UnrealEngineUWP/Engine/Shaders/Private/LocalVertexFactoryCommon.ush

// Copyright Epic Games, Inc. All Rights Reserved.

/*=============================================================================
	LocalVertexFactoryCommon.usf: Local vertex factory common functionality
=============================================================================*/

struct FVertexFactoryInterpolantsVSToPS
{
	TANGENTTOWORLD_INTERPOLATOR_BLOCK

#if INTERPOLATE_VERTEX_COLOR
	half4	Color : COLOR0;
#endif

#if USE_INSTANCING || USE_INSTANCE_CULLING
	// x = per-instance random, y = per-instance fade out amount, z = hide/show flag, w dither fade cutoff
	float4  PerInstanceParams : COLOR1;
#endif

#if NUM_TEX_COORD_INTERPOLATORS
	float4	TexCoords[(NUM_TEX_COORD_INTERPOLATORS+1)/2]	: TEXCOORD0;
#elif USE_PARTICLE_SUBUVS
	float4	TexCoords[1] : TEXCOORD0;
#endif

#if NEEDS_LIGHTMAP_COORDINATE
	float4	LightMapCoordinate : TEXCOORD4;
#endif

#if INSTANCED_STEREO
	nointerpolation uint EyeIndex : PACKED_EYE_INDEX;
#endif
#if VF_USE_PRIMITIVE_SCENE_DATA
	nointerpolation uint PrimitiveId : PRIMITIVE_ID;
	#if NEEDS_LIGHTMAP_COORDINATE
		nointerpolation uint LightmapDataIndex : LIGHTMAP_ID;
	#endif
#endif
#if HAIR_STRAND_MESH_FACTORY || HAIR_CARD_MESH_FACTORY
	nointerpolation uint HairPrimitiveId	: HAIR_PRIMITIVE_ID; // Control point ID
	float2 HairPrimitiveUV					: HAIR_PRIMITIVE_UV; // U: parameteric distance between the two surrounding control points. V: parametric distance along the width.
#endif
};

#if NUM_TEX_COORD_INTERPOLATORS || USE_PARTICLE_SUBUVS
float2 GetUV(FVertexFactoryInterpolantsVSToPS Interpolants, int UVIndex)
{
	float4 UVVector = Interpolants.TexCoords[UVIndex / 2];
	return UVIndex % 2 ? UVVector.zw : UVVector.xy;
}

void SetUV(inout FVertexFactoryInterpolantsVSToPS Interpolants, int UVIndex, float2 InValue)
{
	FLATTEN
	if (UVIndex % 2)
	{
		Interpolants.TexCoords[UVIndex / 2].zw = InValue;
	}
	else
	{
		Interpolants.TexCoords[UVIndex / 2].xy = InValue;
	}
}
#endif

float4 GetColor(FVertexFactoryInterpolantsVSToPS Interpolants)
{
#if INTERPOLATE_VERTEX_COLOR
	return Interpolants.Color;
#else
	return 0;
#endif
}

void SetColor(inout FVertexFactoryInterpolantsVSToPS Interpolants, float4 InValue)
{
#if INTERPOLATE_VERTEX_COLOR
	Interpolants.Color = InValue;
#endif
}

#if NEEDS_LIGHTMAP_COORDINATE
void GetLightMapCoordinates(FVertexFactoryInterpolantsVSToPS Interpolants, out float2 LightmapUV0, out float2 LightmapUV1, out uint LightmapDataIndex)
{
	LightmapUV0 = Interpolants.LightMapCoordinate.xy * float2( 1, 0.5 );
	LightmapUV1 = LightmapUV0 + float2( 0, 0.5 );

#if VF_USE_PRIMITIVE_SCENE_DATA && NEEDS_LIGHTMAP_COORDINATE
	LightmapDataIndex = Interpolants.LightmapDataIndex;
#else
	LightmapDataIndex = 0;
#endif
}

void GetShadowMapCoordinate(FVertexFactoryInterpolantsVSToPS Interpolants, out float2 ShadowMapCoordinate, out uint LightmapDataIndex)
{
#if VF_USE_PRIMITIVE_SCENE_DATA && NEEDS_LIGHTMAP_COORDINATE
	LightmapDataIndex = Interpolants.LightmapDataIndex;
#else
	LightmapDataIndex = 0;
#endif
	ShadowMapCoordinate = Interpolants.LightMapCoordinate.zw;
}

void SetLightMapCoordinate(inout FVertexFactoryInterpolantsVSToPS Interpolants, float2 InLightMapCoordinate, float2 InShadowMapCoordinate)
{
	Interpolants.LightMapCoordinate.xy = InLightMapCoordinate;
	Interpolants.LightMapCoordinate.zw = InShadowMapCoordinate;
}
#endif

float4 GetTangentToWorld2(FVertexFactoryInterpolantsVSToPS Interpolants)
{
	return Interpolants.TangentToWorld2;
}

float4 GetTangentToWorld0(FVertexFactoryInterpolantsVSToPS Interpolants)
{
	return Interpolants.TangentToWorld0;
}

void SetTangents(inout FVertexFactoryInterpolantsVSToPS Interpolants, float3 InTangentToWorld0, float3 InTangentToWorld2, float InTangentToWorldSign)
{
	Interpolants.TangentToWorld0 = float4(InTangentToWorld0,0);
	Interpolants.TangentToWorld2 = float4(InTangentToWorld2,InTangentToWorldSign);
#if USE_WORLDVERTEXNORMAL_CENTER_INTERPOLATION
	Interpolants.TangentToWorld2_Center = Interpolants.TangentToWorld2;
#endif
}

uint GetPrimitiveId(FVertexFactoryInterpolantsVSToPS Interpolants)
{
#if VF_USE_PRIMITIVE_SCENE_DATA
	return Interpolants.PrimitiveId;
#else
	return 0;
#endif
}

void SetPrimitiveId(inout FVertexFactoryInterpolantsVSToPS Interpolants, uint PrimitiveId)
{
#if VF_USE_PRIMITIVE_SCENE_DATA
	Interpolants.PrimitiveId = PrimitiveId;
#endif
}

void SetLightmapDataIndex(inout FVertexFactoryInterpolantsVSToPS Interpolants, uint LightmapDataIndex)
{
#if VF_USE_PRIMITIVE_SCENE_DATA && NEEDS_LIGHTMAP_COORDINATE
	Interpolants.LightmapDataIndex = LightmapDataIndex;
#endif
}