FlaxEngine/Content/Editor/MaterialTemplates/VolumeParticle.shader

// File generated by Flax Materials Editor
// Version: @0

#define MATERIAL 1
#define USE_PER_VIEW_CONSTANTS 1
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#include "./Flax/Common.hlsl"
#include "./Flax/MaterialCommon.hlsl"
#include "./Flax/GBufferCommon.hlsl"
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// Primary constant buffer (with additional material parameters)
META_CB_BEGIN(0, Data)
float4x4 InverseViewProjectionMatrix;
float4x3 WorldMatrix;
float4x3 WorldMatrixInverseTransposed;
float3 GridSize;
float PerInstanceRandom;
float Dummy0;
float VolumetricFogMaxDistance;
int ParticleStride;
int ParticleIndex;
@1META_CB_END

// Particles attributes buffer
ByteAddressBuffer ParticlesData : register(t0);

// Shader resources
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// Material properties generation input
struct MaterialInput
{
	float3 WorldPosition;
	float TwoSidedSign;
	float2 TexCoord;
	uint ParticleIndex;
#if USE_VERTEX_COLOR
	half4 VertexColor;
#endif
	float3x3 TBN;
	float4 SvPosition;
	float3 PreSkinnedPosition;
	float3 PreSkinnedNormal;
	float3 InstanceOrigin;
	float InstanceParams;
#if USE_CUSTOM_VERTEX_INTERPOLATORS
	float4 CustomVSToPS[CUSTOM_VERTEX_INTERPOLATORS_COUNT];
#endif
};

#define GetInstanceTransform(input) ToMatrix4x4(WorldMatrix);

// Removes the scale vector from the local to world transformation matrix (supports instancing)
float3x3 RemoveScaleFromLocalToWorld(float3x3 localToWorld)
{
	// Extract per axis scales from localToWorld transform
	float scaleX = length(localToWorld[0]);
	float scaleY = length(localToWorld[1]);
	float scaleZ = length(localToWorld[2]);
	float3 invScale = float3(
		scaleX > 0.00001f ? 1.0f / scaleX : 0.0f,
		scaleY > 0.00001f ? 1.0f / scaleY : 0.0f,
		scaleZ > 0.00001f ? 1.0f / scaleZ : 0.0f);
	localToWorld[0] *= invScale.x;
	localToWorld[1] *= invScale.y;
	localToWorld[2] *= invScale.z;
	return localToWorld;
}

// Transforms a vector from tangent space to world space
float3 TransformTangentVectorToWorld(MaterialInput input, float3 tangentVector)
{
	return mul(tangentVector, input.TBN);
}

// Transforms a vector from world space to tangent space
float3 TransformWorldVectorToTangent(MaterialInput input, float3 worldVector)
{
	return mul(input.TBN, worldVector);
}

// Transforms a vector from world space to view space
float3 TransformWorldVectorToView(MaterialInput input, float3 worldVector)
{
	return mul(worldVector, (float3x3)ViewMatrix);
}

// Transforms a vector from view space to world space
float3 TransformViewVectorToWorld(MaterialInput input, float3 viewVector)
{
	return mul((float3x3)ViewMatrix, viewVector);
}

// Transforms a vector from local space to world space
float3 TransformLocalVectorToWorld(MaterialInput input, float3 localVector)
{
	float3x3 localToWorld = (float3x3)GetInstanceTransform(input);
	//localToWorld = RemoveScaleFromLocalToWorld(localToWorld);
	return mul(localVector, localToWorld);
}

// Transforms a vector from local space to world space
float3 TransformWorldVectorToLocal(MaterialInput input, float3 worldVector)
{
	float3x3 localToWorld = (float3x3)GetInstanceTransform(input);
	//localToWorld = RemoveScaleFromLocalToWorld(localToWorld);
	return mul(localToWorld, worldVector);
}

// Gets the current object position (supports instancing)
float3 GetObjectPosition(MaterialInput input)
{
	return input.InstanceOrigin.xyz;
}

// Gets the current object size
float3 GetObjectSize(MaterialInput input)
{
	return float3(1, 1, 1);
}

