// Copyright 1998-2019 Epic Games, Inc. All Rights Reserved.

#include "RenderUtils.h"
#include "Containers/ResourceArray.h"
#include "Containers/DynamicRHIResourceArray.h"
#include "RenderResource.h"
#include "RHIStaticStates.h"
#include "RenderGraphUtils.h"
#include "PipelineStateCache.h"

#if WITH_EDITOR
#include "Misc/CoreMisc.h"
#include "Interfaces/ITargetPlatform.h"
#include "Interfaces/ITargetPlatformManagerModule.h"
#endif

const uint16 GCubeIndices[12*3] =
{
	0, 2, 3,
	0, 3, 1,
	4, 5, 7,
	4, 7, 6,
	0, 1, 5,
	0, 5, 4,
	2, 6, 7,
	2, 7, 3,
	0, 4, 6,
	0, 6, 2,
	1, 3, 7,
	1, 7, 5,
};

TGlobalResource<FCubeIndexBuffer> GCubeIndexBuffer;
TGlobalResource<FTwoTrianglesIndexBuffer> GTwoTrianglesIndexBuffer;
TGlobalResource<FScreenSpaceVertexBuffer> GScreenSpaceVertexBuffer;

//
// FPackedNormal serializer
//
FArchive& operator<<(FArchive& Ar, FDeprecatedSerializedPackedNormal& N)
{
	Ar << N.Vector.Packed;
	return Ar;
}

FArchive& operator<<(FArchive& Ar, FPackedNormal& N)
{
	Ar << N.Vector.Packed;
	return Ar;
}

FArchive& operator<<(FArchive& Ar, FPackedRGBA16N& N)
{
	Ar << N.X;
	Ar << N.Y;
	Ar << N.Z;
	Ar << N.W;
	return Ar;
}

//
//	Pixel format information.
//

FPixelFormatInfo	GPixelFormats[PF_MAX] =
{
	// Name						BlockSizeX	BlockSizeY	BlockSizeZ	BlockBytes	NumComponents	PlatformFormat	Supported		UnrealFormat

	{ TEXT("unknown"),			0,			0,			0,			0,			0,				0,				0,				PF_Unknown			},
	{ TEXT("A32B32G32R32F"),	1,			1,			1,			16,			4,				0,				1,				PF_A32B32G32R32F	},
	{ TEXT("B8G8R8A8"),			1,			1,			1,			4,			4,				0,				1,				PF_B8G8R8A8			},
	{ TEXT("G8"),				1,			1,			1,			1,			1,				0,				1,				PF_G8				},
	{ TEXT("G16"),				1,			1,			1,			2,			1,				0,				1,				PF_G16				},
	{ TEXT("DXT1"),				4,			4,			1,			8,			3,				0,				1,				PF_DXT1				},
	{ TEXT("DXT3"),				4,			4,			1,			16,			4,				0,				1,				PF_DXT3				},
	{ TEXT("DXT5"),				4,			4,			1,			16,			4,				0,				1,				PF_DXT5				},
	{ TEXT("UYVY"),				2,			1,			1,			4,			4,				0,				0,				PF_UYVY				},
	{ TEXT("FloatRGB"),			1,			1,			1,			4,			3,				0,				1,				PF_FloatRGB			},
	{ TEXT("FloatRGBA"),		1,			1,			1,			8,			4,				0,				1,				PF_FloatRGBA		},
	{ TEXT("DepthStencil"),		1,			1,			1,			4,			1,				0,				0,				PF_DepthStencil		},
	{ TEXT("ShadowDepth"),		1,			1,			1,			4,			1,				0,				0,				PF_ShadowDepth		},
	{ TEXT("R32_FLOAT"),		1,			1,			1,			4,			1,				0,				1,				PF_R32_FLOAT		},
	{ TEXT("G16R16"),			1,			1,			1,			4,			2,				0,				1,				PF_G16R16			},
	{ TEXT("G16R16F"),			1,			1,			1,			4,			2,				0,				1,				PF_G16R16F			},
	{ TEXT("G16R16F_FILTER"),	1,			1,			1,			4,			2,				0,				1,				PF_G16R16F_FILTER	},
	{ TEXT("G32R32F"),			1,			1,			1,			8,			2,				0,				1,				PF_G32R32F			},
	{ TEXT("A2B10G10R10"),      1,          1,          1,          4,          4,              0,              1,				PF_A2B10G10R10		},
	{ TEXT("A16B16G16R16"),		1,			1,			1,			8,			4,				0,				1,				PF_A16B16G16R16		},
	{ TEXT("D24"),				1,			1,			1,			4,			1,				0,				1,				PF_D24				},
	{ TEXT("PF_R16F"),			1,			1,			1,			2,			1,				0,				1,				PF_R16F				},
	{ TEXT("PF_R16F_FILTER"),	1,			1,			1,			2,			1,				0,				1,				PF_R16F_FILTER		},
	{ TEXT("BC5"),				4,			4,			1,			16,			2,				0,				1,				PF_BC5				},
	{ TEXT("V8U8"),				1,			1,			1,			2,			2,				0,				1,				PF_V8U8				},
	{ TEXT("A1"),				1,			1,			1,			1,			1,				0,				0,				PF_A1				},
	{ TEXT("FloatR11G11B10"),	1,			1,			1,			4,			3,				0,				0,				PF_FloatR11G11B10	},
	{ TEXT("A8"),				1,			1,			1,			1,			1,				0,				1,				PF_A8				},	
	{ TEXT("R32_UINT"),			1,			1,			1,			4,			1,				0,				1,				PF_R32_UINT			},
	{ TEXT("R32_SINT"),			1,			1,			1,			4,			1,				0,				1,				PF_R32_SINT			},

	// IOS Support
	{ TEXT("PVRTC2"),			8,			4,			1,			8,			4,				0,				0,				PF_PVRTC2			},
	{ TEXT("PVRTC4"),			4,			4,			1,			8,			4,				0,				0,				PF_PVRTC4			},

