IHeadMountedDisplay.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreMinimal.h"
#include "Modules/ModuleInterface.h"
#include "HeadMountedDisplayTypes.h"
#include "StereoRendering.h"
#include "LateUpdateManager.h"
#include "SceneInterface.h"
 
class FSceneInterface;
class UCanvas;
struct FPostProcessSettings;
struct FWorldContext;
class UTexture;
class FSceneViewFamily;
class FSceneView;
class FRHICommandListImmediate;
class FTexture;
 
struct FHeadMountedDisplayPassContext
{
    FHeadMountedDisplayPassContext(FRHICommandListImmediate& InRHICmdList, const FSceneView& InView)
        : RHICmdList(InRHICmdList)
        , View(InView)
    {}
 
    FRHICommandListImmediate& RHICmdList;
    const FSceneView& View;
};
 
class IHeadMountedDisplay : public IModuleInterface
{
 
public:
    HEADMOUNTEDDISPLAY_API IHeadMountedDisplay();
 
    virtual bool IsHMDConnected() = 0;
 
    virtual bool IsHMDEnabled() const = 0;
 
    virtual EHMDWornState::Type GetHMDWornState() { return EHMDWornState::Unknown; };
 
    virtual void EnableHMD(bool bEnable = true) = 0;
 
    virtual FName GetHMDName() const = 0;
 
    struct MonitorInfo
    {
        FString MonitorName;
        size_t  MonitorId;
        int     DesktopX, DesktopY;
        int     ResolutionX, ResolutionY;
        int     WindowSizeX, WindowSizeY;
        bool    bShouldTestResolution;
 
        MonitorInfo() : MonitorId(0)
            , DesktopX(0)
            , DesktopY(0)
            , ResolutionX(0)
            , ResolutionY(0)
            , WindowSizeX(0)
            , WindowSizeY(0)
            , bShouldTestResolution(false)
        {
        }
 
    };
 
    virtual bool    GetHMDMonitorInfo(MonitorInfo&) = 0;
 
    virtual void    GetFieldOfView(float& InOutHFOVInDegrees, float& InOutVFOVInDegrees) const = 0;
 
    virtual void    SetClippingPlanes(float NCP, float FCP) {}
 
    virtual void    GetEyeRenderParams_RenderThread(const struct FHeadMountedDisplayPassContext& Context, FVector2D& EyeToSrcUVScaleValue, FVector2D& EyeToSrcUVOffsetValue) const {}
 
    virtual void    SetInterpupillaryDistance(float NewInterpupillaryDistance) = 0;
    virtual float   GetInterpupillaryDistance() const = 0;
 
    virtual bool GetHMDDistortionEnabled(EShadingPath ShadingPath) const = 0;
 
    // Are we outputting so a Spectator Screen now.
    virtual bool IsSpectatorScreenActive() const { return false; }
 
    virtual class ISpectatorScreenController* GetSpectatorScreenController() { return nullptr; }
    virtual class ISpectatorScreenController const* GetSpectatorScreenController() const { return nullptr; }
 
    virtual void CreateHMDPostProcessPass_RenderThread(FRDGBuilder& GraphBuilder, const FSceneView& View, const struct FHMDDistortionInputs& Inputs, struct FScreenPassTexture& OutPass) const {}
 
public:
 
    virtual float GetPixelDenity() const { check(IsInGameThread() || IsInRenderingThread()); return 1.0f; }
 
    virtual void SetPixelDensity(const float NewDensity) { };
 
    virtual FIntPoint GetIdealRenderTargetSize() const { check(IsInGameThread() || IsInRenderingThread()); return FIntPoint(); }
 
    virtual FIntPoint GetIdealDebugCanvasRenderTargetSize() const { return FIntPoint(1024, 1024); }
 
    virtual float GetDistortionScalingFactor() const { return 0; }
 
    virtual float GetLensCenterOffset() const { return 0; }
 
    virtual void GetDistortionWarpValues(FVector4& K) const  { }
 
    virtual bool IsChromaAbCorrectionEnabled() const = 0;
 
    virtual bool GetChromaAbCorrectionValues(FVector4& K) const  { return false; }
 
    virtual bool HasHiddenAreaMesh() const { return false; }
 
    virtual bool HasVisibleAreaMesh() const { return false; }
 
    virtual void DrawHiddenAreaMesh(class FRHICommandList& RHICmdList, int32 ViewIndex) const {};
 
    virtual void DrawHiddenAreaMesh(class FRHICommandList& RHICmdList, int32 ViewIndex, int32 InstanceCount) const {};
 
    virtual void DrawVisibleAreaMesh(class FRHICommandList& RHICmdList, int32 ViewIndex) const {};
 
    virtual void DrawVisibleAreaMesh(class FRHICommandList& RHICmdList, int32 ViewIndex, int32 InstanceCount) const {};
 
    virtual void DrawDistortionMesh_RenderThread(struct FHeadMountedDisplayPassContext& Context, const FIntPoint& TextureSize) {}
 
    virtual void UpdateScreenSettings(const class FViewport* InViewport) {} 
 
    virtual FTexture* GetDistortionTextureLeft() const {return NULL;}
    virtual FTexture* GetDistortionTextureRight() const {return NULL;}
    virtual FVector2D GetTextureOffsetLeft() const {return FVector2D::ZeroVector;}
    virtual FVector2D GetTextureOffsetRight() const {return FVector2D::ZeroVector;}
    virtual FVector2D GetTextureScaleLeft() const {return FVector2D::ZeroVector;}
    virtual FVector2D GetTextureScaleRight() const {return FVector2D::ZeroVector;}
    virtual const float* GetRedDistortionParameters() const { return nullptr; }
    virtual const float* GetGreenDistortionParameters() const { return nullptr; }
    virtual const float* GetBlueDistortionParameters() const { return nullptr; }
 
    virtual bool NeedsUpscalePostProcessPass()  { return false; }
 
    virtual void RecordAnalytics() {}
 
    HEADMOUNTEDDISPLAY_API virtual bool DoesAppUseVRFocus() const;
 
    HEADMOUNTEDDISPLAY_API virtual bool DoesAppHaveVRFocus() const;
 
    virtual bool IsRenderingPaused() const { return false; }
 
    virtual bool SetColorScaleAndBias(FLinearColor ColorScale, FLinearColor ColorBias) { return false;  };
};