Support PBR properties/maps in Obj importer

code/AssetLib/Obj/ObjFileData.h

@@ -133,6 +133,10 @@ struct Material {
     aiString textureSpecularity;
     aiString textureOpacity;
     aiString textureDisp;
+    aiString textureRoughness;
+    aiString textureMetallic;
+    aiString textureSheen;
+    aiString textureRMA;
 
     enum TextureType {
         TextureDiffuseType = 0,
@@ -151,6 +155,10 @@ struct Material {
         TextureSpecularityType,
         TextureOpacityType,
         TextureDispType,
+        TextureRoughnessType,
+        TextureMetallicType,
+        TextureSheenType,
+        TextureRMAType,
         TextureTypeCount
     };
     bool clamp[TextureTypeCount];
@@ -174,6 +182,19 @@ struct Material {
     //! Transparency color
     aiColor3D transparent;
 
+    //! PBR Roughness
+    ai_real roughness;
+    //! PBR Metallic
+    ai_real metallic;
+    //! PBR Metallic
+    aiColor3D sheen;
+    //! PBR Clearcoat Thickness
+    ai_real clearcoat_thickness;
+    //! PBR Clearcoat Rougness
+    ai_real clearcoat_roughness;
+    //! PBR Anisotropy
+    ai_real anisotropy;
+
     //! Constructor
     Material() :
             diffuse(ai_real(0.6), ai_real(0.6), ai_real(0.6)),
@@ -181,7 +202,13 @@ struct Material {
             shineness(ai_real(0.0)),
             illumination_model(1),
             ior(ai_real(1.0)),
-            transparent(ai_real(1.0), ai_real(1.0), ai_real(1.0)) {
+            transparent(ai_real(1.0), ai_real(1.0), ai_real(1.0)),
+            roughness(ai_real(1.0)),
+            metallic(ai_real(0.0)),
+            sheen(ai_real(1.0), ai_real(1.0), ai_real(1.0)),
+            clearcoat_thickness(ai_real(0.0)),
+            clearcoat_roughness(ai_real(0.0)),
+            anisotropy(ai_real(0.0)) {
         std::fill_n(clamp, static_cast<unsigned int>(TextureTypeCount), false);
     }
 

code/AssetLib/Obj/ObjFileImporter.cpp

@@ -618,6 +618,12 @@ void ObjFileImporter::createMaterials(const ObjFile::Model *pModel, aiScene *pSc
         mat->AddProperty(&pCurrentMaterial->shineness, 1, AI_MATKEY_SHININESS);
         mat->AddProperty(&pCurrentMaterial->alpha, 1, AI_MATKEY_OPACITY);
         mat->AddProperty(&pCurrentMaterial->transparent, 1, AI_MATKEY_COLOR_TRANSPARENT);
+        mat->AddProperty(&pCurrentMaterial->roughness, 1, AI_MATKEY_ROUGHNESS_FACTOR);
+        mat->AddProperty(&pCurrentMaterial->metallic, 1, AI_MATKEY_METALLIC_FACTOR);
+        mat->AddProperty(&pCurrentMaterial->sheen, 1, AI_MATKEY_SHEEN_COLOR_FACTOR);
+        mat->AddProperty(&pCurrentMaterial->clearcoat_thickness, 1, AI_MATKEY_CLEARCOAT_FACTOR);
+        mat->AddProperty(&pCurrentMaterial->clearcoat_roughness, 1, AI_MATKEY_CLEARCOAT_ROUGHNESS_FACTOR);
+        mat->AddProperty(&pCurrentMaterial->anisotropy, 1, AI_MATKEY_ANISOTROPY_FACTOR);
 
         // Adding refraction index
         mat->AddProperty(&pCurrentMaterial->ior, 1, AI_MATKEY_REFRACTI);
@@ -709,6 +715,39 @@ void ObjFileImporter::createMaterials(const ObjFile::Model *pModel, aiScene *pSc
             }
         }
 
