Merge branch 'master' into vs_gitignore_update

Build.md

@@ -1,6 +1,6 @@
-# Build Instructions
+# Build / Install Instructions
 
-## Build on all platforms using vcpkg
+## Install on all platforms using vcpkg
 You can download and install assimp using the [vcpkg](https://github.com/Microsoft/vcpkg/) dependency manager:
 ```bash
     git clone https://github.com/Microsoft/vcpkg.git
@@ -11,6 +11,18 @@ You can download and install assimp using the [vcpkg](https://github.com/Microso
 ```
 The assimp port in vcpkg is kept up to date by Microsoft team members and community contributors. If the version is out of date, please [create an issue or pull request](https://github.com/Microsoft/vcpkg) on the vcpkg repository.
 
+## Install on Ubuntu
+You can install the Asset-Importer-Lib via apt:
+```
+sudo apt-get install assimp
+```
+
+## Install pyassimp
+You need to have pip installed:
+```
+pip install pyassimp
+```
+
 ## Manual build instructions
 
 ### Install CMake
@@ -24,6 +36,12 @@ Make sure you have a working git-installation. Open a command prompt and clone t
 ```bash
 git clone https://github.com/assimp/assimp.git
 ```
+### Build from source:
+```bash
+cd assimp
+cmake CMakeLists.txt 
+cmake --build .
+```
 
 ### Build instructions for Windows with Visual-Studio
 

CMakeLists.txt

@@ -61,7 +61,6 @@ OPTION( BUILD_SHARED_LIBS
   "Build package with shared libraries."
   ON
 )
-
 OPTION( ASSIMP_BUILD_FRAMEWORK
   "Build package as Mac OS X Framework bundle."
   OFF
@@ -133,9 +132,22 @@ OPTION ( ASSIMP_IGNORE_GIT_HASH
 )
 
 IF ( WIN32 )
-    OPTION ( ASSIMP_BUILD_ASSIMP_VIEW
+  # Use subset of Windows.h
-      "If the Assimp view tool is built. (requires DirectX)"
+  ADD_DEFINITIONS( -DWIN32_LEAN_AND_MEAN )
-      OFF )
+
+  OPTION ( ASSIMP_BUILD_ASSIMP_VIEW
+    "If the Assimp view tool is built. (requires DirectX)"
+    OFF )
+
+  IF(MSVC)
+    OPTION( ASSIMP_INSTALL_PDB
+      "Install MSVC debug files."
+      ON )
+    IF(NOT (MSVC_VERSION LESS 1900))
+      # Multibyte character set is deprecated since at least MSVC2015 (possibly earlier)
+      ADD_DEFINITIONS( -DUNICODE -D_UNICODE )
+    ENDIF()
+  ENDIF()
 ENDIF()
 
 IF (IOS AND NOT ASSIMP_HUNTER_ENABLED)
@@ -145,21 +157,6 @@ IF (IOS AND NOT ASSIMP_HUNTER_ENABLED)
   ADD_DEFINITIONS(-DENABLE_BITCODE)
 ENDIF ()
 
-# Use subset of Windows.h
-if (WIN32)
-  ADD_DEFINITIONS( -DWIN32_LEAN_AND_MEAN )
-endif()
-
-IF(MSVC)
-  OPTION( ASSIMP_INSTALL_PDB
-    "Install MSVC debug files."
-    ON
-  )
-  IF(NOT (MSVC_VERSION LESS 1900))
-    # Multibyte character set is deprecated since at least MSVC2015 (possibly earlier)
-    ADD_DEFINITIONS( -DUNICODE -D_UNICODE )
-  ENDIF()
-ENDIF()
 
 IF (ASSIMP_BUILD_FRAMEWORK)
   SET (BUILD_SHARED_LIBS ON)

code/AssetLib/STL/STLExporter.cpp

@@ -147,7 +147,7 @@ STLExporter::STLExporter(const char* _filename, const aiScene* pScene, bool expo
         for(unsigned int i = 0; i < pScene->mNumMeshes; ++i) {
             WriteMesh(pScene->mMeshes[ i ]);
         }
-        mOutput << EndSolidToken << name << endl;
+        mOutput << EndSolidToken << " " << name << endl;
     }
 }
 

code/AssetLib/glTF2/glTF2Importer.cpp

@@ -383,6 +383,22 @@ static inline bool CheckValidFacesIndices(aiFace *faces, unsigned nFaces, unsign
 }
 #endif // ASSIMP_BUILD_DEBUG
 
