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Rename SubsurfaceScattering Settings/Editor to DiffusionProfile + various file renaming/moving
/main
Rename SubsurfaceScattering Settings/Editor to DiffusionProfile + various file renaming/moving
/main
Sebastien Lagarde
7 年前
当前提交
a8ab890d
共有 52 个文件被更改，包括 742 次插入 和 715 次删除
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10SampleScenes/HDTest/GraphicTest/SSS/Materials/SSSHead.mat
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10SampleScenes/HDTest/GraphicTest/Two Sided/Material/GroundLeaf_DoubleSidedFlipSSS.mat
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5ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/HDAssetFactory.cs
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2ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/HDRenderPipelineInspector.Styles.cs
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10ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/HDRenderPipelineInspector.cs
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52ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/HDRenderPipelineMenuItems.cs
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10ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/Material/Lit/LitUI.cs
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14ScriptableRenderPipeline/HDRenderPipeline/HDRP/HDRenderPipeline.cs
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3ScriptableRenderPipeline/HDRenderPipeline/HDRP/HDRenderPipelineAsset.asset
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2ScriptableRenderPipeline/HDRenderPipeline/HDRP/HDRenderPipelineAsset.cs
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2ScriptableRenderPipeline/HDRenderPipeline/HDRP/Lighting/Deferred.shader
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2ScriptableRenderPipeline/HDRenderPipeline/HDRP/Lighting/LightLoop/Deferred.compute
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21ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/Lit/Lit.hlsl
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4ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/SubsurfaceScattering/SubsurfaceScattering.compute
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36ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/SubsurfaceScattering/SubsurfaceScattering.hlsl
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4ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/SubsurfaceScattering/SubsurfaceScattering.shader
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4ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/SubsurfaceScattering/SubsurfaceScatteringManager.cs
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5ScriptableRenderPipeline/HDRenderPipeline/HDRP/RenderPipelineResources/RenderPipelineResources.cs
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2ScriptableRenderPipeline/HDRenderPipeline/HDRP/ShaderPass/ShaderPassForward.hlsl
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3ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/Material/DiffusionProfile/DiffusionProfileSettingsEditor.Styles.cs
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20ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/Material/DiffusionProfile/DiffusionProfileSettingsEditor.cs
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18ScriptableRenderPipeline/HDRenderPipeline/HDRP/RenderPipelineResources/Default Diffusion Profile Settings.asset
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8ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/Material/DiffusionProfile/DrawDiffusionProfile.shader
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4ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/Material/DiffusionProfile/DrawTransmittanceGraph.shader
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8ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/Material/DiffusionProfile.meta
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8ScriptableRenderPipeline/HDRenderPipeline/HDRP/RenderPipelineResources/Default Diffusion Profile Settings.asset.meta
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44ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/DiffusionProfile/DiffusionProfile.hlsl
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513ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/DiffusionProfile/DiffusionProfileSettings.cs
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21ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/DiffusionProfile/DiffusionProfileSettings.cs.hlsl
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8ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/Material/SubsurfaceScattering.meta
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61ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/SubsurfaceScattering/CommonSubsurfaceScattering.hlsl
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21ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/SubsurfaceScattering/SubsurfaceScatteringSettings.cs.hlsl
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513ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/SubsurfaceScattering/SubsurfaceScatteringSettings.cs
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9ScriptableRenderPipeline/HDRenderPipeline/HDRP/SceneSettings.meta
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0/ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/DiffusionProfile/DiffusionProfile.hlsl.meta
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0/ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/DiffusionProfile/DiffusionProfileSettings.cs.hlsl.meta
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0/ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/DiffusionProfile/DiffusionProfileSettings.cs.meta
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0/ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/DiffusionProfile.meta
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0/ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/Material/DiffusionProfile/DiffusionProfileSettingsEditor.Styles.cs.meta
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0/ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/Material/DiffusionProfile/DiffusionProfileSettingsEditor.cs.meta
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0/ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/Material/DiffusionProfile/DiffusionProfileSettingsEditor.Styles.cs
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0/ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/Material/DiffusionProfile/DiffusionProfileSettingsEditor.cs
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0/ScriptableRenderPipeline/HDRenderPipeline/HDRP/RenderPipelineResources/Default Diffusion Profile Settings.asset
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0/ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/Material/DiffusionProfile/DrawDiffusionProfile.shader.meta
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0/ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/Material/DiffusionProfile/DrawTransmittanceGraph.shader.meta
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0/ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/Material/DiffusionProfile/DrawDiffusionProfile.shader
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0/ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/Material/DiffusionProfile/DrawTransmittanceGraph.shader
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// ---------------------------------------------------------------------------- |
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// SSS/Transmittance helper |
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// ---------------------------------------------------------------------------- |
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// Computes the fraction of light passing through the object. |
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// Evaluate Int{0, inf}{2 * Pi * r * R(sqrt(r^2 + d^2))}, where R is the diffusion profile. |
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// Note: 'volumeAlbedo' should be premultiplied by 0.25. |
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// Ref: Approximate Reflectance Profiles for Efficient Subsurface Scattering by Pixar (BSSRDF only). |
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float3 ComputeTransmittanceDisney(float3 S, float3 volumeAlbedo, float thickness, float radiusScale) |
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{ |
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// Thickness and SSS radius are decoupled for artists. |
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// In theory, we should modify the thickness by the inverse of the radius scale of the profile. |
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// thickness /= radiusScale; |
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#if 0 |
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float3 expOneThird = exp(((-1.0 / 3.0) * thickness) * S); |
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#else |
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// Help the compiler. |
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float k = (-1.0 / 3.0) * LOG2_E; |
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float3 p = (k * thickness) * S; |
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float3 expOneThird = exp2(p); |
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#endif |
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// Premultiply & optimize: T = (1/4 * A) * (e^(-t * S) + 3 * e^(-1/3 * t * S)) |
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return volumeAlbedo * (expOneThird * expOneThird * expOneThird + 3 * expOneThird); |
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} |
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// Evaluates transmittance for a linear combination of two normalized 2D Gaussians. |
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// Ref: Real-Time Realistic Skin Translucency (2010), equation 9 (modified). |
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// Note: 'volumeAlbedo' should be premultiplied by 0.25, correspondingly 'lerpWeight' by 4, |
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// and 'halfRcpVariance1' should be prescaled by (0.1 * DiffusionProfileConstants.SSS_BASIC_DISTANCE_SCALE)^2. |
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float3 ComputeTransmittanceJimenez(float3 halfRcpVariance1, float lerpWeight1, |
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float3 halfRcpVariance2, float lerpWeight2, |
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float3 volumeAlbedo, float thickness, float radiusScale) |
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{ |
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// Thickness and SSS radius are decoupled for artists. |
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// In theory, we should modify the thickness by the inverse of the radius scale of the profile. |
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// thickness /= radiusScale; |
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float t2 = thickness * thickness; |
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// T = A * lerp(exp(-t2 * halfRcpVariance1), exp(-t2 * halfRcpVariance2), lerpWeight2) |
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return volumeAlbedo * (exp(-t2 * halfRcpVariance1) * lerpWeight1 + exp(-t2 * halfRcpVariance2) * lerpWeight2); |
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} |
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using System; |
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namespace UnityEngine.Experimental.Rendering.HDPipeline |
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{ |
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[GenerateHLSL] |
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public class DiffusionProfileConstants |
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{ |
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public const int DIFFUSION_N_PROFILES = 16; // Max. number of profiles, including the slot taken by the neutral profile
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public const int DIFFUSION_NEUTRAL_PROFILE_ID = 0; // Does not result in blurring
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public const int SSS_N_SAMPLES_NEAR_FIELD = 55; // Used for extreme close ups; must be a Fibonacci number
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public const int SSS_N_SAMPLES_FAR_FIELD = 21; // Used at a regular distance; must be a Fibonacci number
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public const int SSS_LOD_THRESHOLD = 4; // The LoD threshold of the near-field kernel (in pixels)
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public const int TRANSMISSION_MODE_NONE = 0; |
