How do you read from the raw HID?

So, I have a controller adapter/input sniffer that makes itself usable on PC via HID, but some of the HID's elements are undefined - and those elements store usable controller input data. I'm trying to read this data so that I can build my own input display.

I can't target this data through the Input Actions window (I really wish I could set action binding paths to specific HID descriptor elements or bit/byte offsets!), so I need to be able to target the specific device that I'm trying to read HID data from, read bits/bytes from specific offsets, and parse that data into values I can use (float/integer/axis/bool).

Unfortunately for me, the documentation for HID support isn't complete, so I have zero clues about where to start. Any help would be greatly appreciated.

 

Did you ever find the solution to this?
I am also having the same problem.

 

I can't remember exactly how I handled the Unity side of this, but I can share the work that I did. All I remember is that I got walled by a different bug, and ended up abandoning my attempt. What I ended up with was mostly functional though.

The documentation has improved since I last saw it, though it still suffers from not showing a complete script. There's zero mention of what needs to be included via "using" or the namespace required. I'll include my entire script, but I highly encourage Unity to correct this on the documentation side.

First, two tools that helped me along the way:
HID Trace by "Atomix Productions", and SimpleHIDWrite.
http://domoticx.com/usb-hid-sniffer-software-windows/

You only need one of the above tools - I ended up sticking with SimpleHIDWrite, but both tools do the same job. Pick whichever is easier for you to use.

If you don't have any info about the inner workings of the controller, figuring out how a controller's HID is laid out is a matter of trial and error. Test each input, and see which bytes react. Write them down somewhere.

Here are the notes I took while figuring out how the PS2 variant of the MUNIA adapter (MUSIA) was laid out.
Later on, I got in contact with the developer of the adapter, and they pointed me towards the struct for the adapter for verification.

Code (text):

1. Vendor name: "munia.io"
2. Product name: "MUSIA PS2 controller"
3. Serial No: "03003200"
4.  
5.      VID (hex): 1209
6.      PID (hex): 8844
7. Revision (hex): 010B
8.  
9. Report size (including ReportID):
10.   Input: 20 Bytes
11. Output:  0 Bytes
12. Feature:  0 Bytes
13.  
14.  
15.  
16.        00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F 10 11 12
17.        --------------------------------------------------------
18. RD 00  00 80 80 80 80 80 01 00 00 00 00 00 00 00 00 00 00 00 00
19. _____
20.  
21. 00:  (00 Default)
22. Buttons, Part 1 of 2
23. - 01 Cross
24. - 02 Square
25. - 04 Circle
26. - 08 Triangle
27. - 10 Select
28. - 20 Start
29. - 40 L3
30. - 80 R3
31. _____
32.  
33. 01:  (80 Default)
34. Buttons, Part 2 of 2
35. - 01 L1
36. - 02 R1
37. - 04 L2
38. - 08 R2
39.  
40. D-Pad Directions
41. - 00 Up
42. - 10 Up+Right
43. - 20 Right
44. - 30 Right+Down
45. - 40 Down
46. - 50 Down+Left
47. - 60 Left
48. - 70 Left+Up
49. - 80 D-Pad Rest
50. _____
51.  
52. 02:
53. Left Stick X (80 Default)
54. - 00 Left
55. - FF Right
56. _____
57.  
58. 03:
59. Left Stick Y (80 Default)
60. - 00 Up
61. - FF Down
62. _____
63.  
64. 04:
65. Right Stick X (80 Default)
66. - 00 Left
67. - FF Right
68. _____
69.  
70. 05:
71. Right Stick Y (80 Default)
72. - 00 Up
73. - FF Down
74. _____
75.  
76. 06:
77. Analog Enabled/Disabled Switch (01 Default)
78. - 00 Disabled
79. - 01 Enabled
80. _____
81.  
82. Everything from here onwards is an axis, related to Pressure Sensitivity (00 Default)
83. - 00 Rest
84. - FF Full Press
85.  
86. 07: D-Pad Right
87. 08: D-Pad Left
88. 09: D-Pad Up
89. 0A: D-Pad Down
90. 0B: Triangle
91. 0C: Circle
92. 0D: Cross
93. 0E: Square
94. 0F: L1
95. 10: R1
96. 11: L2
97. 12: R2

And here's the HID script that I ended up with. Take note of [FieldOffset(X)], and how it aligns with each byte above. [FieldOffset(0)] seems to be reserved for the reportID, so the number for each byte will need to be shifted up by one. EG: Byte 00 / [FieldOffset(1)] = All the face buttons, Byte 01 / [FieldOffset(2)] = The shoulders, triggers, and D-Pad directions.. And so on.

