HDRenderPipeline: Repalce surface albedo + volume mean free path by scattering distance

8 年前 · cc0717b3
--- a/Assets/ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/SubsurfaceScatteringProfile.cs
+++ b/Assets/ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/SubsurfaceScatteringProfile.cs
        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 Color            surfaceAlbedo;              // Color, 0 to 1
+        [ColorUsageAttribute(false, true, 0f, 8f, 0.125f, 3f)]
+        public Color            scatteringDistance;         // HDR Color (similar to length of volume mean free path in mm (but it is not))
        public Color            volumeAlbedo;               // Color, 0 to 1
        public float            lenVolMeanFreePath;         // Length of the volume mean free path (in millimeters)
        public TexturingMode    texturingMode;
        [SerializeField]
        Vector3                 m_VolumeShapeParam;         // RGB = shape parameter: S = 1 / D
        [SerializeField]
-        float                   m_ScatteringDistance;       // Filter radius (in millimeters)
+        float                   m_KernelSize;               // Filter radius (in millimeters)
        [SerializeField]
        Vector2[]               m_FilterKernelNearField;    // X = radius, Y = reciprocal of the PDF
        [SerializeField]

        public SubsurfaceScatteringProfile()
        {
-            surfaceAlbedo      = Color.white;
+            scatteringDistance = Color.white;
            volumeAlbedo       = Color.white;
            lenVolMeanFreePath = 0.5f;
            texturingMode      = TexturingMode.PreAndPostScatter;
            m_SurfaceShapeParam = new Vector3();

            // Evaluate the fit for diffuse surface transmission.
-            m_SurfaceShapeParam.x = FindFitForS(surfaceAlbedo.r);
-            m_SurfaceShapeParam.y = FindFitForS(surfaceAlbedo.g);
-            m_SurfaceShapeParam.z = FindFitForS(surfaceAlbedo.b);
+            // We substitute s = 1 / d in all formulas. so s = m_SurfaceShapeParam
-            m_SurfaceShapeParam *= 1.0f / lenVolMeanFreePath;
-            // We importance sample the color channel with the highest albedo value,
+            // We importance sample the color channel with the highest s value,
-            // S(A) is a monotonically decreasing function.
+            // s is a monotonically decreasing function.
            float s = Mathf.Min(m_SurfaceShapeParam.x, m_SurfaceShapeParam.y, m_SurfaceShapeParam.z);

            // Importance sample the normalized diffusion profile for the computed value of 's'.
                m_FilterKernelNearField[i].y = 1.0f / KernelPdf(r, s);
            }

-            m_ScatteringDistance = m_FilterKernelNearField[SssConstants.SSS_N_SAMPLES_NEAR_FIELD - 1].x;
+            m_KernelSize = m_FilterKernelNearField[SssConstants.SSS_N_SAMPLES_NEAR_FIELD - 1].x;

            // Importance sample the far field kernel.
            for (int i = 0; i < SssConstants.SSS_N_SAMPLES_FAR_FIELD; i++)
            get { return m_VolumeShapeParam; }
        }

-        public float scatteringDistance
+        public float kernelSize
-            get { return m_ScatteringDistance; }
+            get { return m_KernelSize; }
        }

        public Vector2[] filterKernelNearField
                thicknessRemaps[2 * i + 1] = profiles[i].thicknessRemap.y - profiles[i].thicknessRemap.x;
                worldScales[i]             = profiles[i].worldScale;
                surfaceShapeParams[i]      = profiles[i].surfaceShapeParameter;
-                surfaceShapeParams[i].w    = profiles[i].scatteringDistance;
+                surfaceShapeParams[i].w    = profiles[i].kernelSize;
                volumeShapeParams[i]       = profiles[i].volumeShapeParameter;
                volumeAlbedos[i]           = profiles[i].volumeAlbedo;

            public readonly GUIContent   sssTransmittancePreview0     = new GUIContent("Transmittance Preview");
            public readonly GUIContent   sssTransmittancePreview1     = new GUIContent("Shows the fraction of light passing through the object for thickness values from the remap.");
            public readonly GUIContent   sssTransmittancePreview2     = new GUIContent("Can be viewed as a cross section of a slab of material illuminated by white light from the left.");
-            public readonly GUIContent   sssProfileSurfaceAlbedo      = new GUIContent("Surface Albedo", "Color which determines the shape of the profile. Alpha is ignored. Typically, it is similar to the diffuse color.");
+            public readonly GUIContent   sssProfileScatteringDistance = new GUIContent("Scattering distance", "Color which determines the shape of the profile. Alpha is ignored. Typically, it is desired subsurface color.");
-            public readonly GUIContent   sssProfileScatteringDistance = new GUIContent("Scattering Distance", "Effective radius of the filter (in millimeters). The blur is energy-preserving, so a wide filter results in a large area with small contributions of individual samples. Reducing the distance increases the sharpness of the result.");
+            public readonly GUIContent   sssProfileKernelSize          = new GUIContent("Kernel size", "Effective radius of the filter (in millimeters). The blur is energy-preserving, so a wide filter results in a large area with small contributions of individual samples. Reducing the distance increases the sharpness of the result.");
            public readonly GUIContent   sssTexturingMode             = new GUIContent("Texturing Mode", "Specifies when the diffuse texture should be applied.");
            public readonly GUIContent[] sssTexturingModeOptions      = new GUIContent[2]
            {

            public readonly GUIStyle     centeredMiniBoldLabel     = new GUIStyle(GUI.skin.label);