	{ TEXT("R16_UINT"),			1,			1,			1,			2,			1,				0,				1,				PF_R16_UINT			},
	{ TEXT("R16_SINT"),			1,			1,			1,			2,			1,				0,				1,				PF_R16_SINT			},
	{ TEXT("R16G16B16A16_UINT"),1,			1,			1,			8,			4,				0,				1,				PF_R16G16B16A16_UINT},
	{ TEXT("R16G16B16A16_SINT"),1,			1,			1,			8,			4,				0,				1,				PF_R16G16B16A16_SINT},
	{ TEXT("R5G6B5_UNORM"),     1,          1,          1,          2,          3,              0,              1,              PF_R5G6B5_UNORM		},
	{ TEXT("R8G8B8A8"),			1,			1,			1,			4,			4,				0,				1,				PF_R8G8B8A8			},
	{ TEXT("A8R8G8B8"),			1,			1,			1,			4,			4,				0,				1,				PF_A8R8G8B8			},
	{ TEXT("BC4"),				4,			4,			1,			8,			1,				0,				1,				PF_BC4				},
	{ TEXT("R8G8"),				1,			1,			1,			2,			2,				0,				1,				PF_R8G8				},

	{ TEXT("ATC_RGB"),			4,			4,			1,			8,			3,				0,				0,				PF_ATC_RGB			},
	{ TEXT("ATC_RGBA_E"),		4,			4,			1,			16,			4,				0,				0,				PF_ATC_RGBA_E		},
	{ TEXT("ATC_RGBA_I"),		4,			4,			1,			16,			4,				0,				0,				PF_ATC_RGBA_I		},
	{ TEXT("X24_G8"),			1,			1,			1,			1,			1,				0,				0,				PF_X24_G8			},
	{ TEXT("ETC1"),				4,			4,			1,			8,			3,				0,				0,				PF_ETC1				},
	{ TEXT("ETC2_RGB"),			4,			4,			1,			8,			3,				0,				0,				PF_ETC2_RGB			},
	{ TEXT("ETC2_RGBA"),		4,			4,			1,			16,			4,				0,				0,				PF_ETC2_RGBA		},
	{ TEXT("PF_R32G32B32A32_UINT"),1,		1,			1,			16,			4,				0,				1,				PF_R32G32B32A32_UINT},
	{ TEXT("PF_R16G16_UINT"),	1,			1,			1,			4,			4,				0,				1,				PF_R16G16_UINT},

	// ASTC support
	{ TEXT("ASTC_4x4"),			4,			4,			1,			16,			4,				0,				0,				PF_ASTC_4x4			},
	{ TEXT("ASTC_6x6"),			6,			6,			1,			16,			4,				0,				0,				PF_ASTC_6x6			},
	{ TEXT("ASTC_8x8"),			8,			8,			1,			16,			4,				0,				0,				PF_ASTC_8x8			},
	{ TEXT("ASTC_10x10"),		10,			10,			1,			16,			4,				0,				0,				PF_ASTC_10x10		},
	{ TEXT("ASTC_12x12"),		12,			12,			1,			16,			4,				0,				0,				PF_ASTC_12x12		},

	{ TEXT("BC6H"),				4,			4,			1,			16,			3,				0,				1,				PF_BC6H				},
	{ TEXT("BC7"),				4,			4,			1,			16,			4,				0,				1,				PF_BC7				},
	{ TEXT("R8_UINT"),			1,			1,			1,			1,			1,				0,				1,				PF_R8_UINT			},
	{ TEXT("L8"),				1,			1,			1,			1,			1,				0,				0,				PF_L8				},
	{ TEXT("XGXR8"),			1,			1,			1,			4,			4,				0,				1,				PF_XGXR8 			},
	{ TEXT("R8G8B8A8_UINT"),	1,			1,			1,			4,			4,				0,				1,				PF_R8G8B8A8_UINT	},
	{ TEXT("R8G8B8A8_SNORM"),	1,			1,			1,			4,			4,				0,				1,				PF_R8G8B8A8_SNORM	},

	{ TEXT("R16G16B16A16_UINT"),1,			1,			1,			8,			4,				0,				1,				PF_R16G16B16A16_UNORM },
	{ TEXT("R16G16B16A16_SINT"),1,			1,			1,			8,			4,				0,				1,				PF_R16G16B16A16_SNORM },
	{ TEXT("PLATFORM_HDR_0"),	0,			0,			0,			0,			0,				0,				0,				PF_PLATFORM_HDR_0   },
	{ TEXT("PLATFORM_HDR_1"),	0,			0,			0,			0,			0,				0,				0,				PF_PLATFORM_HDR_1   },
	{ TEXT("PLATFORM_HDR_2"),	0,			0,			0,			0,			0,				0,				0,				PF_PLATFORM_HDR_2   },

	// NV12 contains 2 textures: R8 luminance plane followed by R8G8 1/4 size chrominance plane.
	// BlockSize/BlockBytes/NumComponents values don't make much sense for this format, so set them all to one.
	{ TEXT("NV12"),				1,			1,			1,			1,			1,				0,				0,				PF_NV12             },

	{ TEXT("PF_R32G32_UINT"),   1,   		1,			1,			8,			2,				0,				1,				PF_R32G32_UINT      },
};

static struct FValidatePixelFormats
{
	FValidatePixelFormats()
	{
		for (int32 X = 0; X < ARRAY_COUNT(GPixelFormats); ++X)
		{
			// Make sure GPixelFormats has an entry for every unreal format
			check(X == GPixelFormats[X].UnrealFormat);
		}
	}
} ValidatePixelFormats;

//
//	CalculateImageBytes
//

SIZE_T CalculateImageBytes(uint32 SizeX,uint32 SizeY,uint32 SizeZ,uint8 Format)
{
	if ( Format == PF_A1 )
	{
		// The number of bytes needed to store all 1 bit pixels in a line is the width of the image divided by the number of bits in a byte
		uint32 BytesPerLine = SizeX / 8;
		// The number of actual bytes in a 1 bit image is the bytes per line of pixels times the number of lines
		return sizeof(uint8) * BytesPerLine * SizeY;
	}
	else if( SizeZ > 0 )
	{
		return (SizeX / GPixelFormats[Format].BlockSizeX) * (SizeY / GPixelFormats[Format].BlockSizeY) * (SizeZ / GPixelFormats[Format].BlockSizeZ) * GPixelFormats[Format].BlockBytes;
	}
	else
	{	
		return (SizeX / GPixelFormats[Format].BlockSizeX) * (SizeY / GPixelFormats[Format].BlockSizeY) * GPixelFormats[Format].BlockBytes;
	}
}

//
// FWhiteTexture implementation
//

/**
 * A solid-colored 1x1 texture.
 */
template <int32 R, int32 G, int32 B, int32 A>
class FColoredTexture : public FTextureWithSRV
{
public:
	// FResource interface.
	virtual void InitRHI() override
	{
		// Create the texture RHI.  		
		FRHIResourceCreateInfo CreateInfo(TEXT("ColoredTexture"));
		FTexture2DRHIRef Texture2D = RHICreateTexture2D(1, 1, PF_B8G8R8A8, 1, 1, TexCreate_ShaderResource, CreateInfo);
		TextureRHI = Texture2D;

