ScriptableRenderPipeline/ScriptableRenderPipeline/Core/ShaderLibrary/Shadow/Shadow.hlsl

#ifndef SHADOW_HLSL
#define SHADOW_HLSL
//
// Shadow master include header.
//
// There are four relevant files for shadows.
// First ShadowContext.hlsl must declare the specific ShadowContext struct and the loader that goes along with it.
// ShadowContext loading and resource setup from C# must be in sync.
//
// Second there are two headers for shadow algorithms, whose signatures must match any of the Get...Attenuation function prototypes.
// The first header contains engine defaults, whereas the second header is empty by default. All project specific custom shadow algorithms should go in there or leave empty.
//
// Last there's a dispatcher include. By default the Get...Attenuation functions are rerouted to their default implementations. This can be overridden for each
// shadow type in the dispatcher source. For each overridden shadow type a specific define must be defined to prevent falling back to the default functions.
//


#define SHADOW_SUPPORTS_DYNAMIC_INDEXING 0 // only on >= sm 5.1
#define SHADOW_OPTIMIZE_REGISTER_USAGE   0 // redefine this as 1 in your ShadowContext.hlsl to optimize for register usage over instruction count

#include "../../../Core/Shadow/ShadowBase.cs.hlsl"	// ShadowData definition, auto generated (don't modify)
#include "ShadowTexFetch.hlsl"						// Resource sampling definitions (don't modify)

// Declares a shadow context struct with members and sampling code based on whether _...Slots > 0
#define SHADOWCONTEXT_DECLARE( _Tex2DArraySlots, _TexCubeArraySlots, _SamplerCompSlots, _SamplerSlots )				\
																													\
	struct ShadowContext																							\
	{																												\
		StructuredBuffer<ShadowData>	shadowDatas;																\
		StructuredBuffer<int4>			payloads;																	\
		SHADOWCONTEXT_DECLARE_TEXTURES( _Tex2DArraySlots, _TexCubeArraySlots, _SamplerCompSlots, _SamplerSlots )	\
	};																												\
																													\
	SHADOW_DEFINE_SAMPLING_FUNCS( _Tex2DArraySlots, _TexCubeArraySlots, _SamplerCompSlots, _SamplerSlots )


// Shadow context definition and initialization, i.e. resource binding (project header, must be kept in sync with C# runtime)
#define SHADOW_CONTEXT_INCLUDE
#include "../../ShadowIncludes.hlsl"
#undef SHADOW_CONTEXT_INCLUDE

// helper function to extract shadowmap data from the ShadowData struct
void UnpackShadowmapId( uint shadowmapId, out uint texIdx, out uint sampIdx, out float slice )
{
	texIdx  = (shadowmapId >> 24) & 0xff;
	sampIdx = (shadowmapId >> 16) & 0xff;
	slice   = (float)(shadowmapId & 0xffff);
}
void UnpackShadowmapId( uint shadowmapId, out uint texIdx, out uint sampIdx )
{
	texIdx  = (shadowmapId >> 24) & 0xff;
	sampIdx = (shadowmapId >> 16) & 0xff;
}
void UnpackShadowmapId( uint shadowmapId, out float slice )
{
	slice = (float)(shadowmapId & 0xffff);
}

void UnpackShadowType( uint packedShadowType, out uint shadowType, out uint shadowAlgorithm )
{
	shadowType		= packedShadowType >> 10;
	shadowAlgorithm = packedShadowType & 0x1ff;
}

void UnpackShadowType( uint packedShadowType, out uint shadowType )
{
	shadowType = packedShadowType >> 10;
}


