Have OpenXR create a depth texture chain so we can supply our depth b…

…uffer

demo/addons/godot-openxr/CHANGES.md

@@ -4,6 +4,7 @@ Changes to the Godot OpenXR asset
 1.3.0
 -------------------
 - Added default interaction profiles for Samsung Odyssey, HTC Cosmos, HTC Focus and Huawei controllers.
+- Depth buffers are now created by OpenXR and used by Godot enabling advanced reprojection features in OpenXR.
 
 1.2.0
 -------------------

src/ARVRInterface.cpp

@@ -16,6 +16,7 @@ typedef struct arvr_data_struct {
 	OpenXRApi *openxr_api;
 
 	bool has_external_texture_support;
+	bool has_external_depth_support;
 } arvr_data_struct;
 
 godot_string godot_arvr_get_name(const void *p_data) {
@@ -294,7 +295,7 @@ void godot_arvr_commit_for_eye(void *p_data, godot_int p_eye, godot_rid *p_rende
 
 	if (arvr_data->openxr_api != nullptr) {
 		uint32_t texid = godot::arvr_api->godot_arvr_get_texid(p_render_target);
-		arvr_data->openxr_api->render_openxr(p_eye - 1, texid, arvr_data->has_external_texture_support);
+		arvr_data->openxr_api->render_openxr(p_eye - 1, texid, arvr_data->has_external_texture_support, arvr_data->has_external_depth_support);
 	}
 }
 
@@ -367,8 +368,16 @@ int godot_arvr_get_camera_feed_id(void *) {
 }
 
 int godot_arvr_get_external_depth_for_eye(void *p_data, int p_eye) {
-	// stub
-	return 0;
+	arvr_data_struct *arvr_data = (arvr_data_struct *)p_data;
+
+	// this only gets called from Godot 3.2 and newer, allows us to use
+	// OpenXR swapchain directly.
+
+	if (arvr_data->openxr_api != nullptr) {
+		return arvr_data->openxr_api->get_external_depthbuffer_for_eye(p_eye - 1, &arvr_data->has_external_depth_support);
+	} else {
+		return 0;
+	}
 }
 
 const godot_arvr_interface_gdnative interface_struct = {