Merge branch 'AcademySoftwareFoundation:main' into downstream_traversal

.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

libraries/lights/genmsl/lights_genmsl_impl.mtlx

@@ -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/pbrlib/genglsl/lib/mx_environment_fis.glsl

@@ -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/pbrlib/genglsl/lib/mx_microfacet_specular.glsl

@@ -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)));

libraries/pbrlib/pbrlib_defs.mtlx

@@ -76,8 +76,8 @@
   -->
   <nodedef name="ND_conductor_bsdf" node="conductor_bsdf" bsdf="R" nodegroup="pbr" doc="A reflection BSDF node based on a microfacet model and a Fresnel curve for conductors/metals.">
     <input name="weight" type="float" value="1.0" uimin="0.0" uimax="1.0" />
-    <input name="ior" type="color3" value="0.271, 0.677, 1.316" colorspace="none" />
-    <input name="extinction" type="color3" value="3.609, 2.625, 2.292" colorspace="none" />
+    <input name="ior" type="color3" value="0.183, 0.421, 1.373" colorspace="none" />
+    <input name="extinction" type="color3" value="3.424, 2.346, 1.770" colorspace="none" />
     <input name="roughness" type="vector2" value="0.05, 0.05" />
     <input name="normal" type="vector3" defaultgeomprop="Nworld" />
     <input name="tangent" type="vector3" defaultgeomprop="Tworld" />

libraries/stdlib/stdlib_defs.mtlx

@@ -2280,7 +2280,7 @@
     <input name="in2" type="vector4" uiname="in2" value="0.0, 0.0, 0.0, 0.0" />
     <output name="out" type="float" />
   </nodedef>
-  
+
   <!--
     Node: <dotproduct>
     Perform a dot product of two 2-4 channel vectors

libraries/stdlib/stdlib_ng.mtlx

@@ -291,7 +291,7 @@
     <dotproduct name="N_dotBlendedN" type="float">
       <input name="in1" type="vector3" nodename="N_blendPower" />
       <input name="in2" type="vector3" value="1.0, 1.0, 1.0" />
-    </dotproduct> 
+    </dotproduct>
     <divide name="N_normalizeBlendedWeights" type="vector3">
       <input name="in1" type="vector3" nodename="N_blendPower" />
       <input name="in2" type="float" nodename="N_dotBlendedN" />
@@ -411,7 +411,7 @@
     <dotproduct name="N_dotBlendedN" type="float">
       <input name="in1" type="vector3" nodename="N_blendPower" />
       <input name="in2" type="vector3" value="1.0, 1.0, 1.0" />
-    </dotproduct> 
+    </dotproduct>
     <divide name="N_normalizeBlendedWeights" type="vector3">
       <input name="in1" type="vector3" nodename="N_blendPower" />
       <input name="in2" type="float" nodename="N_dotBlendedN" />
@@ -531,7 +531,7 @@
     <dotproduct name="N_dotBlendedN" type="float">
       <input name="in1" type="vector3" nodename="N_blendPower" />
       <input name="in2" type="vector3" value="1.0, 1.0, 1.0" />
-    </dotproduct> 
+    </dotproduct>
     <divide name="N_normalizeBlendedWeights" type="vector3">
       <input name="in1" type="vector3" nodename="N_blendPower" />
       <input name="in2" type="float" nodename="N_dotBlendedN" />
@@ -651,7 +651,7 @@
     <dotproduct name="N_dotBlendedN" type="float">
       <input name="in1" type="vector3" nodename="N_blendPower" />
       <input name="in2" type="vector3" value="1.0, 1.0, 1.0" />
-    </dotproduct> 
+    </dotproduct>
     <divide name="N_normalizeBlendedWeights" type="vector3">
       <input name="in1" type="vector3" nodename="N_blendPower" />
       <input name="in2" type="float" nodename="N_dotBlendedN" />
@@ -771,7 +771,7 @@
     <dotproduct name="N_dotBlendedN" type="float">
       <input name="in1" type="vector3" nodename="N_blendPower" />
       <input name="in2" type="vector3" value="1.0, 1.0, 1.0" />
-    </dotproduct> 
+    </dotproduct>
     <divide name="N_normalizeBlendedWeights" type="vector3">
       <input name="in1" type="vector3" nodename="N_blendPower" />
       <input name="in2" type="float" nodename="N_dotBlendedN" />
@@ -891,7 +891,7 @@
     <dotproduct name="N_dotBlendedN" type="float">
       <input name="in1" type="vector3" nodename="N_blendPower" />
       <input name="in2" type="vector3" value="1.0, 1.0, 1.0" />
-    </dotproduct> 
+    </dotproduct>
     <divide name="N_normalizeBlendedWeights" type="vector3">
       <input name="in1" type="vector3" nodename="N_blendPower" />
       <input name="in2" type="float" nodename="N_dotBlendedN" />
@@ -1540,7 +1540,7 @@
     </magnitude>
     <output name="out" type="float" nodename="N_mtlxmagnitude" />
   </nodegraph>
-  
+
   <!-- ======================================================================== -->
   <!-- Adjustment nodes                                                         -->
   <!-- ======================================================================== -->