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public const int TRANSMISSION_MODE_THIN = 1; |
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// Old SSS Model >>>
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public const int SSS_BASIC_N_SAMPLES = 11; // Must be an odd number
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public const int SSS_BASIC_DISTANCE_SCALE = 3; // SSS distance units per centimeter
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// <<< Old SSS Model
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} |
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[Serializable] |
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public sealed class DiffusionProfile |
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{ |
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public enum TexturingMode : uint |
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{ |
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PreAndPostScatter = 0, |
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PostScatter = 1 |
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} |
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public enum TransmissionMode : uint |
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{ |
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None = DiffusionProfileConstants.TRANSMISSION_MODE_NONE, |
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ThinObject = DiffusionProfileConstants.TRANSMISSION_MODE_THIN, |
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Regular |
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} |
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public string name; |
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[ColorUsage(false, true)] |
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public Color scatteringDistance; // Per color channel (no meaningful units)
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[ColorUsage(false)] |
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public Color transmissionTint; // Color, 0 to 1
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public TexturingMode texturingMode; |
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public TransmissionMode transmissionMode; |
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public Vector2 thicknessRemap; // X = min, Y = max (in millimeters)
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public float worldScale; // Size of the world unit in meters
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public float fresnel0; // Fresnel0, 0.028 for skin
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// Old SSS Model >>>
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[ColorUsage(false, true)] |
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public Color scatterDistance1; |
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[ColorUsage(false, true)] |
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public Color scatterDistance2; |
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[Range(0f, 1f)] |
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public float lerpWeight; |
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// <<< Old SSS Model
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public Vector3 shapeParam { get; private set; } // RGB = shape parameter: S = 1 / D
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public float maxRadius { get; private set; } // In millimeters
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public Vector2[] filterKernelNearField { get; private set; } // X = radius, Y = reciprocal of the PDF
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public Vector2[] filterKernelFarField { get; private set; } // X = radius, Y = reciprocal of the PDF
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public Vector4 halfRcpWeightedVariances { get; private set; } |
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public Vector4[] filterKernelBasic { get; private set; } |
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public DiffusionProfile(string name) |
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{ |
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this.name = name; |
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scatteringDistance = Color.grey; |
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transmissionTint = Color.white; |
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texturingMode = TexturingMode.PreAndPostScatter; |
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transmissionMode = TransmissionMode.None; |
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thicknessRemap = new Vector2(0f, 5f); |
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worldScale = 1f; |
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fresnel0 = 0.028f; // TYpical value for skin specular reflectance
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// Old SSS Model >>>
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scatterDistance1 = new Color(0.3f, 0.3f, 0.3f, 0f); |
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scatterDistance2 = new Color(0.5f, 0.5f, 0.5f, 0f); |
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lerpWeight = 1f; |
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// <<< Old SSS Model
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} |
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public void Validate() |
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{ |
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thicknessRemap.y = Mathf.Max(thicknessRemap.y, 0f); |
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thicknessRemap.x = Mathf.Clamp(thicknessRemap.x, 0f, thicknessRemap.y); |
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worldScale = Mathf.Max(worldScale, 0.001f); |
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fresnel0 = Mathf.Clamp(fresnel0, 0.0f, 0.1f); |
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// Old SSS Model >>>
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scatterDistance1 = new Color |
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{ |
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r = Mathf.Max(0.05f, scatterDistance1.r), |
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g = Mathf.Max(0.05f, scatterDistance1.g), |
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b = Mathf.Max(0.05f, scatterDistance1.b), |
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a = 0.0f |
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}; |
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scatterDistance2 = new Color |
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{ |
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r = Mathf.Max(0.05f, scatterDistance2.r), |
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g = Mathf.Max(0.05f, scatterDistance2.g), |
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b = Mathf.Max(0.05f, scatterDistance2.b), |
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a = 0f |
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}; |
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// <<< Old SSS Model
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UpdateKernel(); |
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} |
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// Ref: Approximate Reflectance Profiles for Efficient Subsurface Scattering by Pixar.
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public void UpdateKernel() |
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{ |
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if (filterKernelNearField == null || filterKernelNearField.Length != DiffusionProfileConstants.SSS_N_SAMPLES_NEAR_FIELD) |
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filterKernelNearField = new Vector2[DiffusionProfileConstants.SSS_N_SAMPLES_NEAR_FIELD]; |
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if (filterKernelFarField == null || filterKernelFarField.Length != DiffusionProfileConstants.SSS_N_SAMPLES_FAR_FIELD) |
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filterKernelFarField = new Vector2[DiffusionProfileConstants.SSS_N_SAMPLES_FAR_FIELD]; |
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// Clamp to avoid artifacts.
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shapeParam = new Vector3( |
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1f / Mathf.Max(0.001f, scatteringDistance.r), |
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1f / Mathf.Max(0.001f, scatteringDistance.g), |
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1f / Mathf.Max(0.001f, scatteringDistance.b) |
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); |
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// We importance sample the color channel with the widest scattering distance.
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float s = Mathf.Min(shapeParam.x, shapeParam.y, shapeParam.z); |
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// Importance sample the normalized diffuse reflectance profile for the computed value of 's'.
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// ------------------------------------------------------------------------------------
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// R[r, phi, s] = s * (Exp[-r * s] + Exp[-r * s / 3]) / (8 * Pi * r)
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// PDF[r, phi, s] = r * R[r, phi, s]
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// CDF[r, s] = 1 - 1/4 * Exp[-r * s] - 3/4 * Exp[-r * s / 3]
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// ------------------------------------------------------------------------------------
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// Importance sample the near field kernel.
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for (int i = 0, n = DiffusionProfileConstants.SSS_N_SAMPLES_NEAR_FIELD; i < n; i++) |
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{ |
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float p = (i + 0.5f) * (1f / n); |
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float r = DisneyProfileCdfInverse(p, s); |
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// N.b.: computation of normalized weights, and multiplication by the surface albedo
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// of the actual geometry is performed at runtime (in the shader).
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filterKernelNearField[i].x = r; |
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filterKernelNearField[i].y = 1f / DisneyProfilePdf(r, s); |
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} |
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// Importance sample the far field kernel.
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for (int i = 0, n = DiffusionProfileConstants.SSS_N_SAMPLES_FAR_FIELD; i < n; i++) |
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{ |
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float p = (i + 0.5f) * (1f / n); |
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float r = DisneyProfileCdfInverse(p, s); |
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// N.b.: computation of normalized weights, and multiplication by the surface albedo
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// of the actual geometry is performed at runtime (in the shader).
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filterKernelFarField[i].x = r; |
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filterKernelFarField[i].y = 1f / DisneyProfilePdf(r, s); |
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} |
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maxRadius = filterKernelFarField[DiffusionProfileConstants.SSS_N_SAMPLES_FAR_FIELD - 1].x; |
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// Old SSS Model >>>
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UpdateKernelAndVarianceData(); |
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// <<< Old SSS Model
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} |
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// Old SSS Model >>>
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public void UpdateKernelAndVarianceData() |
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{ |
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const int kNumSamples = DiffusionProfileConstants.SSS_BASIC_N_SAMPLES; |
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const int kDistanceScale = DiffusionProfileConstants.SSS_BASIC_DISTANCE_SCALE; |
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if (filterKernelBasic == null || filterKernelBasic.Length != kNumSamples) |
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filterKernelBasic = new Vector4[kNumSamples]; |
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// Apply the three-sigma rule, and rescale.