		// Write the contents of the texture.
		uint32 DestStride;
		FColor* DestBuffer = (FColor*)RHILockTexture2D(Texture2D, 0, RLM_WriteOnly, DestStride, false);
		*DestBuffer = FColor(R, G, B, A);
		RHIUnlockTexture2D(Texture2D, 0, false);

		// Create the sampler state RHI resource.
		FSamplerStateInitializerRHI SamplerStateInitializer(SF_Point,AM_Wrap,AM_Wrap,AM_Wrap);
		SamplerStateRHI = RHICreateSamplerState(SamplerStateInitializer);

		// Create a view of the texture
		ShaderResourceViewRHI = RHICreateShaderResourceView(TextureRHI, 0u);
	}

	/** Returns the width of the texture in pixels. */
	virtual uint32 GetSizeX() const override
	{
		return 1;
	}

	/** Returns the height of the texture in pixels. */
	virtual uint32 GetSizeY() const override
	{
		return 1;
	}
};

FTextureWithSRV* GWhiteTextureWithSRV = new TGlobalResource<FColoredTexture<255,255,255,255> >;
FTextureWithSRV* GBlackTextureWithSRV = new TGlobalResource<FColoredTexture<0,0,0,255> >;
FTexture* GWhiteTexture = GWhiteTextureWithSRV;
FTexture* GBlackTexture = GBlackTextureWithSRV;

/**
 * Bulk data interface for providing a single black color used to initialize a
 * volume texture.
 */
class FBlackVolumeTextureResourceBulkDataInterface : public FResourceBulkDataInterface
{
public:

	/** Default constructor. */
	FBlackVolumeTextureResourceBulkDataInterface()
		: Color(0)
	{
	}

	/**
	 * Returns a pointer to the bulk data.
	 */
	virtual const void* GetResourceBulkData() const override
	{
		return &Color;
	}

	/** 
	 * @return size of resource memory
	 */
	virtual uint32 GetResourceBulkDataSize() const override
	{
		return sizeof(Color);
	}

	/**
	 * Free memory after it has been used to initialize RHI resource 
	 */
	virtual void Discard() override
	{
	}

private:

	/** Storage for the color. */
	FColor Color;
};

/**
 * A class representing a 1x1x1 black volume texture.
 */
template <EPixelFormat PixelFormat>
class FBlackVolumeTexture : public FTexture
{
public:
	
	/**
	 * Initialize RHI resources.
	 */
	virtual void InitRHI() override
	{
		if (GSupportsTexture3D)
		{
			// Create the texture.
			FBlackVolumeTextureResourceBulkDataInterface BlackTextureBulkData;
			FRHIResourceCreateInfo CreateInfo(&BlackTextureBulkData);
			CreateInfo.DebugName = TEXT("BlackVolumeTexture");
			FTexture3DRHIRef Texture3D = RHICreateTexture3D(1,1,1,PixelFormat,1,TexCreate_ShaderResource,CreateInfo);
			TextureRHI = Texture3D;	
		}
		else
		{
			// Create a texture, even though it's not a volume texture
			FBlackVolumeTextureResourceBulkDataInterface BlackTextureBulkData;
			FRHIResourceCreateInfo CreateInfo(&BlackTextureBulkData);
			FTexture2DRHIRef Texture2D = RHICreateTexture2D(1, 1, PixelFormat, 1, 1, TexCreate_ShaderResource, CreateInfo);
			TextureRHI = Texture2D;
		}

		// Create the sampler state.
		FSamplerStateInitializerRHI SamplerStateInitializer(SF_Point, AM_Wrap, AM_Wrap, AM_Wrap);
		SamplerStateRHI = RHICreateSamplerState(SamplerStateInitializer);
	}

	/**
	 * Return the size of the texture in the X dimension.
	 */
	virtual uint32 GetSizeX() const override
	{
		return 1;
	}

	/**
	 * Return the size of the texture in the Y dimension.
	 */
	virtual uint32 GetSizeY() const override
	{
		return 1;
	}
};

/** Global black volume texture resource. */
FTexture* GBlackVolumeTexture = new TGlobalResource<FBlackVolumeTexture<PF_B8G8R8A8>>();

/** Global black volume texture resource. */
FTexture* GBlackUintVolumeTexture = new TGlobalResource<FBlackVolumeTexture<PF_R8G8B8A8_UINT>>();

class FBlackArrayTexture : public FTexture
{
public:
	// FResource interface.
	virtual void InitRHI() override
	{
		if (GetFeatureLevel() >= ERHIFeatureLevel::SM4)
		{
			// Create the texture RHI.
			FBlackVolumeTextureResourceBulkDataInterface BlackTextureBulkData;
			FRHIResourceCreateInfo CreateInfo(&BlackTextureBulkData);
			CreateInfo.DebugName = TEXT("BlackArrayTexture");
			FTexture2DArrayRHIRef TextureArray = RHICreateTexture2DArray(1, 1, 1, PF_B8G8R8A8, 1, 1, TexCreate_ShaderResource, CreateInfo);
			TextureRHI = TextureArray;

			// Create the sampler state RHI resource.
			FSamplerStateInitializerRHI SamplerStateInitializer(SF_Point,AM_Wrap,AM_Wrap,AM_Wrap);
			SamplerStateRHI = RHICreateSamplerState(SamplerStateInitializer);
		}
	}

	/** Returns the width of the texture in pixels. */
	virtual uint32 GetSizeX() const override
	{
		return 1;
	}

	/** Returns the height of the texture in pixels. */
	virtual uint32 GetSizeY() const override
	{
		return 1;
	}
};

FTexture* GBlackArrayTexture = new TGlobalResource<FBlackArrayTexture>;

//
// FMipColorTexture implementation
//

/**
 * A texture that has a different solid color in each mip-level
 */
class FMipColorTexture : public FTexture
{
public:
	enum
	{
		NumMips = 12
	};
	static const FColor MipColors[NumMips];

	// FResource interface.
	virtual void InitRHI() override
	{
		// Create the texture RHI.
		int32 TextureSize = 1 << (NumMips - 1);
		FRHIResourceCreateInfo CreateInfo;
		FTexture2DRHIRef Texture2D = RHICreateTexture2D(TextureSize,TextureSize,PF_B8G8R8A8,NumMips,1,TexCreate_ShaderResource,CreateInfo);
		TextureRHI = Texture2D;

