reconfiguring directory

README.md

@@ -6,14 +6,62 @@ experiments with [uxn](https://wiki.xxiivv.com/site/uxn.html) programming.
 
 ## nibble dice tracker
 
-`nibble-dice-tracker.tal` a tracker based on nibble dice as described by maleza:
+`nibble-dice-tracker.tal` a 3-channel music tracker based on the nibble dice described by maleza.
+
+[uxn nibble dice tracker - demo video](https://video.anartist.org/videos/watch/6d2d4a2c-78ef-48c8-abd0-e124451805cb)
+
+### interface
+
+the interface consists in 3 sections, one for each audio channel/device.
+
+each section consists in 2 columns. the right column of a section has an indicator for the position of the "beat", and its state (playing or not).
+
+each column consists in 8 bytes.
+
+a byte consists in 2 contiguous nibble dice: the one at the left is the *high* nibble, and the one at the right is the *low* nibble.
+
+the bytes in a section map to the following aspects of the tracker and [audio device](https://wiki.xxiivv.com/site/uxnemu.html#audio):
+
+* period ( 1 byte ) - how many frames have to happen to trigger a beat. 
+	- if 0, the device is off
+* pattern ( 8 bits ) - each bit indicates if a note has to be played or not in that beat
+	- bit 0 (least significant bit) corresponds to beat 0, bit 1 to beat 1, and so on.
+* beatcount ( 2 nibbles ) - definition of the beat count behavior
+	- low nibble: how many beats happen in a cycle. if 0, there are no beats.
+	- high nibble: beat offset; starting value for the beat count.
+	- e.g. if high nibble is 2, and low nibble is 4, the beat count will repeat as 2, 3, 4, 5
+* adsr ( 2 bytes ) - envelope values, as described by the [audio device](https://wiki.xxiivv.com/site/uxnemu.html#audio) reference
+* volume ( 2 nibbles ) - left and right volume values, as described by the audio device reference
+* sample ( 2 nibbles and 1 byte ) - definition of the sample to be used
+	- high nibble: index of sample to use:
+		* 0: saw
+		* 1: main (program code)
+		* 2: piano
+		* 3: triangular
+	- low nibble + byte: length of the sample to use
+* melody ( 8 bytes ) - [midi](https://wiki.xxiivv.com/site/midi.html) notes corresponding to beats 0 to 7, from top to bottom.
+
+
+### controls
+
+* Arrow key up, or `k` : move cursor to previous byte
+* Arrow key down, or `j`: move cursor to next byte
+* Arrow key left, or `h`: move cursor to previous nibble
+* Arrow key right, or `l`: move cursor to next nibble
+* `Ctrl` or `+`: increment nibble
+* `Alt` or `-`: decrement nibble
+
+### nibble dice references
 
 * [no binario - pachapunk](https://pachapunk.space/nobinario.html)
 * [XXIIVV nibble dice](https://wiki.xxiivv.com/site/nibble_dice.html)
 
 # roms
 
-ready-assembled projects
+ready-assembled projects:
+
+* `nibble-dice-tracker.rom`
+* `darena.rom`
 
 # sketches
 

projects/nibble-dice-tracker.tal

@@ -65,13 +65,6 @@
 &period $1 &pattern $1 &beatcount $1 &adsr $2 &volume $1 &sample $2
 &melody $8
 
-@framecount0 $1
-@framecount1 $1
-@framecount2 $1
-@beat0 $1
-@beat1 $1
-@beat2 $1
-
 
 ( program )
 @main
@@ -274,6 +267,8 @@ RTN
 	.Controller/key DEI
   DUP LIT 'j EQU ,&down JCN
   DUP LIT 'k EQU ,&up JCN
+  DUP LIT 'h EQU ,&left JCN
+  DUP LIT 'l EQU ,&right JCN
   DUP LIT '+ EQU ,&inc-nibble JCN
   DUP LIT '- EQU ,&dec-nibble JCN
   POP BRK