual reality systems. © 2011 Springer-Verlag.