Expose angle offset below (N.L)

Signed-off-by: Santi Paprika <santi.gonzalez.cs@gmail.com>
2021-12-02 13:04:16 +01:00
parent 9f8994823b
commit 348c3cc0f6
5 changed files with 24 additions and 4 deletions
@@ -351,6 +351,9 @@ PbrLightingOutput SkinPS_Common(VSOutput IN)
    lightingData.specularResponse = FresnelSchlickWithRoughness(lightingData.NdotV, surface.specularF0, surface.roughnessLinear);
    lightingData.diffuseResponse = 1.0 - lightingData.specularResponse;

+    // Angle offset for subsurface scattering through thin objects
+    lightingData.angleOffset = MaterialSrg::m_angleOffset;
+
    // ------- Occlusion -------
    
    lightingData.diffuseAmbientOcclusion = GetOcclusionInput(MaterialSrg::m_diffuseOcclusionMap, MaterialSrg::m_sampler, IN.m_uv[MaterialSrg::m_diffuseOcclusionMapUvIndex], MaterialSrg::m_diffuseOcclusionFactor, o_diffuseOcclusion_useTexture);
@@ -650,6 +650,19 @@
                        "name": "m_shrinkFactor"
                    }
                },
+                {
+                    "name": "angleOffset",
+                    "displayName": "    Angle Offset",
+                    "description": "Angle to accept below (N . L = 0) in scattering through thin objects",
+                    "type": "float",
+                    "defaultValue": 0.1,
+                    "min": -1.0,
+                    "softMax": 1.0,
+                    "connection": {
+                        "type": "ShaderInput",
+                        "name": "m_angleOffset"
+                    }
+                },
                {
                    "name": "transmissionScale",
                    "displayName": "    Scale",
@@ -657,7 +670,7 @@
                    "type": "float",
                    "defaultValue": 3.0,
                    "min": 0.0,
-                    "softMax": 20.0
+                    "softMax": 100.0
                }
            ],
            "wrinkleLayers": [
@@ -72,6 +72,7 @@ ShaderResourceGroup MaterialSrg : SRG_PerMaterial
    Texture2D m_transmissionThicknessMap;
    uint m_transmissionThicknessMapUvIndex;
    float m_shrinkFactor;
+    float m_angleOffset;
    
    Texture2D m_wrinkle_baseColor_texture1;
    Texture2D m_wrinkle_baseColor_texture2;
@@ -65,10 +65,10 @@ float3 GetBackLighting(Surface surface, LightingData lightingData, float3 lightI
            {
                // Irradiance arround surface point. 
                // Begin the transmittance dot product slightly before it would with the regular dot(N,L)
-                float E = max(0.30 + dot(-surface.normal, dirToLight), 0.0);
+                float E = saturate(lightingData.angleOffset + dot(-surface.normal, dirToLight));

                // Transmission distance computed from shadowmaps modulated by editor-exposed parameters
-                float s = transmissionDistance * surface.transmission.thickness * (50 - transmissionParams.w) * 10;
+                float s = transmissionDistance * surface.transmission.thickness * (100 - transmissionParams.w) * 10;
                
                // Albedo at front (surface point) is used to approximate irradiance at the back of the object
                // See observation 4 in [Jimenez J. et al, 2010] 
@@ -28,9 +28,12 @@ class LightingData
    // Direction light shadow coordinates
    float3 shadowCoords[ViewSrg::MaxCascadeCount];

-    // Direction light shadow coordinates for shrinked positions
+    // Direction light shadow coordinates for shrinked positions (used in scattering through thin objects)
    float3 shrinkedShadowCoords[ViewSrg::MaxCascadeCount];

+    // Angle to accept below (N . L = 0) in scattering through thin objects
+    float angleOffset; 
+
    // Normalized direction from surface to camera
    float3 dirToCamera;