		// Write the contents of the texture.
		uint32 DestStride;
		int32 Size = TextureSize;
		for ( int32 MipIndex=0; MipIndex < NumMips; ++MipIndex )
		{
			FColor* DestBuffer = (FColor*)RHILockTexture2D(Texture2D, MipIndex, RLM_WriteOnly, DestStride, false);
			for ( int32 Y=0; Y < Size; ++Y )
			{
				for ( int32 X=0; X < Size; ++X )
				{
					DestBuffer[X] = MipColors[NumMips - 1 - MipIndex];
				}
				DestBuffer += DestStride / sizeof(FColor);
			}
			RHIUnlockTexture2D(Texture2D, MipIndex, false);
			Size >>= 1;
		}

		// Create the sampler state RHI resource.
		FSamplerStateInitializerRHI SamplerStateInitializer(SF_Point,AM_Wrap,AM_Wrap,AM_Wrap);
		SamplerStateRHI = RHICreateSamplerState(SamplerStateInitializer);
	}

	/** Returns the width of the texture in pixels. */
	virtual uint32 GetSizeX() const override
	{
		int32 TextureSize = 1 << (NumMips - 1);
		return TextureSize;
	}

	/** Returns the height of the texture in pixels. */
	// PVS-Studio notices that the implementation of GetSizeX is identical to this one
	// and warns us. In this case, it is intentional, so we disable the warning:
	virtual uint32 GetSizeY() const override //-V524
	{
		int32 TextureSize = 1 << (NumMips - 1);
		return TextureSize;
	}
};

const FColor FMipColorTexture::MipColors[NumMips] =
{
	FColor(  80,  80,  80, 0 ),		// Mip  0: 1x1			(dark grey)
	FColor( 200, 200, 200, 0 ),		// Mip  1: 2x2			(light grey)
	FColor( 200, 200,   0, 0 ),		// Mip  2: 4x4			(medium yellow)
	FColor( 255, 255,   0, 0 ),		// Mip  3: 8x8			(yellow)
	FColor( 160, 255,  40, 0 ),		// Mip  4: 16x16		(light green)
	FColor(   0, 255,   0, 0 ),		// Mip  5: 32x32		(green)
	FColor(   0, 255, 200, 0 ),		// Mip  6: 64x64		(cyan)
	FColor(   0, 170, 170, 0 ),		// Mip  7: 128x128		(light blue)
	FColor(  60,  60, 255, 0 ),		// Mip  8: 256x256		(dark blue)
	FColor( 255,   0, 255, 0 ),		// Mip  9: 512x512		(pink)
	FColor( 255,   0,   0, 0 ),		// Mip 10: 1024x1024	(red)
	FColor( 255, 130,   0, 0 ),		// Mip 11: 2048x2048	(orange)
};

RENDERCORE_API FTexture* GMipColorTexture = new FMipColorTexture;
RENDERCORE_API int32 GMipColorTextureMipLevels = FMipColorTexture::NumMips;

// 4: 8x8 cubemap resolution, shader needs to use the same value as preprocessing
RENDERCORE_API const uint32 GDiffuseConvolveMipLevel = 4;

/** A solid color cube texture. */
class FSolidColorTextureCube : public FTexture
{
public:
	FSolidColorTextureCube(const FColor& InColor)
		: bInitToZero(false)
		, PixelFormat(PF_B8G8R8A8)
		, ColorData(InColor.DWColor())
	{}

	FSolidColorTextureCube(EPixelFormat InPixelFormat)
		: bInitToZero(true)
		, PixelFormat(InPixelFormat)
		, ColorData(0)
	{}

	// FRenderResource interface.
	virtual void InitRHI() override
	{
		// Create the texture RHI.
		FRHIResourceCreateInfo CreateInfo(TEXT("SolidColorCube"));
		FTextureCubeRHIRef TextureCube = RHICreateTextureCube(1, PixelFormat, 1, TexCreate_ShaderResource, CreateInfo);
		TextureRHI = TextureCube;

		// Write the contents of the texture.
		for (uint32 FaceIndex = 0; FaceIndex < 6; FaceIndex++)
		{
			uint32 DestStride;
			void* DestBuffer = RHILockTextureCubeFace(TextureCube, FaceIndex, 0, 0, RLM_WriteOnly, DestStride, false);
			if (bInitToZero)
			{
				FMemory::Memzero(DestBuffer, GPixelFormats[PixelFormat].BlockBytes);
			}
			else
			{
				FMemory::Memcpy(DestBuffer, &ColorData, sizeof(ColorData));
			}
			RHIUnlockTextureCubeFace(TextureCube, FaceIndex, 0, 0, false);
		}

		// Create the sampler state RHI resource.
		FSamplerStateInitializerRHI SamplerStateInitializer(SF_Point, AM_Wrap, AM_Wrap, AM_Wrap);
		SamplerStateRHI = RHICreateSamplerState(SamplerStateInitializer);
	}

	/** Returns the width of the texture in pixels. */
	virtual uint32 GetSizeX() const override
	{
		return 1;
	}

	/** Returns the height of the texture in pixels. */
	virtual uint32 GetSizeY() const override
	{
		return 1;
	}

private:
	const bool bInitToZero;
	const EPixelFormat PixelFormat;
	const uint32 ColorData;
};

/** A white cube texture. */
class FWhiteTextureCube : public FSolidColorTextureCube
{
public:
	FWhiteTextureCube() : FSolidColorTextureCube(FColor::White) {}
};
FTexture* GWhiteTextureCube = new TGlobalResource<FWhiteTextureCube>;

/** A black cube texture. */
class FBlackTextureCube : public FSolidColorTextureCube
{
public:
	FBlackTextureCube() : FSolidColorTextureCube(FColor::Black) {}
};
FTexture* GBlackTextureCube = new TGlobalResource<FBlackTextureCube>;

