// Copyright 1998-2015 Epic Games, Inc. All Rights Reserved.

/*=============================================================================
	BasePassCommon.usf: Base pass definitions used by both vertex and pixel shader
=============================================================================*/

#undef NEEDS_LIGHTMAP_COORDINATE

#define NEEDS_LIGHTMAP_COORDINATE		(HQ_TEXTURE_LIGHTMAP || LQ_TEXTURE_LIGHTMAP)
// Translucent materials need to compute fogging in the forward shading pass
// Materials that read from scene color skip getting fogged, because the contents of the scene color lookup have already been fogged
// This is not foolproof, as any additional color the material adds will then not be fogged correctly
#define NEEDS_BASEPASS_FOGGING			(ENABLE_TRANSLUCENCY_VERTEX_FOG && ((MATERIALBLENDING_TRANSLUCENT || MATERIALBLENDING_ADDITIVE || MATERIALBLENDING_MODULATE) && !MATERIAL_USES_SCENE_COLOR_COPY))
#define NEEDS_LIGHTMAP					(NEEDS_LIGHTMAP_COORDINATE)

#define USES_GBUFFER						(FEATURE_LEVEL >= FEATURE_LEVEL_SM4 && (MATERIALBLENDING_SOLID || MATERIALBLENDING_MASKED) && !NO_GBUFFER)

// Only some shader models actually need custom data.
#define WRITES_CUSTOMDATA_TO_GBUFFER		(USES_GBUFFER && (!SELECTIVE_BASEPASS_OUTPUTS || MATERIAL_SHADINGMODEL_SUBSURFACE || MATERIAL_SHADINGMODEL_PREINTEGRATED_SKIN || MATERIAL_SHADINGMODEL_SUBSURFACE_PROFILE || MATERIAL_SHADINGMODEL_CLEAR_COAT))

// Based on GetPrecomputedShadowMasks()
#define WRITES_PRECSHADOWFACTOR_TO_GBUFFER	(USES_GBUFFER && ALLOW_STATIC_LIGHTING && (!SELECTIVE_BASEPASS_OUTPUTS || (STATICLIGHTING_TEXTUREMASK && STATICLIGHTING_SIGNEDDISTANCEFIELD)))
#define WRITES_PRECSHADOWFACTOR_ZERO		(USES_GBUFFER && ALLOW_STATIC_LIGHTING && (!SELECTIVE_BASEPASS_OUTPUTS || HQ_TEXTURE_LIGHTMAP || LQ_TEXTURE_LIGHTMAP))

// If a primitive has static lighting, we assume it is not moving. If it is, it will be rerendered in an extra renderpass.
#define WRITES_VELOCITY_TO_GBUFFER			(USES_GBUFFER && OUTPUT_GBUFFER_VELOCITY && (!SELECTIVE_BASEPASS_OUTPUTS || !(STATICLIGHTING_TEXTUREMASK || STATICLIGHTING_SIGNEDDISTANCEFIELD || HQ_TEXTURE_LIGHTMAP || LQ_TEXTURE_LIGHTMAP)))

// Use an extra interpolator for position
#define WRITES_VELOCITY_TO_GBUFFER_USE_POS_INTERPOLATOR		(WRITES_VELOCITY_TO_GBUFFER && USING_TESSELLATION)

struct FSharedBasePassInterpolants
{
	//for texture-lightmapped translucency we can pass the vertex fog in its own interpolator
#if NEEDS_BASEPASS_FOGGING
	float4 VertexFog		: TEXCOORD7;
#endif

#if !PC_D3D && !GL4_PROFILE
	// Note: TEXCOORD8 is unused

	#if USE_WORLD_POSITION_EXCLUDING_SHADER_OFFSETS
	float3 PixelPositionExcludingWPO : TEXCOORD9;
	#endif
#endif

#if WRITES_VELOCITY_TO_GBUFFER
	// .xy is clip position, pre divide by w; .w is clip W; .z is 0 or 1 to mask out the velocity output
	float4 VelocityPrevScreenPosition : VELOCITY_PREV_POS;
	#if WRITES_VELOCITY_TO_GBUFFER_USE_POS_INTERPOLATOR
		float4 VelocityScreenPosition : VELOCITY_POS;
	#endif
#endif
};

#if PC_D3D || GL4_PROFILE

/** Interpolants passed from the vertex shader to the pixel shader. */
struct FBasePassInterpolantsVSToPS : FSharedBasePassInterpolants
{
	// Note: TEXCOORD8 is unused

	#if USE_WORLD_POSITION_EXCLUDING_SHADER_OFFSETS
	float3 PixelPositionExcludingWPO : TEXCOORD9;
	#endif
};

/** Interpolants passed from the vertex shader to the domain shader. */
struct FBasePassInterpolantsVSToDS : FSharedBasePassInterpolants
{
	#if USE_WORLD_POSITION_EXCLUDING_SHADER_OFFSETS
	float3 WorldPositionExcludingWPO : TEXCOORD9;
	#endif
};

#else

// Only the PC shader compiler supports HLSL inheritance
#define FBasePassInterpolantsVSToPS FSharedBasePassInterpolants

#endif