Code (CSharp):

1.  
2. using UnityEngine;
3. using UnityEditor;
4. using System.Runtime.InteropServices;
5. using UnityEngine.InputSystem.Layouts;
6. using UnityEngine.InputSystem.LowLevel;
7. using UnityEngine.InputSystem.Utilities;
8.  
9. namespace UnityEngine.InputSystem.LowLevel
10. {
11.     [StructLayout(LayoutKind.Explicit, Size = 20)]
12.     struct DualShock2HIDInputReport : IInputStateTypeInfo
13.     {
14.         public FourCC format => new FourCC('H', 'I', 'D');
15.  
16.         [FieldOffset(0)] public byte reportId;
17.  
18.         [InputControl(name = "buttonSouth", format = "BIT", displayName = "Cross", layout = "Button", bit = 0)]
19.         [InputControl(name = "buttonWest", format = "BIT", displayName = "Square", layout = "Button", bit = 1)]
20.         [InputControl(name = "buttonEast", format = "BIT", displayName = "Circle", layout = "Button", bit = 2)]
21.         [InputControl(name = "buttonNorth", format = "BIT", displayName = "Triangle", layout = "Button", bit = 3)]
22.         [InputControl(name = "select", format = "BIT", displayName = "Select", layout = "Button", bit = 4)]
23.         [InputControl(name = "start", format = "BIT", displayName = "Start", layout = "Button", bit = 5)]
24.         [InputControl(name = "leftStickPress", format = "BIT", displayName = "L3", layout = "Button", bit = 6)]
25.         [InputControl(name = "rightStickPress", format = "BIT", displayName = "R3", layout = "Button", bit = 7)]
26.         [FieldOffset(1)] public byte buttons1;
27.  
28.         [InputControl(name = "leftShoulder", format = "BIT", displayName = "L1", layout = "Button", bit = 0)]
29.         [InputControl(name = "rightShoulder", format = "BIT", displayName = "R1", layout = "Button", bit = 1)]
30.         [InputControl(name = "leftTrigger", format = "BIT", displayName = "L2", layout = "Button", bit = 2)]
31.         [InputControl(name = "rightTrigger", format = "BIT", displayName = "R2", layout = "Button", bit = 3)]
32.         [InputControl(name = "dpad", format = "BIT", layout = "Dpad", sizeInBits = 4, defaultState = 8)]
33.         [InputControl(name = "dpad/up", format = "BIT", layout = "DiscreteButton", bit = 4, sizeInBits = 4, parameters = "minValue=7, maxValue=1, wrapAtValue=7, nullValue=8")]
34.         [InputControl(name = "dpad/right", format = "BIT", layout = "DiscreteButton", bit = 4, sizeInBits = 4, parameters = "minValue=1, maxValue=3")]
35.         [InputControl(name = "dpad/down", format = "BIT", layout = "DiscreteButton", bit = 4, sizeInBits = 4, parameters = "minValue=3, maxValue=5")]
36.         [InputControl(name = "dpad/left", format = "BIT", layout = "DiscreteButton", bit = 4, sizeInBits = 4, parameters = "minValue=5, maxValue=7")]
37.         [FieldOffset(2)] public byte buttons2;
38.  
39.         [InputControl(name = "leftStick", layout = "Stick", format = "VC2B")]
40.         [InputControl(name = "leftStick/x", layout = "Axis", offset = 0, format = "BYTE", parameters = "normalize,normalizeMin=0,normalizeMax=1,normalizeZero=0.5")]
41.         [InputControl(name = "leftStick/left", layout = "Button", offset = 0, format = "BYTE", parameters = "normalize,normalizeMin=0,normalizeMax=1,normalizeZero=0.5,clamp,clampMin=0,clampMax=0.5,invert")]
42.         [InputControl(name = "leftStick/right", layout = "Button", offset = 0, format = "BYTE", parameters = "normalize,normalizeMin=0,normalizeMax=1,normalizeZero=0.5,clamp,clampMin=0.5,clampMax=1")]
43.         [InputControl(name = "leftStick/y", layout = "Axis", offset = 1, format = "BYTE", parameters = "invert,normalize,normalizeMin=0,normalizeMax=1,normalizeZero=0.5")]
44.         [InputControl(name = "leftStick/up", layout = "Button", offset = 1, format = "BYTE", parameters = "normalize,normalizeMin=0,normalizeMax=1,normalizeZero=0.5,clamp,clampMin=0,clampMax=0.5,invert")]
45.         [InputControl(name = "leftStick/down", layout = "Button", offset = 1, format = "BYTE", parameters = "normalize,normalizeMin=0,normalizeMax=1,normalizeZero=0.5,clamp,clampMin=0.5,clampMax=1,invert=false")]
46.         [FieldOffset(3)] public byte leftStickX;
47.         [FieldOffset(4)] public byte leftStickY;
48.  
49.         [InputControl(name = "rightStick", layout = "Stick", format = "VC2B")]
50.         [InputControl(name = "rightStick/x", layout = "Axis", offset = 0, format = "BYTE", parameters = "normalize,normalizeMin=0,normalizeMax=1,normalizeZero=0.5")]
51.         [InputControl(name = "rightStick/left", layout = "Button", offset = 0, format = "BYTE", parameters = "normalize,normalizeMin=0,normalizeMax=1,normalizeZero=0.5,clamp,clampMin=0,clampMax=0.5,invert")]
