Passthrough.h

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/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */
 
#ifndef META_OCEAN_PLATFORM_META_QUEST_OPENXR_PASSTHROUGH_H
#define META_OCEAN_PLATFORM_META_QUEST_OPENXR_PASSTHROUGH_H
 
#include "ocean/platform/meta/quest/openxr/OpenXR.h"
 
#include "ocean/platform/openxr/Session.h"
 
namespace Ocean
{
 
namespace Platform
{
 
namespace Meta
{
 
namespace Quest
{
 
namespace OpenXR
{
 
/**
 * This class implements a wrapper for passthrough.
 * This object uses the Android feature 'com.oculus.feature.PASSTHROUGH'.
 * @ingroup platformmetaquestopenxr
 */
class OCEAN_PLATFORM_META_QUEST_OPENXR_EXPORT Passthrough final
{
    public:
 
        /**
         * Definition of an unordered set holding strings.
         */
        typedef std::unordered_set<std::string> StringSet;
 
        /**
         * This class implements a scoped state object allowing to reset all passthrough states of a visualizer.
         * The state can be stored locally or states can be pushed onto a stack.
         * @see pushState(), popState().
         */
        class ScopedState
        {
            public:
 
                /**
                 * Default constructor.
                 */
                ScopedState() = default;
 
                /**
                 * Creates a new state object.
                 * @param passthrough The visualizer to which this new object belongs
                 */
                ScopedState(Passthrough& passthrough);
 
                /**
                 * Move constructor.
                 * @param scopedState The state object to be moved
                 */
                ScopedState(ScopedState&& scopedState);
 
                /**
                 * Destructs this object and releases the state.
                 */
                ~ScopedState();
 
                /**
                 * Explicitly releases this state.
                 * The properties of the owning visualizer will be reset to the situation when the state was created.
                 */
                void release();
 
                /**
                 * Move operator.
                 * @param scopedState The state object to be moved
                 * @return Reference to this object
                 */
                ScopedState& operator=(ScopedState&& scopedState);
 
            protected:
 
                /**
                 * Disabled copy constructor.
                 */
                ScopedState(const ScopedState&) = delete;
 
                /**
                 * Disabled assign operator.
                 * @return The reference to this object
                 */
                ScopedState& operator=(const ScopedState&) = delete;
 
            protected:
 
                /// The visualizer to which this state object belongs.
                Passthrough* passthrough_ = nullptr;
 
                /// True, if the passthrough service was actively running when this object was created.
                bool wasRunning_ = false;
        };
 
        /**
         * Definition of a vector holding state objects.
         */
        typedef std::vector<ScopedState> ScopedStates;
 
    public:
 
        /**
         * Default constructor.
         */
        Passthrough() = default;
 
        /**
         * Destructs this passthrough object and releases all associated resources.
         */
        ~Passthrough();
 
        /**
         * Move constructor.
         * @param passthrough The object to be moved
         */
        inline Passthrough(Passthrough&& passthrough);
 
        /**
         * Initializes this passthrough object.
         * @param session The OpenXR session to be used, must be valid
         * @param xrPassthroughLayerPurposeFB The purpose to be used
         * @return True, if succeeded
         */
        inline bool initialize(const Platform::OpenXR::Session& session, const XrPassthroughLayerPurposeFB& xrPassthroughLayerPurposeFB = XR_PASSTHROUGH_LAYER_PURPOSE_RECONSTRUCTION_FB);
 
        /**
         * Initializes this passthrough object.
         * @param xrInstance The OpenXR instance to be used, must be valid
         * @param xrSession The OpenXR session to be used, must be valid
         * @param xrPassthroughLayerPurposeFB The purpose to be used
         * @return True, if succeeded
         */
        bool initialize(const XrInstance& xrInstance, const XrSession& xrSession, const XrPassthroughLayerPurposeFB& xrPassthroughLayerPurposeFB = XR_PASSTHROUGH_LAYER_PURPOSE_RECONSTRUCTION_FB);
 
        /**
         * Starts passthrough.
         * @return True, if succeeded
         */
        bool start();
 
        /**
         * Pauses passthrough.
         * @return True, if succeeded
         */
        bool pause();
 
        /**
         * Returns whether passthrough is started.
         * @return True, if so
         */
        bool isStarted() const;
 
        /**
         * Explicitly releases the passthrough object and all associated resources.
         */
        void release();
 
        /**
         * Returns the OpenXR passthrough layer.
         * @return The passthrough's layer
         */
        inline XrPassthroughLayerFB xrPassthroughLayerFB() const;
 
