Thursday, January 10, 2013

Kick-ass Lighting Part 1: Sector Based

Back in the days of yore, when Wadauthor was king and Mordeth was definitely going to be released 'any day now',  lighting was a much more laborious process. Good lighting was something to be revered as there was no easy way to go about implementing it.  Some of the lighting methods in Doom wads that were created out of necessity had become standardized in that time and unfortunately have carried over in the glorious years of Doombuilder. The old dominion is dead, and many of the restricted ways in which lighting is looked at can go with it. Huzzah!

There's two very important features in DB2 that make implementing less restricted lighting possible. The first is automatic texture alignments in a real-time 3d viewing mode.  With the clunky mapping interface of Wadauthor and other editors of the like,  it became pretty easy to avoid lighting walls as well as floors/ceilings.  Aligning textures was the bane of every mapper's build process.  The second is being able to recklessly draw across and divide sectors till your heart's content.  This allows mappers to not have to choose between complex floor/ceiling geometry and smooth, gradient lighting.

Lighting is really hard to pin down as to what's going to look good in what kind of map. My personal preference is in hellish type maps,  big, bold sweeping lighting over large areas and more high contrast, tighter lighting in base type maps.  This is all on the mapper as to what your taste is and what's going to look appropriate to your map,  but perhaps I can lay down my process and it can be of some assistance.




What a godawful mess!   I categorize a room into two sides; Pre-lighting and post-lighting.  Pre-lighting is all the geometry laid out, where I'm 100% satisfied with how the room looks from a design point of view.  Post-lighting,  there's really no going back.  After the core of the design is done, I put myself at the mercy of however I placed light textures. "The lights gonna light how the lights gonna light", which basically translates to, if I put a light in an area with some heavy duty geometry,  that light isn't going to be less bright or gradient less because it isn't convenient for me to implement it.  I get really reckless in this process and draw across many sectors,  leaving many smaller, micro sectors, and triangle slivers.  Not exactly safe passage for any perfectionist.

This is personal preference,  but square lights I almost gradient out in a square pattern.  I find that a lot of angles in light gradients look wonky in Doom. I do, however, adore the look of a squared gradient over a curved surface, as you can see in the top right and bottom left hand corner of the editor mode shot.


Natural, outdoor lighting I'll play around with a bit more.  Outdoor areas are almost entirely 'high noon',  as in no highfalutin' angular shadows or anything like that.  Again,  personal preference. I've seen it executed really well,  but when you open that can of worms, it's going to affect the geometry you can work with and still have the effect look convincing.  Another thing you might notice in the second shot is the light coming into the room is only slightly brighter than the base, indoor levels.  It's more of a strong, subtraction gradient behind the columns that adds a nice bit of contrast   You can also see how unworkable that room is in the post-lighting process. 

The last thing I'll mention is a few rules of thumb I abide by in the lighting process:
- Give the walls as much if not more attention than floors - The vertical stays in the players field of view more-so than the flat.

- 9 times out of 10, Doom's standard sector lighting mode looks better than a lighting level transfer.  Unless there is a serious vertical difference in the ceiling and the light (more than 16 units), I'll almost always use standard.  It may not be more "realistic" (ugh),  but having the light cover more space just looks that much more aesthetically pleasing.

- If at all possible,  subtract!  Shadow casting can look really slick if used properly.

That's it for now - I'll get into GZDoom and mixing 3d lights with sector based lighting next time around.

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