using System ;
#if UNITY_EDITOR
using UnityEditor ;
using UnityEditor ;
#endif
namespace UnityEngine.Experimental.Rendering.HDPipeline
public const int SSS_LOD_THRESHOLD = 4 ; // The LoD threshold of the near-field kernel (in pixels)
public const int SSS_TRSM_MODE_NONE = 0 ;
public const int SSS_TRSM_MODE_THIN = 1 ;
// Old SSS Model >>>
public const int SSS_BASIC_N_SAMPLES = 1 1 ; // Must be an odd number
public const int SSS_BASIC_DISTANCE_SCALE = 3 ; // SSS distance units per centimeter
// <<< Old SSS Model
}
[Serializable]
Vector2 [ ] m_FilterKernelNearField ; // X = radius, Y = reciprocal of the PDF
[SerializeField]
Vector2 [ ] m_FilterKernelFarField ; // X = radius, Y = reciprocal of the PDF
// Old SSS Model >>>
[ColorUsage(false, true, 0.05f, 2.0f, 1.0f, 1.0f)]
public Color scatterDistance1 ;
[ColorUsage(false, true, 0.05f, 2.0f, 1.0f, 1.0f)]
public Color scatterDistance2 ;
public float lerpWeight ;
[SerializeField]
Vector4 m_HalfRcpWeightedVariances ;
[SerializeField]
Vector4 [ ] m_FilterKernelBasic ;
// <<< Old SSS Model
// --- Public Methods ---
thicknessRemap = new Vector2 ( 0.0f , 5.0f ) ;
worldScale = 1.0f ;
settingsIndex = SssConstants . SSS_NEUTRAL_PROFILE_ID ; // Updated by SubsurfaceScatteringSettings.OnValidate() once assigned
// Old SSS Model >>>
scatterDistance1 = new Color ( 0.3f , 0.3f , 0.3f , 0.0f ) ;
scatterDistance2 = new Color ( 0.5f , 0.5f , 0.5f , 0.0f ) ;
lerpWeight = 1.0f ;
// <<< Old SSS Model
BuildKernel ( ) ;
}
// PDF(r, s) = s * (Exp[-r * s] + Exp[-r * s / 3]) / 4
// CDF(r, s) = 1 - 1/4 * Exp[-r * s] - 3/4 * Exp[-r * s / 3]
// ------------------------------------------------------------------------------------
// N.b.: computation of normalized weights, and multiplication by the surface albedo
// of the actual geometry is performed at runtime (in the shader).
m_FilterKernelNearField [ i ] . x = r ;
m_FilterKernelFarField [ i ] . x = r ;
m_FilterKernelFarField [ i ] . y = 1.0f / KernelPdf ( r , s ) ;
}
// Old SSS Model >>>
UpdateKernelAndVarianceData ( ) ;
// <<< Old SSS Model
// Old SSS Model >>>
public void UpdateKernelAndVarianceData ( )
{
const int numSamples = SssConstants . SSS_BASIC_N_SAMPLES ;
const int distanceScale = SssConstants . SSS_BASIC_DISTANCE_SCALE ;
if ( m_FilterKernelBasic = = null | | m_FilterKernelBasic . Length ! = numSamples )
{
m_FilterKernelBasic = new Vector4 [ numSamples ] ;
}
// Apply the three-sigma rule, and rescale.
Color stdDev1 = ( ( 1.0f / 3.0f ) * distanceScale ) * scatterDistance1 ;
Color stdDev2 = ( ( 1.0f / 3.0f ) * distanceScale ) * scatterDistance2 ;
// Our goal is to blur the image using a filter which is represented
// as a product of a linear combination of two normalized 1D Gaussians
// as suggested by Jimenez et al. in "Separable Subsurface Scattering".
// A normalized (i.e. energy-preserving) 1D Gaussian with the mean of 0
// is defined as follows: G1(x, v) = exp(-x * x / (2 * v)) / sqrt(2 * Pi * v),
// where 'v' is variance and 'x' is the radial distance from the origin.
