Name: Module effects description
Tracker: Protracker & Compatible
Players: all? :)
Description by: Firelight
Taken from: FireModDoc 1.0
┌────────────────────────────────────────────────────────────────────────────┐
│ ░▒▓ : SECTION 5 : ▓▒░ │
│ ░▒▓ Effects ▓▒░ │
└────────────────────────────────────────────────────────────────────────────┘
This part of the document is one of the most sorely needed, it actually tells
you HOW to code the effect, not just some vague reference on it and a basic
explanation like I have seen in so many other docs.
TERMINOLOGY:
============
Beside each effect, there are the 2 Y/N boxes.. these are;
T0 : (TICK 0) This means the effect is updated or taken care of at the
start of the row, or when the row is first encountered.
INBETWEEN : This means the effect is updated on the other (speed-1) ticks
that lie inbetween rows.
When coding your player, go for effect Cxy first. It is the easiest and most
substantial effect to enable. It will even make your tune resemble its
normal self :). Then go for effect Fxy (set speed).
┌───────────────────────────────────┐
│ ░▒▓ 5.1 Effect 0xy (Arpeggio) ▓▒░ │ UPDATED: T0 [N] : INBETWEEN [Y]
└───────────────────────────────────┘
This effect alternates the pitch rapidly to simulate a chord. It usually
sounds very grating or harsh so it isnt used much except for chip tunes.
EG:
C-2 01 047 (I want to add to the pitch by 4 half notes then 7)
Range: x = 1st semitone to add to note (0h-Fh)
y = 2nd semitone to add to note (0h-Fh)
so the effect 047 would generate a major, while effect 037 causes a minor.
This is a tick based effect:
Tick 0 Do nothing,
Tick 1 you add the x arg,
Tick 2 you add the y arg,
Tick 3 you reset the frequency
.... go back and do from tick 1 until we reach the next row
You notice if SPEED is 1, then there will be no arpeggiation because there
are no ticks inbetween. If SPEED is 2, then only the x arg is taken into
account.
Each note is 8 fine tunes apart, so use your finetune table to calculate the
next row down if you like, or use a special arpeggio table to find the values
to add.
It is done something like this:
- increment arpcounter by 1
- if arpcounter > 2 arpcounter = 0
- if arpcounter = 0 set the frequency to the normal value
- if arpcounter = 1 set the frequency to the normal value + x # of finetunes
- if arpcounter = 2 set the frequency to the normal value + y # of finetunes
┌───────────────────────────────────┐
│ ░▒▓ 5.2 Effect 1xy (Porta Up) ▓▒░ │ UPDATED: T0 [N] : INBETWEEN [Y]
└───────────────────────────────────┘
This effect causes a pitch slide that goes up.
EG:
C-2 01 104 (I want to slide the frequency up 4 amiga values every tick)
--- 00 104 (slide againt 4 values every tick)
Range: xy = 00h-FFh
You do this by resetting the frequency every tick, EXCEPT for the first one.
The amount to slide by is the value given in EFFECT_PARAMETER
You add the value to the AMIGA value of the frequency.
Tick 0 Do nothing.
Tick 1 add EFFECT_PARAMETER to the amiga frequency, and set it.
Tick 2 add EFFECT_PARAMETER to the amiga frequency, and set it.
Tick 3 add EFFECT_PARAMETER to the amiga frequency, and set it.
.... keep going until end of note
Remember B-3 is the highest note you can use, there is no law against sliding
above it but it is not standard (some mods might be written thinking that
the porta WILL stop at B-3, so be carefull). Personally I stop at 54, or
approximately B-5.
┌─────────────────────────────────────┐
│ ░▒▓ 5.3 Effect 2xy (Porta Down) ▓▒░ │ UPDATED: T0 [N] : INBETWEEN [Y]
└─────────────────────────────────────┘
This effect causes a pitch slide that goes down.
EG:
C-2 01 204 (I want to slide the frequency down 4 amiga values every tick)
--- 00 204 (slide again 4 amiga values every tick)
Range: xy = 00h-FFh
You do this by resetting the frequency every tick, EXCEPT for the first one.
The amount to slide by is the amound given in EFFECT_PARAMETER.
You subtract the value from the AMIGA value of the frequency.
Tick 0 Do nothing.
