1 Initialization

2 --------------

3

4 Before calling any other function you need to initialize the VR library by

5 calling ``vr_init``. Similarly, ``vr_shutdown`` frees up all resources held by

6 the library.

7

8 Libgoatvr has a number of backend modules for interfacing with VR headsets, and

9 there might be multiple modules compiled with your version of libgoatvr. If you

10 don't want to rely on the built-in defaults, you might want to enumerate and

11 select which module to use.

12

13 The following example initializes the library, and prints the list of available

14 VR modules:

15

16 .. code:: c

17

18 #include <stdio.h>

19 #include <goatvr.h>

20

21 int main(void)

22 {

23 int i, nmod;

24

25 if(vr_init() == -1) {

26 fprintf(stderr, "failed to initialize goatvr\n");

27 return 1;

28 }

29

30 nmod = vr_module_count();

31 printf("There are %d modules:\n", nmod);

32 for(i=0; i<nmod; i++) {

33 printf(" %2d - %s\n", i, vr_module_name(i));

34 }

35 vr_shutdown();

36 return 0;

37 }

38

39 Running this on my computer, with the Oculus Rift DK2 connected, and oculusd

40 running, produces this output::

41

42 initialized LibOVR 0.4.4

43 1 Oculus HMD(s) found

44 [0]: Oculus VR - Oculus Rift DK2

45 using vr module: libovr

46 There are 2 modules:

47 0 - libovr

48 1 - null

49

50 The first four lines come from the initialization of the ``libovr`` module which

51 is selected by default if it's available. If however I turn off the DK2 or stop

52 the daemon, then I'm getting just the ``null`` module in this list.

53

54 If you'd like to override the default selected module, and use the ``null``

55 module instead of ``libovr``, which is useful during development to avoid having

56 to put the HMD on and off all the time, you can call ``vr_use_module(1)``, or

57 ``vr_use_module_named("null")``.