Merge branch 'main' into pbr_blackbody

Author: jstone-lucasfilm

.github/workflows/main.yml

@@ -203,7 +203,7 @@ jobs:
       run: |
         python MaterialXTest/main.py
         python MaterialXTest/genshader.py
-        python Scripts/mxformat.py ../resources/Materials/TestSuite/stdlib/upgrade --yes --upgradeVersion True
+        python Scripts/mxformat.py ../resources/Materials/TestSuite/stdlib/upgrade --yes --upgrade
         python Scripts/mxvalidate.py ../resources/Materials/Examples/StandardSurface/standard_surface_marble_solid.mtlx --stdlib --verbose
         python Scripts/mxdoc.py --docType md ../libraries/pbrlib/pbrlib_defs.mtlx
         python Scripts/mxdoc.py --docType html ../libraries/bxdf/standard_surface.mtlx

README.md

@@ -34,27 +34,27 @@ The [MaterialX Viewer](documents/DeveloperGuide/Viewer.md) leverages shader gene
 
 **Figure 1:** Procedural and uniform materials in the MaterialX viewer
 <p float="left">
-  <img src="/documents/Images/MaterialXView_Marble.png" width="204" />
-  <img src="/documents/Images/MaterialXView_Copper.png" width="204" /> 
-  <img src="/documents/Images/MaterialXView_Plastic.png" width="204" /> 
-  <img src="/documents/Images/MaterialXView_Carpaint.png" width="204" /> 
+  <img src="documents/Images/MaterialXView_Marble.png" width="204" />
+  <img src="documents/Images/MaterialXView_Copper.png" width="204" /> 
+  <img src="documents/Images/MaterialXView_Plastic.png" width="204" /> 
+  <img src="documents/Images/MaterialXView_Carpaint.png" width="204" /> 
 </p>
 
 **Figure 2:** Textured, color-space-managed materials in the MaterialX viewer
 <p float="left">
-  <img src="/documents/Images/MaterialXView_TiledBrass.png" width="412" />
-  <img src="/documents/Images/MaterialXView_TiledWood.png" width="412" /> 
+  <img src="documents/Images/MaterialXView_TiledBrass.png" width="412" />
+  <img src="documents/Images/MaterialXView_TiledWood.png" width="412" /> 
 </p>
 
 ### Open Chess Set
 
 The Open Chess Set is an open reference asset, consisting of a [MaterialX file](resources/Materials/Examples/StandardSurface/standard_surface_chess_set.mtlx) in the Standard Surface shading model and a [geometry file](resources/Geometry) in the glTF format.  It was authored by Moeen Sayed and Mujtaba Sayed, and was contributed to the MaterialX project by Side Effects.
 
 **Figure 3:** The Open Chess Set, rendered in Arnold for Maya
-<img src="/documents/Images/OpenChessSet_Arnold_01.png" />
+<img src="documents/Images/OpenChessSet_Arnold_01.png" />
 
 **Figure 4:** The Open Chess Set, rendered in Karma XPU for Houdini
-<img src="/documents/Images/OpenChessSet_Karma_01.png" />
+<img src="documents/Images/OpenChessSet_Karma_01.png" />
 
 ### Pre-Built Binaries
 

javascript/MaterialXTest/package-lock.json

@@ -16,17 +16,17 @@
   "author": "",
   "license": "ISC",
   "devDependencies": {
-    "@babel/core": "^7.20.2",
-    "@babel/preset-env": "^7.20.2",
-    "@babel/register": "^7.18.9",
+    "@babel/core": "^7.22.5",
+    "@babel/preset-env": "^7.22.5",
+    "@babel/register": "^7.22.5",
     "chai": "^4.3.7",
     "copyfiles": "^2.4.1",
-    "karma": "^6.4.1",
+    "karma": "^6.4.2",
     "karma-chai": "^0.1.0",
-    "karma-chrome-launcher": "^3.1.1",
+    "karma-chrome-launcher": "^3.2.0",
     "karma-mocha": "^2.0.1",
     "karma-mocha-reporter": "^2.2.5",
-    "mocha": "^10.1.0",
+    "mocha": "^10.2.0",
     "rimraf": "^3.0.2"
   }
 }