// Using the weight 'w', our 1D and the resulting 2D filters are given as:
// A1(v1, v2, w, x) = G1(x, v1) * (1 - w) + G1(r, v2) * w,
// A2(v1, v2, w, x, y) = A1(v1, v2, w, x) * A1(v1, v2, w, y).
// The resulting filter function is a non-Gaussian PDF.
// It is separable by design, but generally not radially symmetric.
// N.b.: our scattering distance is rather limited. Therefore, in order to allow
// for a greater range of standard deviation values for flatter profiles,
// we rescale the world using 'distanceScale', effectively reducing the SSS
// distance units from centimeters to (1 / distanceScale).
// Find the widest Gaussian across 3 color channels.
float maxStdDev1 = Mathf . Max ( stdDev1 . r , stdDev1 . g , stdDev1 . b ) ;
float maxStdDev2 = Mathf . Max ( stdDev2 . r , stdDev2 . g , stdDev2 . b ) ;
Vector3 weightSum = new Vector3 ( 0 , 0 , 0 ) ;
float step = 1.0f / ( numSamples - 1 ) ;
// Importance sample the linear combination of two Gaussians.
for ( int i = 0 ; i < numSamples ; i + + )
{
// Generate 'u' on (0, 0.5] and (0.5, 1).
float u = ( i < = numSamples / 2 ) ? 0.5f - i * step // The center and to the left
: i * step ; // From the center to the right
u = Mathf . Clamp ( u , 0.001f , 0.999f ) ;
float pos = GaussianCombinationCdfInverse ( u , maxStdDev1 , maxStdDev2 , lerpWeight ) ;
float pdf = GaussianCombination ( pos , maxStdDev1 , maxStdDev2 , lerpWeight ) ;
Vector3 val ;
val . x = GaussianCombination ( pos , stdDev1 . r , stdDev2 . r , lerpWeight ) ;
val . y = GaussianCombination ( pos , stdDev1 . g , stdDev2 . g , lerpWeight ) ;
val . z = GaussianCombination ( pos , stdDev1 . b , stdDev2 . b , lerpWeight ) ;
// We do not divide by 'numSamples' since we will renormalize, anyway.
m_FilterKernelBasic [ i ] . x = val . x * ( 1 / pdf ) ;
m_FilterKernelBasic [ i ] . y = val . y * ( 1 / pdf ) ;
m_FilterKernelBasic [ i ] . z = val . z * ( 1 / pdf ) ;
m_FilterKernelBasic [ i ] . w = pos ;
weightSum . x + = m_FilterKernelBasic [ i ] . x ;
weightSum . y + = m_FilterKernelBasic [ i ] . y ;
weightSum . z + = m_FilterKernelBasic [ i ] . z ;
}
// Renormalize the weights to conserve energy.
for ( int i = 0 ; i < numSamples ; i + + )
{
m_FilterKernelBasic [ i ] . x * = 1 / weightSum . x ;
m_FilterKernelBasic [ i ] . y * = 1 / weightSum . y ;
m_FilterKernelBasic [ i ] . z * = 1 / weightSum . z ;
}
Vector4 weightedStdDev ;
weightedStdDev . x = Mathf . Lerp ( stdDev1 . r , stdDev2 . r , lerpWeight ) ;
weightedStdDev . y = Mathf . Lerp ( stdDev1 . g , stdDev2 . g , lerpWeight ) ;
weightedStdDev . z = Mathf . Lerp ( stdDev1 . b , stdDev2 . b , lerpWeight ) ;
weightedStdDev . w = Mathf . Lerp ( maxStdDev1 , maxStdDev2 , lerpWeight ) ;
// Store (1 / (2 * WeightedVariance)) per color channel.
m_HalfRcpWeightedVariances . x = 0.5f / ( weightedStdDev . x * weightedStdDev . x ) ;
m_HalfRcpWeightedVariances . y = 0.5f / ( weightedStdDev . y * weightedStdDev . y ) ;
m_HalfRcpWeightedVariances . z = 0.5f / ( weightedStdDev . z * weightedStdDev . z ) ;
m_HalfRcpWeightedVariances . w = 0.5f / ( weightedStdDev . w * weightedStdDev . w ) ;
}
// <<< Old SSS Model
public Vector3 surfaceShapeParameter
{
// Set in BuildKernel().