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var stdDev1 = ((1f / 3f) * kDistanceScale) * scatterDistance1; |
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var stdDev2 = ((1f / 3f) * kDistanceScale) * scatterDistance2; |
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// Our goal is to blur the image using a filter which is represented
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// as a product of a linear combination of two normalized 1D Gaussians
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// as suggested by Jimenez et al. in "Separable Subsurface Scattering".
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// A normalized (i.e. energy-preserving) 1D Gaussian with the mean of 0
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// is defined as follows: G1(x, v) = exp(-x * x / (2 * v)) / sqrt(2 * Pi * v),
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// where 'v' is variance and 'x' is the radial distance from the origin.
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// Using the weight 'w', our 1D and the resulting 2D filters are given as:
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// A1(v1, v2, w, x) = G1(x, v1) * (1 - w) + G1(r, v2) * w,
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// A2(v1, v2, w, x, y) = A1(v1, v2, w, x) * A1(v1, v2, w, y).
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// The resulting filter function is a non-Gaussian PDF.
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// It is separable by design, but generally not radially symmetric.
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// N.b.: our scattering distance is rather limited. Therefore, in order to allow
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// for a greater range of standard deviation values for flatter profiles,
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// we rescale the world using 'distanceScale', effectively reducing the SSS
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// distance units from centimeters to (1 / distanceScale).
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// Find the widest Gaussian across 3 color channels.
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float maxStdDev1 = Mathf.Max(stdDev1.r, stdDev1.g, stdDev1.b); |
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float maxStdDev2 = Mathf.Max(stdDev2.r, stdDev2.g, stdDev2.b); |
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var weightSum = Vector3.zero; |
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float step = 1f / (kNumSamples - 1); |
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// Importance sample the linear combination of two Gaussians.
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for (int i = 0; i < kNumSamples; i++) |
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{ |
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// Generate 'u' on (0, 0.5] and (0.5, 1).
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float u = (i <= kNumSamples / 2) ? 0.5f - i * step // The center and to the left
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: i * step; // From the center to the right
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u = Mathf.Clamp(u, 0.001f, 0.999f); |
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float pos = GaussianCombinationCdfInverse(u, maxStdDev1, maxStdDev2, lerpWeight); |
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float pdf = GaussianCombination(pos, maxStdDev1, maxStdDev2, lerpWeight); |
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Vector3 val; |
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val.x = GaussianCombination(pos, stdDev1.r, stdDev2.r, lerpWeight); |
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val.y = GaussianCombination(pos, stdDev1.g, stdDev2.g, lerpWeight); |
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val.z = GaussianCombination(pos, stdDev1.b, stdDev2.b, lerpWeight); |
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// We do not divide by 'numSamples' since we will renormalize, anyway.
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filterKernelBasic[i].x = val.x * (1 / pdf); |
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filterKernelBasic[i].y = val.y * (1 / pdf); |
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filterKernelBasic[i].z = val.z * (1 / pdf); |
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filterKernelBasic[i].w = pos; |
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weightSum.x += filterKernelBasic[i].x; |
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weightSum.y += filterKernelBasic[i].y; |
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weightSum.z += filterKernelBasic[i].z; |
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} |
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// Renormalize the weights to conserve energy.
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for (int i = 0; i < kNumSamples; i++) |
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{ |
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filterKernelBasic[i].x *= 1 / weightSum.x; |
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filterKernelBasic[i].y *= 1 / weightSum.y; |
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filterKernelBasic[i].z *= 1 / weightSum.z; |
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} |
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Vector4 weightedStdDev; |
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weightedStdDev.x = Mathf.Lerp(stdDev1.r, stdDev2.r, lerpWeight); |
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weightedStdDev.y = Mathf.Lerp(stdDev1.g, stdDev2.g, lerpWeight); |
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weightedStdDev.z = Mathf.Lerp(stdDev1.b, stdDev2.b, lerpWeight); |
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weightedStdDev.w = Mathf.Lerp(maxStdDev1, maxStdDev2, lerpWeight); |
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// Store (1 / (2 * WeightedVariance)) per color channel.
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// Warning: do not use halfRcpWeightedVariances.Set(). It will not work.
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halfRcpWeightedVariances = new Vector4(0.5f / (weightedStdDev.x * weightedStdDev.x), |
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0.5f / (weightedStdDev.y * weightedStdDev.y), |
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0.5f / (weightedStdDev.z * weightedStdDev.z), |
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0.5f / (weightedStdDev.w * weightedStdDev.w)); |
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} |
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// <<< Old SSS Model
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static float DisneyProfile(float r, float s) |
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{ |
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return s * (Mathf.Exp(-r * s) + Mathf.Exp(-r * s * (1.0f / 3.0f))) / (8.0f * Mathf.PI * r); |
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} |
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static float DisneyProfilePdf(float r, float s) |
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{ |
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return r * DisneyProfile(r, s); |
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} |
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static float DisneyProfileCdf(float r, float s) |
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{ |
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return 1.0f - 0.25f * Mathf.Exp(-r * s) - 0.75f * Mathf.Exp(-r * s * (1.0f / 3.0f)); |
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} |
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static float DisneyProfileCdfDerivative1(float r, float s) |
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{ |
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return 0.25f * s * Mathf.Exp(-r * s) * (1.0f + Mathf.Exp(r * s * (2.0f / 3.0f))); |
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} |
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static float DisneyProfileCdfDerivative2(float r, float s) |
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{ |
|||
return (-1.0f / 12.0f) * s * s * Mathf.Exp(-r * s) * (3.0f + Mathf.Exp(r * s * (2.0f / 3.0f))); |
|||
} |
|||
|
|||
// The CDF is not analytically invertible, so we use Halley's Method of root finding.
|
|||
// { f(r, s, p) = CDF(r, s) - p = 0 } with the initial guess { r = (10^p - 1) / s }.
|
|||
static float DisneyProfileCdfInverse(float p, float s) |
|||
{ |
|||
// Supply the initial guess.
|
|||
float r = (Mathf.Pow(10f, p) - 1f) / s; |
|||
float t = float.MaxValue; |
|||
|
|||
while (true) |
|||
{ |
|||
float f0 = DisneyProfileCdf(r, s) - p; |
|||
float f1 = DisneyProfileCdfDerivative1(r, s); |
|||
float f2 = DisneyProfileCdfDerivative2(r, s); |
|||
float dr = f0 / (f1 * (1f - f0 * f2 / (2f * f1 * f1))); |
|||
|
|||
if (Mathf.Abs(dr) < t) |
|||
{ |
|||
r = r - dr; |
|||
t = Mathf.Abs(dr); |
|||
} |
|||
else |
|||
{ |
|||
// Converged to the best result.
|
|||
break; |
|||
} |
|||
} |
|||
|
|||
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(-2f * Mathf.Log(p))); |
|||
} |
|||
else |
|||
{ |
|||
// F^-1(p) = G^-1(1-p)
|
|||
x = RationalApproximation(Mathf.Sqrt(-2f * Mathf.Log(1f - 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
|
|||
} |
|||
|
|||
public sealed class DiffusionProfileSettings : ScriptableObject |
|||
{ |
|||
public DiffusionProfile[] profiles; |
|||
|
|||
[NonSerialized] public uint texturingModeFlags; // 1 bit/profile; 0 = PreAndPostScatter, 1 = PostScatter
|
|||
[NonSerialized] public uint transmissionFlags; // 2 bit/profile; 0 = inf. thick, 1 = thin, 2 = regular
|
|||
[NonSerialized] public Vector4[] thicknessRemaps; // Remap: 0 = start, 1 = end - start
|
|||
[NonSerialized] public Vector4[] worldScales; // X = meters per world unit; Y = world units per meter
|
|||
[NonSerialized] public Vector4[] shapeParams; // RGB = S = 1 / D, A = filter radius
|
|||
[NonSerialized] public Vector4[] transmissionTintsAndFresnel0; // RGB = color, A = fresnel0
|
|||
[NonSerialized] public Vector4[] filterKernels; // XY = near field, ZW = far field; 0 = radius, 1 = reciprocal of the PDF
|
|||
|
|||
// Old SSS Model >>>
|
|||
[NonSerialized] public Vector4[] halfRcpWeightedVariances; |
|||
[NonSerialized] public Vector4[] halfRcpVariancesAndWeights; |
|||
[NonSerialized] public Vector4[] filterKernelsBasic; |
|||
// <<< Old SSS Model
|
|||
|
|||
public DiffusionProfile this[int index] |
|||
{ |
|||
get |
|||
{ |
|||
if (index >= DiffusionProfileConstants.DIFFUSION_N_PROFILES - 1) |
|||
throw new IndexOutOfRangeException("index"); |
|||
|
|||
return profiles[index]; |
|||
} |
|||
} |
|||
|
|||
void OnEnable() |
|||
{ |
|||
// The neutral profile is not a part of the array.
