http://www.icarusindie.com/DoItYourSelf/rtsr/index.php?section=java I've been developing software rendering tutorials for a while now and the latest series covers raycasting using Java. There are also tutorials on creating raycasters in Javascript and C++. As you will see from the screenshots at the above link I've got transparent floors, walls and ceilings. Textures have no size limit and all textures are true color. This all started from the http://www.wolf5k.com code. Lesson 7 looks like it will be covering reorganizing the code a bit and defining levels using text files.