rm TRACKER devices for now;

This is not the correct way to expose them.  It doesn't seem like
there is consensus on how to expose them yet.  At the very least
LÖVR should instead use the hardcoded OpenVR tracker paths like
/camera, /keyboard, /foot/left, /foot/right, etc.

See these issues:

- https://github.com/ValveSoftware/openvr/issues/1030
- https://github.com/ValveSoftware/openvr/issues/962

src/api/l_headset.c

@@ -32,10 +32,6 @@ const char* Devices[] = {
   [DEVICE_HAND_RIGHT] = "hand/right",
   [DEVICE_EYE_LEFT] = "eye/left",
   [DEVICE_EYE_RIGHT] = "eye/right",
-  [DEVICE_TRACKER_1] = "tracker/1",
-  [DEVICE_TRACKER_2] = "tracker/2",
-  [DEVICE_TRACKER_3] = "tracker/3",
-  [DEVICE_TRACKER_4] = "tracker/4",
   NULL
 };
 
@@ -516,47 +512,16 @@ static int l_lovrHeadsetGetMirrorTexture(lua_State* L) {
   return 1;
 }
 
-static int deviceIterator(lua_State* L) {
-  size_t index = lua_tointeger(L, lua_upvalueindex(1));
-  Device* devices = (Device*) lua_touserdata(L, lua_upvalueindex(2));
-  size_t count = lua_tointeger(L, lua_upvalueindex(3));
-  float position[3], orientation[4];
-
-  while (index < count) {
-    FOREACH_TRACKING_DRIVER(driver) {
-      if (driver->getPose(devices[index], position, orientation)) {
-        lua_pushstring(L, Devices[devices[index]]);
-        lua_pushinteger(L, ++index);
-        lua_replace(L, lua_upvalueindex(1));
-        return 1;
-      }
-    }
-    index++;
-  }
-
-  return 0;
-}
-
-static Device hands[] = {
-  DEVICE_HAND_LEFT,
-  DEVICE_HAND_RIGHT
-};
-
-static Device trackers[] = {
-  DEVICE_TRACKER_1,
-  DEVICE_TRACKER_2,
-  DEVICE_TRACKER_3,
-  DEVICE_TRACKER_4
-};
-
 static int l_lovrHeadsetGetHands(lua_State* L) {
   if (lua_istable(L, 1)) {
     lua_settop(L, 1);
   } else {
     lua_newtable(L);
   }
+
   int count = 0;
   float position[3], orientation[4];
+  Device hands[] = { DEVICE_HAND_LEFT, DEVICE_HAND_RIGHT };
   for (size_t i = 0; i < sizeof(hands) / sizeof(hands[0]); i++) {
     FOREACH_TRACKING_DRIVER(driver) {
       if (driver->getPose(hands[i], position, orientation)) {
@@ -570,19 +535,29 @@ static int l_lovrHeadsetGetHands(lua_State* L) {
   return 1;
 }
 
-static int l_lovrHeadsetHands(lua_State* L) {
-  lua_pushinteger(L, 0);
-  lua_pushlightuserdata(L, hands);
-  lua_pushinteger(L, sizeof(hands) / sizeof(hands[0]));
-  lua_pushcclosure(L, deviceIterator, 3);
-  return 1;
+static int handIterator(lua_State* L) {
+  Device hands[] = { DEVICE_HAND_LEFT, DEVICE_HAND_RIGHT };
+  size_t index = lua_tointeger(L, lua_upvalueindex(1));
+  float position[3], orientation[4];
+
+  while (index < 2) {
+    FOREACH_TRACKING_DRIVER(driver) {
+      if (driver->getPose(hands[index], position, orientation)) {
+        lua_pushstring(L, Devices[hands[index]]);
+        lua_pushinteger(L, ++index);
+        lua_replace(L, lua_upvalueindex(1));
+        return 1;
+      }
+    }
+    index++;
+  }
+
+  return 0;
 }
 
-static int l_lovrHeadsetTrackers(lua_State* L) {
+static int l_lovrHeadsetHands(lua_State* L) {
   lua_pushinteger(L, 0);
-  lua_pushlightuserdata(L, trackers);
-  lua_pushinteger(L, sizeof(trackers) / sizeof(trackers[0]));
-  lua_pushcclosure(L, deviceIterator, 3);
+  lua_pushcclosure(L, handIterator, 1);
   return 1;
 }
 
@@ -618,7 +593,6 @@ static const luaL_Reg lovrHeadset[] = {
   { "getMirrorTexture", l_lovrHeadsetGetMirrorTexture },
   { "getHands", l_lovrHeadsetGetHands },
   { "hands", l_lovrHeadsetHands },
-  { "trackers", l_lovrHeadsetTrackers },
   { NULL, NULL }
 };
 

src/modules/headset/headset.h

@@ -28,10 +28,6 @@ typedef enum {
   DEVICE_HAND_RIGHT,
   DEVICE_EYE_LEFT,
   DEVICE_EYE_RIGHT,
-  DEVICE_TRACKER_1,
-  DEVICE_TRACKER_2,
-  DEVICE_TRACKER_3,
-  DEVICE_TRACKER_4,
   MAX_DEVICES
 } Device;
 

src/modules/headset/openvr.c

@@ -96,15 +96,6 @@ static TrackedDeviceIndex_t getDeviceIndex(Device device) {
     case DEVICE_HEAD: return HEADSET;
     case DEVICE_HAND_LEFT: return state.system->GetTrackedDeviceIndexForControllerRole(ETrackedControllerRole_TrackedControllerRole_LeftHand);
     case DEVICE_HAND_RIGHT: return state.system->GetTrackedDeviceIndexForControllerRole(ETrackedControllerRole_TrackedControllerRole_RightHand);
-    case DEVICE_TRACKER_1:
-    case DEVICE_TRACKER_2:
-    case DEVICE_TRACKER_3:
-    case DEVICE_TRACKER_4: {
-      TrackedDeviceIndex_t trackers[4];
-      uint32_t trackerCount = state.system->GetSortedTrackedDeviceIndicesOfClass(ETrackedDeviceClass_TrackedDeviceClass_GenericTracker, trackers, 4, 0);
-      uint32_t i = device - DEVICE_TRACKER_1;
-      return i < trackerCount ? trackers[i] : INVALID_DEVICE;
-    }
     default: return INVALID_DEVICE;
   }
 }