+template<typename T>
+aiColor4D* GetVertexColorsForType(glTF2::Ref<glTF2::Accessor> input) {
+    float max = std::numeric_limits<T>::max();
+    aiColor4t<T>* colors;
+    input->ExtractData(colors);
+    auto output = new aiColor4D[input->count];
+    for (size_t i = 0; i < input->count; i++) {
+        output[i] = aiColor4D(
+            colors[i].r / max, colors[i].g / max,
+            colors[i].b / max, colors[i].a / max
+        );
+    }
+    delete[] colors;
+    return output;
+}
+
 void glTF2Importer::ImportMeshes(glTF2::Asset &r) {
     ASSIMP_LOG_DEBUG_F("Importing ", r.meshes.Size(), " meshes");
     std::vector<std::unique_ptr<aiMesh>> meshes;
@@ -463,7 +479,17 @@ void glTF2Importer::ImportMeshes(glTF2::Asset &r) {
                                                "\" does not match the vertex count");
                     continue;
                 }
-                attr.color[c]->ExtractData(aim->mColors[c]);
+                
+                auto componentType = attr.color[c]->componentType;
+                if (componentType == glTF2::ComponentType_FLOAT) {
+                    attr.color[c]->ExtractData(aim->mColors[c]);
+                } else {
+                    if (componentType == glTF2::ComponentType_UNSIGNED_BYTE) {
+                        aim->mColors[c] = GetVertexColorsForType<unsigned char>(attr.color[c]);
+                    } else if (componentType == glTF2::ComponentType_UNSIGNED_SHORT) {
+                        aim->mColors[c] = GetVertexColorsForType<unsigned short>(attr.color[c]);
+                    }
+                }
             }
             for (size_t tc = 0; tc < attr.texcoord.size() && tc < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++tc) {
                 if (!attr.texcoord[tc]) {

code/CMakeLists.txt

@@ -665,6 +665,10 @@ if (NOT ASSIMP_NO_EXPORT)
     AssetLib/3MF/D3MFExporter.h
     AssetLib/3MF/D3MFExporter.cpp)
 
+  ADD_ASSIMP_EXPORTER( PBRT
+    Pbrt/PbrtExporter.h
+    Pbrt/PbrtExporter.cpp)
+
   ADD_ASSIMP_EXPORTER( ASSJSON
     AssetLib/Assjson/cencode.c
     AssetLib/Assjson/cencode.h

code/Common/Exporter.cpp

@@ -138,6 +138,9 @@ void ExportSceneM3DA(const char*, IOSystem*, const aiScene*, const ExportPropert
 #ifndef ASSIMP_BUILD_NO_ASSJSON_EXPORTER
 void ExportAssimp2Json(const char* , IOSystem*, const aiScene* , const Assimp::ExportProperties*);
 #endif
+#ifndef ASSIMP_BUILD_NO_PBRT_EXPORTER
+void ExportScenePbrt(const char*, IOSystem*, const aiScene*, const ExportProperties*);
+#endif
 
 static void setupExporterArray(std::vector<Exporter::ExportFormatEntry> &exporters) {
 	(void)exporters;
@@ -221,6 +224,10 @@ static void setupExporterArray(std::vector<Exporter::ExportFormatEntry> &exporte
 	exporters.push_back(Exporter::ExportFormatEntry("3mf", "The 3MF-File-Format", "3mf", &ExportScene3MF, 0));
 #endif
 
+#ifndef ASSIMP_BUILD_NO_PBRT_EXPORTER
+	exporters.push_back(Exporter::ExportFormatEntry("pbrt", "pbrt-v4 scene description file", "pbrt", &ExportScenePbrt, aiProcess_Triangulate | aiProcess_SortByPType));
+#endif
+
 #ifndef ASSIMP_BUILD_NO_ASSJSON_EXPORTER
 	exporters.push_back(Exporter::ExportFormatEntry("assjson", "Assimp JSON Document", "json", &ExportAssimp2Json, 0));
 #endif

