Plan for Brett Fattori

Decals, skidmarks, and UV Coordinates... oh my!

Hey folks, it's been a while since I last posted a .plan for y'all to read. I've been watching others post theirs and got the itch to submit my latest developments. dRacer progresses -- slowly. We're addressing the issues that would cause us to go from being a good title, to a great title. Lately I've been working on getting the static decal system merged with our dynamic decaler.



The dynamic decaler is a system that lets us put decals anywhere on the level, on any surface, and network them to the clients. Decals can be spot decals (essentially a square of texture) or a linked decal (like a smear or a skid). The system handles all the under-the-hood stuff like memory pooling and resource management, and exposes a couple of simple methods to add, update, and remove decals.

Here is what the skidmarks looked like, and what I was aiming for:

vs.

These skids were essentially a solid texture that was alpha blended onto the track as a linked decal. The UV coordinates weren't really calculated since the texture was solid. This was the simplest way of doing things, but I was never happy with how they looked. The edges were too sharp, making them look too "computerized".

I sat down and started working out the way to get texture coordinates in a format that I needed to support nice soft skidmarks. I needed to be able to draw a texture across the decal, regardless of how it lined up in world or object coordinates. This led to some challenges and late nights, but eventually I came up with (what I think is) a good solution. I knew it worked when I first saw my test texture line up properly.



Now I could be assured that the skids would bend and twist properly as the car bounced off of walls and careened across the road. I had to try it, so let me share my first test image after getting them to work properly:



...and, just a little showing off -- letting the AI generate lots and lots of skids:



- Brett