/** A black cube texture. */
class FBlackTextureDepthCube : public FSolidColorTextureCube
{
public:
	FBlackTextureDepthCube() : FSolidColorTextureCube(PF_ShadowDepth) {}
};
FTexture* GBlackTextureDepthCube = new TGlobalResource<FBlackTextureDepthCube>;

class FBlackCubeArrayTexture : public FTexture
{
public:
	// FResource interface.
	virtual void InitRHI() override
	{
		if (GetFeatureLevel() >= ERHIFeatureLevel::SM5)
		{
			// Create the texture RHI.
			FRHIResourceCreateInfo CreateInfo(TEXT("BlackCubeArray"));
			FTextureCubeRHIRef TextureCubeArray = RHICreateTextureCubeArray(1,1,PF_B8G8R8A8,1,TexCreate_ShaderResource,CreateInfo);
			TextureRHI = TextureCubeArray;

			for(uint32 FaceIndex = 0;FaceIndex < 6;FaceIndex++)
			{
				uint32 DestStride;
				FColor* DestBuffer = (FColor*)RHILockTextureCubeFace(TextureCubeArray, FaceIndex, 0, 0, RLM_WriteOnly, DestStride, false);
				// Note: alpha is used by reflection environment to say how much of the foreground texture is visible, so 0 says it is completely invisible
				*DestBuffer = FColor(0, 0, 0, 0);
				RHIUnlockTextureCubeFace(TextureCubeArray, FaceIndex, 0, 0, false);
			}

			// Create the sampler state RHI resource.
			FSamplerStateInitializerRHI SamplerStateInitializer(SF_Point,AM_Wrap,AM_Wrap,AM_Wrap);
			SamplerStateRHI = RHICreateSamplerState(SamplerStateInitializer);
		}
	}

	/** Returns the width of the texture in pixels. */
	virtual uint32 GetSizeX() const override
	{
		return 1;
	}

	/** Returns the height of the texture in pixels. */
	virtual uint32 GetSizeY() const override
	{
		return 1;
	}
};
FTexture* GBlackCubeArrayTexture = new TGlobalResource<FBlackCubeArrayTexture>;

/*
	3 XYZ packed in 4 bytes. (11:11:10 for X:Y:Z)
*/

/**
*	operator FVector - unpacked to -1 to 1
*/
FPackedPosition::operator FVector() const
{

	return FVector(Vector.X/1023.f, Vector.Y/1023.f, Vector.Z/511.f);
}

/**
* operator VectorRegister
*/
VectorRegister FPackedPosition::GetVectorRegister() const
{
	FVector UnpackedVect = *this;

	VectorRegister VectorToUnpack = VectorLoadFloat3_W0(&UnpackedVect);

	return VectorToUnpack;
}

/**
* Pack this vector(-1 to 1 for XYZ) to 4 bytes XYZ(11:11:10)
*/
void FPackedPosition::Set( const FVector& InVector )
{
	check (FMath::Abs<float>(InVector.X) <= 1.f && FMath::Abs<float>(InVector.Y) <= 1.f &&  FMath::Abs<float>(InVector.Z) <= 1.f);
	
#if !WITH_EDITORONLY_DATA
	// This should not happen in Console - this should happen during Cooking in PC
	check (false);
#else
	// Too confusing to use .5f - wanted to use the last bit!
	// Change to int for easier read
	Vector.X = FMath::Clamp<int32>(FMath::TruncToInt(InVector.X * 1023.0f),-1023,1023);
	Vector.Y = FMath::Clamp<int32>(FMath::TruncToInt(InVector.Y * 1023.0f),-1023,1023);
	Vector.Z = FMath::Clamp<int32>(FMath::TruncToInt(InVector.Z * 511.0f),-511,511);
#endif
}

/**
* operator << serialize
*/
FArchive& operator<<(FArchive& Ar,FPackedPosition& N)
{
	// Save N.Packed
	return Ar << N.Packed;
}

void CalcMipMapExtent3D( uint32 TextureSizeX, uint32 TextureSizeY, uint32 TextureSizeZ, EPixelFormat Format, uint32 MipIndex, uint32& OutXExtent, uint32& OutYExtent, uint32& OutZExtent )
{
	OutXExtent = FMath::Max<uint32>(TextureSizeX >> MipIndex, GPixelFormats[Format].BlockSizeX);
	OutYExtent = FMath::Max<uint32>(TextureSizeY >> MipIndex, GPixelFormats[Format].BlockSizeY);
	OutZExtent = FMath::Max<uint32>(TextureSizeZ >> MipIndex, GPixelFormats[Format].BlockSizeZ);
}

SIZE_T CalcTextureMipMapSize3D( uint32 TextureSizeX, uint32 TextureSizeY, uint32 TextureSizeZ, EPixelFormat Format, uint32 MipIndex )
{
	uint32 XExtent;
	uint32 YExtent;
	uint32 ZExtent;
	CalcMipMapExtent3D(TextureSizeX, TextureSizeY, TextureSizeZ, Format, MipIndex, XExtent, YExtent, ZExtent);

	// Offset MipExtent to round up result
	XExtent += GPixelFormats[Format].BlockSizeX - 1;
	YExtent += GPixelFormats[Format].BlockSizeY - 1;
	ZExtent += GPixelFormats[Format].BlockSizeZ - 1;

	const uint32 XPitch = (XExtent / GPixelFormats[Format].BlockSizeX) * GPixelFormats[Format].BlockBytes;
	const uint32 NumRows = YExtent / GPixelFormats[Format].BlockSizeY;
	const uint32 NumLayers = ZExtent / GPixelFormats[Format].BlockSizeZ;

	return NumLayers * NumRows * XPitch;
}

SIZE_T CalcTextureSize3D( uint32 SizeX, uint32 SizeY, uint32 SizeZ, EPixelFormat Format, uint32 MipCount )
{
	SIZE_T Size = 0;
	for ( uint32 MipIndex=0; MipIndex < MipCount; ++MipIndex )
	{
		Size += CalcTextureMipMapSize3D(SizeX,SizeY,SizeZ,Format,MipIndex);
	}
	return Size;
}

FIntPoint CalcMipMapExtent( uint32 TextureSizeX, uint32 TextureSizeY, EPixelFormat Format, uint32 MipIndex )
{
	return FIntPoint(FMath::Max<uint32>(TextureSizeX >> MipIndex, GPixelFormats[Format].BlockSizeX), FMath::Max<uint32>(TextureSizeY >> MipIndex, GPixelFormats[Format].BlockSizeY));
}

SIZE_T CalcTextureMipWidthInBlocks(uint32 TextureSizeX, EPixelFormat Format, uint32 MipIndex)
{
	const uint32 BlockSizeX = GPixelFormats[Format].BlockSizeX;
	const uint32 WidthInTexels = FMath::Max<uint32>(TextureSizeX >> MipIndex, 1);
	const uint32 WidthInBlocks = (WidthInTexels + BlockSizeX - 1) / BlockSizeX;
	return WidthInBlocks;
}