code/Pbrt/PbrtExporter.cpp

@@ -0,0 +1,949 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2020, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+copyright notice, this list of conditions and the
+following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the
+following disclaimer in the documentation and/or other
+materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+contributors may be used to endorse or promote products
+derived from this software without specific prior
+written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/* TODO:
+
+Material improvements:
+- don't export embedded textures that we're not going to use
+- diffuse roughness
+- what is with the uv mapping, uv transform not coming through??
+- metal? glass? mirror?  detect these better?
+  - eta/k from RGB?
+- emissive textures: warn at least
+
+Other:
+- use aiProcess_GenUVCoords if needed to handle spherical/planar uv mapping?
+- don't build up a big string in memory but write directly to a file
+- aiProcess_Triangulate meshes to get triangles only?
+- animation (allow specifying a time)
+
+ */
+
+#ifndef ASSIMP_BUILD_NO_EXPORT
+#ifndef ASSIMP_BUILD_NO_PBRT_EXPORTER
+
+#include "PbrtExporter.h"
+
+#include <assimp/version.h>
+#include <assimp/DefaultIOSystem.h>
+#include <assimp/IOSystem.hpp>
+#include <assimp/Exporter.hpp>
+#include <assimp/DefaultLogger.hpp>
+#include <assimp/StreamWriter.h>
+#include <assimp/Exceptional.h>
+#include <assimp/material.h>
+#include <assimp/scene.h>
+#include <assimp/mesh.h>
+
+#include <algorithm>
+#include <cctype>
+#include <cmath>
+#include <fstream>
+#include <functional>
+#include <iostream>
+#include <memory>
+#include <sstream>
+#include <string>
+
+#define STB_IMAGE_IMPLEMENTATION
+#include "stb_image.h"
+
+using namespace Assimp;
+
+namespace Assimp {
+
+void ExportScenePbrt (
+    const char* pFile,
+    IOSystem* pIOSystem,
+    const aiScene* pScene,
+    const ExportProperties* /*pProperties*/
+){
+    std::string path = DefaultIOSystem::absolutePath(std::string(pFile));
+    std::string file = DefaultIOSystem::completeBaseName(std::string(pFile));
+
+    // initialize the exporter
+    PbrtExporter exporter(pScene, pIOSystem, path, file);
+}
+
+} // end of namespace Assimp
+
+// Constructor
+PbrtExporter::PbrtExporter (
+    const aiScene* pScene, IOSystem* pIOSystem,
+    const std::string path, const std::string file)
+: mScene(pScene),
+  mIOSystem(pIOSystem),
+  mPath(path),
+  mFile(file)
+{
+    // Export embedded textures.
+    if (mScene->mNumTextures > 0)
+        if (!mIOSystem->CreateDirectory("textures"))
+            throw DeadlyExportError("Could not create textures/ directory.");
+    for (unsigned int i = 0; i < mScene->mNumTextures; ++i) {
+        aiTexture* tex = mScene->mTextures[i];
+        std::string fn = CleanTextureFilename(tex->mFilename, false);
+        std::cerr << "Writing embedded texture: " << tex->mFilename.C_Str() << " -> "
+                  << fn << "\n";
+
+        std::unique_ptr<IOStream> outfile(mIOSystem->Open(fn, "wb"));
+        if (!outfile) {
+            throw DeadlyExportError("could not open output texture file: " + fn);
+        }
+        if (tex->mHeight == 0) {
+            // It's binary data
+            outfile->Write(tex->pcData, tex->mWidth, 1);
+        } else {
+            std::cerr << fn << ": TODO handle uncompressed embedded textures.\n";
+        }
+    }
+
+#if 0
+    // Debugging: print the full node hierarchy
+    std::function<void(aiNode*, int)> visitNode;
+    visitNode = [&](aiNode* node, int depth) {
+        for (int i = 0; i < depth; ++i) std::cerr << "    ";
+        std::cerr << node->mName.C_Str() << "\n";
+        for (int i = 0; i < node->mNumChildren; ++i)
+            visitNode(node->mChildren[i], depth + 1);
+    };
+    visitNode(mScene->mRootNode, 0);
+#endif
+
+    mOutput.precision(ASSIMP_AI_REAL_TEXT_PRECISION);
+
+    // Write everything out
+    WriteMetaData();
+    WriteCameras();
+    WriteWorldDefinition();
+
+    // And write the file to disk...
+    std::unique_ptr<IOStream> outfile(mIOSystem->Open(mPath,"wt"));
+    if (!outfile) {
+        throw DeadlyExportError("could not open output .pbrt file: " + std::string(mFile));
+    }
+    outfile->Write(mOutput.str().c_str(), mOutput.str().length(), 1);
+}
+
+// Destructor
+PbrtExporter::~PbrtExporter() {
+    // Empty
+}
+
+void PbrtExporter::WriteMetaData() {
+    mOutput << "#############################\n";
+    mOutput << "# Scene metadata:\n";
+
+    aiMetadata* pMetaData = mScene->mMetaData;
+    for (unsigned int i = 0; i < pMetaData->mNumProperties; i++) {
+        mOutput << "# - ";
+        mOutput << pMetaData->mKeys[i].C_Str() << " :";
+        switch(pMetaData->mValues[i].mType) {
+            case AI_BOOL : {
+                mOutput << " ";
+                if (*static_cast<bool*>(pMetaData->mValues[i].mData))
+                    mOutput << "TRUE\n";
+                else
+                    mOutput << "FALSE\n";
+                break;
+            }
+            case AI_INT32 : {
+                mOutput << " " <<
+                    *static_cast<int32_t*>(pMetaData->mValues[i].mData) <<
