FlaxEngine/Source/Shaders/Common.hlsl

// Copyright (c) 2012-2020 Wojciech Figat. All rights reserved.

#ifndef __COMMON__
#define __COMMON__

// Platform macros
#if !defined(DIRECTX)
#define DIRECTX 0
#endif
#if !defined(OPENGL)
#define OPENGL 0
#endif
#if !defined(VULKAN)
#define VULKAN 0
#endif
#if defined(PLATFORM_PS4)
#include "./FlaxPlatforms/PS4/Shaders/PS4Common.hlsl"
#endif

// Feature levels
#define FEATURE_LEVEL_ES2 0
#define FEATURE_LEVEL_ES3 1
#define FEATURE_LEVEL_ES3_1 2
#define FEATURE_LEVEL_SM4 3
#define FEATURE_LEVEL_SM5 4
#if !defined(FEATURE_LEVEL)
#error "Invalid platform defines"
#endif

// Meta macros used by shaders parser
#define META_VS(isVisible, minFeatureLevel)
#define META_VS_IN_ELEMENT(type, index, format, slot, offset, slotClass, stepRate, isVisible)
#define META_HS(isVisible, minFeatureLevel)
#define META_HS_PATCH(inControlPoints)
#define META_DS(isVisible, minFeatureLevel)
#define META_GS(isVisible, minFeatureLevel)
#define META_PS(isVisible, minFeatureLevel)
#define META_CS(isVisible, minFeatureLevel)
#define META_FLAG(flag)
#define META_PERMUTATION_1(param0)
#define META_PERMUTATION_2(param0, param1)
#define META_PERMUTATION_3(param0, param1, param2)
#define META_PERMUTATION_4(param0, param1, param2, param3)
#define META_CB_BEGIN(index, name) cbuffer name : register(b##index) {
#define META_CB_END };

#define SHADING_MODEL_UNLIT 0
#define SHADING_MODEL_LIT 1
#define SHADING_MODEL_SUBSURFACE 2
#define SHADING_MODEL_FOLIAGE 3

// Detect feature level support
#if FEATURE_LEVEL >= FEATURE_LEVEL_SM5
#define CAN_USE_GATHER 1
#else
#define CAN_USE_GATHER 0
#endif
#if FEATURE_LEVEL >= FEATURE_LEVEL_SM5
#define CAN_USE_COMPUTE_SHADER 1
#else
#define CAN_USE_COMPUTE_SHADER 0
#endif
#if FEATURE_LEVEL >= FEATURE_LEVEL_SM4
#define CAN_USE_GEOMETRY_SHADER 1
#else
#define CAN_USE_GEOMETRY_SHADER 0
#endif
#if FEATURE_LEVEL >= FEATURE_LEVEL_SM5
#define CAN_USE_TESSELLATION 1
#else
#define CAN_USE_TESSELLATION 0
#endif

// Compiler attributes

#if DIRECTX || VULKAN

// Avoids flow control constructs.
#define UNROLL [unroll]

// Gives preference to flow control constructs.
#define LOOP [loop]

// Performs branching by using control flow instructions like jmp and label.
#define BRANCH [branch]

/// Performs branching by using the cnd instructions.
#define FLATTEN [flatten]

#endif

// Compiler attribute fallback

#ifndef UNROLL
#define UNROLL
#endif

#ifndef LOOP
#define LOOP
#endif

#ifndef BRANCH
#define BRANCH
#endif

#ifndef FLATTEN
#define FLATTEN
#endif

// TODO: cleanup global samplers with per-platform customization support
#ifndef SamplerLinearClamp

// Static samplers
sampler SamplerLinearClamp : register(s0);
sampler SamplerPointClamp : register(s1);
sampler SamplerLinearWrap : register(s2);
sampler SamplerPointWrap : register(s3);

// TODO: use custom pipeline layouts and bind different sampler during shadows rendering
SamplerComparisonState ShadowSampler : register(s4);
SamplerComparisonState ShadowSamplerPCF : register(s5);