Tick 1 subtract EFFECT_PARAMETER from the frequency, and set it.
Tick 2 subtract EFFECT_PARAMETER from the frequency, and set it.
Tick 3 subtract EFFECT_PARAMETER from the frequency, and set it.
.... keep going until end of note
Be careful you don't slide too low. Going below C-1 is non standard, and
going below a frequency of 1 could cause horrible side effects :)
┌────────────────────────────────────────┐
│ ░▒▓ 5.4 Effect 3xy (Porta To Note) ▓▒░ │ UPDATED: T0 [Y] : INBETWEEN [Y]
└────────────────────────────────────────┘
This effect causes the pitch to slide towards the note specified.
If there is no note specified it slides towards the last note specified in
the Porta to Note effect.
If no parameter use the last porta speed used for that channel.
EG:
C-2 01 000
D-2 01 301 (I want to set D-2 as the note to slide towards, and with a speed
--- 00 300 of 1, then I just want to keep it sliding to D-2, and you already
--- 00 300 know the speed so I wont bother telling you again)
--- 00 300
Range: xy = 00h-FFh
This effect can be buggy at first, but not too hard.
on TICK 0:
- If there is an argument given to the effect, then you must record that as
PORTA_SPEED[channel]. (You need to remember all 4-8 channels worth of porta
information - I have them as a global array)
- If there is a note given, then you must store that as
NOTE_TO_PORTA_TO[channel].
- But don't slide here, just like the other porta effects.
- also, don't reset the note like you would normally if there was a frequency
given (i.e. the D-2 in our example)
On OTHER ticks:
- Subtract or add PORTA_SPEED to the frequency (in AMIGA units), and set it.
Subtract or add depending on if the current frequency is smaller or larger
than NOTE_TO_PORTA_TO.
┌──────────────────────────────────┐
│ ░▒▓ 5.5 Effect 4xy (Vibrato) ▓▒░ │ UPDATED: T0 [N] : INBETWEEN [Y]
└──────────────────────────────────┘
This effect causes the pitch to waver up and down around the base note.
If no parameter use the last vibrato parameters used for that channel.
EG:
D-2 01 4A2 <- I want to vibrato the note D-2 with speed of A, and depth of 2
--- 00 400 <- Keep vibrating at A2
--- 00 4B3 <- now change to B3
--- 00 400 <- Continue vibrating at B3
Range: x = speed to vibrate at (0h-Fh)
y = depth of vibrato (0h-Fh)
This is simply a case of getting a sine table (the default wavecontrol - see
section 5.20 for other vibrato wavecontrols), and following along it
adjusting the frequency by adding or subtracting the value found according to
the the position of the table, which is incremented by VIBRATO_SPEED.
(ie you skip through the sine table VIBRATO_SPEED positions every tick)
On TICK 0 the 2 vibrato values (position and neg flag) should be cleared to 0
if a new note is played, so we restart the waveform at the start again.
Positioning vibrato pointer
----------------------------
There are 32 positions in the sine table. You want to ADD the values in
the sinetable to the frequency, then once it gets to the end, you want to
go back and SUBTRACT the same values from the frequency. This gives a nice
wave. The reason we do this is because the sine table only contains half
a wave (ie. a bump - see diagram). Running through it once then turning it
upside down by negating it would produce a smooth running wave which
oscillates up and down..
+1| **** /At this point we subtract from frequency
| *** *** /
Current 0 |**** ***|**** **** -> time
| | *** ***
-1| | ****
32
So once your VIBRATO_POS has gone past 32, then subtract 32 from it so it
starts at a respectable place at the beginning again. THEN change the
negation flag (ie flag: 0 for add values, 1 for subtract values).
Sine Table
----------
This is the sine table used by Protracker. If a player calls itself
fully protracker compatible, it really should be using this table. GUSPlay
by Cascada uses a table that is slightly different, but I cant hear the
difference :)
0, 24, 49, 74, 97,120,141,161,
180,197,212,224,235,244,250,253,
255,253,250,244,235,224,212,197,
180,161,141,120, 97, 74, 49, 24
Calculating depth
-----------------
To calculate the amount or depth of the vibrato, you multiply the siner value
by the effect parameter y, THEN you divide it by 128. Remember the divide
by 128 (or shift right 7bits) must be implemented or you'll have some HUGE
vibrato :)
Setting the frequency.