+                    std::endl;
+                break;
+            }
+            case AI_UINT64 :
+                mOutput << " " <<
+                    *static_cast<uint64_t*>(pMetaData->mValues[i].mData) <<
+                    std::endl;
+                break;
+            case AI_FLOAT :
+                mOutput << " " <<
+                    *static_cast<float*>(pMetaData->mValues[i].mData) <<
+                    std::endl;
+                break;
+            case AI_DOUBLE :
+                mOutput << " " <<
+                    *static_cast<double*>(pMetaData->mValues[i].mData) <<
+                    std::endl;
+                break;
+            case AI_AISTRING : {
+                aiString* value =
+                    static_cast<aiString*>(pMetaData->mValues[i].mData);
+                std::string svalue = value->C_Str();
+                std::size_t found = svalue.find_first_of("\n");
+                mOutput << "\n";
+                while (found != std::string::npos) {
+                    mOutput << "#     " << svalue.substr(0, found) << "\n";
+                    svalue = svalue.substr(found + 1);
+                    found = svalue.find_first_of("\n");
+                }
+                mOutput << "#     " << svalue << "\n";
+                break;
+            }
+            case AI_AIVECTOR3D :
+                // TODO
+                mOutput << " Vector3D (unable to print)\n";
+                break;
+            default:
+                // AI_META_MAX and FORCE_32BIT
+                mOutput << " META_MAX or FORCE_32Bit (unable to print)\n";
+                break;
+        }
+    }
+}
+
+void PbrtExporter::WriteCameras() {
+    mOutput << "\n";
+    mOutput << "###############################\n";
+    mOutput << "# Cameras (" << mScene->mNumCameras << ") total\n\n";
+
+    if (mScene->mNumCameras == 0) {
+        std::cerr << "Warning: No cameras found in scene file.\n";
+        return;
+    }
+
+    if (mScene->mNumCameras > 1) {
+        std::cerr << "Multiple cameras found in scene file; defaulting to first one specified.\n";
+    }
+
+    for (unsigned int i = 0; i < mScene->mNumCameras; i++) {
+        WriteCamera(i);
+    }
+}
+
+aiMatrix4x4 PbrtExporter::GetNodeTransform(const aiString &name) const {
+    aiMatrix4x4 m;
+    auto node = mScene->mRootNode->FindNode(name);
+    if (!node) {
+        std::cerr << '"' << name.C_Str() << "\": node not found in scene tree.\n";
+        throw DeadlyExportError("Could not find node");
+    }
+    else {
+        while (node) {
+            m = node->mTransformation * m;
+            node = node->mParent;
+        }
+    }
+    return m;
+}
+
+std::string PbrtExporter::TransformAsString(const aiMatrix4x4 &m) {
+    // Transpose on the way out to match pbrt's expected layout (sanity
+    // check: the translation component should be the last 3 entries
+    // before a '1' as the final entry in the matrix, assuming it's
+    // non-projective.)
+    std::stringstream s;
+    s << m.a1 << " " << m.b1 << " " << m.c1 << " " << m.d1 << " "
+      << m.a2 << " " << m.b2 << " " << m.c2 << " " << m.d2 << " "
+      << m.a3 << " " << m.b3 << " " << m.c3 << " " << m.d3 << " "
+      << m.a4 << " " << m.b4 << " " << m.c4 << " " << m.d4;
+    return s.str();
+}
+
+void PbrtExporter::WriteCamera(int i) {
+    auto camera = mScene->mCameras[i];
+    bool cameraActive = i == 0;
+
+    mOutput << "# - Camera " << i+1 <<  ": "
+        << camera->mName.C_Str() << "\n";
+
+    // Get camera aspect ratio
+    float aspect = camera->mAspect;
+    if (aspect == 0) {
+        aspect = 4.f/3.f;
+        mOutput << "#   - Aspect ratio : 1.33333 (no aspect found, defaulting to 4/3)\n";
+    } else {
+        mOutput << "#   - Aspect ratio : " << aspect << "\n";
+    }
+
+    // Get Film xres and yres
+    int xres = 1920;
+    int yres = (int)round(xres/aspect);
+
+    // Print Film for this camera
+    if (!cameraActive)
+        mOutput << "# ";
+    mOutput << "Film \"rgb\" \"string filename\" \"" << mFile << ".exr\"\n";
+    if (!cameraActive)
+        mOutput << "# ";
+    mOutput << "    \"integer xresolution\" [" << xres << "]\n";
+    if (!cameraActive)
+        mOutput << "# ";
+    mOutput << "    \"integer yresolution\" [" << yres << "]\n";
+
+    // Get camera fov
+    float hfov = AI_RAD_TO_DEG(camera->mHorizontalFOV);
+    float fov = (aspect >= 1.0) ? hfov : (hfov * aspect);
+    if (fov < 5) {
+        std::cerr << fov << ": suspiciously low field of view specified by camera. Setting to 45 degrees.\n";
+        fov = 45;
+    }
+
+    // Get camera transform
+    aiMatrix4x4 worldFromCamera = GetNodeTransform(camera->mName);
+
+    // Print Camera LookAt
+    auto position = worldFromCamera * camera->mPosition;
+    auto lookAt = worldFromCamera * (camera->mPosition + camera->mLookAt);
+    aiMatrix3x3 worldFromCamera3(worldFromCamera);
+    auto up = worldFromCamera3 * camera->mUp;
+    up.Normalize();
+
+    if (!cameraActive)
+        mOutput << "# ";
+    mOutput << "Scale -1 1 1\n";  // right handed -> left handed
+    if (!cameraActive)
+        mOutput << "# ";
+    mOutput << "LookAt "
