Advanced Graphics

Abstract

The previous chapter dealt with some elementary aspects of image creation. Here, we shall build on our newly acquired knowledge and explore the graphical features of the C-64 still further. We begin with the moving object blocks (MOBs) or, as they are commonly known, sprites. These are high-resolution images, designed especially for use with movement. Consequently, they are ideal candidates for animation, which is also dealt with in this chapter. In addition, the high-resolution mode covered before consisted of two colours — pixels that were turned on had the chosen colour, whereas those turned off had the colour of the display area, thus rendering them invisible. This restriction, however, is not necessary, and on completing this chapter you should be able to produce multicoloured bit-mapped displays. Further, all the characters available to you from the keyboard are produced by the character generator. We shall find out how to change some (or even all) characters to those of your choice. That technique enables you to create special characters, for instance, letters of the Greek alphabet. This feature will be especially appreciated when dealing with mathematical formulae containing special symbols, or when dealing with a foreign text. This chapter also includes a way to enable you to speed up the program execution, by blanking the screen.