notes.txt

Mute Groups
-----------

Menu to select which tracks are muted when pressing Mute Group key combo (need to think of one!)

Echo Speed for Each Voice?
--------------------------

Might be more flexible but needs more parameters/editing space


Multi-Automation
----------------

MLD - LFO Delay, ABC
MLS - LFO Delay, ABC
MLW - LFO Delay, ABC

MAV - AMP Volume, ABD
MAE - AMP Envelope, ABD
MAT - AMP Time, ABCD


Echo
----

Switch  - 1 byte (ABD on, sync mode)
Level A - 1 byte
Level B - 1 byte
Level D - 1 byte
Decay   - 1 byte
Speed   - 1 byte


Song
----
Loop Start Table
Loop Length Table
Song Speed Table
Song Swing Table

00 - FF Song Steps

Modes

OFF = playback is current Pattern in a loop, nothing affects Song
PLY = playback is Song, changing Pattern in Grid not allowed, changing Pattern in Song not allowed
      changing BAR will change playback position (FFW and RWD)
REC = changing Pattern in Song or Grid will change Pattern number on current BAR whether Song is playing
      or not

Song loops unless LP LEN = 0 then it will play to end


If Stopped
	If Song Mode = OFF
		set plyrNextPattern to editor current pattern
		set index to 0, set note counter to 0
	If Song Mode = PLY or REC
		set plyrNextPattern to pattern on current bar
		set pattern index to 0, set note counter to 0

If playing
	Stop
	




Pattern
-------

00 Speed
01 Groove
02 Drum for Track 1
03 Drum for Track 2
04 Drum for Track 3
05 Drum for Track 4
06 Drum for Track 5
07 Drum for Track 6
08 Phrase for Track 1
09 Phrase for Track 2
0A Phrase for Track 3
0B Phrase for Track 4
0C Phrase for Track 5
0D Phrase for Track 6
0E - padding -
0F - padding -

Phrases = 16 steps * 6 bytes per step = 80

COMPRESSION
-----------

480 byte editing buffer in RAM (and 6 bytes for drum allocation per track)
When pattern is selected, decompress selected pattern to editing buffer.
Temporarily replace bank/address pointer of pattern (pointer table would need to be in SRAM)
While editing, edit functions and playback is done on edit buffer
If pattern number changed:
  recompress pattern in edit buffer
  see if it will fit in old place (size compare)
  if not, copy compressed pattern to end of memory, set free space pointer to address where patter used to be
  (always have 480 bytes + 6 free)
  initiate defrag task
If defrag task active, move all pattern date from end of free space to beginning of free space, update
  pattern pointers as we go (all pointers will be valid if done one at a time). Do this X bytes per frame 
  until done. Stop defrag task.

Nice Compression Method
-----------------------
	lda #<source
	sta tmp0
	lda #>source
	sta tmp1
	lda #<dest
	sta tmp2
	lda #>dest
	sta tmp3
	ldx #$60		;96 blocks

:	ldy #$00
	lda (source),y
	beq :+
	sta (dest),y
	iny
	lda (source),y
	sta (dest),y
	iny
	lda (source),y
	sta (dest),y
	iny
	lda (source),y
	sta (dest),y
	iny
	lda (source),y	
	
:	sta (dest),y
	lda tmp2
	clc
	adc #$05
	sta tmp2
	bcc :+
	inc tmp3
:	lda tmp0
	clc
	adc #$05
	sta tmp0
	bcc :+
	inc tmp1
:	dex
	bne :----

	ldy #$00
	lda tmp2
	sta (tmp2),y
	iny
	lda tmp3
	sta (tmp2),y
	rts
	
	
	
	



IDEAS
-----

- Have a mod parameter SLD which is slide amount (instead of being a drum parameter). Only slide if new note
  starts before last note finised (portamento). Only for A, B and C
- Retrigger has dual use - if > $10 then value is probability of note playing $10 = most likely, $FF = least

GATE 00
-------

Possible extra mode where sound generation only lasts for a single step of Pattern. Not sure how to implement could be useful.

ECHO
-----
Need to think about whether implementing Echo is possible. Would essentially have to check envelope phase of all 6 tracks to determine gaps. Needs to be tempo synced so "speed" would actually be number of pattern steps. How would this work with "groove"?

Bigger problem is figuring out how to set the echo for the song and have a setting (or multiple settings) to switch echo on or off.




ADSR
----

The 'curve' setting could also be used as a 'break point'. Envelope would go
1) 00->0F (attack speed)
2) decrease amplitude until it <= 'curve' value
3) continue holding at that level for gate time
4) release

VAPU
----
At time of new note, write voice select flag to tempoarary "active voices" flag, one for each track.

Before writing, check "active voice". If bit not set, don't write.

Write values.

For A, B & D, if envelope phase = 0, clear relevant bit in active voice flags. Write 0 to amp?

For C, if gate timeer finished, clear relevant bit in active voice flags. Write 0 to 'amp'?





Adding A Trigger To The Grid
----------------------------

Default should be: C4, RT 00 and P1-P3 copied from drum definition.
When note is modified, pitch is stored and becomes default.

When deleting a trigger (B+A), all 5 values copied to buffer. Then B+A on empty cell should paste those
values in.



-------------------------------------------------------------------------
Process all 6 tracks, writing output values to VAPU if voice is active
Copy VAPU settings to APU



Each Step

1) Read each drum definition (from RAM) and store in working RAM
2) Apply "patch" to working RAM using variables in that step
3) Initialise new note if required. Each cell has four states: nothing, note, tie note, kill note


Controls
--------

6 different "windows"

- Drum allocation for each track
- Grid editor
- Modulation editor
- Drum editor
- Global settings (speed/groove etc)
- Song editor



Tempo/Groove
-------------

Tempo determined by 2 numbers: 1st applied to even number steps, 2nd applied to odd numbered steps.

e.g. if tempo is 12, speeds are 06/06

02 = 01/01
03
04 = 02/02
05
06 = 03/03
07
08 = 04/04
09 = 03/03
10 = 05/05

Case example
Tempo of 06 = 03/03 straight. 25% swing = 04/02, 50% = 04/02, 75% = 05/01
Tempo of 07 = 04/03 straight. 25% swing = 05/02, 50% = 05/02, 75% = 06/01
Tempo of 08 = 04/04 straight. 25% swing = 05/03, 50% = 06/02, 75% = 07/01
Tempo of 09 = 05/04 straight. 25% swing = 06/03, 50% = 07/02, 75% = 08/01
Tempo of 10 = 05/05 straight. 25% swing = 06/04, 50% = 07/03, 75% = 08/02


Optimisation Cheat
------------------

- Don't process synth on first frame of note (when all the drum patches are copied to RAM)?
- open out synth stuff into one big routine (remove jsr/rtses)?
- move some frequently accessed vars into ZP?


Fetching Drum Patches!
----------------------

As you can't change the drum assigned to a track from within a pattern, only need to fetch
the whole drum patch when a) manually changing a drum assignment on a track or b) changing
the pattern manually in the editor or c) during song playback when a new pattern is
encountered.

Instead of fetching 6 drum patches every pattern step, instead you only need to look at what
parameters are assigned to the real-time controllers and first fetch those from the drum patch
then apply the real-time data to those parameters.