+        << position.x << " " << position.y << " " << position.z << "\n";
+    if (!cameraActive)
+        mOutput << "# ";
+    mOutput << "       "
+        << lookAt.x << " " << lookAt.y << " " << lookAt.z << "\n";
+    if (!cameraActive)
+        mOutput << "# ";
+    mOutput << "       "
+        << up.x << " " << up.y << " " << up.z << "\n";
+
+    // Print camera descriptor
+    if (!cameraActive)
+        mOutput << "# ";
+    mOutput << "Camera \"perspective\" \"float fov\" " << "[" << fov << "]\n\n";
+}
+
+void PbrtExporter::WriteWorldDefinition() {
+    // Figure out which meshes are referenced multiple times; those will be
+    // emitted as object instances and the rest will be emitted directly.
+    std::map<int, int> meshUses;
+    std::function<void(aiNode*)> visitNode;
+    visitNode = [&](aiNode* node) {
+        for (unsigned int i = 0; i < node->mNumMeshes; ++i)
+            ++meshUses[node->mMeshes[i]];
+        for (unsigned int i = 0; i < node->mNumChildren; ++i)
+            visitNode(node->mChildren[i]);
+    };
+    visitNode(mScene->mRootNode);
+    int nInstanced = 0, nUnused = 0;
+    for (const auto &u : meshUses) {
+        if (u.second == 0) ++nUnused;
+        else if (u.second > 1) ++nInstanced;
+    }
+    std::cerr << nInstanced << " / " << mScene->mNumMeshes << " meshes instanced.\n";
+    if (nUnused)
+        std::cerr << nUnused << " meshes defined but not used in scene.\n";
+
+    mOutput << "WorldBegin\n";
+
+    WriteLights();
+    WriteTextures();
+    WriteMaterials();
+
+    // Object instance definitions
+    mOutput << "# Object instance definitions\n\n";
+    for (const auto &mu : meshUses) {
+        if (mu.second > 1) {
+            WriteInstanceDefinition(mu.first);
+        }
+    }
+
+    mOutput << "# Geometry\n\n";
+    aiMatrix4x4 worldFromObject;
+    WriteGeometricObjects(mScene->mRootNode, worldFromObject, meshUses);
+}
+
+void PbrtExporter::WriteTextures() {
+    mOutput << "###################\n";
+    mOutput << "# Textures\n\n";
+
+    C_STRUCT aiString path;
+    aiTextureMapping mapping;
+    unsigned int uvIndex;
+    ai_real blend;
+    aiTextureOp op;
+    aiTextureMapMode mapMode[3];
+
+    // For every material in the scene,
+    for (unsigned int m = 0 ; m < mScene->mNumMaterials; m++) {
+        auto material = mScene->mMaterials[m];
+        // Parse through all texture types,
+        for (int tt = 1; tt <= aiTextureType_UNKNOWN; tt++) {
+            int ttCount = material->GetTextureCount(aiTextureType(tt));
+            // ... and get every texture
+            for (int t = 0; t < ttCount; t++) {
+                // TODO write out texture specifics
+                // TODO UV transforms may be material specific
+                //        so those may need to be baked into unique tex name
+                if (material->GetTexture(aiTextureType(tt), t, &path, &mapping,
+                                         &uvIndex, &blend, &op, mapMode) != AI_SUCCESS) {
+                    std::cerr << "Error getting texture! " << m << " " << tt << " " << t << "\n";
+                    continue;
+                }
+
+                std::string filename = CleanTextureFilename(path);
+
+                if (uvIndex != 0)
+                    std::cerr << "Warning: texture \"" << filename << "\" uses uv set #" <<
+                        uvIndex << " but the pbrt converter only exports uv set 0.\n";
+#if 0
+                if (op != aiTextureOp_Multiply)
+                    std::cerr << "Warning: unexpected texture op " << (int)op <<
+                        " encountered for texture \"" <<
+                        filename << "\". The resulting scene may have issues...\n";
+                if (blend != 1)
+                    std::cerr << "Blend value of " << blend << " found for texture \"" << filename
+                              << "\" but not handled in converter.\n";
+#endif
+
+                std::string mappingString;
+#if 0
+                if (mapMode[0] != mapMode[1])
+                    std::cerr << "Different texture boundary mode for u and v for texture \"" <<
+                        filename << "\". Using u for both.\n";
+                switch (mapMode[0]) {
+                case aiTextureMapMode_Wrap:
+                    // pbrt's default
+                    break;
+                case aiTextureMapMode_Clamp:
+                    mappingString = "\"string wrap\" \"clamp\"";
+                    break;
+                case aiTextureMapMode_Decal:
+                    std::cerr << "Decal texture boundary mode not supported by pbrt for texture \"" <<
+                        filename << "\"\n";
+                    break;
+                case aiTextureMapMode_Mirror:
+                    std::cerr << "Mirror texture boundary mode not supported by pbrt for texture \"" <<
+                        filename << "\"\n";
+                    break;
+                default:
+                    std::cerr << "Unexpected map mode " << (int)mapMode[0] << " for texture \"" <<
+                        filename << "\"\n";
+                    //throw DeadlyExportError("Unexpected aiTextureMapMode");
+                }