// Get the current object random value (supports instancing)
float GetPerInstanceRandom(MaterialInput input)
{
	return input.InstanceParams;
}

// Get the current object LOD transition dither factor (supports instancing)
float GetLODDitherFactor(MaterialInput input)
{
	return 0;
}

// Gets the interpolated vertex color (in linear space)
float4 GetVertexColor(MaterialInput input)
{
	return 1;
}

uint GetParticleUint(uint particleIndex, int offset)
{
	return ParticlesData.Load(particleIndex * ParticleStride + offset);
}

int GetParticleInt(uint particleIndex, int offset)
{
	return asint(ParticlesData.Load(particleIndex * ParticleStride + offset));
}

float GetParticleFloat(uint particleIndex, int offset)
{
	return asfloat(ParticlesData.Load(particleIndex * ParticleStride + offset));
}

float2 GetParticleVec2(uint particleIndex, int offset)
{
	return asfloat(ParticlesData.Load2(particleIndex * ParticleStride + offset));
}

float3 GetParticleVec3(uint particleIndex, int offset)
{
	return asfloat(ParticlesData.Load3(particleIndex * ParticleStride + offset));
}

float4 GetParticleVec4(uint particleIndex, int offset)
{
	return asfloat(ParticlesData.Load4(particleIndex * ParticleStride + offset));
}

float3 TransformParticlePosition(float3 input)
{
	return mul(float4(input, 1.0f), ToMatrix4x4(WorldMatrix)).xyz;
}

float3 TransformParticleVector(float3 input)
{
	return mul(float4(input, 0.0f), ToMatrix4x4(WorldMatrixInverseTransposed)).xyz;
}

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// Get material properties function (for vertex shader)
Material GetMaterialVS(MaterialInput input)
{
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}

// Get material properties function (for domain shader)
Material GetMaterialDS(MaterialInput input)
{
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}

// Get material properties function (for pixel shader)
Material GetMaterialPS(MaterialInput input)
{
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}

// Pixel Shader function for Volumetric Fog material injection (local fog)
META_PS(true, FEATURE_LEVEL_SM5)
void PS_VolumetricFog(Quad_GS2PS input, out float4 VBufferA : SV_Target0, out float4 VBufferB : SV_Target1)
{
	uint3 gridCoordinate = uint3(input.Vertex.Position.xy, input.LayerIndex);
	float3 cellOffset = 0.5f;
	float2 volumeUV = (gridCoordinate.xy + cellOffset.xy) / GridSize.xy;
	float zSlice = gridCoordinate.z + cellOffset.z;
	float sceneDepth = (zSlice / GridSize.z) * VolumetricFogMaxDistance / ViewFar;
	float deviceDepth = (ViewInfo.w / sceneDepth) + ViewInfo.z;
	float4 clipPos = float4(volumeUV * float2(2.0, -2.0) + float2(-1.0, 1.0), deviceDepth, 1.0);
	float4 wsPos = mul(clipPos, InverseViewProjectionMatrix);
	float3 positionWS = wsPos.xyz / wsPos.w;

	// Get material parameters
	MaterialInput materialInput = (MaterialInput)0;
	materialInput.WorldPosition = positionWS;
	materialInput.TexCoord = input.Vertex.TexCoord;
	materialInput.ParticleIndex = ParticleIndex;
	materialInput.TBN = float3x3(float3(1, 0, 0), float3(0, 1, 0), float3(0, 0, 1));
	materialInput.TwoSidedSign = 1.0f;
	materialInput.InstanceOrigin = ToMatrix4x4(WorldMatrix)[3].xyz;
	materialInput.InstanceParams = PerInstanceRandom;
	materialInput.SvPosition = clipPos;
	Material material = GetMaterialPS(materialInput);

	// Compute fog properties
	float3 albedo = material.Color;
	float extinction = material.Opacity * material.Mask * 0.001f;
	float3 emission = material.Emissive;
	float3 scattering = albedo * extinction;
	float absorption = max(0.0f, extinction - Luminance(scattering));

	// Write fog properties
	VBufferA = float4(scattering, absorption);
	VBufferB = float4(emission, 0);
}

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