javascript/MaterialXTest/package.json

@@ -12,12 +12,12 @@
   "dependencies": {
     "dat.gui": "^0.7.9",
     "three": "^0.135.0",
-    "webpack": "^5.75.0"
+    "webpack": "^5.88.1"
   },
   "devDependencies": {
     "copy-webpack-plugin": "^8.1.1",
-    "html-webpack-plugin": "^5.5.0",
+    "html-webpack-plugin": "^5.5.3",
     "webpack-cli": "^4.10.0",
-    "webpack-dev-server": "^4.11.1"
+    "webpack-dev-server": "^4.15.1"
   }
 }

javascript/MaterialXView/package-lock.json

@@ -148,11 +148,6 @@
     <!-- Thin-film + Dielectric
          Note: Due to limitations in codegen, the base layer BSDF is duplicated (#1035). -->
 
-    <oren_nayar_diffuse_bsdf name="tf_diffuse_bsdf" type="BSDF">
-      <input name="color" type="color3" interfacename="base_color" />
-      <input name="normal" type="vector3" interfacename="normal" />
-    </oren_nayar_diffuse_bsdf>
-
     <dielectric_bsdf name="tf_transmission_bsdf" type="BSDF">
       <input name="weight" type="float" value="1" />
       <input name="tint" type="color3" interfacename="base_color" />
@@ -173,7 +168,7 @@
     </generalized_schlick_bsdf>
 
     <mix name="tf_transmission_mix" type="BSDF">
-      <input name="bg" type="BSDF" nodename="tf_diffuse_bsdf" />
+      <input name="bg" type="BSDF" nodename="diffuse_bsdf" />
       <input name="fg" type="BSDF" nodename="tf_transmission_bsdf" />
       <input name="mix" type="float" interfacename="transmission" />
     </mix>

javascript/MaterialXView/package.json

@@ -1,5 +1,5 @@
 <?xml version="1.0"?>
-<materialx version="1.37">
+<materialx version="1.38">
 
   <!-- <point_light> -->
   <implementation name="IM_point_light_genmsl" nodedef="ND_point_light" file="mx_point_light.metal" function="mx_point_light" target="genmsl" />

libraries/bxdf/gltf_pbr.mtlx

@@ -23,6 +23,7 @@ vec3 mx_environment_radiance(vec3 N, vec3 V, vec3 X, vec2 alpha, int distributio
     // Compute derived properties.
     float NdotV = clamp(V.z, M_FLOAT_EPS, 1.0);
     float avgAlpha = mx_average_alpha(alpha);
+    float G1V = mx_ggx_smith_G1(NdotV, avgAlpha);
 
     // Integrate outgoing radiance using filtered importance sampling.
     // http://cgg.mff.cuni.cz/~jaroslav/papers/2008-egsr-fis/2008-egsr-fis-final-embedded.pdf
@@ -33,18 +34,16 @@ vec3 mx_environment_radiance(vec3 N, vec3 V, vec3 X, vec2 alpha, int distributio
         vec2 Xi = mx_spherical_fibonacci(i, envRadianceSamples);
 
         // Compute the half vector and incoming light direction.
-        vec3 H = mx_ggx_importance_sample_NDF(Xi, alpha);
+        vec3 H = mx_ggx_importance_sample_VNDF(Xi, V, alpha);
         vec3 L = fd.refraction ? mx_refraction_solid_sphere(-V, H, fd.ior.x) : -reflect(V, H);
 
         // Compute dot products for this sample.
-        float NdotH = clamp(H.z, M_FLOAT_EPS, 1.0);
         float NdotL = clamp(L.z, M_FLOAT_EPS, 1.0);
         float VdotH = clamp(dot(V, H), M_FLOAT_EPS, 1.0);
-        float LdotH = VdotH;
 
         // Sample the environment light from the given direction.
         vec3 Lw = tangentToWorld * L;
-        float pdf = mx_ggx_PDF(H, LdotH, alpha);
+        float pdf = mx_ggx_NDF(H, alpha) * G1V / (4.0 * NdotV);
         float lod = mx_latlong_compute_lod(Lw, pdf, float($envRadianceMips - 1), envRadianceSamples);
         vec3 sampleColor = mx_latlong_map_lookup(Lw, $envMatrix, lod, $envRadiance);
 