+        if (0 != pCurrentMaterial->textureRoughness.length) {
+            mat->AddProperty(&pCurrentMaterial->textureRoughness, _AI_MATKEY_TEXTURE_BASE, aiTextureType_DIFFUSE_ROUGHNESS, 0);
+            mat->AddProperty(&uvwIndex, 1, _AI_MATKEY_UVWSRC_BASE, aiTextureType_DIFFUSE_ROUGHNESS, 0 );
+            if (pCurrentMaterial->clamp[ObjFile::Material::TextureRoughnessType]) {
+                addTextureMappingModeProperty(mat, aiTextureType_DIFFUSE_ROUGHNESS);
+            }
+        }
+
+        if (0 != pCurrentMaterial->textureMetallic.length) {
+            mat->AddProperty(&pCurrentMaterial->textureMetallic, _AI_MATKEY_TEXTURE_BASE, aiTextureType_METALNESS, 0);
+            mat->AddProperty(&uvwIndex, 1, _AI_MATKEY_UVWSRC_BASE, aiTextureType_METALNESS, 0 );
+            if (pCurrentMaterial->clamp[ObjFile::Material::TextureMetallicType]) {
+                addTextureMappingModeProperty(mat, aiTextureType_METALNESS);
+            }
+        }
+
+        if (0 != pCurrentMaterial->textureSheen.length) {
+            mat->AddProperty(&pCurrentMaterial->textureSheen, _AI_MATKEY_TEXTURE_BASE, aiTextureType_SHEEN, 0);
+            mat->AddProperty(&uvwIndex, 1, _AI_MATKEY_UVWSRC_BASE, aiTextureType_SHEEN, 0 );
+            if (pCurrentMaterial->clamp[ObjFile::Material::TextureSheenType]) {
+                addTextureMappingModeProperty(mat, aiTextureType_SHEEN);
+            }
+        }
+
+        if (0 != pCurrentMaterial->textureRMA.length) {
+            // NOTE: glTF importer places Rough/Metal/AO texture in Unknown so doing the same here for consistency.
+            mat->AddProperty(&pCurrentMaterial->textureRMA, _AI_MATKEY_TEXTURE_BASE, aiTextureType_UNKNOWN, 0);
+            mat->AddProperty(&uvwIndex, 1, _AI_MATKEY_UVWSRC_BASE, aiTextureType_UNKNOWN, 0 );
+            if (pCurrentMaterial->clamp[ObjFile::Material::TextureRMAType]) {
+                addTextureMappingModeProperty(mat, aiTextureType_UNKNOWN);
+            }
+        }
+
         // Store material property info in material array in scene
         pScene->mMaterials[pScene->mNumMaterials] = mat;
         pScene->mNumMaterials++;

code/AssetLib/Obj/ObjFileMtlImporter.cpp

@@ -67,6 +67,10 @@ static const std::string ReflectionTexture = "refl";
 static const std::string DisplacementTexture1 = "map_disp";
 static const std::string DisplacementTexture2 = "disp";
 static const std::string SpecularityTexture = "map_ns";
+static const std::string RoughnessTexture = "map_Pr";
+static const std::string MetallicTexture = "map_Pm";
+static const std::string SheenTexture = "map_Ps";
+static const std::string RMATexture = "map_Ps";
 
 // texture option specific token
 static const std::string BlendUOption = "-blendu";
@@ -178,10 +182,45 @@ void ObjFileMtlImporter::load() {
                     case 'e': // New material
                         createMaterial();
                         break;
+                    case 'o': // Norm texture
+                        --m_DataIt;
+                        getTexture();
+                        break;
                 }
                 m_DataIt = skipLine<DataArrayIt>(m_DataIt, m_DataItEnd, m_uiLine);
             } break;
 