|
|||
int profileArraySize = DiffusionProfileConstants.DIFFUSION_N_PROFILES - 1; |
|||
|
|||
if (profiles != null && profiles.Length != profileArraySize) |
|||
Array.Resize(ref profiles, profileArraySize); |
|||
|
|||
if (profiles == null) |
|||
profiles = new DiffusionProfile[profileArraySize]; |
|||
|
|||
for (int i = 0; i < profileArraySize; i++) |
|||
{ |
|||
if (profiles[i] == null) |
|||
profiles[i] = new DiffusionProfile("Profile " + (i + 1)); |
|||
|
|||
profiles[i].Validate(); |
|||
} |
|||
|
|||
ValidateArray(ref thicknessRemaps, DiffusionProfileConstants.DIFFUSION_N_PROFILES); |
|||
ValidateArray(ref worldScales, DiffusionProfileConstants.DIFFUSION_N_PROFILES); |
|||
ValidateArray(ref shapeParams, DiffusionProfileConstants.DIFFUSION_N_PROFILES); |
|||
ValidateArray(ref transmissionTintsAndFresnel0, DiffusionProfileConstants.DIFFUSION_N_PROFILES); |
|||
ValidateArray(ref filterKernels, DiffusionProfileConstants.DIFFUSION_N_PROFILES * DiffusionProfileConstants.SSS_N_SAMPLES_NEAR_FIELD); |
|||
|
|||
// Old SSS Model >>>
|
|||
ValidateArray(ref halfRcpWeightedVariances, DiffusionProfileConstants.DIFFUSION_N_PROFILES); |
|||
ValidateArray(ref halfRcpVariancesAndWeights, DiffusionProfileConstants.DIFFUSION_N_PROFILES * 2); |
|||
ValidateArray(ref filterKernelsBasic, DiffusionProfileConstants.DIFFUSION_N_PROFILES * DiffusionProfileConstants.SSS_BASIC_N_SAMPLES); |
|||
|
|||
Debug.Assert(DiffusionProfileConstants.DIFFUSION_NEUTRAL_PROFILE_ID < 16, "Transmission flags (32-bit integer) cannot support more than 16 profiles (2 bits per profile)."); |
|||
|
|||
UpdateCache(); |
|||
} |
|||
|
|||
static void ValidateArray<T>(ref T[] array, int len) |
|||
{ |
|||
if (array == null || array.Length != len) |
|||
array = new T[len]; |
|||
} |
|||
|
|||
public void UpdateCache() |
|||
{ |
|||
for (int i = 0; i < DiffusionProfileConstants.DIFFUSION_N_PROFILES - 1; i++) |
|||
{ |
|||
UpdateCache(i); |
|||
} |
|||
|
|||
// Fill the neutral profile.
|
|||
int neutralId = DiffusionProfileConstants.DIFFUSION_NEUTRAL_PROFILE_ID; |
|||
|
|||
worldScales[neutralId] = Vector4.one; |
|||
shapeParams[neutralId] = Vector4.zero; |
|||
|
|||
for (int j = 0, n = DiffusionProfileConstants.SSS_N_SAMPLES_NEAR_FIELD; j < n; j++) |
|||
{ |
|||
filterKernels[n * neutralId + j].x = 0f; |
|||
filterKernels[n * neutralId + j].y = 1f; |
|||
filterKernels[n * neutralId + j].z = 0f; |
|||
filterKernels[n * neutralId + j].w = 1f; |
|||
} |
|||
|
|||
// Old SSS Model >>>
|
|||
halfRcpWeightedVariances[neutralId] = Vector4.one; |
|||
|
|||
for (int j = 0, n = DiffusionProfileConstants.SSS_BASIC_N_SAMPLES; j < n; j++) |
|||
{ |
|||
filterKernelsBasic[n * neutralId + j] = Vector4.one; |
|||
filterKernelsBasic[n * neutralId + j].w = 0f; |
|||
} |
|||
// <<< Old SSS Model
|
|||
} |
|||
|
|||
public void UpdateCache(int p) |
|||
{ |
|||
// 'p' is the profile array index. 'i' is the index in the shader (accounting for the neutral profile).
|
|||
int i = p + 1; |
|||
|
|||
// Erase previous value (This need to be done here individually as in the SSS editor we edit individual component)
|
|||
uint mask = 1u << i; |
|||
texturingModeFlags &= ~mask; |
|||
mask = 3u << i * 2; |
|||
transmissionFlags &= ~mask; |
|||
|
|||
texturingModeFlags |= (uint)profiles[p].texturingMode << i; |
|||
transmissionFlags |= (uint)profiles[p].transmissionMode << i * 2; |
|||
|
|||
thicknessRemaps[i] = new Vector4(profiles[p].thicknessRemap.x, profiles[p].thicknessRemap.y - profiles[p].thicknessRemap.x, 0f, 0f); |
|||
worldScales[i] = new Vector4(profiles[p].worldScale, 1.0f / profiles[p].worldScale, 0f, 0f); |
|||
shapeParams[i] = profiles[p].shapeParam; |
|||
shapeParams[i].w = profiles[p].maxRadius; |
|||
transmissionTintsAndFresnel0[i] = new Vector4(profiles[p].transmissionTint.r * 0.25f, profiles[p].transmissionTint.g * 0.25f, profiles[p].transmissionTint.b * 0.25f, profiles[p].fresnel0); // Premultiplied
|
|||
|
|||
for (int j = 0, n = DiffusionProfileConstants.SSS_N_SAMPLES_NEAR_FIELD; j < n; j++) |
|||
{ |
|||
filterKernels[n * i + j].x = profiles[p].filterKernelNearField[j].x; |
|||
filterKernels[n * i + j].y = profiles[p].filterKernelNearField[j].y; |
|||
|
|||
if (j < DiffusionProfileConstants.SSS_N_SAMPLES_FAR_FIELD) |
|||
{ |
|||
filterKernels[n * i + j].z = profiles[p].filterKernelFarField[j].x; |
|||
filterKernels[n * i + j].w = profiles[p].filterKernelFarField[j].y; |
|||
} |
|||
} |
|||
|
|||
// Old SSS Model >>>
|
|||
halfRcpWeightedVariances[i] = profiles[p].halfRcpWeightedVariances; |
|||
|
|||
var stdDev1 = ((1f / 3f) * DiffusionProfileConstants.SSS_BASIC_DISTANCE_SCALE) * (Vector4)profiles[p].scatterDistance1; |
|||
var stdDev2 = ((1f / 3f) * DiffusionProfileConstants.SSS_BASIC_DISTANCE_SCALE) * (Vector4)profiles[p].scatterDistance2; |
|||
|
|||
// Multiply by 0.1 to convert from millimeters to centimeters. Apply the distance scale.
