XrStruct.h

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// Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.
 
#pragma once
 
#include <string_view>
 
namespace xr {
    struct NameVersion {
        NameVersion(std::string name, uint32_t version)
            : Name(std::move(name))
            , Version(version) {
        }
        std::string Name;
        uint32_t Version;
    };
 
    inline void SetApplicationInfo(XrApplicationInfo& appInfo,
                                   const xr::NameVersion& appNameVersion,
                                   const xr::NameVersion& engineNameVersion,
                                   XrVersion apiVersion = XR_CURRENT_API_VERSION) {
        strncpy_s(appInfo.applicationName, XR_MAX_APPLICATION_NAME_SIZE, appNameVersion.Name.data(), appNameVersion.Name.size());
        appInfo.applicationVersion = appNameVersion.Version;
        strncpy_s(appInfo.engineName, XR_MAX_ENGINE_NAME_SIZE, engineNameVersion.Name.data(), engineNameVersion.Name.size());
        appInfo.engineVersion = engineNameVersion.Version;
        appInfo.apiVersion = apiVersion;
    }
 
    // extensions can be const or non-const.
    template <typename T>
    void SetEnabledExtensions(XrInstanceCreateInfo& info, T& extensions) {
        info.enabledExtensionCount = static_cast<uint32_t>(std::size(extensions));
        info.enabledExtensionNames = std::data(extensions);
    }
 
    // Don't allow rvalues to be passed because the memory that enabledExtensionNames points to
    // needs to live longer than this function.
    template <typename T>
    void SetEnabledExtensions(XrInstanceCreateInfo& info, T&& extensions) = delete;
 
    // Insert an extension struct into the next chain of an xrStruct
    template <typename XrStruct, typename XrExtension>
    void InsertExtensionStruct(XrStruct& xrStruct, XrExtension& xrExtension) {
        xrExtension.next = xrStruct.next;
        xrStruct.next = &xrExtension;
    }
 
    // Cast event data buffer to strongly typed event data if eventData->type matches.
    template <typename XrEventData>
    const XrEventData* event_cast(const XrEventDataBuffer* eventData) = delete;
 
#define DEFINE_EVENT_TYPE(XrEventData, XR_TYPE_EVENT_DATA)                                  \
    template <>                                                                             \
    inline const XrEventData* event_cast<XrEventData>(const XrEventDataBuffer* eventData) { \
        if (eventData->type == XR_TYPE_EVENT_DATA) {                                        \
            return reinterpret_cast<const XrEventData*>(eventData);                         \
        }                                                                                   \
        return nullptr;                                                                     \
    }
 
    DEFINE_EVENT_TYPE(XrEventDataEventsLost, XR_TYPE_EVENT_DATA_EVENTS_LOST);
    DEFINE_EVENT_TYPE(XrEventDataInteractionProfileChanged, XR_TYPE_EVENT_DATA_INTERACTION_PROFILE_CHANGED);
    DEFINE_EVENT_TYPE(XrEventDataInstanceLossPending, XR_TYPE_EVENT_DATA_INSTANCE_LOSS_PENDING);
    DEFINE_EVENT_TYPE(XrEventDataReferenceSpaceChangePending, XR_TYPE_EVENT_DATA_REFERENCE_SPACE_CHANGE_PENDING);
    DEFINE_EVENT_TYPE(XrEventDataPerfSettingsEXT, XR_TYPE_EVENT_DATA_PERF_SETTINGS_EXT);
    DEFINE_EVENT_TYPE(XrEventDataSessionStateChanged, XR_TYPE_EVENT_DATA_SESSION_STATE_CHANGED);
    DEFINE_EVENT_TYPE(XrEventDataVisibilityMaskChangedKHR, XR_TYPE_EVENT_DATA_VISIBILITY_MASK_CHANGED_KHR);
#undef DEFINE_EVENT_TYPE
} // namespace xr