Effect commands

What are effect commands

A pattern table is composed of cells telling the tracker which notes to play in which order. It also has a field for effect commands. It is often represented as a three digit hexadecimal value. The first hex digit represents the effect command, the latter represent parameter values used by the command. The table below summarises all available effects in ProTracker.

Code	Effect	Description
0xy	Arpeggio	This effect alternates the pitch each tick to simulate a chord. xy needs to be greater than 00. First the specified note is played, then the pitch is increased with x semitones, then with y semitones.
1xy	Porta up	Decrease the period value with xy every tick but the first.
2xy	Porta down	Increase the period value with xy every tick but the first.
3xy	Porta to note	Change the period value with xy every tick but the first, untill the specified target note is reached.
4xy	Vibrato	Oscillate the pitch with magnitude x. Where y relates to the oscillation frequency.
5xy	Porta to note + Volume slide	A combination of porta to note (3xy) and volume slide (Axy).
6xy	Vibrato + Volume slide	A combination of vibrato (4xy) and volume slide (Axy).
7xy	Tremolo	Oscillate the volume with magnitude x. Where y relates to the oscillation frequency.
8xy	Not implemented	This effect command is not implemented in ProTracker, nor will it be in this package.
9xy	Set sample offset	This effect causes the note to start playing at an offset (of 256 times xy samples) into the sample, instead of just from the start.
Axy	Volume slide	Change the volume every but the first tick: increase with x, decrease with y.
Bxy	Position jump	Jump to position xy of the pattern sequence table.
Cxy	Set volume	Set the volume with xy.
Dxy	Pattern break	Break to row xy in the next pattern. Note: xy is (even though it is a hexadecimal) interpreted as a decimal.
E0x	Turn filter on/off	If x is even, the (emulated) hardware filter is turned on (for all tracks). It is turned off if x is odd.
E1x	Porta up (fine)	The period value is decreased with x, at the first tick.
E2x	Porta down (fine)	The period value is increased with x, at the first tick.
E3x	Glissando Control	This effect causes a change in the effect 3xy (porta to note). It toggles whether to do a smooth slide or whether to slide in jumps of semitones. When x is 0 it uses a smooth slide, non-zero values will result in jumps.
E4x	Vibrato Waveform	This effect sets the waveform for the vibrato command to follow. With x modulo 4 equals 0, a sine wave is used, with 1 ramp down, with 2 or 3 a square wave. Values greater than 4 causes the ossicating waveform not to retrigger it when a new note is played.
E5x	Set finetune	Set the finetune with x, where x is interpreted as a signed nybble.
E6x	Pattern loop	Set pattern loop start with E60, and loop x times when x is non-zero.
E7x	Tremolo waveform	Same as E4x, but this controls the wave form for the tremolo effect (7xy) rather than the vibrato effect.
E8x	Not implemented	According to official documentation this command is not implemented in ProTracker, but it is. Applies a filter on a looped sample, therewith destroying the original sample data. In many cases this effect is not used like this, rather programmers used this to trigger certain (visual) effects and synchronise those with the music being played.
E9x	Retrigger note	Retrigger the note every x-th tick.
EAx	Volume slide up (fine)	Increase the volume with x at the first tick.
EBx	Volume slide down (fine)	Decrease the volume with x at the first tick.
ECx	Cut note	Cut the volume of the note to zero after x ticks.
EDx	Delay note	The note is triggered with a delay of x ticks.
EEx	Pattern delay	The duration of the row in ticks is multiplied by (x + 1).
EFx	Not implemented	According to official documentation this command is not implemented in ProTracker, but it is. It flips sample data in a looped sample, therewith destroying the original sample data.
Fxy	Set speed or tempo	When xy is smaller then 32, it sets the speed in ticks per row. When xy is greater than 31, it will set the tempo, wich is inversely related to the duration of each tick. Speed and tempo can be defined in combination.

Extracting and updating effect commands

To get an effect command from a ProTracker module, you can simply call pt2_command() to a pt2cell or pt2celllist class object (see vignette("s3class") for a ProTrackR2 object tree). There, are several ways of extracting cells as documented in vignette("sel_assign"). In the example below there is one way shown of getting the effect commands of the first 8 rows of the second column in the third pattern.

mod <- pt2_read_mod(pt2_demo())
pt2_command(
  mod$patterns[[ 3 ]] [ 1:8, 2 ])
#> C40
#> C30
#> 000
#> 000
#> 000
#> 000
#> 000
#> 000

You can also assign new effect commands to your selection like this:

pt2_command(
  mod$patterns[[ 3 ]] [ 1:8, 2 ]) <- "C10"