= Sunday, August 26, 2007 =
Roto-Tracker
“…a primitive drum loop tracker, allowing the user to pick out simple repeating patterns with various percussion instruments.”
“The concept is fairly straightforward.
A central physical rotor smoothly turns (counterclockwise) through 360 degrees, using llTargetOmega. Spaced out over 180 degrees (22.5 degrees apart) are eight collision sensors (shown as white columns of light), which use filtered collision events and llVolumeDetect to sense the passing of the rotor.
Each time the rotor passes through the sensor’s volume, the light briefly flickers off (as if the rotor is blocking it- a superfluous effect, but kind of neat) and the selected sound sample is played. The rotor moves on, the next sample is played, and so on.
Each collision sensor comes loaded with 15 drum sounds, including various tom-toms, a bass drum, a taiko drum, a snare, a couple of cymbals, some wood blocks and, of course, a cow bell. The user cycles through the sound samples by clicking on the base of the lights. The sounds for a given sensor can be turned off altogether, as well.
The rotor has three speeds: low (about 48 beats per minute), medium (96 BPM), and high (192 BPM), where a “beat” in this case is defined as a single sample played by a sensor. The random control directs the eight sensors to select random sound samples, or randomly turn themselves off. A sync control is provided to synchronize the rotors of multiple adjacent Roto-Trackers, allowing more complex patterns. Using multiple trackers, and a relatively lag-free sim (unfortunately, severe lag sometimes pulls rotors back out of sync), some fairly complex drum loops can be created.”