|
|||
// Rescale by 4 to counter rescaling of transmission tints.
|
|||
float a = 0.1f * DiffusionProfileConstants.SSS_BASIC_DISTANCE_SCALE; |
|||
halfRcpVariancesAndWeights[2 * i + 0] = new Vector4(a * a * 0.5f / (stdDev1.x * stdDev1.x), a * a * 0.5f / (stdDev1.y * stdDev1.y), a * a * 0.5f / (stdDev1.z * stdDev1.z), 4f * (1f - profiles[p].lerpWeight)); |
|||
halfRcpVariancesAndWeights[2 * i + 1] = new Vector4(a * a * 0.5f / (stdDev2.x * stdDev2.x), a * a * 0.5f / (stdDev2.y * stdDev2.y), a * a * 0.5f / (stdDev2.z * stdDev2.z), 4f * profiles[p].lerpWeight); |
|||
|
|||
for (int j = 0, n = DiffusionProfileConstants.SSS_BASIC_N_SAMPLES; j < n; j++) |
|||
{ |
|||
filterKernelsBasic[n * i + j] = profiles[p].filterKernelBasic[j]; |
|||
} |
|||
// <<< Old SSS Model
|
|||
} |
|||
} |
|||
} |
|||
|
|||
// |
|||
// This file was automatically generated. Please don't edit by hand. |
|||
// |
|||
|
|||
#ifndef SUBSURFACESCATTERINGSETTINGS_CS_HLSL |
|||
#define SUBSURFACESCATTERINGSETTINGS_CS_HLSL |
|||
// |
|||
// UnityEngine.Experimental.Rendering.HDPipeline.DiffusionProfileConstants: static fields |
|||
// |
|||
#define DIFFUSION_N_PROFILES (16) |
|||
#define DIFFUSION_NEUTRAL_PROFILE_ID (0) |
|||
#define SSS_N_SAMPLES_NEAR_FIELD (55) |
|||
#define SSS_N_SAMPLES_FAR_FIELD (21) |
|||
#define SSS_LOD_THRESHOLD (4) |
|||
#define TRANSMISSION_MODE_NONE (0) |
|||
#define TRANSMISSION_MODE_THIN (1) |
|||
#define SSS_BASIC_N_SAMPLES (11) |
|||
#define SSS_BASIC_DISTANCE_SCALE (3) |
|||
|
|||
|
|||
#endif |
|||
|
|||
fileFormatVersion: 2 |
|||
guid: fb3f658c087068440b2c5063fc3abaed |
|||
folderAsset: yes |
|||
DefaultImporter: |
|||
externalObjects: {} |
|||
userData: |
|||
assetBundleName: |
|||
assetBundleVariant: |
|||
|
|||
// ---------------------------------------------------------------------------- |
|||
// SSS/Transmittance helper |
|||
// ---------------------------------------------------------------------------- |
|||
|
|||
// Computes the fraction of light passing through the object. |
|||
// Evaluate Int{0, inf}{2 * Pi * r * R(sqrt(r^2 + d^2))}, where R is the diffusion profile. |
|||
// Note: 'volumeAlbedo' should be premultiplied by 0.25. |
|||
// Ref: Approximate Reflectance Profiles for Efficient Subsurface Scattering by Pixar (BSSRDF only). |
|||
float3 ComputeTransmittanceDisney(float3 S, float3 volumeAlbedo, float thickness, float radiusScale) |
|||
{ |
|||
// Thickness and SSS radius are decoupled for artists. |
|||
// In theory, we should modify the thickness by the inverse of the radius scale of the profile. |
|||
// thickness /= radiusScale; |
|||
|
|||
#if 0 |
|||
float3 expOneThird = exp(((-1.0 / 3.0) * thickness) * S); |
|||
#else |
|||
// Help the compiler. |
|||
float k = (-1.0 / 3.0) * LOG2_E; |
|||
float3 p = (k * thickness) * S; |
|||
float3 expOneThird = exp2(p); |
|||
#endif |
|||
|
|||
// Premultiply & optimize: T = (1/4 * A) * (e^(-t * S) + 3 * e^(-1/3 * t * S)) |
|||
return volumeAlbedo * (expOneThird * expOneThird * expOneThird + 3 * expOneThird); |
|||
} |
|||
|
|||
// Evaluates transmittance for a linear combination of two normalized 2D Gaussians. |
|||
// Ref: Real-Time Realistic Skin Translucency (2010), equation 9 (modified). |
|||
// Note: 'volumeAlbedo' should be premultiplied by 0.25, correspondingly 'lerpWeight' by 4, |
|||
// and 'halfRcpVariance1' should be prescaled by (0.1 * SssConstants.SSS_BASIC_DISTANCE_SCALE)^2. |
|||
float3 ComputeTransmittanceJimenez(float3 halfRcpVariance1, float lerpWeight1, |
|||
float3 halfRcpVariance2, float lerpWeight2, |
|||
float3 volumeAlbedo, float thickness, float radiusScale) |
|||
{ |
|||
// Thickness and SSS radius are decoupled for artists. |
|||
// In theory, we should modify the thickness by the inverse of the radius scale of the profile. |
|||
// thickness /= radiusScale; |
|||
|
|||
float t2 = thickness * thickness; |
|||
|
|||
// T = A * lerp(exp(-t2 * halfRcpVariance1), exp(-t2 * halfRcpVariance2), lerpWeight2) |
|||
return volumeAlbedo * (exp(-t2 * halfRcpVariance1) * lerpWeight1 + exp(-t2 * halfRcpVariance2) * lerpWeight2); |
|||
} |
|||
|
|||
// In order to support subsurface scattering, we need to know which pixels have an SSS material. |
|||
// It can be accomplished by reading the stencil buffer. |
|||
// A faster solution (which avoids an extra texture fetch) is to simply make sure that |
|||
// all pixels which belong to an SSS material are not black (those that don't always are). |
|||
// We choose the blue color channel since it's perceptually the least noticeable. |
|||
float3 TagLightingForSSS(float3 subsurfaceLighting) |
|||
{ |
|||
subsurfaceLighting.b = max(subsurfaceLighting.b, HALF_MIN); |
|||
return subsurfaceLighting; |
|||
} |
|||
|
|||
// See TagLightingForSSS() for details. |
|||
bool TestLightingForSSS(float3 subsurfaceLighting) |
|||
{ |
|||
return subsurfaceLighting.b > 0; |
|||
} |
|||
|
|||
// |
|||
// This file was automatically generated. Please don't edit by hand. |
|||
// |
|||
|
|||
#ifndef SUBSURFACESCATTERINGSETTINGS_CS_HLSL |
|||
#define SUBSURFACESCATTERINGSETTINGS_CS_HLSL |
|||
// |
|||
// UnityEngine.Experimental.Rendering.HDPipeline.SssConstants: static fields |
|||
// |
|||
#define SSS_N_PROFILES (16) |
|||
#define SSS_NEUTRAL_PROFILE_ID (0) |
|||
#define SSS_N_SAMPLES_NEAR_FIELD (55) |
|||
#define SSS_N_SAMPLES_FAR_FIELD (21) |
|||
#define SSS_LOD_THRESHOLD (4) |
|||
#define SSS_TRSM_MODE_NONE (0) |
|||
#define SSS_TRSM_MODE_THIN (1) |
|||
#define SSS_BASIC_N_SAMPLES (11) |
|||
#define SSS_BASIC_DISTANCE_SCALE (3) |
|||
|
|||
|
|||
#endif |
|||
|
|||
using System; |
|||
|
|||
namespace UnityEngine.Experimental.Rendering.HDPipeline |
|||
{ |
|||
[GenerateHLSL] |
|||
public class SssConstants |
|||
{ |
|||
public const int SSS_N_PROFILES = 16; // Max. number of profiles, including the slot taken by the neutral profile
|
|||
