VSC DB #5 – Mipmaps, Audio, Car pivot and more

(Retrospective August 2015)

Here we are again,

yet more highlights from our August updates.

Added ability to save favourite camera positions while in debug camera mode – this became invaluable later on for our video.
Driver helmet gets its very own colour picker interface :) The helmet is the next coolest thing after the car right? So, it has to look good.
We ended up fixing the pivot position for the guide on the cars, since before it was fixed to the front of the bounding box in the centre, now it is correctly set farther back, and even adjustable as in the real world slot cars. As you can see in the image, where an in-line motor chassis example is shown, the maximum drift threshold of 35 degrees is affected considerably by the change, resulting in a far more slot car like experience.

Mipmaps added on all textures: We seemed to have an aliasing problem, especially on the track strips, and with sparkling decals on the cars when moving along the track. There was also an ugly time aliasing seen on the walls and windows when the camera was moving – this was seen as a sort of banding that moved on the texture. Mipmapping to the rescue! Although that wasn’t quite enough. The very low resolution mipmaps went a bit funky and blocky when seen at a greater distance, this was clearly evident when looking down the track at the entire spectrum of mipmaps from full quality to lowest. After putting our thinking caps on... Anisotropic filtering to the rescue! Mission accomplished :) . It's kind of hard to illustrate the true benefit we received from adding the mipmaps in a static image, but if you at least look in the top right hand corner in the image below, you should at least see some of the darker aliasing reduced near the air duct.

Added 16 hand made crash sounds. Lot's of work went into these so that they really give the impression of a mechanically complex metal and plastic car smacking either a wall or another car. They are in several classes from light to heavy collision, and are played accordingly by the engine based on the impact force on the car, with checks to make sure no two instances are the same sample + some random mild pitch shifts for good measure.
Finalised the motor sound for the cars. This was done after 13 iterations, not an easy process. We had to cater to motors varying from 20k RPM to 100K RPM, so it had to sound good after the in game pitch adjuster kicked in for the different motors, and after the Doppler effect did its thing. It was also clear we needed more than a motor sound, we needed all the gears, the chassis, and the movement of the car on the track and the guide rattling in the slot as well. The entire sound was hand made and tweaked to best match what we thought was a good generic sound for slot cars. Later on we would like to make bespoke sounds that better suit the different track types, wooden or plastic, but we think it is very nice for now :).