UnrealEngineUWP/Engine/Shaders/Shared/SubstrateDefinitions.h

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

/*================================================================================================
	SubstrateDefinitions.ush: used in ray tracing shaders and C++ code to define common constants
	!!! Changing this file requires recompilation of the engine !!!
=================================================================================================*/

#pragma once

#ifndef __cplusplus
// Change this to force recompilation of all Substrate dependent shaders (for instance https://guidgenerator.com/online-guid-generator.aspx)
#pragma message("UESHADERMETADATA_VERSION B013B52C-494E-4FC3-9EB5-B16B754E5CA4")
#endif

// Closure offsets are packed into 32bits, each entry using SUBSTRATE_CLOSURE_OFFSET_BIT_COUNT bits
#define SUBSTRATE_MAX_CLOSURE_COUNT_FOR_CLOSUREOFFSET	8u
#define SUBSTRATE_CLOSURE_OFFSET_BIT_COUNT				4u
#define SUBSTRATE_CLOSURE_OFFSET_BIT_MASK				0xF

// We can only ever use SUBSTRATE_MAX_CLOSURE_COUNT_FOR_CLOSUREOFFSET for Lumen, so we use that as a global closure count limit today.
#define SUBSTRATE_MAX_CLOSURE_COUNT						SUBSTRATE_MAX_CLOSURE_COUNT_FOR_CLOSUREOFFSET
#define SUBSTRATE_MAX_OPERATOR_COUNT					15

// It this is changed, STATE_BIT_COUNT_SHAREDLOCALBASESID and HEADER_BIT_COUNT_SHAREDLOCALBASES_COUNT also needs to be updated
#define SUBSTRATE_MAX_SHAREDLOCALBASES_REGISTERS		4

#define SUBSTRATE_PACKED_SHAREDLOCALBASIS_STRIDE_BYTES	4

// As of today, a fully simplified material is a slab with all features allowed. It can thus be complex if anisotropy is enabled and in this case eats up to 32bytes.
// SUBSTRATE_TODO: fully simplified should remove all features but fuzz maybe. 
#define SUBSTRATE_FULLY_SIMPLIFIED_NUM_UINTS			(32/4)

#define SUBSTRATE_BSDF_TYPE_SLAB						0
#define SUBSTRATE_BSDF_TYPE_VOLUMETRICFOGCLOUD			1
#define SUBSTRATE_BSDF_TYPE_UNLIT						2
#define SUBSTRATE_BSDF_TYPE_HAIR						3
#define SUBSTRATE_BSDF_TYPE_SINGLELAYERWATER			4
#define SUBSTRATE_BSDF_TYPE_EYE							5
// When more than 7 BSDF must exists, please update STATE_BIT_COUNT_BSDF and FSubstrateClassification.ShadingModels packing in Substrate.ush

// The size of Substrate material classification tiles on screen
#define SUBSTRATE_TILE_SIZE								8
#define SUBSTRATE_TILE_SIZE_DIV_AS_SHIFT				3

// The default thickness of a layer is considered to be 0.01 centimeter = 0.1 millimeter
#define SUBSTRATE_LAYER_DEFAULT_THICKNESS_CM			0.01f

// Min Fuzz Roughness to avoid numerical issue
#define SUBSTRATE_MIN_FUZZ_ROUGHNESS					0.02f

#define SUBSTRATE_BASE_PASS_MRT_OUTPUT_COUNT			3

#define SUBSTRATE_SSS_DATA_UINT_COUNT					2

#define SUBSTRATE_OPERATOR_WEIGHT						0
#define SUBSTRATE_OPERATOR_VERTICAL						1
#define SUBSTRATE_OPERATOR_HORIZONTAL					2
#define SUBSTRATE_OPERATOR_ADD							3
#define SUBSTRATE_OPERATOR_BSDF							4
#define SUBSTRATE_OPERATOR_BSDF_LEGACY					5

// This must map directly to ESubstrateTileMaterialType
#define SUBSTRATE_TILE_TYPE_SIMPLE						0
#define SUBSTRATE_TILE_TYPE_SINGLE						1
#define SUBSTRATE_TILE_TYPE_COMPLEX						2
#define SUBSTRATE_TILE_TYPE_COMPLEX_SPECIAL				3
#define SUBSTRATE_TILE_TYPE_ROUGH_REFRACT				4
#define SUBSTRATE_TILE_TYPE_ROUGH_REFRACT_SSS_WITHOUT	5
#define SUBSTRATE_TILE_TYPE_DECAL_SIMPLE				6
#define SUBSTRATE_TILE_TYPE_DECAL_SINGLE				7
#define SUBSTRATE_TILE_TYPE_DECAL_COMPLEX				8
#define SUBSTRATE_TILE_TYPE_COUNT						9

#define SUBSTRATE_MATERIAL_TYPE_SIMPLE					0
#define SUBSTRATE_MATERIAL_TYPE_SINGLE					1
#define SUBSTRATE_MATERIAL_TYPE_COMPLEX					2
#define SUBSTRATE_MATERIAL_TYPE_COMPLEX_SPECIAL			3

#define SUBSTRATE_TILE_ENCODING_16BITS 					0
#define SUBSTRATE_TILE_ENCODING_8BITS  					1

// Specular profile
#define SUBSTRATE_SPECULAR_PROFILE_ENTRY_LIGHT			0u
#define SUBSTRATE_SPECULAR_PROFILE_ENTRY_ENV			1u
#define SUBSTRATE_SPECULAR_PROFILE_ENTRY_COUNT			2u

// sizeof(FRHIDrawIndirectParameters) = 4 uints = 16 bytes
#define GetSubstrateTileTypeDrawIndirectArgOffset_Byte(x)  (x * 16)
#define GetSubstrateTileTypeDrawIndirectArgOffset_DWord(x) (x * 4)

// sizeof(FRHIDispatchIndirectParameters) can vary per-platform
#ifdef __cplusplus
	#define GetSubstrateTileTypeDispatchIndirectArgOffset_Byte(x)  (x * sizeof(FRHIDispatchIndirectParameters))
	#define GetSubstrateTileTypeDispatchIndirectArgOffset_DWord(x) (x * sizeof(FRHIDispatchIndirectParameters) / sizeof(uint32))
#else
	#define GetSubstrateTileTypeDispatchIndirectArgOffset_Byte(x)  (x * DISPATCH_INDIRECT_UINT_COUNT * 4)
	#define GetSubstrateTileTypeDispatchIndirectArgOffset_DWord(x) (x * DISPATCH_INDIRECT_UINT_COUNT)
#endif