Lighting and shadows rendering in natural scenes

Abstract

In natural scene rendering, the light is the most important factor. The global lighting models are based on the reflection and diffusion of light on the surfaces of objects. The lighting environment can be considered as a composition of the outgoing radiance due to the direct lighting from the sky and the reflection of skylight of the ground, the outgoing radiance due to the direct Sun lighting, and the outgoing radiance due to the indirect lighting from the Sun though neighbour leaves. Also, the bidirectional reflectance distribution functions for different types of materials can be designed using physically-based approach. In this chapter, some models, such as Lambertian surfaces, Phong’s reflectance model, Blinn-Phong’s reflectance model, and microfacet models, are discussed. In spite of a shadowing is still an expensive component, the virtual environment without shadows cannot be realistic. Some hard and soft shadow techniques, suitable for the natural scene rendering, are represented in the chapter.