52.         [InputControl(name = "rightStick/right", layout = "Button", offset = 0, format = "BYTE", parameters = "normalize,normalizeMin=0,normalizeMax=1,normalizeZero=0.5,clamp,clampMin=0.5,clampMax=1")]
53.         [InputControl(name = "rightStick/y", layout = "Axis", offset = 1, format = "BYTE", parameters = "invert,normalize,normalizeMin=0,normalizeMax=1,normalizeZero=0.5")]
54.         [InputControl(name = "rightStick/up", layout = "Button", offset = 1, format = "BYTE", parameters = "normalize,normalizeMin=0,normalizeMax=1,normalizeZero=0.5,clamp,clampMin=0,clampMax=0.5,invert")]
55.         [InputControl(name = "rightStick/down", layout = "Button", offset = 1, format = "BYTE", parameters = "normalize,normalizeMin=0,normalizeMax=1,normalizeZero=0.5,clamp,clampMin=0.5,clampMax=1,invert=false")]
56.         [FieldOffset(5)] public byte rightStickX;
57.         [FieldOffset(6)] public byte rightStickY;
58.  
59.         [InputControl(name = "isPressureOn", format = "BIT", displayName = "Is Pressure On", layout = "Button", bit = 0)]
60.         [FieldOffset(7)] public byte isPressureOn;
61.  
62.         [InputControl(name = "dpadRightPressure", displayName = "DpadRight Pressure", layout = "Axis", format = "BYTE")]
63.         [FieldOffset(8)] public byte pressureDR;
64.  
65.         [InputControl(name = "dpadLeftPressure", displayName = "DpadLeft Pressure", layout = "Axis", format = "BYTE")]
66.         [FieldOffset(9)] public byte pressureDL;
67.  
68.         [InputControl(name = "dpadUpPressure", displayName = "DpadUp Pressure", layout = "Axis", format = "BYTE")]
69.         [FieldOffset(10)] public byte pressureDU;
70.  
71.         [InputControl(name = "dpadDownPressure", displayName = "DpadDown Pressure", layout = "Axis", format = "BYTE")]
72.         [FieldOffset(11)] public byte pressureDD;
73.  
74.         [InputControl(name = "buttonNorthPressure", displayName = "Triangle Pressure", layout = "Axis", format = "BYTE")]
75.         [FieldOffset(12)] public byte pressureBU;
76.  
77.         [InputControl(name = "buttonEastPressure", displayName = "Circle Pressure", layout = "Axis", format = "BYTE")]
78.         [FieldOffset(13)] public byte pressureBR;
79.  
80.         [InputControl(name = "buttonSouthPressure", displayName = "Cross Pressure", layout = "Axis", format = "BYTE")]
81.         [FieldOffset(14)] public byte pressureBD;
82.  
83.         [InputControl(name = "buttonWestPressure", displayName = "Square Pressure", layout = "Axis", format = "BYTE")]
84.         [FieldOffset(15)] public byte pressureBL;
85.  
86.         [InputControl(name = "leftShoulderPressure", displayName = "L1 Pressure", layout = "Axis", format = "BYTE")]
87.         [FieldOffset(16)] public byte pressureL1;
88.  
89.         [InputControl(name = "rightShoulderPressure", displayName = "R1 Pressure", layout = "Axis", format = "BYTE")]
90.         [FieldOffset(17)] public byte pressureR1;
91.  
92.         [InputControl(name = "leftTriggerPressure", displayName = "L2 Pressure", layout = "Axis", format = "BYTE")]
93.         [FieldOffset(18)] public byte pressureL2;
94.  
95.         [InputControl(name = "rightTriggerPressure", displayName = "R2 Pressure", layout = "Axis", format = "BYTE")]
96.         [FieldOffset(19)] public byte pressureR2;
97.     }
98.  
99.     [InputControlLayout(stateType = typeof(DualShock2HIDInputReport))]
100.     #if UNITY_EDITOR
101.     [InitializeOnLoad] // Make sure static constructor is called during startup.
102.     #endif
103.     public class DualShock2GamepadHID : Gamepad
104.     {
105.     static DualShock2GamepadHID()
106.         {
107.         InputSystem.RegisterLayout<DualShock2GamepadHID>(
108.             matches: new InputDeviceMatcher()
109.                 .WithInterface("HID")
110.                 .WithProduct("MUSIA PS2 controller"));
111.         }
112.  
113.         // In the player, trigger the calling of our static constructor
114.         // by having an empty method annotated with RuntimeInitializeOnLoadMethod.
115.         [RuntimeInitializeOnLoadMethod]
116.         static void Init() {}
117.     }
118. }
119.  

I hope these examples point you in the right direction!

 

You can view raw HID memory for figuring out the layout in unity itself without a third party program now. Window -> Analysis -> Input Debugger. Then double click on the device and there is a button that says "state" that will show the raw HID descriptor.

 

I'm guessing it's possible to read Mouse HID?
I have two mice plugged into my PC. Since Unity will only read one Mouse. Can I just read the raw HID values from my second mouse?