// Set in BuildKernel().
get { return m_FilterKernelNearField ; }
}
// Old SSS Model >>>
public Vector4 [ ] filterKernelBasic
{
// Set via UpdateKernelAndVarianceData().
get { return m_FilterKernelBasic ; }
}
public Vector4 halfRcpWeightedVariances
{
// Set via UpdateKernelAndVarianceData().
get { return m_HalfRcpWeightedVariances ; }
}
// <<< Old SSS Model
// --- Private Methods ---
return r ;
}
// Old SSS Model >>>
static float Gaussian ( float x , float stdDev )
{
float variance = stdDev * stdDev ;
return Mathf . Exp ( - x * x / ( 2 * variance ) ) / Mathf . Sqrt ( 2 * Mathf . PI * variance ) ;
}
static float GaussianCombination ( float x , float stdDev1 , float stdDev2 , float lerpWeight )
{
return Mathf . Lerp ( Gaussian ( x , stdDev1 ) , Gaussian ( x , stdDev2 ) , lerpWeight ) ;
}
static float RationalApproximation ( float t )
{
// Abramowitz and Stegun formula 26.2.23.
// The absolute value of the error should be less than 4.5 e-4.
float [ ] c = { 2.515517f , 0.802853f , 0.010328f } ;
float [ ] d = { 1.432788f , 0.189269f , 0.001308f } ;
return t - ( ( c [ 2 ] * t + c [ 1 ] ) * t + c [ 0 ] ) / ( ( ( d [ 2 ] * t + d [ 1 ] ) * t + d [ 0 ] ) * t + 1.0f ) ;
}
// Ref: https://www.johndcook.com/blog/csharp_phi_inverse/
static float NormalCdfInverse ( float p , float stdDev )
{
float x ;
if ( p < 0.5 )
{
// F^-1(p) = - G^-1(p)
x = - RationalApproximation ( Mathf . Sqrt ( - 2.0f * Mathf . Log ( p ) ) ) ;
}
else
{
// F^-1(p) = G^-1(1-p)
x = RationalApproximation ( Mathf . Sqrt ( - 2.0f * Mathf . Log ( 1.0f - p ) ) ) ;
}
return x * stdDev ;
}
static float GaussianCombinationCdfInverse ( float p , float stdDev1 , float stdDev2 , float lerpWeight )
{
return Mathf . Lerp ( NormalCdfInverse ( p , stdDev1 ) , NormalCdfInverse ( p , stdDev2 ) , lerpWeight ) ;
}
// <<< Old SSS Model
}
[Serializable]
[NonSerialized] public float [ ] worldScales ; // Size of the world unit in meters
[NonSerialized] public float [ ] filterKernelsNearField ; // 0 = radius, 1 = reciprocal of the PDF
[NonSerialized] public float [ ] filterKernelsFarField ; // 0 = radius, 1 = reciprocal of the PDF
// Old SSS Model >>>
public bool useDisneySSS ;
[NonSerialized] public Vector4 [ ] halfRcpWeightedVariances ;
[NonSerialized] public Vector4 [ ] filterKernelsBasic ;
// <<< Old SSS Model
// --- Public Methods ---
volumeShapeParams = null ;
