IHeadMountedDisplayModule.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreMinimal.h"
#include "Modules/ModuleInterface.h"
#include "Misc/ConfigCacheIni.h"
#include "Features/IModularFeatures.h"
#include "Features/IModularFeature.h"
 
//#include "IHeadMountedDisplayVulkanExtensions.h"
class IHeadMountedDisplayVulkanExtensions;
class IXRTrackingSystem;
 
class IHeadMountedDisplayModule : public IModuleInterface, public IModularFeature
{
public:
    static FName GetModularFeatureName()
    {
        static FName HMDFeatureName = FName(TEXT("HMD"));
        return HMDFeatureName;
    }
 
    virtual FString GetModuleKeyName() const = 0;
    virtual void GetModuleAliases(TArray<FString>& AliasesOut) const {}
    
    float GetModulePriority() const
    {
        TArray<FString> ModuleAliases;
        GetModuleAliases(ModuleAliases);
 
        FString DefaultName = GetModuleKeyName();
        if (DefaultName.IsEmpty())
        {
            ModuleAliases.Add(TEXT("Default"));
        }
        else
        {
            // Search for aliases first. This favors old module names, and ensures 
            // that overrides in project specific ini files get found (not just the one in BaseEngine.ini)
            ModuleAliases.Add(DefaultName);
        }
 
        float ModulePriority = 0.f;
        for (const FString& KeyName : ModuleAliases)
        {
            if (GConfig->GetFloat(TEXT("HMDPluginPriority"), *KeyName, ModulePriority, GEngineIni))
            {
                break;
            }
        }   
        return ModulePriority;
    }
 
    struct FCompareModulePriority
    {
        bool operator()(IHeadMountedDisplayModule& A, IHeadMountedDisplayModule& B) const
        {
            return A.GetModulePriority() > B.GetModulePriority();
        }
    };
 
    static inline IHeadMountedDisplayModule& Get()
    {
        check(IsInGameThread());
        TArray<IHeadMountedDisplayModule*> HMDModules = IModularFeatures::Get().GetModularFeatureImplementations<IHeadMountedDisplayModule>(GetModularFeatureName());
        HMDModules.Sort(FCompareModulePriority());
        return *HMDModules[0];
    }
 
    static inline bool IsAvailable()
    {
        check(IsInGameThread());
        return IModularFeatures::Get().IsModularFeatureAvailable(GetModularFeatureName());
    }
 
    virtual void StartupModule() override
    {
        IModularFeatures::Get().RegisterModularFeature(GetModularFeatureName(), this);
    }
 
    virtual bool PreInit() { return true; }
 
    virtual bool IsHMDConnected() { return false; }
 
    virtual uint64 GetGraphicsAdapterLuid() 
    { 
#if PLATFORM_MAC
        return (uint64)-1;
#else
        return 0;
#endif
    }
 
    virtual FString GetAudioInputDevice() { return FString(); }
 
    virtual FString GetAudioOutputDevice() { return FString(); }
 
    virtual FString GetDeviceSystemName() { return FString(); }
 
    virtual TSharedPtr< class IXRTrackingSystem, ESPMode::ThreadSafe > CreateTrackingSystem() = 0;
 
    virtual TSharedPtr< IHeadMountedDisplayVulkanExtensions, ESPMode::ThreadSafe > GetVulkanExtensions() { return nullptr; }
 
    virtual bool IsStandaloneStereoOnlyDevice() { return false; }
};