Things That Didn't Work

As well as the awesome stuff that does work, I thought it might be interesting to talk a little about areas where I've screwed up.  As well as giving the "tried that, it didn't work" perspective on some things that might become feature requests, as well as offering an explanation for why some things might be the way they are, it's also fun to look at some of the things I've tried that were - in retrospect - plain stupid, trying too hard to be clever or cute, or quite obviously heading for a trainwreck.

It also illustrates some things that might be bad but the alternative is worse.  You'll see....

One past example of this was my early attempts at trying to detect if a player could see through water and allowing r_wateralpha to be set depending on the result.  Edge cases and special cases just kept on mounting up, the whole thing was becoming far too complex, and despite everything it was still fragile and throwing up unwanted failure cases.  There was some wisdom in knowing when to just walk away from something that wasn't working, and it took me a long time to realise it.

Here's another one (the one I promised you'd see) that just came up.

Interpolating Particle Ramp Colours

These are used for some particle effects, and give the result of the particle colour shifting over time with rocket trails and explosions.  In vanilla Quake it's an abrupt shift from one colour to another after a certain amount of time (half a second or so) has passed.

So in a fit of "wouldn't it be cool if..." I decided to try interpolating between the colours.  On paper this looks awesome - it's easy to set up, can be quickly done on the GPU, has no measurable performance overhead, and seems like a subtle but worthwhile visual quality improvement.

In reality however the common case is rocket trails, and rocket trails contain a sudden shift from orange to grey.  When you interpolate those the end result is that these particles spend a small but significant portion of their lifetimes as a rather nasty shade of green.

Yes, GREEN.

There's probably a workable solution in there - something like only interpolating between two colours if they lie on the same row of the Quake palette, otherwise do a sudden shift - but with discretion being the better part of valour, this feature was grabbed by the ears and unceremoniously ripped out.

For now a clear case of accepting second best because a technically better and quite elegant alternative turned out to have completely unwanted consequences.  It's not been the first and I'm sure that it won't be the last.