----------------------
- Work out the size of the delta (delta means how much to add or subtract)
- ie. delta = vibrato_depth[CHANNEL] * sine_table[vibrato_pos[CHANNEL] / 128
- if vibrato_negflag[CHANNEL] = 0, then SetFrequency(freq[CHANNEL]+delta)
- else SetFrequency(freq[CHANNEL] - delta)
Example code.
-------------
For those interested this is how mine works, but I don't think it is 100%
if (effect == 0x4 || effect == 0x6) {
// work out the delta
vib = vibdep[track]*sintab[vibpos[track]] >> 7; // >> 7 = div 128
// add the delta to the track's frequency if neg flag = 0
// subtract the delta to the track's frequency if neg flag = 1
if (vibneg[track] == 0) GUSSetFreq(track, GUSfreq(freq[track]+vib));
else GUSSetFreq(track, GUSfreq(freq[track]-vib));
vibpos[track]+=vibspe[track]; // increment vib position
if (vibpos[track] > 31) {
vibpos[track] -=32; // jump back to start
if (vibneg[track]==0) vibneg[track] = 1; // change neg flag
else vibneg[track]=0;
}
}
┌────────────────────────────────────────────┐
│ ░▒▓ 5.6 Effect 5xy (Porta + Vol Slide) ▓▒░ │ UPDATED: T0 [N] : INBETWEEN [Y]
└────────────────────────────────────────────┘
This is a combination of Porta to Note (3xy), and volume slide (Axy).
The parameter does not affect the porta, only the volume.
If no parameter use the last porta to note parameter used for that channel.
EG:
C-1 01 000
D-1 01 301 <- start porta to note using speed of 3.
--- 00 501 <- from here on keep doing porta, but slide volume down 1 as well.
--- 00 501
--- 00 501
Range: x = amount to slide volume up by or (0h-Fh)
y = amount to slide volume down by. (0h-Fh)
This is exactly what it means, just do a 3xy first, then do a volume slide.
The arguments only refer to the volume slide though and do not affect the
porta. The porta is carried on from the last porta to note.
So when you code your effect routine, it's like
if (effect = 03h OR effect = 05h) DO_PORTA_TO_NOTE
if (effect = 0Ah OR effect = 05h) DO_VOLUME_SLIDE
kill 2 birds with 1 stone!
┌────────────────────────────────────────────┐
│ ░▒▓ 5.7 Effect 6xy (Vibrato+Vol Slide) ▓▒░ │ UPDATED: T0 [N] : INBETWEEN [Y]
└────────────────────────────────────────────┘
This is a combination of Vibrato (4xy), and volume slide (Axy).
The parameter does not affect the vibrato, only the volume.
If no parameter use the vibrato parameters used for that channel.
EG:
C-1 01 4A2 <- start Vibrato with speed 0Ah, and depth 2.
--- 00 601 <- from here on keep doing vibrato, but slide volume down 1 as
--- 00 601 well.
--- 00 601
Range: x = amount to slide volume up by or, (0h-Fh)
y = amount to slide volume down by. (0h-Fh)
This is exactly like effect 5xy, but just do a 4xy first, then do a volume
slide.
The arguments only refer to the volume slide though and do not affect the
vibrato. The Vibrato is carried on from the Vibrato.
So when you code your effect routine, it's like
if (effect = 04h OR effect = 06h) DO_PORTA_TO_NOTE
if (effect = 0Ah OR effect = 06h) DO_VOLUME_SLIDE
kill 2 birds with 1 stone again! (hrmm thats 4 birds now :)
┌──────────────────────────────────┐
│ ░▒▓ 5.8 Effect 7xy (Tremolo) ▓▒░ │ UPDATED: T0 [N] : INBETWEEN [Y]
└──────────────────────────────────┘
This effect causes the volume to oscillate up and down in a fluctuating style
around the current volume, like vibrato but affecting volume not pitch.
If no parameter use the last tremolo parameter used for that channel.
EG:
C-2 01 772 (I want to vibrate the volume up and down using speed 7 & depth 2)
--- 00 700 (continue with the tremolo at 7,2)
Range: x = speed to vibrate volume at (0h-Fh)
y = depth of tremolo (0h-Fh)
Seeing as this is a similar effect to vibrato, then we will use the same
tables as it does. The only difference with tremolo is that you divide the
delta (or deviation) by 64 and not 128. You also have to check for if the
volume goes over or under 0 and 64.
