Merge development branch for version 3.0.1 (#128)

### Bug fixes:

- Fix invalid head transformation initialization (Fixes #127 and godotengine/godot#41943).

config.gradle

@@ -5,4 +5,5 @@ ext.versions = [
     targetSdk          : 30,
     buildTools         : '30.0.1',
     kotlinVersion      : '1.4.10',
+    ndkVersion         : "21.3.6528147"
 ]

demo/android/plugins/gdovrmobile.gdap

@@ -2,4 +2,4 @@
 
 name="OVRMobile"
 binary_type="local"
-binary="gdovrmobile.3.0.0-release.aar"
+binary="gdovrmobile.3.0.1-release.aar"

plugin/build.gradle

@@ -4,13 +4,13 @@ apply plugin: "kotlin-android"
 android {
     buildToolsVersion = versions.buildTools
     compileSdkVersion versions.compileSdk
-    ndkVersion "21.1.6352462"
+    ndkVersion versions.ndkVersion
 
     defaultConfig {
         minSdkVersion versions.minSdk
         targetSdkVersion versions.targetSdk
-        versionCode 4
-        versionName '3.0.0'
+        versionCode 5
+        versionName '3.0.1'
         setProperty("archivesBaseName", "gdovrmobile.${versionName}")
 
         externalNativeBuild {

plugin/gdovrmobile.gdap

@@ -2,4 +2,4 @@
 
 name="OVRMobile"
 binary_type="local"
-binary="gdovrmobile.3.0.0-release.aar"
+binary="gdovrmobile.3.0.1-release.aar"

plugin/src/main/cpp/ovr_mobile_session.cpp

@@ -39,6 +39,8 @@ OvrMobileSession::OvrMobileSession() :
     default_layer_color_scale.z = 1.0f;
     default_layer_color_scale.w = 1.0f;
 
+    head_tracker.Status = 0;
+
     ovr_mobile_controller = new OvrMobileController();
 }
 
@@ -111,16 +113,20 @@ godot_transform OvrMobileSession::get_transform_for_eye(godot_int godot_eye,
     godot_transform reference_frame = godot::arvr_api->godot_arvr_get_reference_frame();
     godot_real world_scale = godot::arvr_api->godot_arvr_get_worldscale();
 
-    if (in_vr_mode()) {
+    // Validate that we're in vr mode and have valid orientation and position data.
+    if (!in_vr_mode() ||
+        (head_tracker.Status &
+         (VRAPI_TRACKING_STATUS_ORIENTATION_VALID + VRAPI_TRACKING_STATUS_POSITION_VALID)) !=
+                (VRAPI_TRACKING_STATUS_ORIENTATION_VALID + VRAPI_TRACKING_STATUS_POSITION_VALID)) {
+        godot::api->godot_transform_new_identity(&transform_for_eye);
+    } else {
         if (godot_eye == 1 || godot_eye == 2) { // check if we have the left(1) or right(2) eye
             ovrMatrix4f *ovrEyeMatrix = &head_tracker.Eye[godot_eye - 1].ViewMatrix;
             godot_transform_from_ovrMatrix(&transform_for_eye, ovrEyeMatrix, world_scale);
         } else { // mono eye (godot_eye == 0); used by godot to set the ARVRCamera matrix
             godot_transform_from_ovr_pose(
                     &transform_for_eye, head_tracker.HeadPose.Pose, world_scale);
         }
-    } else {
-        godot::api->godot_transform_new_identity(&transform_for_eye);
     }
 
     ret = *cam_transform;