filterKernelsNearField = null ;
filterKernelsFarField = null ;
// Old SSS Model >>>
useDisneySSS = true ;
halfRcpWeightedVariances = null ;
filterKernelsBasic = null ;
// <<< Old SSS Model
UpdateCache ( ) ;
}
profiles [ i ] . thicknessRemap . x = Mathf . Clamp ( profiles [ i ] . thicknessRemap . x , 0 , profiles [ i ] . thicknessRemap . y ) ;
profiles [ i ] . worldScale = Mathf . Max ( profiles [ i ] . worldScale , 0.001f ) ;
// Old SSS Model >>>
Color c = new Color ( ) ;
c . r = Mathf . Clamp ( profiles [ i ] . scatterDistance1 . r , 0.05f , 2.0f ) ;
c . g = Mathf . Clamp ( profiles [ i ] . scatterDistance1 . g , 0.05f , 2.0f ) ;
c . b = Mathf . Clamp ( profiles [ i ] . scatterDistance1 . b , 0.05f , 2.0f ) ;
c . a = 0.0f ;
profiles [ i ] . scatterDistance1 = c ;
c . r = Mathf . Clamp ( profiles [ i ] . scatterDistance2 . r , 0.05f , 2.0f ) ;
c . g = Mathf . Clamp ( profiles [ i ] . scatterDistance2 . g , 0.05f , 2.0f ) ;
c . b = Mathf . Clamp ( profiles [ i ] . scatterDistance2 . b , 0.05f , 2.0f ) ;
c . a = 0.0f ;
profiles [ i ] . scatterDistance2 = c ;
profiles [ i ] . lerpWeight = Mathf . Clamp01 ( profiles [ i ] . lerpWeight ) ;
// <<< Old SSS Model
profiles [ i ] . BuildKernel ( ) ;
}
filterKernelsFarField = new float [ filterKernelsFarFieldLen ] ;
}
// Old SSS Model >>>
if ( halfRcpWeightedVariances = = null | | halfRcpWeightedVariances . Length ! = SssConstants . SSS_N_PROFILES )
{
halfRcpWeightedVariances = new Vector4 [ SssConstants . SSS_N_PROFILES ] ;
}
const int filterKernelsLen = SssConstants . SSS_N_PROFILES * SssConstants . SSS_BASIC_N_SAMPLES ;
if ( filterKernelsBasic = = null | | filterKernelsBasic . Length ! = filterKernelsLen )
{
filterKernelsBasic = new Vector4 [ filterKernelsLen ] ;
}
// <<< Old SSS Model
for ( int i = 0 ; i < numProfiles ; i + + )
{
// Skip unassigned profiles.
filterKernelsFarField [ 2 * ( n * i + j ) + 0 ] = profiles [ i ] . filterKernelFarField [ j ] . x ;
filterKernelsFarField [ 2 * ( n * i + j ) + 1 ] = profiles [ i ] . filterKernelFarField [ j ] . y ;
}
// Old SSS Model >>>
halfRcpWeightedVariances [ i ] = profiles [ i ] . halfRcpWeightedVariances ;
for ( int j = 0 , n = SssConstants . SSS_BASIC_N_SAMPLES ; j < n ; j + + )
{
filterKernelsBasic [ n * i + j ] = profiles [ i ] . filterKernelBasic [ j ] ;
}
// <<< Old SSS Model
}
// Fill the neutral profile.
