I just made an isometric diamond like you had, by using 46x24 pixel tiles. The tiles are square images with the little diamond drawn on them, then I display them on the screen using textured quads. I then used the exact code what dishmoth posted to convert the coordinates of a mouse click to tile coordinates and it worked perfectly. (changing the origin to fit mine, of course)

I used LWJGL and set up my screen coordinates so that (0, 0) is the top left corner, however, the Mouse class sees the top left as (0, screenHeight) so I had to alter the y coordinate before I used it. This could be part of the problem you have been having, so make sure your screen coordinates match your mouse coordinates with whatever you are using.

Good luck 

You might try the solution this site lists (at the bottom of the page)

http://trac.bookofhook.com/bookofhook/trac.cgi/wiki/OverviewOfIsometricEngineDevelopment

make sure to take note:

Runs great except for the game continuing when I have zero lives and I become invincible. 

Recreating a classic arcade game should be easily doable in this time frame, although I don't think the polish is entirely necessary. Getting the gist of a game is probably the more important thing, if they remake Asteroids with the ship as a square and the asteroids as circles I would consider that a success.


I don't think the students will want to do 3D once they see how much work it can be, however, if they think they can tackle it you can always encourage them to do the research for it outside of class. It all comes down to how much effort they want to put in their project. I would recommend that you focus on 2D though as that would be easier to grasp and will allow you to cover aspects specific to programming.

I recommend taking a look at http://fivedots.coe.psu.ac.th/~ad/jg/ for more information on java 2d game programming.

On a side note, my high school offered a java programming course, it was only a trimester and most people did not know any programming but using Greenfoot most were able to create a mostly functional game in about 3 weeks for our final project. I don't really know how much time people worked on it outside of class though.

Windows 7 Pro 32bit
Intel Core 2 Duo T8300 @ 2.4Gz
GeForce 8400M GS 128MB

Windowed:
Shader         58.2 fps
No Shader    72 fps

Fullscreen:
Shader         62.1 fps
No Shader    100-105.5 fps

I think it would be best if you could at least make the skeleton of the site so people can get a better feel for it and better see that you are definitely committed to making and maintaining this site. In addition, you might want to come up with some rules for games to be submitted, genres, size of files, formats, content (e.g. no nudity, racism, etc...) that sort of thing before too long.

Do have any marketing plan at this point to bring interest to your site?

I don't know of any specific java TD tutorials but I did stumble across this TD tutorial for flash. It will at least give you some ideas on mechanics of the game. There are several parts to it.

http://www.emanueleferonato.com/2007/10/06/make-a-flash-game-like-flash-element-tower-defense-part-1/

And another site detailing features of TD games broken down by skill.

http://world-editor-tutorials.thehelper.net/towerdef.php

Hope that helps.