python/Scripts/mxformat.py

@@ -1,49 +1,38 @@
 #!/usr/bin/env python
 '''
-Format MaterialX document content by reanding and writing files. Optionally
-upgrade the document version. 
+Reformat a folder of MaterialX documents in place, optionally upgrading
+the documents to the latest version of the standard.
 '''
 
 import sys, os, argparse
 import MaterialX as mx
 
-def getFiles(rootPath):
-    filelist = []
-    for subdir, dirs, files in os.walk(rootPath):
-        for file in files:
-            if file.endswith('mtlx'):
-                filelist.append(os.path.join(subdir, file)) 
-    return filelist
-
 def main():
-    parser = argparse.ArgumentParser(description="Format document by reading the file and writing it back out. Optionally update to the latest version.")
+    parser = argparse.ArgumentParser(description="Reformat a folder of MaterialX documents in place.")
     parser.add_argument("--yes", dest="yes", action="store_true", help="Proceed without asking for confirmation from the user.")
-    parser.add_argument('--checkForChanges', dest='checkForChanges', type=mx.stringToBoolean, default=True, help='Check if a file has changed. Default is True')
-    parser.add_argument('--upgradeVersion', dest='upgradeVersion', type=mx.stringToBoolean, default=False, help='Upgrade the document version. Default is False')
+    parser.add_argument('--upgrade', dest='upgrade', action="store_true", help='Upgrade documents to the latest version of the standard.')
     parser.add_argument(dest="inputFolder", help="An input folder to scan for MaterialX documents.")
     opts = parser.parse_args()
 
-    fileList = []
-    rootPath = opts.inputFolder
-    if os.path.isdir(rootPath): 
-        fileList = getFiles(rootPath)
-    else:
-        fileList.append(rootPath)
-
-    # Preserve version, comments and newlines
-    readOptions = mx.XmlReadOptions()
-    readOptions.readComments = True
-    readOptions.readNewlines = True    
-    readOptions.upgradeVersion = opts.upgradeVersion
-
     validDocs = dict()
-    for filename in fileList:
-        doc = mx.createDocument()
-        try:
-            mx.readFromXmlFile(doc, filename, mx.FileSearchPath(), readOptions)
-            validDocs[filename] = doc
-        except mx.Exception:
-            pass
+    for root, dirs, files in os.walk(opts.inputFolder):
+        for file in files:
+            if file.endswith('.mtlx'):
+                filename = os.path.join(root, file)
+                doc = mx.createDocument()
+                try:
+                    readOptions = mx.XmlReadOptions()
+                    readOptions.readComments = True
+                    readOptions.readNewlines = True    
+                    readOptions.upgradeVersion = opts.upgrade
+                    try:
+                        mx.readFromXmlFile(doc, filename, mx.FileSearchPath(), readOptions)
+                    except Exception as err:
+                        print('Skipping "' + file + '" due to exception: ' + str(err))
+                        continue
+                    validDocs[filename] = doc
+                except mx.Exception:
+                    pass
 
     if not validDocs:
         print('No MaterialX documents were found in "%s"' % (opts.inputFolder))
@@ -54,31 +43,21 @@ def main():
     mxVersion = mx.getVersionIntegers()
 
