Ray Tracing is an algorithm for generating photo-realistic pictures of the 3D scenes, given scene description, lighting condition and viewing parameters as inputs. The algorithm is inherently convenient for parallelization and the simplest parallelization scheme is for the shared-memory parallel machines (multiprocessors). This paper presents two implementations of the algorithm developed by the authors for alike machines, one using the POSIX threads API and another one using the OpenMP API. | Yugoslav Journal of Operations Research 16 (2006), Number 1, 125-135 AN IMPLEMENTATION OF RAY TRACING ALGORITHM FOR THE MULTIPROCESSOR MACHINES Aleksandar B. SAMARDŽIĆ Faculty of Mathematics, University of Belgrade, Serbia and Montenegro asamardzic@ Dušan STARČEVIĆ Faculty of Organizational Sciences, University of Belgrade, Serbia and Montenegro starcev@ Milan TUBA Faculty of Mathematics, University of Belgrade, Serbia and Montenegro auba@ Received: November 2004 / Accepted: February 2005 Abstract: Ray Tracing is an algorithm for generating photo-realistic pictures of the 3D scenes, given scene description, lighting condition and viewing parameters as inputs. The algorithm is inherently convenient for parallelization and the simplest parallelization scheme is for the shared-memory parallel machines (multiprocessors). This paper presents two implementations of the algorithm developed by the authors for alike machines, one using the POSIX threads API and another one using the OpenMP API. The paper also presents results of rendering some test scenes using these implementations and discusses our parallel algorithm version efficiency. Keywords: Computer graphics, Ray tracing, parallelization, multiprocessors. 1. INTRODUCTION Ray Tracing is an advanced image generation algorithm ([18]). The algorithm consists of the two phases. First phase concerns the visible surface determination. During this phase, imaginary rays are traced from the viewpoint through the various points on 126 A. Samardžić, D. Starčević, M. Tuba / An Implementation of Ray Tracing Algorithm the projection plane and intersected with all objects in scene. The closest intersection that is in front of the viewpoint determines the visible object along this ray. Second phase of the algorithm is conducted then, in order to calculate the illumination at given intersection point. In that order, rays are traced from the intersection point to each light source in .