filterKernelsFarField [ 2 * ( n * i + j ) + 0 ] = 0.0f ;
filterKernelsFarField [ 2 * ( n * i + j ) + 1 ] = 1.0f ;
}
// Old SSS Model >>>
halfRcpWeightedVariances [ i ] = Vector4 . one ;
for ( int j = 0 , n = SssConstants . SSS_BASIC_N_SAMPLES ; j < n ; j + + )
{
filterKernelsBasic [ n * i + j ] = Vector4 . one ;
filterKernelsBasic [ n * i + j ] . w = 0.0f ;
}
// <<< Old SSS Model
}
}
public readonly GUIContent sssProfileMinMaxThickness = new GUIContent ( "Min-Max Thickness" , "Shows the values of the thickness remap below (in millimeters)." ) ;
public readonly GUIContent sssProfileThicknessRemap = new GUIContent ( "Thickness Remap" , "Remaps the thickness parameter from [0, 1] to the desired range (in millimeters)." ) ;
public readonly GUIContent sssProfileWorldScale = new GUIContent ( "World Scale" , "Size of the world unit in meters." ) ;
// Old SSS Model >>>
public readonly GUIContent sssProfileScatterDistance1 = new GUIContent ( "Scattering Distance #1" , "The radius (in centimeters) of the 1st Gaussian filter, one per color channel. Alpha is ignored. The blur is energy-preserving, so a wide filter results in a large area with small contributions of individual samples. Smaller values increase the sharpness." ) ;
public readonly GUIContent sssProfileScatterDistance2 = new GUIContent ( "Scattering Distance #2" , "The radius (in centimeters) of the 2nd Gaussian filter, one per color channel. Alpha is ignored. The blur is energy-preserving, so a wide filter results in a large area with small contributions of individual samples. Smaller values increase the sharpness." ) ;
public readonly GUIContent sssProfileLerpWeight = new GUIContent ( "Filter Interpolation" , "Controls linear interpolation between the two Gaussian filters." ) ;
// <<< Old SSS Model
public readonly GUIStyle centeredMiniBoldLabel = new GUIStyle ( GUI . skin . label ) ;
public Styles ( )
private Material m_ProfileMaterial , m_TransmittanceMaterial ;
private SerializedProperty m_LenVolMeanFreePath , m_ScatteringDistance , m_SurfaceAlbedo , m_VolumeAlbedo , m_SurfaceShapeParam , m_VolumeShapeParam ,
m_TexturingMode , m_TransmissionMode , m_ThicknessRemap , m_WorldScale ;
// Old SSS Model >>>
private SerializedProperty m_ScatterDistance1 , m_ScatterDistance2 , m_LerpWeight ;
// <<< Old SSS Model
void OnEnable ( )
{
m_TransmissionMode = serializedObject . FindProperty ( "transmissionMode" ) ;
m_ThicknessRemap = serializedObject . FindProperty ( "thicknessRemap" ) ;
m_WorldScale = serializedObject . FindProperty ( "worldScale" ) ;
// Old SSS Model >>>
m_ScatterDistance1 = serializedObject . FindProperty ( "scatterDistance1" ) ;
m_ScatterDistance2 = serializedObject . FindProperty ( "scatterDistance2" ) ;
m_LerpWeight = serializedObject . FindProperty ( "lerpWeight" ) ;
// <<< Old SSS Model
// These shaders don't need to be reference by RenderPipelineResource as they are not use at runtime
m_ProfileMaterial = Utilities . CreateEngineMaterial ( "Hidden/HDRenderPipeline/DrawSssProfile" ) ;
{
serializedObject . Update ( ) ;
// Old SSS Model >>>
bool useDisneySSS ;
{
HDRenderPipeline hdPipeline = RenderPipelineManager . currentPipeline as HDRenderPipeline ;
useDisneySSS = hdPipeline . sssSettings . useDisneySSS ;
}
// <<< Old SSS Model
EditorGUILayout . PropertyField ( m_SurfaceAlbedo , styles . sssProfileSurfaceAlbedo ) ;
m_LenVolMeanFreePath . floatValue = EditorGUILayout . Slider ( styles . sssProfileLenVolMeanFreePath , m_LenVolMeanFreePath . floatValue , 0.01f , 1.0f ) ;
GUI . enabled = false ;
EditorGUILayout . PropertyField ( m_ScatteringDistance , styles . sssProfileScatteringDistance ) ;
GUI . enabled = true ;
if ( useDisneySSS )
{
EditorGUILayout . PropertyField ( m_SurfaceAlbedo , styles . sssProfileSurfaceAlbedo ) ;
m_LenVolMeanFreePath . floatValue = EditorGUILayout . Slider ( styles . sssProfileLenVolMeanFreePath , m_LenVolMeanFreePath . floatValue , 0.01f , 1.0f ) ;
GUI . enabled = false ;
EditorGUILayout . PropertyField ( m_ScatteringDistance , styles . sssProfileScatteringDistance ) ;
GUI . enabled = true ;
}
else
{
EditorGUILayout . PropertyField ( m_ScatterDistance1 , styles . sssProfileScatterDistance1 ) ;
EditorGUILayout . PropertyField ( m_ScatterDistance2 , styles . sssProfileScatterDistance2 ) ;
EditorGUILayout . PropertyField ( m_LerpWeight , styles . sssProfileLerpWeight ) ;
}
m_TexturingMode . intValue = EditorGUILayout . Popup ( styles . sssTexturingMode , m_TexturingMode . intValue , styles . sssTexturingModeOptions ) ;
m_TransmissionMode . intValue = EditorGUILayout . Popup ( styles . sssProfileTransmissionMode , m_TransmissionMode . intValue , styles . sssTransmissionModeOptions ) ;
m_ProfileMaterial . SetFloat ( "_ScatteringDistance" , d ) ;
m_ProfileMaterial . SetVector ( "_SurfaceAlbedo" , aS ) ;
m_ProfileMaterial . SetVector ( "_SurfaceShapeParam" , sS ) ;
// Old SSS Model >>>
Utilities . SelectKeyword ( m_ProfileMaterial , "SSS_MODEL_DISNEY" , "SSS_MODEL_BASIC" , useDisneySSS ) ;
// Apply the three-sigma rule, and rescale.