SIZE_T CalcTextureMipHeightInBlocks(uint32 TextureSizeY, EPixelFormat Format, uint32 MipIndex)
{
	const uint32 BlockSizeY = GPixelFormats[Format].BlockSizeY;
	const uint32 HeightInTexels = FMath::Max<uint32>(TextureSizeY >> MipIndex, 1);
	const uint32 HeightInBlocks = (HeightInTexels + BlockSizeY - 1) / BlockSizeY;
	return HeightInBlocks;
}

SIZE_T CalcTextureMipMapSize( uint32 TextureSizeX, uint32 TextureSizeY, EPixelFormat Format, uint32 MipIndex )
{
	const uint32 WidthInBlocks = CalcTextureMipWidthInBlocks(TextureSizeX, Format, MipIndex);
	const uint32 HeightInBlocks = CalcTextureMipHeightInBlocks(TextureSizeY, Format, MipIndex);
	return WidthInBlocks * HeightInBlocks * GPixelFormats[Format].BlockBytes;
}

SIZE_T CalcTextureSize( uint32 SizeX, uint32 SizeY, EPixelFormat Format, uint32 MipCount )
{
	SIZE_T Size = 0;
	for ( uint32 MipIndex=0; MipIndex < MipCount; ++MipIndex )
	{
		Size += CalcTextureMipMapSize(SizeX,SizeY,Format,MipIndex);
	}
	return Size;
}

void CopyTextureData2D(const void* Source,void* Dest,uint32 SizeY,EPixelFormat Format,uint32 SourceStride,uint32 DestStride)
{
	const uint32 BlockSizeY = GPixelFormats[Format].BlockSizeY;
	const uint32 NumBlocksY = (SizeY + BlockSizeY - 1) / BlockSizeY;

	// a DestStride of 0 means to use the SourceStride
	if(SourceStride == DestStride || DestStride == 0)
	{
		// If the source and destination have the same stride, copy the data in one block.
		FMemory::Memcpy(Dest,Source,NumBlocksY * SourceStride);
	}
	else
	{
		// If the source and destination have different strides, copy each row of blocks separately.
		const uint32 NumBytesPerRow = FMath::Min<uint32>(SourceStride, DestStride);
		for(uint32 BlockY = 0;BlockY < NumBlocksY;++BlockY)
		{
			FMemory::Memcpy(
				(uint8*)Dest   + DestStride   * BlockY,
				(uint8*)Source + SourceStride * BlockY,
				NumBytesPerRow
				);
		}
	}
}

/** Helper functions for text output of texture properties... */
#ifndef CASE_ENUM_TO_TEXT
#define CASE_ENUM_TO_TEXT(txt) case txt: return TEXT(#txt);
#endif

#ifndef TEXT_TO_ENUM
#define TEXT_TO_ENUM(eVal, txt)		if (FCString::Stricmp(TEXT(#eVal), txt) == 0)	return eVal;
#endif

const TCHAR* GetPixelFormatString(EPixelFormat InPixelFormat)
{
	switch (InPixelFormat)
	{
		FOREACH_ENUM_EPIXELFORMAT(CASE_ENUM_TO_TEXT)
	default:
		return TEXT("PF_Unknown");
	}	
}

EPixelFormat GetPixelFormatFromString(const TCHAR* InPixelFormatStr)
{
#define TEXT_TO_PIXELFORMAT(f) TEXT_TO_ENUM(f, InPixelFormatStr);
	FOREACH_ENUM_EPIXELFORMAT(TEXT_TO_PIXELFORMAT)
#undef TEXT_TO_PIXELFORMAT
	return PF_Unknown;
}


const TCHAR* GetCubeFaceName(ECubeFace Face)
{
	switch(Face)
	{
	case CubeFace_PosX:
		return TEXT("PosX");
	case CubeFace_NegX:
		return TEXT("NegX");
	case CubeFace_PosY:
		return TEXT("PosY");
	case CubeFace_NegY:
		return TEXT("NegY");
	case CubeFace_PosZ:
		return TEXT("PosZ");
	case CubeFace_NegZ:
		return TEXT("NegZ");
	default:
		return TEXT("");
	}
}

ECubeFace GetCubeFaceFromName(const FString& Name)
{
	// not fast but doesn't have to be
	if(Name.EndsWith(TEXT("PosX")))
	{
		return CubeFace_PosX;
	}
	else if(Name.EndsWith(TEXT("NegX")))
	{
		return CubeFace_NegX;
	}
	else if(Name.EndsWith(TEXT("PosY")))
	{
		return CubeFace_PosY;
	}
	else if(Name.EndsWith(TEXT("NegY")))
	{
		return CubeFace_NegY;
	}
	else if(Name.EndsWith(TEXT("PosZ")))
	{
		return CubeFace_PosZ;
	}
	else if(Name.EndsWith(TEXT("NegZ")))
	{
		return CubeFace_NegZ;
	}

	return CubeFace_MAX;
}

class FVector4VertexDeclaration : public FRenderResource
{
public:
	FVertexDeclarationRHIRef VertexDeclarationRHI;
	virtual void InitRHI() override
	{
		FVertexDeclarationElementList Elements;
		Elements.Add(FVertexElement(0, 0, VET_Float4, 0, sizeof(FVector4)));
		VertexDeclarationRHI = PipelineStateCache::GetOrCreateVertexDeclaration(Elements);
	}
	virtual void ReleaseRHI() override
	{
		VertexDeclarationRHI.SafeRelease();
	}
};

TGlobalResource<FVector4VertexDeclaration> GVector4VertexDeclaration;

RENDERCORE_API FVertexDeclarationRHIRef& GetVertexDeclarationFVector4()
{
	return GVector4VertexDeclaration.VertexDeclarationRHI;
}

class FVector3VertexDeclaration : public FRenderResource
{
public:
	FVertexDeclarationRHIRef VertexDeclarationRHI;
	virtual void InitRHI() override
	{
		FVertexDeclarationElementList Elements;
		Elements.Add(FVertexElement(0, 0, VET_Float3, 0, sizeof(FVector)));
		VertexDeclarationRHI = PipelineStateCache::GetOrCreateVertexDeclaration(Elements);
	}
	virtual void ReleaseRHI() override
	{
		VertexDeclarationRHI.SafeRelease();
	}
};

TGlobalResource<FVector3VertexDeclaration> GVector3VertexDeclaration;

