How does DirectInput generate the GUID for the guidProduct field in DIDEVICEINSTANCE? The documentation reads:
guidProduct
Unique identifier for the product. This identifier is established by the manufacturer of the device.
I am searching for a way to retrieve or synthesize the product GUID for a joystick without using DirectInput. I have successfully used RawInput to retrieve the device path and class GUID, but I have not yet found a way to retrieve the product GUID using RawInput and/or SetupDi* functions.
While searching, I noticed that MAKELONG(VID, PID) == guidProduct.Data1, which makes me hopeful that there is way to do what I want (DirectInput somehow does it, after all.)
Questions:
- Is there an API to retrieve the product GUID for an HID (esp. joystick) device?
- If not, does anyone know how DirectInput synthesizes this field? (The first fields combines VID and PID. What about the rest?)
Edit:
By hacking around the guidProduct field, I came across an interesting discovery. The product GUID for the P880 USB gamepad has the following format:
010906a3-0000-0000-0000-504944564944
The first 4 bytes are quite evidently the PID and VID for the controller. The last part of the GUID is common for all HID controllers in my possession. After a while it dawned on me - they are ASCII characters! The translation is:
010906a3-0000-0000-0000-504944564944
010906a3-0000-0000-0000- P I D V I D
PID_VID_-0000-0000-0000-'P I D"V I D'
I have verified this using the SDL2 game controller database, and it appears to hold! Of course, this does not cover bluetooth devices (such as the OUYA controller), which is only a minor issue for now.
Does anyone know how guidProduct is composed for bluetooth devices?