+#endif
+
+#if 0
+                aiUVTransform uvTransform;
+                if (material->Get(AI_MATKEY_TEXTURE(tt, t), uvTransform) == AI_SUCCESS) {
+                    mOutput << "# UV transform " << uvTransform.mTranslation.x << " "
+                            << uvTransform.mTranslation.y << " " << uvTransform.mScaling.x << " "
+                            << uvTransform.mScaling.y << " " << uvTransform.mRotation << "\n";
+                }
+#endif
+
+                std::string texName, texType, texOptions;
+                if (aiTextureType(tt) == aiTextureType_SHININESS ||
+                    aiTextureType(tt) == aiTextureType_OPACITY ||
+                    aiTextureType(tt) == aiTextureType_HEIGHT ||
+                    aiTextureType(tt) == aiTextureType_DISPLACEMENT ||
+                    aiTextureType(tt) == aiTextureType_METALNESS ||
+                    aiTextureType(tt) == aiTextureType_DIFFUSE_ROUGHNESS) {
+                    texType = "float";
+                    texName = std::string("float:") + RemoveSuffix(filename);
+
+                    if (aiTextureType(tt) == aiTextureType_SHININESS) {
+                        texOptions = "    \"bool invert\" true\n";
+                        texName += "_Roughness";
+                    }
+                } else if (aiTextureType(tt) == aiTextureType_DIFFUSE ||
+                           aiTextureType(tt) == aiTextureType_BASE_COLOR) {
+                    texType = "spectrum";
+                    texName = std::string("rgb:") + RemoveSuffix(filename);
+                }
+
+                // Don't export textures we're not actually going to use...
+                if (texName.empty())
+                    continue;
+
+                if (mTextureSet.find(texName) == mTextureSet.end()) {
+                    mOutput << "Texture \"" << texName << "\" \"" << texType << "\" \"imagemap\"\n"
+                            << texOptions
+                            << "    \"string filename\" \"" << filename << "\" " << mappingString << '\n';
+                    mTextureSet.insert(texName);
+                }
+
+                // Also emit a float version for use with alpha testing...
+                if ((aiTextureType(tt) == aiTextureType_DIFFUSE ||
+                     aiTextureType(tt) == aiTextureType_BASE_COLOR) &&
+                    TextureHasAlphaMask(filename)) {
+                    texType = "float";
+                    texName = std::string("alpha:") + filename;
+                    if (mTextureSet.find(texName) == mTextureSet.end()) {
+                        mOutput << "Texture \"" << texName << "\" \"" << texType << "\" \"imagemap\"\n"
+                                << "    \"string filename\" \"" << filename << "\" " << mappingString << '\n';
+                        mTextureSet.insert(texName);
+                    }
+                }
+            }
+        }
+    }
+}
+
+bool PbrtExporter::TextureHasAlphaMask(const std::string &filename) {
+    // TODO: STBIDEF int      stbi_info               (char const *filename,     int *x, int *y, int *comp);
+    // quick return if it's 3
+
+    int xSize, ySize, nComponents;
+    unsigned char *data = stbi_load(filename.c_str(), &xSize, &ySize, &nComponents, 0);
+    if (!data) {
+        std::cerr << filename << ": unable to load texture and check for alpha mask in texture. "
+        "Geometry will not be alpha masked with this texture.\n";
+        return false;
+    }
+
+    bool hasMask = false;
+    switch (nComponents) {
+    case 1:
+        for (int i = 0; i < xSize * ySize; ++i)
+            if (data[i] != 255) {
+                hasMask = true;
+                break;
+            }
+        break;
+    case 2:
+          for (int y = 0; y < ySize; ++y)
+              for (int x = 0; x < xSize; ++x)
+                  if (data[2 * (x + y * xSize) + 1] != 255) {
+                      hasMask = true;
+                      break;
+                  }
+        break;
+    case 3:
+        break;
+    case 4:
+          for (int y = 0; y < ySize; ++y)
+              for (int x = 0; x < xSize; ++x)
+                  if (data[4 * (x + y * xSize) + 3] != 255) {
+                      hasMask = true;
+                      break;
+                  }
+          break;
+    default:
+        std::cerr << filename << ": unexpected number of image channels, " <<
+            nComponents << ".\n";
+    }
+
+    stbi_image_free(data);
+    return hasMask;
+}
+
+void PbrtExporter::WriteMaterials() {
+    mOutput << "\n";
+    mOutput << "####################\n";
+    mOutput << "# Materials (" << mScene->mNumMaterials << ") total\n\n";
+
+    for (unsigned int i = 0; i < mScene->mNumMaterials; i++) {
+        WriteMaterial(i);
+    }
+    mOutput << "\n\n";
+}
+
+void PbrtExporter::WriteMaterial(int m) {
+    aiMaterial* material = mScene->mMaterials[m];
+
+    // get material name
+    auto materialName = material->GetName();
+    mOutput << std::endl << "# - Material " << m+1 <<  ": " << materialName.C_Str() << "\n";
+
+    // Print out number of properties
+    mOutput << "#   - Number of Material Properties: " << material->mNumProperties << "\n";
