Made usePbrSpecGloss a exportproperty, fixed mat_specular to spec

code/AssetLib/glTF2/glTF2Exporter.cpp

@@ -642,13 +642,7 @@ aiReturn glTF2Exporter::GetMatColor(const aiMaterial &mat, vec3 &prop, const cha
 
 // This extension has been deprecated, only export with the specific flag enabled, defaults to false. Uses KHR_material_specular default.
 bool glTF2Exporter::GetMatSpecGloss(const aiMaterial &mat, glTF2::PbrSpecularGlossiness &pbrSG) {
-    int usePbrSpecGloss;
-    if (mat.Get(AI_MATKEY_USE_GLTF_PBR_SPECULAR_GLOSSINESS, usePbrSpecGloss) != AI_SUCCESS) {
-        return false;
-    }
-    
     bool result = false;
-    
     // If has Glossiness, a Specular Color or Specular Texture, use the KHR_materials_pbrSpecularGlossiness extension
     if (mat.Get(AI_MATKEY_GLOSSINESS_FACTOR, pbrSG.glossinessFactor) == AI_SUCCESS) {
         result = true;
@@ -681,15 +675,21 @@ bool glTF2Exporter::GetMatSpecGloss(const aiMaterial &mat, glTF2::PbrSpecularGlo
 
 bool glTF2Exporter::GetMatSpecular(const aiMaterial &mat, glTF2::MaterialSpecular &specular) {
     // Specular requires either/or, default factors of zero disables specular, so do not export
-    bool result = false;
+    if (GetMatColor(mat, specular.specularColorFactor, AI_MATKEY_COLOR_SPECULAR) != AI_SUCCESS || mat.Get(AI_MATKEY_SPECULAR_FACTOR, specular.specularFactor) != AI_SUCCESS) {
-    if (GetMatColor(mat, specular.specularColorFactor, AI_MATKEY_COLOR_SPECULAR) == AI_SUCCESS && specular.specularFactor != 0.0f) {
+        return false;
-        GetMatTex(mat, specular.specularColorTexture, aiTextureType_SPECULAR);
-        result = true;
-    } else if (mat.Get(AI_MATKEY_SPECULAR_FACTOR, specular.specularFactor) == AI_SUCCESS && !(specular.specularColorFactor[0] == defaultSpecularColorFactor[0] && specular.specularColorFactor[1] == defaultSpecularColorFactor[1] && specular.specularColorFactor[2] == defaultSpecularColorFactor[2])) {
-        GetMatTex(mat, specular.specularTexture, aiTextureType_SPECULAR);
-        result = true;
     }
-    return result;
+    // The spec states that the default is 1.0 and [1.0, 1.0, 1.0]. We if both are 0, which should disable specular. Otherwise, if one is 0, set to 1.0
+    const bool colorFactorIsZero = specular.specularColorFactor[0] == defaultSpecularColorFactor[0] && specular.specularColorFactor[1] == defaultSpecularColorFactor[1] && specular.specularColorFactor[2] == defaultSpecularColorFactor[2];
+    if (specular.specularFactor == 0.0f && colorFactorIsZero) {
+        return false;
+    } else if (specular.specularFactor == 0.0f) {
+        specular.specularFactor = 1.0f;
+    } else if (colorFactorIsZero) {
+        specular.specularColorFactor[0] = specular.specularColorFactor[1] = specular.specularColorFactor[2] = 1.0f;
+    }
+    GetMatTex(mat, specular.specularColorTexture, aiTextureType_SPECULAR);
+    GetMatTex(mat, specular.specularTexture, aiTextureType_SPECULAR);
+    return true;
 }
 
 bool glTF2Exporter::GetMatSheen(const aiMaterial &mat, glTF2::MaterialSheen &sheen) {
@@ -755,7 +755,7 @@ bool glTF2Exporter::GetMatEmissiveStrength(const aiMaterial &mat, glTF2::Materia
     return mat.Get(AI_MATKEY_EMISSIVE_INTENSITY, emissiveStrength.emissiveStrength) == aiReturn_SUCCESS;
 }
 
-void glTF2Exporter::ExportMaterials() {
+void glTF2Exporter::ExportMaterials(ExportProperties *pProperties) {
     aiString aiName;
     for (unsigned int i = 0; i < mScene->mNumMaterials; ++i) {
         ai_assert(mScene->mMaterials[i] != nullptr);
@@ -836,9 +836,9 @@ void glTF2Exporter::ExportMaterials() {
             m->alphaMode = alphaMode.C_Str();
         }
 
