If you were to load this particular sprite and draw it transparently, the transparent pixels around the ball would not be drawn, so you would only see the ball. Figure 11.1 illustrates this concept.įigure 11.1: The dark circle represents the pixels used by the sprite, and the lighter color around the circle represents the transparent pixels. When the sprite is drawn on the screen, any pixels with that transparent color are not drawn, which results in the background showing through the sprite in those places. Transparency in a sprite is defined by pixels in the source bitmap that are set to a certain color. Will a particular sprite be a solid image or will it have transparent pixels? Will the sprite automatically move in a specified way on the screen, or will it respond interactively to the player? Before these questions even arise, however, how do you create a sprite and load the graphic image (or images) it uses? This chapter addresses these questions. There are many ways to create a sprite and many ways to program its functionality. This chapter explains not only how to use sprites, but also why you would want to learn about sprite programming in this modern era of 3D gaming.Ī sprite is a small, two-dimensional bitmap that is drawn to the screen at a specified position and usually with transparency. There are some games that are meant to be played a certain way, and Civilization III just wouldn't be a Civilization game if it didn't run in 2D. In fact, Civilization III uses 3D models in a 2D fashion. The reason is not that 2D games are easier to program or that 3D models are difficult to design. Why do you suppose anyone would develop a 2D game in today's world of advanced 3D video cards? The argument might be made that games have not been able to tap the potential of the latest generation of video cards, and yet new graphics chips are developed every six to twelve months, often doubling the performance of the previous chip. Yet despite the fact that this game is 2D, it is a phenomenal best-selling game. The game is designed as an isometric turn-based strategy game, and simply does not need to run in 3D mode. That game has some fantastic 3D models in it, but the models are all pre-rendered and stored as snapshots to be drawn on the screen as sprites. Numerous commercial games are released each year that run in 2D using graphics very much like the sprites used in classic arcade games such as Heavy Barrel and Akari Warriors.Ĭonsider Sid Meier's Civilization III, for instance. Although the subject of sprites might seem dated and irrelevant today, the truth is quite contrary. In the old days, before video games ran in 3D, all game graphics were hand-drawn and displayed on the screen as static, non-moving objects or as animated sprites.

Galaxian sprites