Game Programming with the Simple DirectMedia Layer
The animation routine uses the dirty pixels technique so only a small portion of the screen is redrawn for each frame. With this technique, we keep track of the last position in which an object was drawn and the new position. When Bounce draws the Earth, first it erases the dirty pixels where it was by filling them with the background color, and then it draws the Earth in its new location. We fill rectangles and draw images using:
SDL_FillRect(screen, rectangle, color); SDL_BlitSurface(image, NULL, screen, rectangle);
SDL_FillRect() fills a rectangle in an SDL_Surface, like the screen, with a color. The rectangle is specified using an SDL_Rect structure, and the color is created using SDL_MapRGB(). SDL_BlitSurface() copies a rectangle from one surface into a rectangle in another surface. If the source rectangle is NULL then the whole surface is copied. SDL_BlitSurface() is the routine that applies the color key and takes advantage of RLE encoding.
SDL reduces the time it takes to write games on Linux. It is small enough that learning it is a project, not a career, and it is powerful enough for commercial applications. I hope that between the information in this article and the source code for Bounce, you have learned enough of SDL to start modifying Bounce and building your own SDL games.
Bob Pendleton's first programming assignment was to port games from an HP minicomputer to a UNIVAC mainframe, and he has been fascinated by computer games ever since. He has been working with various versions of UNIX and Linux since 1981. He is an independent software developer and writer. You can reach him at Bob@Pendleton.com.
One Click, Universal Protection: Implementing Centralized Security Policies on Linux Systems
Join editor Bill Childers and Bit9's Paul Riegle on April 27 at 12pm Central to learn how to keep your Linux systems secure.
Free to Linux Journal readers.Register Now!
|diff -u: What's New in Kernel Development||Aug 20, 2014|
|Security Hardening with Ansible||Aug 18, 2014|
|Monitoring Android Traffic with Wireshark||Aug 14, 2014|
|IndieBox: for Gamers Who Miss Boxes!||Aug 13, 2014|
|Non-Linux FOSS: a Virtualized Cisco Infrastructure?||Aug 11, 2014|
|Linux Security Threats on the Rise||Aug 08, 2014|
- diff -u: What's New in Kernel Development
- NSA: Linux Journal is an "extremist forum" and its readers get flagged for extra surveillance
- Security Hardening with Ansible
- Raspberry Pi: the Perfect Home Server
- Containers—Not Virtual Machines—Are the Future Cloud
- Tech Tip: Really Simple HTTP Server with Python
- Monitoring Android Traffic with Wireshark
- Examining Load Average
- Returning Values from Bash Functions
- Managing Initscripts with Red Hat's chkconfig