+
+    // Print out texture type counts
+    mOutput << "#   - Non-Zero Texture Type Counts: ";
+    for (int i = 1; i <= aiTextureType_UNKNOWN; i++) {
+        int count = material->GetTextureCount(aiTextureType(i));
+        if (count > 0)
+            mOutput << TextureTypeToString(aiTextureType(i)) << ": " <<  count << " ";
+    }
+    mOutput << "\n";
+
+    auto White = [](aiColor3D c) { return c.r == 1 && c.g == 1 && c.b == 1; };
+    auto Black = [](aiColor3D c) { return c.r == 0 && c.g == 0 && c.b == 0; };
+
+    aiColor3D diffuse, specular, transparency;
+    bool constantDiffuse = (material->Get(AI_MATKEY_COLOR_DIFFUSE, diffuse) == AI_SUCCESS &&
+                            !White(diffuse));
+    bool constantSpecular = (material->Get(AI_MATKEY_COLOR_SPECULAR, specular) == AI_SUCCESS &&
+                             !White(specular));
+    bool constantTransparency = (material->Get(AI_MATKEY_COLOR_TRANSPARENT, transparency) == AI_SUCCESS &&
+                                 !Black(transparency));
+
+    float opacity, shininess, shininessStrength, eta;
+    bool constantOpacity = (material->Get(AI_MATKEY_OPACITY, opacity) == AI_SUCCESS &&
+                            opacity != 0);
+    bool constantShininess = material->Get(AI_MATKEY_SHININESS, shininess) == AI_SUCCESS;
+    bool constantShininessStrength = material->Get(AI_MATKEY_SHININESS_STRENGTH, shininessStrength) == AI_SUCCESS;
+    bool constantEta = (material->Get(AI_MATKEY_REFRACTI, eta) == AI_SUCCESS &&
+                        eta != 1);
+
+    mOutput << "#    - Constants: diffuse " << constantDiffuse << " specular " << constantSpecular <<
+        " transprency " << constantTransparency << " opacity " << constantOpacity <<
+        " shininess " << constantShininess << " shininess strength " << constantShininessStrength <<
+        " eta " << constantEta << "\n";
+
+    aiString roughnessMap;
+    if (material->Get(AI_MATKEY_TEXTURE_SHININESS(0), roughnessMap) == AI_SUCCESS) {
+        std::string roughnessTexture = std::string("float:") +
+            RemoveSuffix(CleanTextureFilename(roughnessMap)) + "_Roughness";
+        mOutput << "MakeNamedMaterial \"" << materialName.C_Str() << "\""
+                << " \"string type\" \"coateddiffuse\"\n"
+                << "    \"texture roughness\" \"" << roughnessTexture << "\"\n";
+    } else if (constantShininess) {
+        // Assume plastic for now at least
+        float roughness = std::max(0.f, 1.f - shininess);
+        mOutput << "MakeNamedMaterial \"" << materialName.C_Str() << "\""
+                << " \"string type\" \"coateddiffuse\"\n"
+                << "    \"float roughness\" " << roughness << "\n";
+    } else
+        // Diffuse
+        mOutput << "MakeNamedMaterial \"" << materialName.C_Str() << "\""
+                << " \"string type\" \"diffuse\"\n";
+
+    aiString diffuseTexture;
+    if (material->Get(AI_MATKEY_TEXTURE_DIFFUSE(0), diffuseTexture) == AI_SUCCESS)
+        mOutput << "    \"texture reflectance\" \"rgb:" << RemoveSuffix(CleanTextureFilename(diffuseTexture)) << "\"\n";
+    else
+        mOutput << "    \"rgb reflectance\" [ " << diffuse.r << " " << diffuse.g <<
+            " " << diffuse.b << " ]\n";
+
+    aiString displacementTexture, normalMap;
+    if (material->Get(AI_MATKEY_TEXTURE_NORMALS(0), displacementTexture) == AI_SUCCESS)
+        mOutput << "    \"string normalmap\" \"" << CleanTextureFilename(displacementTexture) << "\"\n";
+    else if (material->Get(AI_MATKEY_TEXTURE_HEIGHT(0), displacementTexture) == AI_SUCCESS)
+        mOutput << "    \"texture displacement\" \"float:" <<
+            RemoveSuffix(CleanTextureFilename(displacementTexture)) << "\"\n";
+    else if (material->Get(AI_MATKEY_TEXTURE_DISPLACEMENT(0), displacementTexture) == AI_SUCCESS)
+        mOutput << "    \"texture displacement\" \"float:" <<
+            RemoveSuffix(CleanTextureFilename(displacementTexture)) << "\"\n";
+}
+
+std::string PbrtExporter::CleanTextureFilename(const aiString &f, bool rewriteExtension) const {
+    std::string fn = f.C_Str();
+    // Remove directory name
+    size_t offset = fn.find_last_of("/\\");
+    if (offset != std::string::npos) {
+        fn.erase(0, offset + 1);
+    }
+
+    // Expect all textures in textures
+    fn = std::string("textures") + mIOSystem->getOsSeparator() + fn;
+
+    // Rewrite extension for unsupported file formats.
+    if (rewriteExtension) {
+        offset = fn.rfind('.');
+        if (offset != std::string::npos) {
+            std::string extension = fn;
+            extension.erase(0, offset + 1);
+            std::transform(extension.begin(), extension.end(), extension.begin(),
+                           [](unsigned char c) { return (char)std::tolower(c); });
+
+            if (extension != "tga" && extension != "exr" && extension != "png" &&
+                extension != "pfm" && extension != "hdr") {
+                std::string orig = fn;
+                fn.erase(offset + 1);
+                fn += "png";
+
+                // Does it already exist? Warn if not.
+                std::ifstream filestream(fn);
+                if (!filestream.good())