This means if the biggest value in the sine table 255 is divided by 64,
then the biggest deviation with depth parameter of 1 would only be 4, on its
peak.
You're probably asking, what if the volume of the channel is 64? Well in
this case you would only hear the negative side of the tremolo, when the
volume dips down and then back to full. Same for the vice versa case if
the volume is set to 0.
On TICK 0 the 2 tremolo values (position and neg flag) should be cleared to 0
if a new note is played, so we restart the waveform at the start again.
This is how it works.
- Work out the size of the delta (delta means how much to add or subtract)
- ie. delta = tremolo_depth[CHANNEL] * sine_table[tremolo_pos[CHANNEL] / 64
if tremolo_negflag[CHANNEL] = 0, then {
check if volume[CHANNEL] + delta > 64 and clip delta accordingly
SetVolume(volume[CHANNEL]+delta)
}
else {
check if volume[CHANNEL] - delta < 0 and clip delta accordingly
SetVolume(volume[CHANNEL] - delta)
}
- increase tremolo_position pointer and set neg flag accordingly (For any
more information check vibrato because they really are the same. It is
explained in more detail, and the sine table mentioned is stored in there
also.)
┌──────────────────────────────┐
│ ░▒▓ 5.9 Effect 8xy (Pan) ▓▒░ │ UPDATED: T0 [N] : INBETWEEN [Y]
└──────────────────────────────┘
This effect is non-Protracker, but is worth mentioning. It was introduced
by Otto Chrons in DMP (dual mod player), and causes the left/right position
of the current channel to be set to the position specified. Hence Panning.
EG:
--- 00 800 (Set the position of the channel to the far left)
00 = far left
40 = middle
80 = far right
A4 = surround *
(* Surround is usually achieved by having 2 copies of the sample, 1 inverted,
and you play them at -exactly- the same time, with one of the pair panned
fully left, and the other (the inverted one say) panned fully right. This
will give a surround effect. If you play both the samples in the same pan
position they will cancel each other out. Experiment with this in a
tracker. Using GoldWave(tm) you can invert a sample.
As efffect 8xy is a channel command, you will have to in effect have 2
channels (voices) ready for this channel, and make sure you set one
voice to the full left, and the other inverted, and to the full left.
You CAN have surround sound on a GUS.)
┌─────────────────────────────────────────┐
│ ░▒▓ 5.10 Effect 9xy (Sample Offset) ▓▒░ │ UPDATED: T0 [Y] : INBETWEEN [N]
└─────────────────────────────────────────┘
This effect causes the note to start playing at an offset into the sample,
instead of just from the start. It is used so that the beginning of a sample
is not played, but skipped.
EG:
C-2 01 942 (I want to start the note playing at 4200h bytes into the sample)
Range: xy = 00h-FFh
As seen in the example, the argument is the first 2 digits of a 4 digit
number (in hex) that the offset should take place from.
so SAMPLE_OFFSET = EFFECT_PARAMETER * 0100h
What you do to enable this effect is when you tell your soundcard or mixing
buffer the start of the sample, also add to it the value SAMPLE_OFFSET and
then play it. Quite simple really.
Remember to check if the user set an offset that is larger than the sample!
┌────────────────────────────────────────┐
│ ░▒▓ 5.11 Effect Axy (Volume Slide) ▓▒░ │ UPDATED: T0 [N] : INBETWEEN [Y]
└────────────────────────────────────────┘
This effect causes the volume of the track to slide up or down.
EG:
A-2 01 A01 <- slide the volume down 1 * (speed-1) units
--- 00 A01 <- slide the volume down 1 * (speed-1) units
--- 00 A01 <- slide the volume down 1 * (speed-1) units
--- 00 A20 <- now slide the volume up 2 * (speed-1) units
--- 00 A20 <- slide the volume up 2 * (speed-1) units
Range: x = amount to slide volume up by or, (0h-Fh)
y = amount to slide volume down by. (0h-Fh)
On this affect you either slide the volume up x, or down y, but not both.
This is a tick based effect so should be processed once a tick but not tick 0.
if x > 0 then slide volume up x
if y > 0 then slide volume down y
if x > 0 and y > 0 then do nothing.
