The Observer and the Orthographic Projection

Abstract

We now address the problem of representing views of three-dimensional scenes on the graphics viewport. There are three major stages. In chapter 7 we saw how to construct a model of a three-dimensional scene in ACTUAL position. In this chapter we consider observing the scene and the display of a corresponding view. The display of the scene is co-ordinated by routine DRAWIT which may take a number of different forms, depending on the type of image required (line drawing, colour etc). This routine will be called at the end of the SCENE routine after the construction of the model and the positioning of the observer. We shall deal with the observer before going on to consider the DRAWIT display.