public const int SSS_NEUTRAL_PROFILE_ID = 0; // Does not result in blurring
|
|||
public const int SSS_N_SAMPLES_NEAR_FIELD = 55; // Used for extreme close ups; must be a Fibonacci number
|
|||
public const int SSS_N_SAMPLES_FAR_FIELD = 21; // Used at a regular distance; must be a Fibonacci number
|
|||
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 = 11; // Must be an odd number
|
|||
public const int SSS_BASIC_DISTANCE_SCALE = 3; // SSS distance units per centimeter
|
|||
// <<< Old SSS Model
|
|||
} |
|||
|
|||
[Serializable] |
|||
public sealed class SubsurfaceScatteringProfile |
|||
{ |
|||
public enum TexturingMode : uint |
|||
{ |
|||
PreAndPostScatter = 0, |
|||
PostScatter = 1 |
|||
} |
|||
|
|||
public enum TransmissionMode : uint |
|||
{ |
|||
None = SssConstants.SSS_TRSM_MODE_NONE, |
|||
ThinObject = SssConstants.SSS_TRSM_MODE_THIN, |
|||
Regular |
|||
} |
|||
|
|||
public string name; |
|||
|
|||
[ColorUsage(false, true)] |
|||
public Color scatteringDistance; // Per color channel (no meaningful units)
|
|||
[ColorUsage(false)] |
|||
public Color transmissionTint; // Color, 0 to 1
|
|||
public TexturingMode texturingMode; |
|||
public TransmissionMode transmissionMode; |
|||
public Vector2 thicknessRemap; // X = min, Y = max (in millimeters)
|
|||
public float worldScale; // Size of the world unit in meters
|
|||
public float fresnel0; // Fresnel0, 0.028 for skin
|
|||
|
|||
// Old SSS Model >>>
|
|||
[ColorUsage(false, true)] |
|||
public Color scatterDistance1; |
|||
[ColorUsage(false, true)] |
|||
public Color scatterDistance2; |
|||
[Range(0f, 1f)] |
|||
public float lerpWeight; |
|||
// <<< Old SSS Model
|
|||
|
|||
public Vector3 shapeParam { get; private set; } // RGB = shape parameter: S = 1 / D
|
|||
public float maxRadius { get; private set; } // In millimeters
|
|||
public Vector2[] filterKernelNearField { get; private set; } // X = radius, Y = reciprocal of the PDF
|
|||
public Vector2[] filterKernelFarField { get; private set; } // X = radius, Y = reciprocal of the PDF
|
|||
public Vector4 halfRcpWeightedVariances { get; private set; } |
|||
public Vector4[] filterKernelBasic { get; private set; } |
|||
|
|||
public SubsurfaceScatteringProfile(string name) |
|||
{ |
|||
this.name = name; |
|||
|
|||
scatteringDistance = Color.grey; |
|||
transmissionTint = Color.white; |
|||
texturingMode = TexturingMode.PreAndPostScatter; |
|||
transmissionMode = TransmissionMode.None; |
|||
thicknessRemap = new Vector2(0f, 5f); |
|||
worldScale = 1f; |
|||
fresnel0 = 0.028f; // TYpical value for skin specular reflectance
|
|||
|
|||
// Old SSS Model >>>
|
|||
scatterDistance1 = new Color(0.3f, 0.3f, 0.3f, 0f); |
|||
scatterDistance2 = new Color(0.5f, 0.5f, 0.5f, 0f); |
|||
lerpWeight = 1f; |
|||
// <<< Old SSS Model
|
|||
} |
|||
|
|||
public void Validate() |
|||
{ |
|||
thicknessRemap.y = Mathf.Max(thicknessRemap.y, 0f); |
|||
thicknessRemap.x = Mathf.Clamp(thicknessRemap.x, 0f, thicknessRemap.y); |
|||
worldScale = Mathf.Max(worldScale, 0.001f); |
|||
fresnel0 = Mathf.Clamp(fresnel0, 0.0f, 0.1f); |
|||
|
|||
// Old SSS Model >>>
|
|||
scatterDistance1 = new Color |
|||
{ |
|||
r = Mathf.Max(0.05f, scatterDistance1.r), |
|||
g = Mathf.Max(0.05f, scatterDistance1.g), |
|||
b = Mathf.Max(0.05f, scatterDistance1.b), |
|||
a = 0.0f |
|||
}; |
|||
|
|||
scatterDistance2 = new Color |
|||
{ |
|||
r = Mathf.Max(0.05f, scatterDistance2.r), |
|||
g = Mathf.Max(0.05f, scatterDistance2.g), |
|||
b = Mathf.Max(0.05f, scatterDistance2.b), |
|||
a = 0f |
|||
}; |
|||
// <<< Old SSS Model
|
|||
|
|||
UpdateKernel(); |
|||
} |
|||
|
|||
// Ref: Approximate Reflectance Profiles for Efficient Subsurface Scattering by Pixar.
|
|||
public void UpdateKernel() |
|||
{ |
|||
if (filterKernelNearField == null || filterKernelNearField.Length != SssConstants.SSS_N_SAMPLES_NEAR_FIELD) |
|||
filterKernelNearField = new Vector2[SssConstants.SSS_N_SAMPLES_NEAR_FIELD]; |
|||
|
|||
if (filterKernelFarField == null || filterKernelFarField.Length != SssConstants.SSS_N_SAMPLES_FAR_FIELD) |
|||
filterKernelFarField = new Vector2[SssConstants.SSS_N_SAMPLES_FAR_FIELD]; |
|||
|
|||
// Clamp to avoid artifacts.
|
|||
shapeParam = new Vector3( |
|||
1f / Mathf.Max(0.001f, scatteringDistance.r), |
|||
1f / Mathf.Max(0.001f, scatteringDistance.g), |
|||
1f / Mathf.Max(0.001f, scatteringDistance.b) |
|||
); |
|||
|
|||
// We importance sample the color channel with the widest scattering distance.
|
|||
float s = Mathf.Min(shapeParam.x, shapeParam.y, shapeParam.z); |
|||
|
|||
// Importance sample the normalized diffuse reflectance profile for the computed value of 's'.
|
|||
// ------------------------------------------------------------------------------------
|
|||
// R[r, phi, s] = s * (Exp[-r * s] + Exp[-r * s / 3]) / (8 * Pi * r)
|
|||
// PDF[r, phi, s] = r * R[r, phi, s]
|
|||
// CDF[r, s] = 1 - 1/4 * Exp[-r * s] - 3/4 * Exp[-r * s / 3]
|
|||
// ------------------------------------------------------------------------------------
|
|||
|
|||
// Importance sample the near field kernel.
|
|||
for (int i = 0, n = SssConstants.SSS_N_SAMPLES_NEAR_FIELD; i < n; i++) |
|||
{ |
|||
float p = (i + 0.5f) * (1f / n); |
|||
float r = DisneyProfileCdfInverse(p, s); |
|||
|
|||
// N.b.: computation of normalized weights, and multiplication by the surface albedo
|
|||
// of the actual geometry is performed at runtime (in the shader).
|
|||
filterKernelNearField[i].x = r; |
|||
filterKernelNearField[i].y = 1f / DisneyProfilePdf(r, s); |
|||
} |
|||
|
|||
// Importance sample the far field kernel.
|
|||
for (int i = 0, n = SssConstants.SSS_N_SAMPLES_FAR_FIELD; i < n; i++) |
|||
{ |
|||
float p = (i + 0.5f) * (1f / n); |
|||
float r = DisneyProfileCdfInverse(p, s); |
|||
|
|||
// N.b.: computation of normalized weights, and multiplication by the surface albedo
|
|||
// of the actual geometry is performed at runtime (in the shader).