On tick 0:
Take note of the volume slide, but do nothing
On other ticks:
if x > 0 then add x to volume[CHANNEL] and set the volume
if y > 0 then subtract y to volume[CHANNEL] and set the volume
* before setting the volume, make sure you havent slid past 0 or 64.
┌───────────────────────────────────────────┐
│ ░▒▓ 5.12 Effect Bxy (Jump To Pattern) ▓▒░ │ UPDATED: T0 [Y] : INBETWEEN [N]
└───────────────────────────────────────────┘
This effect jumps to a specified channel (in hex)
EG:
--- 00 B10 (I want to jump to order 10h, or 16)
Range: xy = 00h-FFh
This effect is fairly simple, after the ticks for the note are finished,
then reset the position of the order, starting at row 0 again.
Make sure you don't jump over the end of the song length, and if you do then
set it to the last order.
* if you increment your row after your PlayNote() function, then row should
be set to -1, so it is 1 less than 0, then as the tick handler adds 1 to
the row it is 0 again, and nothing is wrong.
┌──────────────────────────────────────┐
│ ░▒▓ 5.13 Effect Cxy (Set Volume) ▓▒░ │ UPDATED: T0 [Y] : INBETWEEN [N]
└──────────────────────────────────────┘
This effect sets the volume of a channel.
EG:
C-2 01 C20 (I want to set the volume of the channel to 20h)
Range: xy = 00h-40h
This is about the easiest and first effect you should code. It is just a
simple case of setting the tracks volume to the argument specified (in hex)
The volume cannot be set past 40h, and if it is then set it to 40h.
Only process this effect on tick 0, and likewise only set the volume on tick
0.
┌─────────────────────────────────────────┐
│ ░▒▓ 5.14 Effect Dxy (Pattern Break) ▓▒░ │ UPDATED: T0 [Y] : INBETWEEN [N]
└─────────────────────────────────────────┘
This effect breaks to the next pattern starting at the specified row.
EG:
--- 00 D32 (I want to break from this pattern and start at row 32 on the next
pattern)
Range: xy = 00h-3Fh (0-63 decimal)
This effect is similair to effect Bxy or pattern jump. You only jump to
the next pattern though, and you start tracking again at the specified row.
The row should not be bigger than 63, and if it is take it as 0.
It works something like this:
- increment order (only once, some mods have more than 1 pbreak on a row
which could cause an increment order twice or more!)
- set row to be x*10 + y. (we have to get the decimal value not the hex)
* if you increment your row after your PlayNote() function, then row should
be set to (x*10+y -1), so it is 1 less, then as the tick handler adds 1 to
to the row again, nothing is wrong.
┌─────────────────────────────────────┐
│ ░▒▓ 5.15 Effect Fxy (Set Speed) ▓▒░ │ UPDATED: T0 [Y] : INBETWEEN [N]
└─────────────────────────────────────┘
This effect sets the speed of the song or the BPM.
EG:
--- 00 F07 (I want to set the speed of the song to 7 ticks a row)
--- 00 F7D (I want to set the bpm of the song to 125 or 7Dh)
Range: xy = 00h-1Fh for speed
xy = 20h-FFh for BPM
This has 2 parts to it. If the user specifies a parameter from 0 - 1Fh, then
it is just simply a case of setting your speed variable, otherwise you need
to set your bpm variable and reset the timer speed. This is demonstrated in
section 3.2 on how to change the speed of the system timer according to
beats per minute.
┌──────────────────────────────────────┐
│ ░▒▓ 5.16 Effect E0x (Set Filter) ▓▒░ │ UPDATED: T0 [Y] : INBETWEEN [N]
└──────────────────────────────────────┘
This effect turns on or off the hardware filter (not applicable to most pc
sound cards)
EG:
--- 00 E01 (I want to turn the filter on)
--- 00 E00 (I want to turn the filter off)
Range: x = 0 to turn hardware filter off, 1 to turn it on (0-1)
There isnt much to say about this effect, except for that it is a hardware
function which was designed to turn on the amiga's filter.
If you wanted to you could try implementing this effect in the SBPro's h/w
filter.
┌─────────────────────────────────────────┐
│ ░▒▓ 5.17 Effect E1x (Fine Porta Up) ▓▒░ │ UPDATED: T0 [Y] : INBETWEEN [N]
└─────────────────────────────────────────┘
This effect slides the pitch up by x amiga value's per row.
