From 7c168688178a2a541d25e559c782bf75f50b6207 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Fri, 23 Sep 2016 19:29:20 +0300
Subject: [PATCH] Add a factory method in DisplayDevice

This avoids applications from needing a compile-time dependency to the
concrete display device classes, which may not be available due to
library configuration.
---
 source/displaydevice.cpp | 29 +++++++++++++++++++++++++++++
 source/displaydevice.h   |  3 +++
 2 files changed, 32 insertions(+)
 create mode 100644 source/displaydevice.cpp

diff --git a/source/displaydevice.cpp b/source/displaydevice.cpp
new file mode 100644
index 0000000..5e11266
--- /dev/null
+++ b/source/displaydevice.cpp
@@ -0,0 +1,29 @@
+#include <msp/strings/format.h>
+#include "displaydevice.h"
+#ifdef WITH_OPENVR
+#include "openvr/openvrdevice.h"
+#endif
+#ifdef WITH_LIBOVR
+#include "ovr/oculusriftdevice.h"
+#endif
+
+using namespace std;
+
+namespace Msp {
+namespace VR {
+
+DisplayDevice *DisplayDevice::create_device(const string &type)
+{
+#ifdef WITH_OPENVR
+	if(type=="openvr")
+		return new OpenVRDevice;
+#endif
+#ifdef WITH_LIBOVR
+	if(type=="libovr")
+		return new OculusRiftDevice;
+#endif
+	throw invalid_argument(format("device type '%s' not supported", type));
+}
+
+} // namespace VR
+} // namespace Msp
diff --git a/source/displaydevice.h b/source/displaydevice.h
index 665ac85..46dfbae 100644
--- a/source/displaydevice.h
+++ b/source/displaydevice.h
@@ -1,6 +1,7 @@
 #ifndef MSP_VR_DISPLAYDEVICE_H_
 #define MSP_VR_DISPLAYDEVICE_H_
 
+#include <string>
 #include <msp/gl/camera.h>
 #include <msp/gl/view.h>
 
@@ -18,6 +19,8 @@ protected:
 public:
 	virtual ~DisplayDevice() { }
 
+	static DisplayDevice *create_device(const std::string &);
+
 	virtual void configure_window(Graphics::Window &) const = 0;
 	virtual void configure_view(StereoView &) const = 0;
 	virtual HeadTrackingCamera *create_camera(const GL::Camera &) = 0;
-- 
2.45.2