     if not opts.yes:
-        question = 'Would you like to update all %i documents in place (y/n)?' % len(validDocs)
-        if opts.upgradeVersion:
-            question = 'Would you like to update all %i documents to MaterialX v%i.%i in place (y/n)?' % (len(validDocs), mxVersion[0], mxVersion[1])
+        if opts.upgrade:
+            question = 'Would you like to upgrade all %i documents to MaterialX v%i.%i in place (y/n)?' % (len(validDocs), mxVersion[0], mxVersion[1])
+        else:
+            question = 'Would you like to reformat all %i documents in place (y/n)?' % len(validDocs)
         answer = input(question)
         if answer != 'y' and answer != 'Y':
             return
 
-    writeCount = 0
     for (filename, doc) in validDocs.items():
-        writeFile = True
-        if opts.checkForChanges:
-            origString = mx.readFile(filename)
-            docString = mx.writeToXmlString(doc)
-            if origString == docString:
-                writeFile = False
-
-        if writeFile:
-            writeCount = writeCount + 1
-            print('- Updated file %s.' % filename)
-            mx.writeToXmlFile(doc, filename)
+        mx.writeToXmlFile(doc, filename)
 
-    if opts.upgradeVersion:
-        print('Updated %i documents to MaterialX v%i.%i' % (writeCount, mxVersion[0], mxVersion[1]))
+    if opts.upgrade:
+        print('Upgraded %i documents to MaterialX v%i.%i' % (len(validDocs), mxVersion[0], mxVersion[1]))
     else:
-        print('Updated %i documents ' % writeCount)
+        print('Reformatted %i documents ' % len(validDocs))
 
 if __name__ == '__main__':
     main()

resources/Lights/goegap_split.mtlx

@@ -1,5 +1,5 @@
 <?xml version="1.0"?>
-<materialx version="1.37">
+<materialx version="1.38">
   <directional_light name="dir_light" type="lightshader">
     <input name="direction" type="vector3" value="0.43277, -0.725547, -0.535062" />
     <input name="color" type="color3" value="0.993688, 1, 0.993529" />

resources/Lights/san_giuseppe_bridge_split.mtlx

@@ -1,5 +1,5 @@
 <?xml version="1.0"?>
-<materialx version="1.37">
+<materialx version="1.38">
   <directional_light name="dir_light" type="lightshader">
     <input name="direction" type="vector3" value="0.514434, -0.479014, -0.711269" />
     <input name="color" type="color3" value="1, 0.894474, 0.567234" />

resources/Lights/table_mountain_split.mtlx

@@ -1,5 +1,5 @@
 <?xml version="1.0"?>
-<materialx version="1.37">
+<materialx version="1.38">
   <directional_light name="dir_light" type="lightshader">
     <input name="direction" type="vector3" value="0.757663, -0.126589, -0.640251" />
     <input name="color" type="color3" value="1, 0.844753, 0.418417" />

resources/Materials/TestSuite/stdlib/upgrade/1_36_to_1_37.mtlx

@@ -1,10 +1,10 @@
 <?xml version="1.0"?>
-<!--
+<materialx version="1.36">
+  <!--
 
-Upgrade path test from 1.36 to 1.37
+  Upgrade path test from 1.36 to 1.37
 
--->
-<materialx version="1.36">
+  -->
 
   <!-- invert matrix to invertmatrix -->
   <invert name="invert1" type="matrix33">

source/PyMaterialX/PyMaterialXRender/PyModule.cpp

@@ -19,6 +19,7 @@ void bindPyOiioImageLoader(py::module& mod);
 void bindPyTinyObjLoader(py::module& mod);
 void bindPyCamera(py::module& mod);
 void bindPyShaderRenderer(py::module& mod);
+void bindPyCgltfLoader(py::module& mod);
 
 PYBIND11_MODULE(PyMaterialXRender, mod)
 {
@@ -36,4 +37,5 @@ PYBIND11_MODULE(PyMaterialXRender, mod)
     bindPyTinyObjLoader(mod);
     bindPyCamera(mod);
     bindPyShaderRenderer(mod);
+    bindPyCgltfLoader(mod);
 }