float s = ( 1.0f / 3.0f ) * SssConstants . SSS_BASIC_DISTANCE_SCALE ;
float rMax = Mathf . Max ( m_ScatterDistance1 . colorValue . r , m_ScatterDistance1 . colorValue . g , m_ScatterDistance1 . colorValue . b ,
m_ScatterDistance2 . colorValue . r , m_ScatterDistance2 . colorValue . g , m_ScatterDistance2 . colorValue . b ) ;
Vector4 stdDev1 = new Vector4 ( s * m_ScatterDistance1 . colorValue . r , s * m_ScatterDistance1 . colorValue . g , s * m_ScatterDistance1 . colorValue . b ) ;
Vector4 stdDev2 = new Vector4 ( s * m_ScatterDistance2 . colorValue . r , s * m_ScatterDistance2 . colorValue . g , s * m_ScatterDistance2 . colorValue . b ) ;
m_ProfileMaterial . SetVector ( "_StdDev1" , stdDev1 ) ;
m_ProfileMaterial . SetVector ( "_StdDev2" , stdDev2 ) ;
m_ProfileMaterial . SetFloat ( "_LerpWeight" , m_LerpWeight . floatValue ) ;
m_ProfileMaterial . SetFloat ( "_MaxRadius" , rMax ) ;
// <<< Old SSS Model
EditorGUILayout . Space ( ) ;
EditorGUILayout . LabelField ( styles . sssTransmittancePreview0 , styles . centeredMiniBoldLabel ) ;
EditorGUILayout . LabelField ( styles . sssTransmittancePreview1 , EditorStyles . centeredGreyMiniLabel ) ;
// Draw the transmittance graph.
m_TransmittanceMaterial . SetFloat ( "_ScatteringDistance" , d ) ;
m_TransmittanceMaterial . SetVector ( "_VolumeAlbedo" , transmissionEnabled ? aV : Vector4 . zero ) ;
m_TransmittanceMaterial . SetVector ( "_VolumeShapeParam" , sV ) ;
m_TransmittanceMaterial . SetVector ( "_ThicknessRemap" , R ) ;
m_TransmittanceMaterial . SetVector ( "_VolumeAlbedo" , transmissionEnabled ? aV : Vector4 . zero ) ;
m_TransmittanceMaterial . SetVector ( "_VolumeShapeParam" , sV ) ;
m_TransmittanceMaterial . SetVector ( "_ThicknessRemap" , R ) ;
EditorGUI . DrawPreviewTexture ( GUILayoutUtility . GetRect ( 1 6 , 1 6 ) , m_TransmittanceImage , m_TransmittanceMaterial , ScaleMode . ScaleToFit , 1 6.0f ) ;
serializedObject . ApplyModifiedProperties ( ) ;
// Validate each individual asset and update caches.
// Validate each individual asset and update caches.
hdPipeline . sssSettings . OnValidate ( ) ;
}
}
GitHub
8 年前