EG:
C-2 01 E11 (I want to start at note C-2, and move pitch up one amiga value)
--- 00 E11 (keep sliding up...)
--- 00 E11
Range: x= amount to slide up by. (0h-Fh)
This effect is only processed once per row, on tick 0, and it is as simple
as just subtracting x from the current channel's frequency. (remember you
subtract to raise the pitch.) You don't subtract any finetunes or anything,
just do a straight subtraction of x from the amigaval.
┌───────────────────────────────────────────┐
│ ░▒▓ 5.18 Effect E2x (Fine Porta Down) ▓▒░ │ UPDATED: T0 [Y] : INBETWEEN [N]
└───────────────────────────────────────────┘
This effect slides the pitch down by x amiga value's per row.
EG:
C-2 01 E21 (I want to start at note C-2, and move pitch down one amiga value)
--- 00 E21 (keep sliding down...)
--- 00 E21
Range: x = amount to slide pitch down by. (0h-Fh)
This is identical to effect E2x, except but you add to the amigaval of the
channel by x, and don't subtract.
┌────────────────────────────────────────────┐
│ ░▒▓ 5.19 Effect E3x (Glissando Contrl) ▓▒░ │ UPDATED: T0 [Y] : INBETWEEN [N]
└────────────────────────────────────────────┘
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.
EG:
--- 00 E31 (I want to turn on Glissando and have portas slide in semitones)
--- 00 E30 (I want to turn off Glissando and have portas slide smoothly)
Range: x = 0 to turn off glissando, 1 to turn it on (0-1)
By default this value should be set as 0, or doing a smooth slide. It is
achieved by adding or subtracting the desired porta value too or from the
amiga value in effect 3xy, but you already knew that :).
With glissando turned on it is a different story. It is just simply a case
of setting the frequency to the next highest semitone (or 8 finetune values)
if you are sliding the pitch up, and vice versa for going down.
To implement this just keep a gliss flag and check it while doing your porta
effect in your UpdateEffect function.
┌────────────────────────────────────────────┐
│ ░▒▓ 5.20 Effect E4x (Vibrato Waveform) ▓▒░ │ UPDATED: T0 [Y] : INBETWEEN [N]
└────────────────────────────────────────────┘
This effect set the waveform for the vibrato command to follow.
EG:
--- 00 E42 (I want to select the squarewave function for the vibrato command)
--- 00 E40 (I want to select the default sinewave for the vibrato command)
Range: x = vibrato function to select (0-7)
The following values of x select its corresponding vibrato function
x=0 : Set sine wave (default)
x=1 : Set Ramp Down |\|\|\ _ _
x=2 : Set Squarewave |_| |_| |_
x=3 : Set Random (anywhere)
x=4 : don't retrig Sine waveform
x=5 : don't retrig RampDown waveform
x=6 : don't retrig Squarewave waveform
x=7 : don't retrig random waveform
- Sine wave is covered in the vibrato section (5.5), just apply a sine wave
to the frequency.
- Square wave is simply subtracting and adding the VIB_DEPTH*256
(then divided by 128) to the current frequency, alternating the
add/subtract every VIB_SPEED number of ticks.
- retrig waveform means that you start the vibrato waveform from position 0
everytime a new note is played. If you have set the wave control flag to
4 or more, then the waveform is not restarted, and just continues from the
previous position in the vibrato waveform.
┌────────────────────────────────────────┐
│ ░▒▓ 5.21 Effect E5x (Set Finetune) ▓▒░ │ UPDATED: T0 [Y] : INBETWEEN [N]
└────────────────────────────────────────┘
This effect sets the finetune on a selected instrument.
EG:
--- 01 E5F (I want to set the finetune of instrument 1 to -1)
Range: x = value of finetune to set (0h-0Fh)
if the value is > 7, just subtract 16 from it to get the signed value.
(ie. 0-7 = 0-7, and 8-15 = -8 to -1)
This effect is really easy, and I don't know why more players support it,
apart from it being a useless effect :).
To implement it, just
- check the instrument number
- get the finetune value in the effect
- set the finetune for that instrument.
