An Effect is a sequence of up to 31 events that are applied to the Pattern note, optionally looped and always run top down.
Offsets in the effects always range from -16 to +15.
The first column is the index, the next red column holds a » symbol to indicate the row is played or a L to indicate the effect is looped to this row after reaching the end. Any row not containing either of these symbols are processed but do not consume any time.
However it is absolutely vital that any looped Effect always contains at least one » in it in order to give the player time to process other elements of the music.
Each entry can be one of 8 types and are as follows
0 Loop or End
A Loop or End is always shown as a blank entry in the Display. A loop may be set to any row in the Effect using (by Default) Shift+L.
Looping is always on the condition the volume has not reached beyond 15 or below 0.
1 Noise Off
On the playing of any note in the pattern the default setting is Noise Off, Tone On, EG Off. However any noise change made in the Effects may need to be switched off using this command.
2 EG Off
If an EG Offset is used in the Effects the EG will automatically take over Volume control for that channel. This command will disconnect the link and restore the original volume.
3 Tone Off
If a pitch offset is used or the effect has just started the Tone flag (which links the Chip channel square wave to the volume (or EG) register) will be enabled. However this command may disable the tone. The usual instance of using this command is where the mixing of EG and chip Pitch is not desired.
4 Tone On and Pitch Offset
This will enable the Tone on the channel and provides an offset for the pitch (always relative to the Ornament or if not used then the Note).
5 Noise On and Noise Offset
This enables noise on the channel (by default noise is disabled) and sets an offset (relative either to Pattern Noise column (if used) or 0). Noise ranges from 0 to 31 (0 being sharp, 31 is rough).
6 EG On and EGPeriod Offset
This command assigns Volume control to the EG and allows one to specify an EG Period Offset which is relative to the last one set in the EGC column.
7 Tone On and Volume Offset
This enables Tone(Which by default is enabled) and permits a volume offset to be specified. Volume offsets are accumulative and when the volume reaches beyond 15 or below 0 this will disable any loop that resides in the Effect.
So a simple decay of the volume from the Pattern volume to zero can be accomplished through an effect like this..
00 L PITCH +00
01 » VOLUME-01
The above effect will decrement the volume in the second row. Then on reaching the end it will loop to row 1 and decrement the volume again. It will continue doing this until the volume has reached below Zero.
Note the inclusion of the Pitch. This is neccesary currently only because the loop will always execute the next instruction immediately so that no delay is heard. Subsequent versions may improve on this.
Another example is to add vibrato to the effect. Vibrato consists of an oscillation of the pitch.
00 L PITCH +00
01 » VOLUME+00
02 PITCH +01
03 » VOLUME+00
04 PITCH +02
05 » VOLUME+00
06 PITCH +03
07 » VOLUME+00
08 PITCH +02
09 » VOLUME+00
10 PITCH +01
11 » VOLUME+00
12 PITCH +00
13 » VOLUME+00
14 PITCH -01
15 » VOLUME+00
16 PITCH -02
17 » VOLUME+00
18 PITCH -03
19 » VOLUME+00
20 PITCH -02
21 » VOLUME+00
22 PITCH -01
23 » VOLUME-01
Note that only the last row decrements the volume which will therefore occur every 23rd time the Effect is called. This gives the Effect time to oscillate the current pitch.
Also note that the offsets are all relative to the original Pattern note pitch but the volume change is always permanent.