182 lines
4.3 KiB
Markdown
182 lines
4.3 KiB
Markdown
Technical Notes
|
|
===============
|
|
|
|
It took me a lot of time digging around the Internet to find some of this stuff.
|
|
I'm writing down the highlights here,
|
|
so that when original sources fall off the net,
|
|
hopefully at least my notes will still be around.
|
|
|
|
|
|
Sample Rate
|
|
-----------
|
|
|
|
If `DEBUGY0' is defined,
|
|
the number of samples taken since the last HID report
|
|
is sent as Y axis on hat 0.
|
|
You can use the
|
|
[included gamepad tester](gamepad.html),
|
|
to see the approximate number of samples as an integer.
|
|
|
|
This is approximate,
|
|
because the browser encodes the value as a real number between -1 and 1.
|
|
We convert it back, but may lose a little precision.
|
|
It's close enough for me,
|
|
hopefully it's close enough for you.
|
|
|
|
This number will not be very useful
|
|
unless you are polling the wammy bar,
|
|
since without that input,
|
|
updates are only sent when a button state changes.
|
|
|
|
|
|
Debouncing
|
|
----------
|
|
|
|
Using `millis()` time to debounce the switch
|
|
roughly halved my sample frequency.
|
|
So instead, I do some preprocessor arithmetic
|
|
to calculate how many samples to take after an edge,
|
|
in order to debounce switches.
|
|
|
|
The drum controller was a partcular pain:
|
|
in addition to the switch bouncing,
|
|
the stick was bouncing on the rubber pad.
|
|
I settled on a 40ms silence window as feeling pretty good.
|
|
You can adjust this if you want to.
|
|
|
|
|
|
|
|
USB Junk
|
|
========
|
|
|
|
Gamepad Buttons
|
|
---------------
|
|
|
|
The `buttons` struct member is a bitmap,
|
|
each bit mapping to one of the 12 buttons reported through HID.
|
|
Here's what each bit means:
|
|
|
|
* 0o00: Blue
|
|
* 0o01: Green
|
|
* 0o02: Red
|
|
* 0o03: Yellow
|
|
* 0o04: Orange
|
|
* 0o05: Tilt Switch / 2x kick
|
|
* 0o06: Solo modifier (second row of buttons on guitar)
|
|
* 0o07: ???
|
|
* 0o10: Minus
|
|
* 0o11: Plus
|
|
* 0o12: Drum pad modifier
|
|
* 0o13: Cymbal modifier
|
|
* 0o14: Select
|
|
|
|
Hats
|
|
----
|
|
|
|
I guess "hats" are what I would have called "joysticks and dpads".
|
|
|
|
|
|
### Hat 0: unknown
|
|
|
|
This doesn't appear to be sent or used.
|
|
|
|
### Hat 1: guitar analog controls
|
|
|
|
The X axis is the position of the wammy bar.
|
|
|
|
The Y axis is the pickup selector.
|
|
I believe this was a 5-position switch on some guitars.
|
|
Only Rock Band 1 seems to use this.
|
|
|
|
### Hat 2: navigation
|
|
|
|
Sent by the dpad on the controller,
|
|
as `hatAndConstant`.
|
|
|
|
Guitars send up/down for the up/down strum buttons.
|
|
Drums send up/down on the blue/yellow cymbal pads.
|
|
|
|
The position of this digital input is reported in only 3 bits:
|
|
|
|
7 0 1
|
|
|
|
6 8 2
|
|
|
|
5 4 3
|
|
|
|
0 is up,
|
|
2 is right,
|
|
4 is down,
|
|
6 is left,
|
|
and 8 is centered.
|
|
|
|
|
|
velocity
|
|
--------
|
|
|
|
I don't know how I can verify that I'm setting this right,
|
|
but the `rbdrum2midi` program looks at these bytes to detect hits.
|
|
I set them to 127 when a hit is detected on the digital pin.
|
|
|
|
Sending these values does not seem to cause problems with my Wii games.
|
|
|
|
|
|
Product ID (PID)
|
|
----------------
|
|
|
|
The following USB PIDs are recognized by various things:
|
|
|
|
* 0x0003: XBox Drum
|
|
* 0x0004: Wii Guitar
|
|
* 0x0005: Wii Drums - Rock Band 1
|
|
* 0x3110: Wii Drums - Rock Band 2
|
|
|
|
There are some quirks to note:
|
|
|
|
* Rock Band 3 won't recognize cymbal hits on PID=0x0005,
|
|
but the same program with PID=0x3110 works fine.
|
|
* Wii games don't appear to recognized PID=0x0003.
|
|
Maybe Rock Band 3 does: I didn't test that one.
|
|
|
|
|
|
Drum Velocity
|
|
--------
|
|
|
|
I split the 12 "reserved" bytes from Nicholas's
|
|
`struct InstrumentButtonState`
|
|
into 4 bytes of I-Don't-Know,
|
|
4 bytes of velocity,
|
|
and 4 more bytes of I-Don't-Know.
|
|
Whenever a pad is hit,
|
|
I send 127 on the corresponding velocity.
|
|
|
|
I did this because a program called `rbdrum2midi`
|
|
ignores the button press events,
|
|
and looks only at the velocity values.
|
|
|
|
None of the Wii games I have
|
|
seem to care what these values are set to.
|
|
Clone Hero also does not care.
|
|
|
|
|
|
Clone Hero
|
|
==========
|
|
|
|
Clone Hero wants Hat 2 up on yellow cymbal hit,
|
|
and Hat 2 down on blue cymbal hit.
|
|
|
|
If it doesn't see these while mapping drum pads,
|
|
then hitting any color bad will trigger both drum and cymbal for that color.
|
|
|
|
|
|
References
|
|
==========
|
|
|
|
The most valuable sources of information I found were:
|
|
|
|
* [Nicholas Angle's reverse-engineering write-up](https://www.niangames.com/articles/reverse-engineering-rockband-guitar-controllers)
|
|
* [Nicholas Angle's guitar controller program](https://github.com/NianZo/WiiGuitarController)
|
|
* [Clone Hero Wiki: Drum Mapping Guide](https://wiki.clonehero.net/books/guitars-drums-controllers/page/drum-mapping-guide)
|
|
* [rbdrum2midi source code](https://github.com/rbdrum2midi/rbdrum2midi)
|
|
|