┌────────────────────────────────────────┐
│ ░▒▓ 5.22 Effect E6x (Pattern Loop) ▓▒░ │ UPDATED: T0 [Y] : INBETWEEN [N]
└────────────────────────────────────────┘
This effect allows the user to loop a part of a pattern x number of times.
EG:
C-2 01 E60 (I want to set the loop start at this point)
--- 00 000
--- 00 E64 (I want to loop back to the starting point 4 times)
Range: x=marks loop starting point, or sets the number of times to loop to
the starting point (0h-0Fh)
This effect is done in the following fashion.
- If parameter x = 0, note down the row number
- if parameter x > 0, then
- if PATTERN_LOOP = 0, then set PATTERN_LOOP = x
else PATTERN_LOOP = PATTERN_LOOP -1
- if PATTERN_LOOP > 0 row = stored row number. (if we are still looping
then jump back)
Remember when declaring the PATTERN_LOOP variable to initialize it as 0.
Jumping back should just be a matter of setting your row number to the stored
pattern loop number, and once the row is finished it should start playing at
the specified position again.
This is how my function works, in the UPDATE_NOTE function, or handler for
tick 0.
case 0x6 : if (eparmy == 0) patlooprow = row; // store position of param=0
else {
if (patloopno == 0) patloopno=eparmy; // set times if 0
else patloopno--; // else subtract 1
if (patloopno > 0) row = patlooprow-1; // if looping do jump
}
┌────────────────────────────────────────────┐
│ ░▒▓ 5.23 Effect E7x (Tremolo WaveForm) ▓▒░ │ UPDATED: T0 [Y] : INBETWEEN [N]
└────────────────────────────────────────────┘
This effect set the waveform for the tremolo command to follow, just like
vibrato.
EG:
--- 00 E42 (I want to select the squarewave function for the tremolo command)
--- 00 E40 (I want to select the default sinewave for the tremolo command)
Range: x = tremolo function to select (0-7)
The following values of x select its corresponding tremolo function
x=0 : Set sine wave (default)
x=1 : Set Ramp Down |\|\|\ _ _
x=2 : Set Squarewave |_| |_| |_
x=3 : Set Random (anywhere)
x=4 : don't retrig Sine waveform
x=5 : don't retrig RampDown waveform
x=6 : don't retrig Squarewave waveform
x=7 : don't retrig random waveform
see section 5.20 for information.
┌──────────────────────────────────────────┐
│ ░▒▓ 5.24 Effect E8x (16 pos panning) ▓▒░ │ UPDATED: T0 [Y] : INBETWEEN [N]
└──────────────────────────────────────────┘
This effect lets you do 16 position panning
EG:
--- 00 E80 (I want to set the channel's pan value to the far left)
--- 00 E8F (I want to set the channel's pan value to the far right)
Range: x=position to pan too (0h-0Fh)
On tick 0, just read in the parameter and set the relative panning value for
the channel.
┌───────────────────────────────────────┐
│ ░▒▓ 5.25 Effect E9x (Retrig Note) ▓▒░ │ UPDATED: T0 [N] : INBETWEEN [Y]
└───────────────────────────────────────┘
This effect retiggers the current note every x ticks.
EG:
C-2 01 E93 (I want to retrig the note every 3 ticks - at speed 6 this would
--- 00 000 retrig it only once)
C-2 01 E91 (I want to retrig the note every tick - at speed 6 this would
retrig the note 5 times)
Range: x=ticks between retriggers (0h-0Fh)
On this effect you need to use the modulus operator to check when the retrig
should happen. If x is 1 say, then it should retrig the note SPEED number of
times in one note.
ie.
tick MOD 1 = 0 always, so you would be retrigging every note.
tick MOD 2 = 0 on even numbers, 1 on odd numbers, so you would be retrigging
every other note.
etc.
When it does happen just play out the note as you would normally. The note is
played on tick 0 as it would normally be.
┌────────────────────────────────────────────┐
│ ░▒▓ 5.26 Effect EAx (Fine VolSlide Up) ▓▒░ │ UPDATED: T0 [Y] : INBETWEEN [N]
└────────────────────────────────────────────┘
This effect slides the volume up x values per row.
EG:
C-2 01 C00 (I want to start at note at volume 0)
--- 00 EA1 (Now I want to slide the volume up for the channel by 1 unit)
--- 00 EA1 (keep sliding up by 1 unit...)