-        {
-            // KHR_materials_pbrSpecularGlossiness extension
         // This extension has been deprecated, only export with the specific flag enabled, defaults to false. Uses KHR_material_specular default.
+        if (pProperties->GetPropertyBool(AI_CONFIG_USE_GLTF_PBR_SPECULAR_GLOSSINESS)) {
+            // KHR_materials_pbrSpecularGlossiness extension
             PbrSpecularGlossiness pbrSG;
             if (GetMatSpecGloss(mat, pbrSG)) {
                 mAsset->extensionsUsed.KHR_materials_pbrSpecularGlossiness = true;

code/AssetLib/glTF2/glTF2Importer.cpp

@@ -292,7 +292,6 @@ static aiMaterial *ImportMaterial(std::vector<int> &embeddedTexIdxs, Asset &r, M
         // pbrSpecularGlossiness
         else if (mat.pbrSpecularGlossiness.isPresent) {
             PbrSpecularGlossiness &pbrSG = mat.pbrSpecularGlossiness.value;
-            aimat->AddProperty(new int(1), 1, AI_MATKEY_USE_GLTF_PBR_SPECULAR_GLOSSINESS);
 
             SetMaterialColorProperty(r, pbrSG.diffuseFactor, aimat, AI_MATKEY_COLOR_DIFFUSE);
             SetMaterialColorProperty(r, pbrSG.specularFactor, aimat, AI_MATKEY_COLOR_SPECULAR);

include/assimp/config.h.in

@@ -1065,6 +1065,17 @@ enum aiComponent
  */
 #define AI_CONFIG_EXPORT_POINT_CLOUDS "EXPORT_POINT_CLOUDS"
 
+/** @brief Specifies whether to use the deprecated KHR_materials_pbrSpecularGlossiness extension
+ * 
+ * When this flag is undefined any material with specularity will use the new KHR_materials_specular
+ * extension. Enabling this flag will revert to the deprecated extension. Note that exporting
+ * KHR_materials_pbrSpecularGlossiness with extensions other than KHR_materials_unlit is unsupported,
+ * including the basic pbrMetallicRoughness spec.
+ *
+ * Property type: Bool. Default value: false.
+ */
+#define AI_CONFIG_USE_GLTF_PBR_SPECULAR_GLOSSINESS "USE_GLTF_PBR_SPECULAR_GLOSSINESS"
+
 /**
  * @brief Specifies the blob name, assimp uses for exporting.
  * 

include/assimp/material.h

@@ -1000,7 +1000,6 @@ extern "C" {
 // Specular Color.
 // Note: Metallic/Roughness may also have a Specular Color
 // AI_MATKEY_COLOR_SPECULAR
-#define AI_MATKEY_USE_GLTF_PBR_SPECULAR_GLOSSINESS "$mat.useGltfPbrSpecularGlossiness", 0, 0
 #define AI_MATKEY_SPECULAR_FACTOR "$mat.specularFactor", 0, 0
 // Glossiness factor. 0.0 = Completely Rough, 1.0 = Perfectly Smooth
 #define AI_MATKEY_GLOSSINESS_FACTOR "$mat.glossinessFactor", 0, 0

test/unit/utglTF2ImportExport.cpp

@@ -220,7 +220,9 @@ TEST_F(utglTF2ImportExport, importglTF2AndExport_KHR_materials_pbrSpecularGlossi
             aiProcess_ValidateDataStructure);
     EXPECT_NE(nullptr, scene);
     // Export
-    EXPECT_EQ(aiReturn_SUCCESS, exporter.Export(scene, "glb2", ASSIMP_TEST_MODELS_DIR "/glTF2/BoxTextured-glTF-pbrSpecularGlossiness/BoxTextured_out.glb"));
+    ExportProperties props;
+    props.SetPropertyBool(, true);
+    EXPECT_EQ(aiReturn_SUCCESS, exporter.Export(scene, "glb2", ASSIMP_TEST_MODELS_DIR "/glTF2/BoxTextured-glTF-pbrSpecularGlossiness/BoxTextured_out.glb", 0, &props));
 
     // And re-import
     EXPECT_TRUE(importerMatTest(ASSIMP_TEST_MODELS_DIR "/glTF2/BoxTextured-glTF-pbrSpecularGlossiness/BoxTextured_out.glb", true));