RENDERCORE_API FVertexDeclarationRHIRef& GetVertexDeclarationFVector3()
{
	return GVector3VertexDeclaration.VertexDeclarationRHI;
}

class FVector2VertexDeclaration : public FRenderResource
{
public:
	FVertexDeclarationRHIRef VertexDeclarationRHI;
	virtual void InitRHI() override
	{
		FVertexDeclarationElementList Elements;
		Elements.Add(FVertexElement(0, 0, VET_Float2, 0, sizeof(FVector2D)));
		VertexDeclarationRHI = PipelineStateCache::GetOrCreateVertexDeclaration(Elements);
	}
	virtual void ReleaseRHI() override
	{
		VertexDeclarationRHI.SafeRelease();
	}
};

TGlobalResource<FVector2VertexDeclaration> GVector2VertexDeclaration;

RENDERCORE_API FVertexDeclarationRHIRef& GetVertexDeclarationFVector2()
{
	return GVector2VertexDeclaration.VertexDeclarationRHI;
}

RENDERCORE_API bool PlatformSupportsSimpleForwardShading(EShaderPlatform Platform)
{
	static const auto SupportSimpleForwardShadingCVar = IConsoleManager::Get().FindTConsoleVariableDataInt(TEXT("r.SupportSimpleForwardShading"));
	// Scalability feature only needed / used on PC
	return IsPCPlatform(Platform) && SupportSimpleForwardShadingCVar->GetValueOnAnyThread() != 0;
}

RENDERCORE_API bool IsSimpleForwardShadingEnabled(EShaderPlatform Platform)
{
	static const auto CVar = IConsoleManager::Get().FindTConsoleVariableDataInt(TEXT("r.SimpleForwardShading"));
	return CVar->GetValueOnAnyThread() != 0 && PlatformSupportsSimpleForwardShading(Platform);
}

RENDERCORE_API bool MobileSupportsGPUScene(EShaderPlatform Platform)
{
	// make it shader platform setting?
	static TConsoleVariableData<int32>* CVar = IConsoleManager::Get().FindTConsoleVariableDataInt(TEXT("r.Mobile.SupportGPUScene"));
	return (CVar && CVar->GetValueOnAnyThread() != 0) ? true : false;
}

RENDERCORE_API bool AllowPixelDepthOffset(EShaderPlatform Platform)
{
	if (IsMobilePlatform(Platform))
	{
		static const auto CVar = IConsoleManager::Get().FindTConsoleVariableDataInt(TEXT("r.Mobile.AllowPixelDepthOffset"));
		return CVar->GetValueOnAnyThread() != 0;
	}
	return true;
}

RENDERCORE_API int32 GUseForwardShading = 0;
static FAutoConsoleVariableRef CVarForwardShading(
	TEXT("r.ForwardShading"),
	GUseForwardShading,
	TEXT("Whether to use forward shading on desktop platforms - requires Shader Model 5 hardware.\n")
	TEXT("Forward shading has lower constant cost, but fewer features supported. 0:off, 1:on\n")
	TEXT("This rendering path is a work in progress with many unimplemented features, notably only a single reflection capture is applied per object and no translucency dynamic shadow receiving."),
	ECVF_RenderThreadSafe | ECVF_ReadOnly
	); 

static TAutoConsoleVariable<int32> CVarDistanceFields(
	TEXT("r.DistanceFields"),
	1,
	TEXT("Enables distance fields rendering.\n") \
	TEXT(" 0: Disabled.\n") \
	TEXT(" 1: Enabled."),
	ECVF_RenderThreadSafe | ECVF_ReadOnly
	); 


RENDERCORE_API uint64 GForwardShadingPlatformMask = 0;
static_assert(SP_NumPlatforms <= sizeof(GForwardShadingPlatformMask) * 8, "GForwardShadingPlatformMask must be large enough to support all shader platforms");

RENDERCORE_API uint64 GDBufferPlatformMask = 0;
static_assert(SP_NumPlatforms <= sizeof(GDBufferPlatformMask) * 8, "GDBufferPlatformMask must be large enough to support all shader platforms");

RENDERCORE_API uint64 GBasePassVelocityPlatformMask = 0;
static_assert(SP_NumPlatforms <= sizeof(GBasePassVelocityPlatformMask) * 8, "GBasePassVelocityPlatformMask must be large enough to support all shader platforms");

RENDERCORE_API uint64 GSelectiveBasePassOutputsPlatformMask = 0;
static_assert(SP_NumPlatforms <= sizeof(GSelectiveBasePassOutputsPlatformMask) * 8, "GSelectiveBasePassOutputsPlatformMask must be large enough to support all shader platforms");

RENDERCORE_API uint64 GDistanceFieldsPlatformMask = 0;
static_assert(SP_NumPlatforms <= sizeof(GDistanceFieldsPlatformMask) * 8, "GDistanceFieldsPlatformMask must be large enough to support all shader platforms");

RENDERCORE_API void RenderUtilsInit()
{
	if (GUseForwardShading)
	{
		GForwardShadingPlatformMask = ~0u;
	}

	static IConsoleVariable* DBufferVar = IConsoleManager::Get().FindConsoleVariable(TEXT("r.DBuffer"));
	if (DBufferVar && DBufferVar->GetInt())
	{
		GDBufferPlatformMask = ~0u;
	}

	static IConsoleVariable* BasePassVelocityCVar = IConsoleManager::Get().FindConsoleVariable(TEXT("r.BasePassOutputsVelocity"));
	if (BasePassVelocityCVar && BasePassVelocityCVar->GetInt())
	{
		GBasePassVelocityPlatformMask = ~0u;
	}

	static IConsoleVariable* SelectiveBasePassOutputsCVar = IConsoleManager::Get().FindConsoleVariable(TEXT("r.SelectiveBasePassOutputs"));
	if (SelectiveBasePassOutputsCVar && SelectiveBasePassOutputsCVar->GetInt())
	{
		GSelectiveBasePassOutputsPlatformMask = ~0u;
	}

	static IConsoleVariable* DistanceFieldsCVar = IConsoleManager::Get().FindConsoleVariable(TEXT("r.DistanceFields")); 
	if (DistanceFieldsCVar && DistanceFieldsCVar->GetInt())
	{
		GDistanceFieldsPlatformMask = ~0u;
	}