        /**
         * Returns the lock of the passthrough.
         * @return The passthrough's lock.
         */
        inline Lock& lock() const;
 
        /**
         * Returns whether this object holds initialized and valid OpenXR hand trackers.
         * @return True, if so
         */
        inline bool isValid() const;
 
        /**
         * Pushes a new configuration state to the stack.
         * Each push needs to be balanced with a pop.
         * @see popState().
         */
        inline void pushState();
 
        /**
         * Pops the most recent state from the stack and resets the visualizer's configuration accordingly.
         */
        inline void popState();
 
        /**
         * Move operator.
         * @param passthrough The object to be moved
         * @return Reference to this object
         */
        Passthrough& operator=(Passthrough&& passthrough);
 
        /**
         * Returns the names of the necessary OpenXR extensions necessary for hand tracking.
         * @return The necessary OpenXR extensions
         */
        static const StringSet& necessaryOpenXRExtensionNames();
 
    protected:
 
        /**
         * Disabled copy constructor.
         */
        Passthrough(const Passthrough&) = delete;
 
        /**
         * Disabled assign operator.
         * @return Reference to this object
         */
        Passthrough& operator=(const Passthrough&) = delete;
 
    protected:
 
        /// The OpenXR instance.
        XrInstance xrInstance_ = XR_NULL_HANDLE;
 
        /// The OpenXR session.
        XrSession xrSession_ = XR_NULL_HANDLE;
 
        /// The OpenXR passthrough handle.
        XrPassthroughFB xrPassthroughFB_ = XR_NULL_HANDLE;
 
        /// The OpenXR passthrough layer handle.
        XrPassthroughLayerFB xrPassthroughLayerFB_ = XR_NULL_HANDLE;
 
        /// The OpenXR passthrough create function.
        PFN_xrCreatePassthroughFB xrCreatePassthroughFB_ = nullptr;
 
        /// The OpenXR passthrough destroy function.
        PFN_xrDestroyPassthroughFB xrDestroyPassthroughFB_ = nullptr;
 
        /// The OpenXR passthrough start function.
        PFN_xrPassthroughStartFB xrPassthroughStartFB_ = nullptr;
 
        /// The OpenXR passthrough pause function.
        PFN_xrPassthroughPauseFB xrPassthroughPauseFB_ = nullptr;
 
        /// The OpenXR passthrough create layer function.
        PFN_xrCreatePassthroughLayerFB xrCreatePassthroughLayerFB_ = nullptr;
 
        /// The OpeXR passthrough destroy layer function.
        PFN_xrDestroyPassthroughLayerFB xrDestroyPassthroughLayerFB_ = nullptr;
 
        /// The OpenXR passthrough resume layer function.
        PFN_xrPassthroughLayerResumeFB xrPassthroughLayerResumeFB_ = nullptr;
 
        /// The OpenXR passthrough set style function.
        PFN_xrPassthroughLayerSetStyleFB xrPassthroughLayerSetStyleFB_ = nullptr;
 
        /// True, if passthrough is currently started.
        bool isStarted_ = false;
 
        /// A stack of visualization states.
        ScopedStates stateStack_;
 
        /// The lock object.
        mutable Lock lock_;
};
 
inline Passthrough::Passthrough(Passthrough&& passthrough)
{
    *this = std::move(passthrough);
}
 
bool Passthrough::initialize(const Platform::OpenXR::Session& session, const XrPassthroughLayerPurposeFB& xrPassthroughLayerPurposeFB)
{
    ocean_assert(session.isValid());
 
    return initialize(session.xrInstance(), session, xrPassthroughLayerPurposeFB);
}
 
inline XrPassthroughLayerFB Passthrough::xrPassthroughLayerFB() const
{
    return xrPassthroughLayerFB_;
}
 
inline Lock& Passthrough::lock() const
{
    return lock_;
}
 
inline bool Passthrough::isValid() const
{
    const ScopedLock scopedLock(lock_);
 
    return xrInstance_ != XR_NULL_HANDLE;
}
 
inline void Passthrough::pushState()
{
    const ScopedLock scopedLock(lock_);
 
    stateStack_.emplace_back(*this);
}
 
inline void Passthrough::popState()
{
    const ScopedLock scopedLock(lock_);
 
    ocean_assert(!stateStack_.empty());
 
    stateStack_.pop_back();
}
 
}
 
}
 
}
 
}
 
}
 
#endif // META_OCEAN_PLATFORM_META_QUEST_OPENXR_PASSTHROUGH_H