// shadow sampling prototypes
float GetPunctualShadowAttenuation( ShadowContext shadowContext, float3 positionWS, float3 normalWS, int shadowDataIndex, float4 L );
float GetPunctualShadowAttenuation( ShadowContext shadowContext, float3 positionWS, float3 normalWS, int shadowDataIndex, float4 L, float2 unPositionSS );
// shadow sampling prototypes with screenspace info
float GetDirectionalShadowAttenuation( ShadowContext shadowContext, float3 positionWS, float3 normalWS, int shadowDataIndex, float3 L );
float GetDirectionalShadowAttenuation( ShadowContext shadowContext, float3 positionWS, float3 normalWS, int shadowDataIndex, float3 L, float2 unPositionSS );


// wedge in the actual shadow sampling algorithms
#include "ShadowSampling.hlsl"			// sampling patterns (don't modify)
#include "ShadowAlgorithms.hlsl"		// engine default algorithms (don't modify)
#include "ShadowAlgorithmsCustom.hlsl"	// project specific custom algorithms (project can modify this)


// default dispatchers for the individual shadow types (with and without screenspace support)
// point/spot light shadows
float GetPunctualShadowAttenuationDefault( ShadowContext shadowContext, float3 positionWS, float3 normalWS, int shadowDataIndex, float4 L )
{
	return EvalShadow_PunctualDepth(shadowContext, positionWS, normalWS, shadowDataIndex, L);
}
float GetPunctualShadowAttenuationDefault( ShadowContext shadowContext, float3 positionWS, float3 normalWS, int shadowDataIndex, float4 L, float2 unPositionSS )
{
	return GetPunctualShadowAttenuationDefault( shadowContext, positionWS, normalWS, shadowDataIndex, L );
}
// directional light shadows
float GetDirectionalShadowAttenuationDefault( ShadowContext shadowContext, float3 positionWS, float3 normalWS, int shadowDataIndex, float3 L )
{
	return EvalShadow_CascadedDepth_Blend( shadowContext, positionWS, normalWS, shadowDataIndex, L );
}
float GetDirectionalShadowAttenuationDefault( ShadowContext shadowContext, float3 positionWS, float3 normalWS, int shadowDataIndex, float3 L, float2 unPositionSS )
{
	return GetDirectionalShadowAttenuationDefault( shadowContext, positionWS, normalWS, shadowDataIndex, L );
}

// include project specific shadow dispatcher. If this file is not empty, it MUST define which default shadows it's overriding
#define SHADOW_DISPATCH_INCLUDE
#include "../../ShadowIncludes.hlsl"
#undef SHADOW_DISPATCH_INCLUDE

// if shadow dispatch is empty we'll fall back to default shadow sampling implementations
#ifndef SHADOW_DISPATCH_USE_CUSTOM_PUNCTUAL
float GetPunctualShadowAttenuation( ShadowContext shadowContext, float3 positionWS, float3 normalWS, int shadowDataIndex, float4 L )
{
	return GetPunctualShadowAttenuationDefault( shadowContext, positionWS, normalWS, shadowDataIndex, L );
}
float GetPunctualShadowAttenuation( ShadowContext shadowContext, float3 positionWS, float3 normalWS, int shadowDataIndex, float4 L, float2 unPositionSS )
{
	return GetPunctualShadowAttenuationDefault( shadowContext, positionWS, normalWS, shadowDataIndex, L, unPositionSS );
}
#endif
#ifndef SHADOW_DISPATCH_USE_CUSTOM_DIRECTIONAL
float GetDirectionalShadowAttenuation( ShadowContext shadowContext, float3 positionWS, float3 normalWS, int shadowDataIndex, float3 L )
{
	return GetDirectionalShadowAttenuationDefault( shadowContext, positionWS, normalWS, shadowDataIndex, L );
}
float GetDirectionalShadowAttenuation( ShadowContext shadowContext, float3 positionWS, float3 normalWS, int shadowDataIndex, float3 L, float2 unPositionSS )
{
	return GetDirectionalShadowAttenuationDefault( shadowContext, positionWS, normalWS, shadowDataIndex, L, unPositionSS );
}
#endif

#endif // SHADOW_HLSL