1.3 KiB
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| uid |
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| arfoundation-extensions |
Extending AR Foundation
Due to platform-specific implementation differences between provider plug-ins, AR Foundation may not expose the entire contents of a platform SDK via C#. Instead, AR Foundation provides a native pointer to access platform-specific functionality and data when applicable. For example, the XRSessionSubsystem has a nativePtr property.
Each provider plug-in defines what each native pointer points to. In general, a pointer points to a struct whose first member is an int that contains a version number followed by the raw pointer.
In C, the XRSessionSubsystem.nativePtr might point to a struct like this:
typedef struct UnityXRNativeSessionPtr
{
int version;
void* session;
} UnityXRNativeSessionPtr;
Structure packing and alignment rules vary by platform, so the void* session pointer isn't necessarily at a 4 byte offset. On a 64-bit platform, for instance, the pointer might be offset by 8 bytes to ensure the pointer is on an 8 byte boundary.
All trackables (such as planes, tracked images, or faces) provide a native pointer. You can use these pointers to access native data structures such as the native frame, session, plane, anchor, and so on.