#endif

// General purpose macros
#define SAMPLE_RT(rt, texCoord) rt.SampleLevel(SamplerPointClamp, texCoord, 0)
#define SAMPLE_RT_LINEAR(rt, texCoord) rt.SampleLevel(SamplerLinearClamp, texCoord, 0)
#define HDR_CLAMP_MAX 65472.0
#define PI 3.1415926535897932

// Structure that contains information about GBuffer
struct GBufferData
{
	float4 ViewInfo; // x-1/Projection[0,0]   y-1/Projection[1,1]   z-(Far / (Far - Near)   w-(-Far * Near) / (Far - Near) / Far)
	float4 ScreenSize; // x-Width               y-Height              z-1/Width               w-1/Height
	float3 ViewPos; // view position (in world space)
	float ViewFar; // view far plane distance (in world space)
	float4x4 InvViewMatrix; // inverse view matrix (4 rows by 4 columns)
	float4x4 InvProjectionMatrix; // inverse projection matrix (4 rows by 4 columns)
};

#ifdef PLATFORM_ANDROID
// #AdrenoVK_CB_STRUCT_MEMBER_ACCESS_BUG
#define DECLARE_GBUFFERDATA_ACCESS(uniformName) GBufferData Get##uniformName##Data() { GBufferData tmp; tmp.ViewInfo = uniformName.ViewInfo; tmp.ScreenSize = uniformName.ScreenSize; tmp.ViewPos = uniformName.ViewPos; tmp.ViewFar = uniformName.ViewFar; tmp.InvViewMatrix = uniformName.InvViewMatrix; tmp.InvProjectionMatrix = uniformName.InvProjectionMatrix; return tmp; }
#else
#define DECLARE_GBUFFERDATA_ACCESS(uniformName) GBufferData Get##uniformName##Data() { return uniformName; }
#endif

// Structure that contains information about atmosphere fog
struct AtmosphericFogData
{
	float AtmosphericFogDensityScale;
	float AtmosphericFogSunDiscScale;
	float AtmosphericFogDistanceScale;
	float AtmosphericFogGroundOffset;

	float AtmosphericFogAltitudeScale;
	float AtmosphericFogStartDistance;
	float AtmosphericFogPower;
	float AtmosphericFogDistanceOffset;

	float3 AtmosphericFogSunDirection;
	float AtmosphericFogSunPower;

	float3 AtmosphericFogSunColor;
	float AtmosphericFogDensityOffset;
};

// Packed env probe data
struct ProbeData
{
	float4 Data0; // x - Position.x,  y - Position.y,  z - Position.z,  w - unused
	float4 Data1; // x - Radius    ,  y - 1 / Radius,  z - Brightness,  w - unused
};

#define ProbePos Data0.xyz
#define ProbeRadius Data1.x
#define ProbeInvRadius Data1.y
#define ProbeBrightness Data1.z

struct Quad_VS2PS
{
	float4 Position : SV_Position;
	noperspective float2 TexCoord : TEXCOORD0;
};

struct Quad_VS2GS
{
	Quad_VS2PS Vertex;
	uint LayerIndex : TEXCOORD1;
};

struct Quad_GS2PS
{
	Quad_VS2PS Vertex;
	uint LayerIndex : SV_RenderTargetArrayIndex;
};

float Luminance(float3 color)
{
	return dot(color, float3(0.299f, 0.587f, 0.114f));
}

// Samples the unwrapped 3D texture (eg. volume texture of size 16x16x16 would be unwrapped to 256x16)
half4 SampleUnwrappedTexture3D(Texture2D tex, SamplerState s, float3 uvw, float size)
{
	float intW = floor(uvw.z * size - 0.5);
	half fracW = uvw.z * size - 0.5 - intW;
	float u = (uvw.x + intW) / size;
	float v = uvw.y;
	half4 rg0 = tex.Sample(s, float2(u, v));
	half4 rg1 = tex.Sample(s, float2(u + 1.0f / size, v));
	return lerp(rg0, rg1, fracW);
}

#endif