+            public readonly GUIContent SSSText = new GUIContent("Subsurface scattering options", "Subsurface scattering options");
+            public readonly GUIContent transmissionText = new GUIContent("Transmission options", "Transmission options");
+            
+
            public Styles()
            {
                centeredMiniBoldLabel.alignment = TextAnchor.MiddleCenter;

        private RenderTexture      m_ProfileImage, m_TransmittanceImage;
        private Material           m_ProfileMaterial, m_TransmittanceMaterial;
-        private SerializedProperty m_LenVolMeanFreePath, m_ScatteringDistance, m_SurfaceAlbedo, m_VolumeAlbedo, m_SurfaceShapeParam, m_VolumeShapeParam,
+        private SerializedProperty m_LenVolMeanFreePath, m_KernelSize, m_ScatteringDistance, m_VolumeAlbedo, m_SurfaceShapeParam, m_VolumeShapeParam,
-            m_SurfaceAlbedo         = serializedObject.FindProperty("surfaceAlbedo");
+            m_ScatteringDistance    = serializedObject.FindProperty("scatteringDistance");
-            m_ScatteringDistance    = serializedObject.FindProperty("m_ScatteringDistance");
+            m_KernelSize            = serializedObject.FindProperty("m_KernelSize");
            m_SurfaceShapeParam     = serializedObject.FindProperty("m_SurfaceShapeParam");
            m_VolumeShapeParam      = serializedObject.FindProperty("m_VolumeShapeParam");
            m_TexturingMode         = serializedObject.FindProperty("texturingMode");

            EditorGUI.BeginChangeCheck();
            {
-                EditorGUILayout.PropertyField(m_SurfaceAlbedo, styles.sssProfileSurfaceAlbedo);
-                m_LenVolMeanFreePath.floatValue = EditorGUILayout.Slider(styles.sssProfileLenVolMeanFreePath, m_LenVolMeanFreePath.floatValue, 0.01f, 1.0f);
-
+                GUILayout.Label(styles.SSSText, EditorStyles.boldLabel);
+                EditorGUI.indentLevel++;
+                EditorGUILayout.PropertyField(m_ScatteringDistance, styles.sssProfileScatteringDistance);                
-                EditorGUILayout.PropertyField(m_ScatteringDistance, styles.sssProfileScatteringDistance);
+                EditorGUILayout.PropertyField(m_KernelSize, styles.sssProfileKernelSize);
+                m_TexturingMode.intValue = EditorGUILayout.Popup(styles.sssTexturingMode, m_TexturingMode.intValue, styles.sssTexturingModeOptions);
+                EditorGUI.indentLevel--;
-                m_TexturingMode.intValue        = EditorGUILayout.Popup(styles.sssTexturingMode,           m_TexturingMode.intValue,    styles.sssTexturingModeOptions);
+                GUILayout.Label(styles.transmissionText, EditorStyles.boldLabel);
+                EditorGUI.indentLevel++;
+                m_LenVolMeanFreePath.floatValue = EditorGUILayout.Slider(styles.sssProfileLenVolMeanFreePath, m_LenVolMeanFreePath.floatValue, 0.01f, 1.0f);
+                EditorGUI.indentLevel--;

                EditorGUILayout.Space();
                EditorGUILayout.LabelField(styles.sssProfilePreview0, styles.centeredMiniBoldLabel);
                EditorGUILayout.Space();
            }

-            float   d  = m_ScatteringDistance.floatValue;
-            Vector4 aS = m_SurfaceAlbedo.colorValue;
+            float   d  = m_KernelSize.floatValue;
-            Vector3 sS = m_SurfaceShapeParam.vector3Value;
+            Vector3 sD = m_SurfaceShapeParam.vector3Value;
-            m_ProfileMaterial.SetFloat("_ScatteringDistance", d);
-            m_ProfileMaterial.SetVector("_SurfaceAlbedo",     aS);
-            m_ProfileMaterial.SetVector("_SurfaceShapeParam", sS);
+            m_ProfileMaterial.SetFloat("_KernelSize", d);
+            m_ProfileMaterial.SetVector("_SurfaceShapeParam", sD);
            EditorGUI.DrawPreviewTexture(GUILayoutUtility.GetRect(256, 256), m_ProfileImage, m_ProfileMaterial, ScaleMode.ScaleToFit, 1.0f);

            EditorGUILayout.Space();
            EditorGUILayout.Space();

            // Draw the transmittance graph.
-            m_TransmittanceMaterial.SetFloat("_ScatteringDistance", d);
+            m_TransmittanceMaterial.SetFloat("_KernelSize", d);
            m_TransmittanceMaterial.SetVector("_VolumeAlbedo",      transmissionEnabled ? aV : Vector4.zero);
            m_TransmittanceMaterial.SetVector("_VolumeShapeParam",  sV);
            m_TransmittanceMaterial.SetVector("_ThicknessRemap",    R);
--- a/Assets/ScriptableRenderPipeline/HDRenderPipeline/SceneSettings/Resources/DrawSssProfile.shader
+++ b/Assets/ScriptableRenderPipeline/HDRenderPipeline/SceneSettings/Resources/DrawSssProfile.shader
            // Inputs & outputs
            //-------------------------------------------------------------------------------------

-            float4 _SurfaceAlbedo, _SurfaceShapeParam;
-            float _ScatteringDistance; // See 'SubsurfaceScatteringProfile'
+            float4 _SurfaceShapeParam;
+            float _KernelSize; // See 'SubsurfaceScatteringProfile'

            //-------------------------------------------------------------------------------------
            // Implementation

            float4 Frag(Varyings input) : SV_Target
            {
-                float  r = (2 * length(input.texcoord - 0.5)) * _ScatteringDistance;
+                float  r = (2 * length(input.texcoord - 0.5)) * _KernelSize;
-                return float4(pow(M, 1.0 / 3.0) * _SurfaceAlbedo.rgb, 1);
+                return float4(pow(M, 1.0 / 3.0), 1);
            }
            ENDHLSL
        }