+            case 'P':
+                {
+                    ++m_DataIt;
+                    switch(*m_DataIt)
+                    {
+                    case 'r':
+                        ++m_DataIt;
+                        getFloatValue(m_pModel->m_pCurrentMaterial->roughness);
+                        break;
+                    case 'm':
+                        ++m_DataIt;
+                        getFloatValue(m_pModel->m_pCurrentMaterial->metallic);
+                        break;
+                    case 's':
+                        ++m_DataIt;
+                        getColorRGBA(&m_pModel->m_pCurrentMaterial->sheen);
+                        break;
+                    case 'c':
+                        ++m_DataIt;
+                        if (*m_DataIt == 'r') {
+                            ++m_DataIt;
+                            getFloatValue(m_pModel->m_pCurrentMaterial->clearcoat_roughness);
+                        } else {
+                            getFloatValue(m_pModel->m_pCurrentMaterial->clearcoat_thickness);
+                        }
+                        break;
+                    }
+                    m_DataIt = skipLine<DataArrayIt>(m_DataIt, m_DataItEnd, m_uiLine);
+                }
+                break;
+
             case 'm': // Texture
             case 'b': // quick'n'dirty - for 'bump' sections
             case 'r': // quick'n'dirty - for 'refl' sections
@@ -197,6 +236,12 @@ void ObjFileMtlImporter::load() {
                 m_DataIt = skipLine<DataArrayIt>(m_DataIt, m_DataItEnd, m_uiLine);
             } break;
 
+            case 'a': // Anisotropy
+            {
+                getFloatValue(m_pModel->m_pCurrentMaterial->anisotropy);
+                m_DataIt = skipLine<DataArrayIt>(m_DataIt, m_DataItEnd, m_uiLine);
+            } break;
+
             default: {
                 m_DataIt = skipLine<DataArrayIt>(m_DataIt, m_DataItEnd, m_uiLine);
             } break;
@@ -334,6 +379,22 @@ void ObjFileMtlImporter::getTexture() {
         // Specularity scaling (glossiness)
         out = &m_pModel->m_pCurrentMaterial->textureSpecularity;
         clampIndex = ObjFile::Material::TextureSpecularityType;
+    } else if ( !ASSIMP_strincmp( pPtr, RoughnessTexture.c_str(), static_cast<unsigned int>(RoughnessTexture.size()))) {
+        // PBR Roughness texture
+        out = & m_pModel->m_pCurrentMaterial->textureRoughness;
+        clampIndex = ObjFile::Material::TextureRoughnessType;
+    } else if ( !ASSIMP_strincmp( pPtr, MetallicTexture.c_str(), static_cast<unsigned int>(MetallicTexture.size()))) {
+        // PBR Metallic texture
+        out = & m_pModel->m_pCurrentMaterial->textureMetallic;
+        clampIndex = ObjFile::Material::TextureMetallicType;
+    } else if (!ASSIMP_strincmp( pPtr, SheenTexture.c_str(), static_cast<unsigned int>(SheenTexture.size()))) {
+        // PBR Sheen (reflectance) texture
+        out = & m_pModel->m_pCurrentMaterial->textureSheen;
+        clampIndex = ObjFile::Material::TextureSheenType;
+    } else if (!ASSIMP_strincmp( pPtr, RMATexture.c_str(), static_cast<unsigned int>(RMATexture.size()))) {
+        // PBR Rough/Metal/AO texture
+        out = & m_pModel->m_pCurrentMaterial->textureRMA;
+        clampIndex = ObjFile::Material::TextureRMAType;
     } else {
         ASSIMP_LOG_ERROR("OBJ/MTL: Encountered unknown texture type");
         return;

include/assimp/material.h

@@ -989,6 +989,9 @@ extern "C" {
 // Roughness factor. 0.0 = Perfectly Smooth, 1.0 = Completely Rough
 #define AI_MATKEY_ROUGHNESS_FACTOR "$mat.roughnessFactor", 0, 0
 #define AI_MATKEY_ROUGHNESS_TEXTURE aiTextureType_DIFFUSE_ROUGHNESS, 0
+// Anisotropy factor. 0.0 = isotropic, 1.0 = anisotropy along tangent direction,
+// -1.0 = anisotropy along bitangent direction
+#define AI_MATKEY_ANISOTROPY_FACTOR "$mat.anisotropyFactor", 0, 0
 
 // Specular/Glossiness Workflow
 // ---------------------------