|
|||
filterKernelFarField[i].x = r; |
|||
filterKernelFarField[i].y = 1f / DisneyProfilePdf(r, s); |
|||
} |
|||
|
|||
maxRadius = filterKernelFarField[SssConstants.SSS_N_SAMPLES_FAR_FIELD - 1].x; |
|||
|
|||
// Old SSS Model >>>
|
|||
UpdateKernelAndVarianceData(); |
|||
// <<< Old SSS Model
|
|||
} |
|||
|
|||
// Old SSS Model >>>
|
|||
public void UpdateKernelAndVarianceData() |
|||
{ |
|||
const int kNumSamples = SssConstants.SSS_BASIC_N_SAMPLES; |
|||
const int kDistanceScale = SssConstants.SSS_BASIC_DISTANCE_SCALE; |
|||
|
|||
if (filterKernelBasic == null || filterKernelBasic.Length != kNumSamples) |
|||
filterKernelBasic = new Vector4[kNumSamples]; |
|||
|
|||
// Apply the three-sigma rule, and rescale.
|
|||
var stdDev1 = ((1f / 3f) * kDistanceScale) * scatterDistance1; |
|||
var stdDev2 = ((1f / 3f) * kDistanceScale) * 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); |
|||
|
|||
var weightSum = Vector3.zero; |
|||
|
|||
float step = 1f / (kNumSamples - 1); |
|||
|
|||
// Importance sample the linear combination of two Gaussians.
|
|||
for (int i = 0; i < kNumSamples; i++) |
|||
{ |
|||
// Generate 'u' on (0, 0.5] and (0.5, 1).
|
|||
float u = (i <= kNumSamples / 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.
|
|||
filterKernelBasic[i].x = val.x * (1 / pdf); |
|||
filterKernelBasic[i].y = val.y * (1 / pdf); |
|||
filterKernelBasic[i].z = val.z * (1 / pdf); |
|||
filterKernelBasic[i].w = pos; |
|||
|
|||
weightSum.x += filterKernelBasic[i].x; |
|||
weightSum.y += filterKernelBasic[i].y; |
|||
weightSum.z += filterKernelBasic[i].z; |
|||
} |
|||
|
|||
// Renormalize the weights to conserve energy.
|
|||
for (int i = 0; i < kNumSamples; i++) |
|||
{ |
|||
filterKernelBasic[i].x *= 1 / weightSum.x; |
|||
filterKernelBasic[i].y *= 1 / weightSum.y; |
|||
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.
|
|||
// Warning: do not use halfRcpWeightedVariances.Set(). It will not work.
|
|||
halfRcpWeightedVariances = new Vector4(0.5f / (weightedStdDev.x * weightedStdDev.x), |
|||
0.5f / (weightedStdDev.y * weightedStdDev.y), |
|||
0.5f / (weightedStdDev.z * weightedStdDev.z), |
|||
0.5f / (weightedStdDev.w * weightedStdDev.w)); |
|||
} |
|||
// <<< Old SSS Model
|
|||
|
|||
static float DisneyProfile(float r, float s) |
|||
{ |
|||
return s * (Mathf.Exp(-r * s) + Mathf.Exp(-r * s * (1.0f / 3.0f))) / (8.0f * Mathf.PI * r); |
|||
} |
|||
|
|||
static float DisneyProfilePdf(float r, float s) |
|||
{ |
|||
return r * DisneyProfile(r, s); |
|||
} |
|||
|
|||
static float DisneyProfileCdf(float r, float s) |
|||
{ |
|||
return 1.0f - 0.25f * Mathf.Exp(-r * s) - 0.75f * Mathf.Exp(-r * s * (1.0f / 3.0f)); |
|||
} |
|||
|
|||
static float DisneyProfileCdfDerivative1(float r, float s) |
|||
{ |
|||
return 0.25f * s * Mathf.Exp(-r * s) * (1.0f + Mathf.Exp(r * s * (2.0f / 3.0f))); |
|||
} |
|||
|
|||
static float DisneyProfileCdfDerivative2(float r, float s) |
|||
{ |
|||
return (-1.0f / 12.0f) * s * s * Mathf.Exp(-r * s) * (3.0f + Mathf.Exp(r * s * (2.0f / 3.0f))); |
|||
} |
|||
|
|||
// The CDF is not analytically invertible, so we use Halley's Method of root finding.
|
|||
// { f(r, s, p) = CDF(r, s) - p = 0 } with the initial guess { r = (10^p - 1) / s }.
|
|||
static float DisneyProfileCdfInverse(float p, float s) |
|||
{ |
|||
// Supply the initial guess.
|
|||
float r = (Mathf.Pow(10f, p) - 1f) / s; |
|||
float t = float.MaxValue; |
|||
|
|||
while (true) |
|||
{ |
|||
float f0 = DisneyProfileCdf(r, s) - p; |
|||
float f1 = DisneyProfileCdfDerivative1(r, s); |
|||
float f2 = DisneyProfileCdfDerivative2(r, s); |
|||
float dr = f0 / (f1 * (1f - f0 * f2 / (2f * f1 * f1))); |
|||
|
|||
if (Mathf.Abs(dr) < t) |
|||
{ |
|||
r = r - dr; |
|||
t = Mathf.Abs(dr); |
|||
} |
|||
else |
|||
{ |
|||
// Converged to the best result.
|
|||
break; |
|||
} |
|||
} |
|||
|
|||
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(-2f * Mathf.Log(p))); |
|||
} |
|||
else |
|||
{ |
|||
// F^-1(p) = G^-1(1-p)
|
|||
x = RationalApproximation(Mathf.Sqrt(-2f * Mathf.Log(1f - 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
|
|||
} |
|||
|
|||
public sealed class SubsurfaceScatteringSettings : ScriptableObject |
|||
{ |
|||
public SubsurfaceScatteringProfile[] profiles; |
|||
|
|||
[NonSerialized] public uint texturingModeFlags; // 1 bit/profile; 0 = PreAndPostScatter, 1 = PostScatter
|
|||
[NonSerialized] public uint transmissionFlags; // 2 bit/profile; 0 = inf. thick, 1 = thin, 2 = regular
|
|||
[NonSerialized] public Vector4[] thicknessRemaps; // Remap: 0 = start, 1 = end - start
|
|||
[NonSerialized] public Vector4[] worldScales; // X = meters per world unit; Y = world units per meter
|
|||
[NonSerialized] public Vector4[] shapeParams; // RGB = S = 1 / D, A = filter radius
|
|||
[NonSerialized] public Vector4[] transmissionTintsAndFresnel0; // RGB = color, A = fresnel0
|
|||
[NonSerialized] public Vector4[] filterKernels; // XY = near field, ZW = far field; 0 = radius, 1 = reciprocal of the PDF
|
|||
|
|||
// Old SSS Model >>>
|
|||
[NonSerialized] public Vector4[] halfRcpWeightedVariances; |
|||
[NonSerialized] public Vector4[] halfRcpVariancesAndWeights; |
|||
[NonSerialized] public Vector4[] filterKernelsBasic; |
|||
// <<< Old SSS Model
|
|||
|
|||
public SubsurfaceScatteringProfile this[int index] |
|||
{ |
|||
get |
|||
{ |
|||
if (index >= SssConstants.SSS_N_PROFILES - 1) |
|||
throw new IndexOutOfRangeException("index"); |
|||
|
|||
return profiles[index]; |
|||
} |
|||
} |
|||
|
|||
void OnEnable() |
|||
{ |
|||
// The neutral profile is not a part of the array.
