Ray casting is a technology used in many old ‘3D’ games such as Wolfenstein 3D,DOOM. Game engine use ray casting is also called a 2.5 D engine. The limitation of a simple ray casting engine in Wolfenstein 3D is that you can't look up or down – you can’t rotate X axis. Ray casting is fast and simple so before flash 10 which supports 3d, many people used this technology to make some 3D effect. Ray casting can easily create a maze-like world of walls. You can render terrains, too. Terrain rendering is much different from walls, it is also called voxel rendering.
Here are some information about voxel terrains and volume rendering:
http://bruce-lab.blogspot.com/2009/01/terrain-rendering-in-flash.html
Ray casting is different from mode7, mode7 is much more simple, good at rendering floors or grounds, but can’t do with walls.
I collected some good examples of flash based ray casting:
1.Wolfenstein 3D flash ported by Glen Rhodes
Flash ray engine
http://www.glenrhodes.com/wolf/

2. Andre Michelle’s ray caster(source available)
(1)AS3 version
http://lab.andre-michelle.com/raycaster-v3
(2)old as2 version
http://recycle.andre-michelle.com/as2/packages.zip
You can find the source in ‘fla/examples/pro/raycasting’
3.fast ray casting engine
http://gimme.badsectoracula.com/rayfaster/

4. half baked ray casting (source available)
very powerful but use c processor.
Demo:http://hbrc.sourceforge.net/
Source:http://sourceforge.net/projects/hbrc
5.Pixel raycasting engine (source available)
http://www.digital-ist-besser.de/tryouts/raycasting_pixelbased/ (Broken link)
6.http://www.furi.dk/raycaster/
7. Strille’s ray caster(flash5)(source available)
http://www.strille.net/works/raycasting_v2.swf
http://www.strille.net/works/raycasting.swf (source available at flashkit)
8.Frédéric Heintz, aka FredH’s flash maze(source available)
http://www.fredheintz.com/sitefred/flash/maze/maze.html
Find the flash8 source at http://www.fredheintz.com
This one also has a simple editor.
9. doomedonline(source available)
A port of Doom for Flash by Max Herkender
http://code.google.com/p/doomedonline/
http://blog.brokenfunction.com/2007/07/20/flash-plays-doom/
10. Ryan A. Chilton’s Flash doom & quake(source available)
http://esl.eng.ohio-state.edu/~rac/hobby.html
11.Another simple as3 raycaster
http://www.signalsondisplay.com/blog/wp-content/uploads/as3/raycaster/Raycaster.html
12.http://peaceoutside.org/3d.php
13.ericlin’s 3d maze(source available)
http://ericlin2.tripod.com/f3d/maze3d5.html
http://www.gotoandplay.it/_articles/2004/07/el_maze3d.php
This one is not ray casting. It skews movieclips to create a perspective wall effect which is similar to raycasting.
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TUTORIALS
1. F. Permadi’s Ray-Casting Tutorial
http://www.permadi.com/tutorial/raycast/
java source:http://www.permadi.com/java/rayc/Rayc.java
2. Lode's Computer Graphics Tutorial-Raycasting (c++ source available)
http://www.student.kuleuven.be/~m0216922/CG/raycasting.html
3.Another Raycasting Engine Tutorial
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LINKS
1. id Software’s Wolfenstein3D source code
Find it here:ftp://ftp.idsoftware.com/idstuff/
2. A fast java raycaster like doom or wolfenstein 3D (source available)
http://www.shinelife.co.uk/java-maze/

3. Wolfenstein 3D in 20 lines of JavaScript by Mathieu 'p01' Henri (source available)http://www.p01.org/releases/20_lines_Castle_Wolfenstein/
4. JavaScript ray caster by Ben Joffe(source available)
http://www.benjoffe.com/code/demos/canvascape/textures
5.Flash AS3 Ray Casting Tutorial with example and source
http://www.rustyarcade.com/blog/read/33/Ray-Casting-Tutorial
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UPDATE(2009-12-4)
rayfaster 2 test:
http://www.badsectoracula.com/peponi/rayfaster2/
标签: 3D
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