/*************************************************************************/
/*  arvr_interface.h                                                     */
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#ifndef ARVR_INTERFACE_H
#define ARVR_INTERFACE_H

#include "core/math/camera_matrix.h"
#include "os/thread_safe.h"
#include "scene/main/viewport.h"
#include "servers/arvr_server.h"

/**
	@author Bastiaan Olij <mux213@gmail.com>

	The ARVR interface is a template class ontop of which we build interface to differt AR, VR and tracking SDKs.
	The idea is that we subclass this class, implement the logic, and then instantiate a singleton of each interface
	when Godot starts. These instances do not initialize themselves but register themselves with the AR/VR server.

	If the user wants to enable AR/VR the choose the interface they want to use and initialize it.

	Note that we may make this into a fully instantiable class for GDNative support.
*/

class ARVRInterface : public Reference {
	GDCLASS(ARVRInterface, Reference);

protected:
	_THREAD_SAFE_CLASS_

	static void _bind_methods();

public:
	enum Eyes {
		EYE_MONO, /* my son says we should call this EYE_CYCLOPS */
		EYE_LEFT,
		EYE_RIGHT
	};

	virtual StringName get_name() const;

	bool is_primary();
	void set_is_primary(bool p_is_primary);

	virtual bool is_installed() = 0; /* returns true if the middle ware related to this interface has been installed */
	virtual bool hmd_is_present() = 0; /* returns true if our HMD is connected */
	virtual bool supports_hmd() = 0; /* returns true is this interface handles output to an HMD or only handles positioning */

	virtual bool is_initialized() = 0; /* returns true if we've initialized this interface */
	virtual bool initialize() = 0; /* initialize this interface, if this has an HMD it becomes the primary interface */
	virtual void uninitialize() = 0; /* deinitialize this interface */

	virtual Size2 get_recommended_render_targetsize() = 0; /* returns the recommended render target size per eye for this device */
	virtual bool is_stereo() = 0; /* returns true if this interface requires stereo rendering (for VR HMDs) or mono rendering (for mobile AR) */
	virtual Transform get_transform_for_eye(ARVRInterface::Eyes p_eye, const Transform &p_cam_transform) = 0; /* get each eyes camera transform, also implement EYE_MONO */
	virtual CameraMatrix get_projection_for_eye(ARVRInterface::Eyes p_eye, real_t p_aspect, real_t p_z_near, real_t p_z_far) = 0; /* get each eyes projection matrix */
	virtual void commit_for_eye(ARVRInterface::Eyes p_eye, RID p_render_target, const Rect2 &p_screen_rect) = 0; /* output the left or right eye */

	virtual void process() = 0;
};

VARIANT_ENUM_CAST(ARVRInterface::Eyes);

#endif