@@ -61,13 +60,15 @@ vec3 mx_environment_radiance(vec3 N, vec3 V, vec3 X, vec2 alpha, int distributio
         // From https://cdn2.unrealengine.com/Resources/files/2013SiggraphPresentationsNotes-26915738.pdf
         //   incidentLight = sampleColor * NdotL
         //   microfacetSpecular = D * F * G / (4 * NdotL * NdotV)
-        //   pdf = D * NdotH / (4 * VdotH)
+        //   pdf = D * G1V / (4 * NdotV);
         //   radiance = incidentLight * microfacetSpecular / pdf
-        radiance += sampleColor * FG * VdotH / (NdotV * NdotH);
+        radiance += sampleColor * FG;
     }
 
-    // Normalize and return the final radiance.
-    radiance /= float(envRadianceSamples);
+    // Apply the global component of the geometric term and normalize.
+    radiance /= G1V * float(envRadianceSamples);
+
+    // Return the final radiance.
     return radiance;
 }
 

libraries/lights/genmsl/lights_genmsl_impl.mtlx

@@ -61,48 +61,22 @@ float mx_ggx_NDF(vec3 H, vec2 alpha)
     return 1.0 / (M_PI * alpha.x * alpha.y * mx_square(denom));
 }
 
-// https://media.disneyanimation.com/uploads/production/publication_asset/48/asset/s2012_pbs_disney_brdf_notes_v3.pdf
-// Appendix B.1 Equation 3
-float mx_ggx_PDF(vec3 H, float LdotH, vec2 alpha)
-{
-    float NdotH = H.z;
-    return mx_ggx_NDF(H, alpha) * NdotH / (4.0 * LdotH);
-}
-
-// https://media.disneyanimation.com/uploads/production/publication_asset/48/asset/s2012_pbs_disney_brdf_notes_v3.pdf
-// Appendix B.2 Equation 15
-vec3 mx_ggx_importance_sample_NDF(vec2 Xi, vec2 alpha)
-{
-    float phi = 2.0 * M_PI * Xi.x;
-    float tanTheta = sqrt(Xi.y / (1.0 - Xi.y));
-    vec3 H = vec3(tanTheta * alpha.x * cos(phi),
-                  tanTheta * alpha.y * sin(phi),
-                  1.0);
-    return normalize(H);
-}
-
-// http://jcgt.org/published/0007/04/01/paper.pdf
-// Appendix A Listing 1
+// https://ggx-research.github.io/publication/2023/06/09/publication-ggx.html
 vec3 mx_ggx_importance_sample_VNDF(vec2 Xi, vec3 V, vec2 alpha)
 {
     // Transform the view direction to the hemisphere configuration.
     V = normalize(vec3(V.xy * alpha, V.z));
 
-    // Construct an orthonormal basis from the view direction.
-    float len = length(V.xy);
-    vec3 T1 = (len > 0.0) ? vec3(-V.y, V.x, 0.0) / len : vec3(1.0, 0.0, 0.0);
-    vec3 T2 = cross(V, T1);
-
-    // Parameterization of the projected area.
-    float r = sqrt(Xi.y);
+    // Sample a spherical cap in (-V.z, 1].
     float phi = 2.0 * M_PI * Xi.x;
-    float t1 = r * cos(phi);
-    float t2 = r * sin(phi);
-    float s = 0.5 * (1.0 + V.z);
-    t2 = (1.0 - s) * sqrt(1.0 - mx_square(t1)) + s * t2;
-
-    // Reprojection onto hemisphere.
-    vec3 H = t1 * T1 + t2 * T2 + sqrt(max(0.0, 1.0 - mx_square(t1) - mx_square(t2))) * V;
+    float z = (1.0 - Xi.y) * (1.0 + V.z) - V.z;
+    float sinTheta = sqrt(clamp(1.0 - z * z, 0.0, 1.0));
+    float x = sinTheta * cos(phi);
+    float y = sinTheta * sin(phi);
+    vec3 c = vec3(x, y, z);
+
+    // Compute the microfacet normal.
+    vec3 H = c + V;
 
     // Transform the microfacet normal back to the ellipsoid configuration.
     H = normalize(vec3(H.xy * alpha, max(H.z, 0.0)));