Game Engine: Level Editor

Since I my last rewrote, I’ve been focusing mainly on background engine stuff that wasn’t quite where I wanted it to be.  At some point I started working on game-specific stuff as well, although most of it is simply in place to test engine functions.  Well, I wanted to get more focused on game-specific stuff but I realized I was missing some way to efficiently make test levels.  So I started working on a level editor… a few days ago I believe.  I don’t need anything fancy.  Just a basic editor that will let me edit the 2D collision geometry alongside the 3D visual aspects of levels.  I started working on collision geometry part.  All that it requires was being able to draw line segments.  Long story short, I ended up requiring to find a point along the ray created by the conversion from Screen to World coordinates.  The collision geometry is always at a z-value of 0 but this required me to find a point along the ray which had a z-value of 0 so the segments would properly line up with the mouse when you’re drawing them.

This gave me a headache.  I tried several solutions, going from seeing if I could form triangles to find the points I need (which, actually might have worked if I stayed with it) to  arbitrarily adding stuff to the slope formula.  I looked around the internet but couldn’t find something that screamed “This is what you need!”  Perhaps I wasn’t wording it quite right, but then again I wasn’t sure how I should be wording it anyways.

As I am partly hopeful for the future of the Internet (and the people who use it), I half jokingly asked on a Counter-strike server I frequent if anyone knew how to solve this problem.  Inititally, I was met with ridicule, so I let it be.  A short time later, another player started asking questions.  A little bit later, he was showing me parametric functions that I need.  So, I am very grateful for him showing me how to go about doing it.  In doing so I have gained two things:

1. Calculus I != Calculus III and it is something I should read up on as I will be doing crazy stuff like this in the future.
2. A new, very useful function to add to the utilities library.

I figured I needed to UnProject so currently I’m using glut’s implementation of Unproject but I will hopefully be creating my own implementation in soon.

Bottom line – the new editor will definitely be more feature complete and in less time than the previous iteration.  Now, I need to find a good GUI Library where I can simply add a toolbar or new windows without having to use a special framing class.

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