|
|||
int profileArraySize = SssConstants.SSS_N_PROFILES - 1; |
|||
|
|||
if (profiles != null && profiles.Length != profileArraySize) |
|||
Array.Resize(ref profiles, profileArraySize); |
|||
|
|||
if (profiles == null) |
|||
profiles = new SubsurfaceScatteringProfile[profileArraySize]; |
|||
|
|||
for (int i = 0; i < profileArraySize; i++) |
|||
{ |
|||
if (profiles[i] == null) |
|||
profiles[i] = new SubsurfaceScatteringProfile("Profile " + (i + 1)); |
|||
|
|||
profiles[i].Validate(); |
|||
} |
|||
|
|||
ValidateArray(ref thicknessRemaps, SssConstants.SSS_N_PROFILES); |
|||
ValidateArray(ref worldScales, SssConstants.SSS_N_PROFILES); |
|||
ValidateArray(ref shapeParams, SssConstants.SSS_N_PROFILES); |
|||
ValidateArray(ref transmissionTintsAndFresnel0, SssConstants.SSS_N_PROFILES); |
|||
ValidateArray(ref filterKernels, SssConstants.SSS_N_PROFILES * SssConstants.SSS_N_SAMPLES_NEAR_FIELD); |
|||
|
|||
// Old SSS Model >>>
|
|||
ValidateArray(ref halfRcpWeightedVariances, SssConstants.SSS_N_PROFILES); |
|||
ValidateArray(ref halfRcpVariancesAndWeights, SssConstants.SSS_N_PROFILES * 2); |
|||
ValidateArray(ref filterKernelsBasic, SssConstants.SSS_N_PROFILES * SssConstants.SSS_BASIC_N_SAMPLES); |
|||
|
|||
Debug.Assert(SssConstants.SSS_NEUTRAL_PROFILE_ID < 16, "Transmission flags (32-bit integer) cannot support more than 16 profiles (2 bits per profile)."); |
|||
|
|||
UpdateCache(); |
|||
} |
|||
|
|||
static void ValidateArray<T>(ref T[] array, int len) |
|||
{ |
|||
if (array == null || array.Length != len) |
|||
array = new T[len]; |
|||
} |
|||
|
|||
public void UpdateCache() |
|||
{ |
|||
for (int i = 0; i < SssConstants.SSS_N_PROFILES - 1; i++) |
|||
{ |
|||
UpdateCache(i); |
|||
} |
|||
|
|||
// Fill the neutral profile.
|
|||
int neutralId = SssConstants.SSS_NEUTRAL_PROFILE_ID; |
|||
|
|||
worldScales[neutralId] = Vector4.one; |
|||
shapeParams[neutralId] = Vector4.zero; |
|||
|
|||
for (int j = 0, n = SssConstants.SSS_N_SAMPLES_NEAR_FIELD; j < n; j++) |
|||
{ |
|||
filterKernels[n * neutralId + j].x = 0f; |
|||
filterKernels[n * neutralId + j].y = 1f; |
|||
filterKernels[n * neutralId + j].z = 0f; |
|||
filterKernels[n * neutralId + j].w = 1f; |
|||
} |
|||
|
|||
// Old SSS Model >>>
|
|||
halfRcpWeightedVariances[neutralId] = Vector4.one; |
|||
|
|||
for (int j = 0, n = SssConstants.SSS_BASIC_N_SAMPLES; j < n; j++) |
|||
{ |
|||
filterKernelsBasic[n * neutralId + j] = Vector4.one; |
|||
filterKernelsBasic[n * neutralId + j].w = 0f; |
|||
} |
|||
// <<< Old SSS Model
|
|||
} |
|||
|
|||
public void UpdateCache(int p) |
|||
{ |
|||
// 'p' is the profile array index. 'i' is the index in the shader (accounting for the neutral profile).
|
|||
int i = p + 1; |
|||
|
|||
// Erase previous value (This need to be done here individually as in the SSS editor we edit individual component)
|
|||
uint mask = 1u << i; |
|||
texturingModeFlags &= ~mask; |
|||
mask = 3u << i * 2; |
|||
transmissionFlags &= ~mask; |
|||
|
|||
texturingModeFlags |= (uint)profiles[p].texturingMode << i; |
|||
transmissionFlags |= (uint)profiles[p].transmissionMode << i * 2; |
|||
|
|||
thicknessRemaps[i] = new Vector4(profiles[p].thicknessRemap.x, profiles[p].thicknessRemap.y - profiles[p].thicknessRemap.x, 0f, 0f); |
|||
worldScales[i] = new Vector4(profiles[p].worldScale, 1.0f / profiles[p].worldScale, 0f, 0f); |
|||
shapeParams[i] = profiles[p].shapeParam; |
|||
shapeParams[i].w = profiles[p].maxRadius; |
|||
transmissionTintsAndFresnel0[i] = new Vector4(profiles[p].transmissionTint.r * 0.25f, profiles[p].transmissionTint.g * 0.25f, profiles[p].transmissionTint.b * 0.25f, profiles[p].fresnel0); // Premultiplied
|
|||
|
|||
for (int j = 0, n = SssConstants.SSS_N_SAMPLES_NEAR_FIELD; j < n; j++) |
|||
{ |
|||
filterKernels[n * i + j].x = profiles[p].filterKernelNearField[j].x; |
|||
filterKernels[n * i + j].y = profiles[p].filterKernelNearField[j].y; |
|||
|
|||
if (j < SssConstants.SSS_N_SAMPLES_FAR_FIELD) |
|||
{ |
|||
filterKernels[n * i + j].z = profiles[p].filterKernelFarField[j].x; |
|||
filterKernels[n * i + j].w = profiles[p].filterKernelFarField[j].y; |
|||
} |
|||
} |
|||
|
|||
// Old SSS Model >>>
|
|||
halfRcpWeightedVariances[i] = profiles[p].halfRcpWeightedVariances; |
|||
|
|||
var stdDev1 = ((1f / 3f) * SssConstants.SSS_BASIC_DISTANCE_SCALE) * (Vector4)profiles[p].scatterDistance1; |
|||
var stdDev2 = ((1f / 3f) * SssConstants.SSS_BASIC_DISTANCE_SCALE) * (Vector4)profiles[p].scatterDistance2; |
|||
|
|||
// Multiply by 0.1 to convert from millimeters to centimeters. Apply the distance scale.
|
|||
// Rescale by 4 to counter rescaling of transmission tints.
|
|||
float a = 0.1f * SssConstants.SSS_BASIC_DISTANCE_SCALE; |
|||
halfRcpVariancesAndWeights[2 * i + 0] = new Vector4(a * a * 0.5f / (stdDev1.x * stdDev1.x), a * a * 0.5f / (stdDev1.y * stdDev1.y), a * a * 0.5f / (stdDev1.z * stdDev1.z), 4f * (1f - profiles[p].lerpWeight)); |
|||
halfRcpVariancesAndWeights[2 * i + 1] = new Vector4(a * a * 0.5f / (stdDev2.x * stdDev2.x), a * a * 0.5f / (stdDev2.y * stdDev2.y), a * a * 0.5f / (stdDev2.z * stdDev2.z), 4f * profiles[p].lerpWeight); |
|||
|
|||
for (int j = 0, n = SssConstants.SSS_BASIC_N_SAMPLES; j < n; j++) |
|||
{ |
|||
filterKernelsBasic[n * i + j] = profiles[p].filterKernelBasic[j]; |
|||
} |
|||
// <<< Old SSS Model
|
|||
} |
|||
} |
|||
} |
|||
|
|||
fileFormatVersion: 2 |
|||
guid: 1b5e87e98ef1994498478f60a6dcdd65 |
|||
folderAsset: yes |
|||
timeCreated: 1481725797 |
|||
licenseType: Pro |
|||
DefaultImporter: |
|||
userData: |
|||
assetBundleName: |
|||
assetBundleVariant: |
|||
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