Range: x= amount to slide up by. (0h-Fh)
This effect is only processed once per row, on tick 0, and it is as simple
as just adding x to the current channel's volume.
It is only processed on tick 0, and is not touched at all in the other ticks.
The only checking to be done is for volumes larger than 64.
hint: for all these volume commands, only do the checking for bounds once,
just before you actually set the volume.
┌──────────────────────────────────────────────┐
│ ░▒▓ 5.27 Effect EBx (Fine VolSlide Down) ▓▒░ │ UPDATED: T0 [Y] : INBETWEEN [N]
└──────────────────────────────────────────────┘
This effect slides the volume up x values per row.
EG:
C-2 01 EB1 (I want to slide the volume down for the channel by 1 unit)
--- 00 EB1 (keep sliding down by 1 unit...)
--- 00 EB1 (keep sliding down by 1 unit...)
Range: x= amount to slide up by. (0h-Fh)
This effect is only processed once per row, on tick 0, and it is as simple
as just subtracting x from the current channel's volume.
It is only processed on tick 0, and is not touched at all in the other ticks.
The only checking to be done is for volumes smaller than 0.
hint: for all these volume commands, only do the checking for bounds once,
just before you actually set the volume.
┌────────────────────────────────────┐
│ ░▒▓ 5.28 Effect ECx (Cut Note) ▓▒░ │ UPDATED: T0 [N] : INBETWEEN [Y]
└────────────────────────────────────┘
This effect cuts the volume of the note to 0 after x amount of ticks.
EG: (at speed 6 say)
C-2 01 EC3 (I want to stop the note at tick 3, or half way between 2 notes)
Range: x= number of ticks to wait before zeroing samples volume. (0h-Fh)
This effect is ignored on tick 0, but on tick x when you are updating tick
based effects, then just set the volume of the channel to 0.
Of course if the user specified x as a number more than the speed of the song,
then it would be ok because it would never get to tick x, and the effect is
ignored.
┌──────────────────────────────────────┐
│ ░▒▓ 5.29 Effect EDx (Delay Note) ▓▒░ │ UPDATED: T0 [N] : INBETWEEN [Y]
└──────────────────────────────────────┘
This effect waits for x amount of ticks before it actually plays the sample.
EG: (at speed 6 say)
C-2 01 ED4 (I want to delay playing this note for another 4 ticks)
Range: x= number of ticks to wait before playing sample. (0h-Fh)
This effect is ignored on tick 0, AND you must make sure you don't play the
sample on tick 0.
When you arrive at tick x then just play the sample as you would normally.
Again if the user specified x as a number more than the speed of the song,
then it would be ok because it would never get to tick x, and the effect is
ignored.
┌─────────────────────────────────────────┐
│ ░▒▓ 5.30 Effect EEx (Pattern Delay) ▓▒░ │ UPDATED: T0 [Y] : INBETWEEN [N]
└─────────────────────────────────────────┘
This effect delays the pattern for the time it would take to play x number of
notes.
EG:
C-2 01 EE8 (I want to play the c-2 note then wait for 8 notes before..
C-2 01 000 ... playing the next note)
Range: x= number of notes to delay pattern for. (0h-Fh)
To implement this effect you are going to have to modify your main interrupt
handler (see section 3.3):
You are going to have to keep a counter that is subtracted every time your
SPEED number of ticks is up, but don't play the note. You must still keep
playing the effects though.
It would look something like this.
if (tick >= speed) {
... blah blah blah etc...
if (patdelay == 0) {
increment row.
playnote.
}
else patdelay --;
}
else doeffects
This just boils down to not playing the note or incrementing the row for x
number of notes, until the pattern delay counter is 0. When it is 0 the mod
should keep playing as if nothing had happened.
┌───────────────────────────────────────┐
│ ░▒▓ 5.31 Effect EFx (Invert Loop) ▓▒░ │ UPDATED: T0 [Y] : INBETWEEN [N]
└───────────────────────────────────────┘
This effect inverts a sample loop or plays it backwards.
EG:
C-2 01 EF4 (I want to play the loop in this sample backwards at speed 4)
Range: x = speed to set invert loop at (0h-0Fh)
This effect is not supported in any player or tracker. Don't bother with it.
Made by: FireLight (firelight@yoyo.cc.monash.edu.au)