#if WITH_EDITOR
	ITargetPlatformManagerModule* TargetPlatformManager = GetTargetPlatformManager();
	if (TargetPlatformManager)
	{
		for (uint32 ShaderPlatformIndex = 0; ShaderPlatformIndex < SP_NumPlatforms; ++ShaderPlatformIndex)
		{
			EShaderPlatform ShaderPlatform = EShaderPlatform(ShaderPlatformIndex);
			FName PlatformName = ShaderPlatformToPlatformName(ShaderPlatform);
			ITargetPlatform* TargetPlatform = TargetPlatformManager->FindTargetPlatform(PlatformName.ToString());
			if (TargetPlatform)
			{
				uint64 Mask = 1ull << ShaderPlatformIndex;

				if (TargetPlatform->UsesForwardShading())
				{
					GForwardShadingPlatformMask |= Mask;
				}
				else
				{
					GForwardShadingPlatformMask &= ~Mask;
				}

				if (TargetPlatform->UsesDBuffer())
				{
					GDBufferPlatformMask |= Mask;
				}
				else
				{
					GDBufferPlatformMask &= ~Mask;
				}

				if (TargetPlatform->UsesBasePassVelocity())
				{
					GBasePassVelocityPlatformMask |= Mask;
				}
				else
				{
					GBasePassVelocityPlatformMask &= ~Mask;
				}

				if (TargetPlatform->UsesSelectiveBasePassOutputs())
				{
					GSelectiveBasePassOutputsPlatformMask |= Mask;
				}
				else
				{
					GSelectiveBasePassOutputsPlatformMask &= ~Mask;
				}

				if (TargetPlatform->UsesDistanceFields())
				{
					GDistanceFieldsPlatformMask |= Mask;
				}
				else
				{
					GDistanceFieldsPlatformMask &= ~Mask;
				}
			}
		}
	}
#endif
}

class FUnitCubeVertexBuffer : public FVertexBuffer
{
public:
	/**
	* Initialize the RHI for this rendering resource
	*/
	void InitRHI() override
	{
		const int32 NumVerts = 8;
		TResourceArray<FVector4, VERTEXBUFFER_ALIGNMENT> Verts;
		Verts.SetNumUninitialized(NumVerts);

		for (uint32 Z = 0; Z < 2; Z++)
		{
			for (uint32 Y = 0; Y < 2; Y++)
			{
				for (uint32 X = 0; X < 2; X++)
				{
					const FVector4 Vertex = FVector4(
					  (X ? -1 : 1),
					  (Y ? -1 : 1),
					  (Z ? -1 : 1),
					  1.0f
					);

					Verts[GetCubeVertexIndex(X, Y, Z)] = Vertex;
				}
			}
		}

		uint32 Size = Verts.GetResourceDataSize();

		// Create vertex buffer. Fill buffer with initial data upon creation
		FRHIResourceCreateInfo CreateInfo(&Verts);
		VertexBufferRHI = RHICreateVertexBuffer(Size, BUF_Static, CreateInfo);
	}
};

class FUnitCubeIndexBuffer : public FIndexBuffer
{
public:
	/**
	* Initialize the RHI for this rendering resource
	*/
	void InitRHI() override
	{
		TResourceArray<uint16, INDEXBUFFER_ALIGNMENT> Indices;
		
		int32 NumIndices = ARRAY_COUNT(GCubeIndices);
		Indices.AddUninitialized(NumIndices);
		FMemory::Memcpy(Indices.GetData(), GCubeIndices, NumIndices * sizeof(uint16));

		const uint32 Size = Indices.GetResourceDataSize();
		const uint32 Stride = sizeof(uint16);

		// Create index buffer. Fill buffer with initial data upon creation
		FRHIResourceCreateInfo CreateInfo(&Indices);
		IndexBufferRHI = RHICreateIndexBuffer(Stride, Size, BUF_Static, CreateInfo);
	}
};

static TGlobalResource<FUnitCubeVertexBuffer> GUnitCubeVertexBuffer;
static TGlobalResource<FUnitCubeIndexBuffer> GUnitCubeIndexBuffer;

RENDERCORE_API FVertexBufferRHIRef& GetUnitCubeVertexBuffer()
{
	return GUnitCubeVertexBuffer.VertexBufferRHI;
}

RENDERCORE_API FIndexBufferRHIRef& GetUnitCubeIndexBuffer()
{
	return GUnitCubeIndexBuffer.IndexBufferRHI;
}

RENDERCORE_API void QuantizeSceneBufferSize(const FIntPoint& InBufferSize, FIntPoint& OutBufferSize)
{
	// Ensure sizes are dividable by the ideal group size for 2d tiles to make it more convenient.
	const uint32 DividableBy = 4;

	check(DividableBy % 4 == 0); // A lot of graphic algorithms where previously assuming DividableBy == 4.

	const uint32 Mask = ~(DividableBy - 1);
	OutBufferSize.X = (InBufferSize.X + DividableBy - 1) & Mask;
	OutBufferSize.Y = (InBufferSize.Y + DividableBy - 1) & Mask;
}

RENDERCORE_API bool UseVirtualTexturing(ERHIFeatureLevel::Type InFeatureLevel, const ITargetPlatform* TargetPlatform)
{
#if !PLATFORM_SUPPORTS_VIRTUAL_TEXTURE_STREAMING
	if (GIsEditor == false)
	{
		return false;
	}
	else
#endif
	{
		// only at SM5 
		if (InFeatureLevel < ERHIFeatureLevel::SM5)
		{
			return false;
		}

		// does the platform supports it.
#if WITH_EDITOR
		if (GIsEditor && TargetPlatform == nullptr)
		{
			ITargetPlatformManagerModule* TPM = GetTargetPlatformManager();
			if (TPM)
			{
				TargetPlatform = TPM->GetRunningTargetPlatform();
			}
		}

		if (TargetPlatform && TargetPlatform->SupportsFeature(ETargetPlatformFeatures::VirtualTextureStreaming) == false)
		{
			return false;
		}
#endif

		// Remove this when UE-80097 is implemented
		static bool bIsVulkanRHI = FCString::Strcmp(GDynamicRHI->GetName(), TEXT("Vulkan")) == 0;
		if (bIsVulkanRHI)
		{
			return false;
		}

		// does the project has it enabled ?
		static const auto CVarVirtualTexture = IConsoleManager::Get().FindTConsoleVariableDataInt(TEXT("r.VirtualTextures"));
		check(CVarVirtualTexture);
		if (CVarVirtualTexture->GetValueOnAnyThread() == 0)
		{
			return false;
		}		

		return true;
	}
}