Implementação e análise de BRDFs difusas e especulares no contexto de Path Tracing Interativo

Abstract

The Path Tracing [39] algorithm is a photorealistic image synthesis method considered state of the art in physics-based rendering (PBR) methods, also known in computer graphics as a method that demands high computational cost. As a result of this, acceleration structures [13][42], sample re nement techniques [32][34] and parallel programming [40], become indispensable tools to optimize it [11]. Inside the Path Tracing, there are different ways of calculating the brightness of the existing materials in nature. The main objective of this study is to analyze the models of the Bidirectional Reflectance Distribution Functions (BRDF) [18], equations responsible for modeling these materials, in order to compare the performance and similarity of the images generated by them. The models analyzed in this study are the diffuse models, Lambert [20] and Oren-Nayar [26], and the specular models, Phong [29] and Cook-Torrance [31]. This comparison has the purpose of listing which di use model and which specular model is suitable for implementation, taking into account the situations of con ict of choice between performance and photorealism, relevant and recurrent question within the context of the real-time algorithm in GPU. This study, by presenting in more detail the elements of the Path Tracing algorithm, an overview of some acceleration techniques and the description and the evaluation of performance of some BRDF models, is a good source of consultation for those who intend to implement the presented models, due to the number of references and discussions cited in the development of this document.