+                    std::cerr << orig << ": must convert this texture to PNG.\n";
+            }
+        }
+    }
+
+    return fn;
+}
+
+std::string PbrtExporter::RemoveSuffix(std::string filename) {
+    size_t offset = filename.rfind('.');
+    if (offset != std::string::npos)
+        filename.erase(offset);
+    return filename;
+}
+
+void PbrtExporter::WriteLights() {
+    mOutput << "\n";
+    mOutput << "#################\n";
+    mOutput << "# Lights\n\n";
+    if (mScene->mNumLights == 0) {
+        // Skip the default light if no cameras and this is flat up geometry
+        if (mScene->mNumCameras > 0) {
+            std::cerr << "No lights specified. Using default infinite light.\n";
+
+            mOutput << "AttributeBegin\n";
+            mOutput << "    # default light\n";
+            mOutput << "    LightSource \"infinite\" \"blackbody L\" [6000 1]\n";
+
+            mOutput << "AttributeEnd\n\n";
+        }
+    } else {
+        for (unsigned int i = 0; i < mScene->mNumLights; ++i) {
+            const aiLight *light = mScene->mLights[i];
+
+            mOutput << "# Light " << light->mName.C_Str() << "\n";
+            mOutput << "AttributeBegin\n";
+
+            aiMatrix4x4 worldFromLight = GetNodeTransform(light->mName);
+            mOutput << "    Transform [ " << TransformAsString(worldFromLight) << " ]\n";
+
+            aiColor3D color = light->mColorDiffuse + light->mColorSpecular;
+            if (light->mAttenuationConstant != 0)
+                color = color * (ai_real)(1. / light->mAttenuationConstant);
+
+            switch (light->mType) {
+            case aiLightSource_DIRECTIONAL: {
+                mOutput << "    LightSource \"distant\"\n";
+                mOutput << "        \"point3 from\" [ " << light->mPosition.x << " " <<
+                    light->mPosition.y << " " << light->mPosition.z << " ]\n";
+                aiVector3D to = light->mPosition + light->mDirection;
+                mOutput << "        \"point3 to\" [ " << to.x << " " << to.y << " " << to.z << " ]\n";
+                mOutput << "        \"rgb L\" [ " << color.r << " " << color.g << " " << color.b << " ]\n";
+                break;
+            } case aiLightSource_POINT:
+                mOutput << "    LightSource \"distant\"\n";
+                mOutput << "        \"point3 from\" [ " << light->mPosition.x << " " <<
+                    light->mPosition.y << " " << light->mPosition.z << " ]\n";
+                mOutput << "        \"rgb L\" [ " << color.r << " " << color.g << " " << color.b << " ]\n";
+                break;
+            case aiLightSource_SPOT: {
+                mOutput << "    LightSource \"spot\"\n";
+                mOutput << "        \"point3 from\" [ " << light->mPosition.x << " " <<
+                    light->mPosition.y << " " << light->mPosition.z << " ]\n";
+                aiVector3D to = light->mPosition + light->mDirection;
+                mOutput << "        \"point3 to\" [ " << to.x << " " << to.y << " " << to.z << " ]\n";
+                mOutput << "        \"rgb L\" [ " << color.r << " " << color.g << " " << color.b << " ]\n";
+                mOutput << "        \"float coneangle\" [ " << AI_RAD_TO_DEG(light->mAngleOuterCone) << " ]\n";
+                mOutput << "        \"float conedeltaangle\" [ " << AI_RAD_TO_DEG(light->mAngleOuterCone -
+                                                                                  light->mAngleInnerCone) << " ]\n";
+                break;
+            } case aiLightSource_AMBIENT:
+                mOutput << "# ignored ambient light source\n";
+                break;
+            case aiLightSource_AREA: {
+                aiVector3D left = light->mDirection ^ light->mUp;
+                // rectangle. center at position, direction is normal vector
+                float dLeft = light->mSize.x / 2, dUp = light->mSize.y / 2;
+                aiVector3D vertices[4] = {
+                     light->mPosition - dLeft * left - dUp * light->mUp,
+                     light->mPosition + dLeft * left - dUp * light->mUp,
+                     light->mPosition - dLeft * left + dUp * light->mUp,
+                     light->mPosition + dLeft * left + dUp * light->mUp };
+                mOutput << "    AreaLightSource \"diffuse\"\n";
+                mOutput << "        \"rgb L\" [ " << color.r << " " << color.g << " " << color.b << " ]\n";
+                mOutput << "    Shape \"bilinearmesh\"\n";
+                mOutput << "        \"point3 p\" [ ";
+                for (int j = 0; j < 4; ++j)
+                    mOutput << vertices[j].x << " " << vertices[j].y << " " << vertices[j].z;
+                mOutput << " ]\n";
+                mOutput << "        \"integer indices\" [ 0 1 2 3 ]\n";
+                break;
+            } default:
+                mOutput << "# ignored undefined light source type\n";
+                break;
+            }
+            mOutput << "AttributeEnd\n\n";
+        }
+    }
+}
+
+void PbrtExporter::WriteMesh(aiMesh* mesh) {
+    mOutput << "# - Mesh: ";
+    if (mesh->mName == aiString(""))
+        mOutput << "<No Name>\n";
+    else
+        mOutput << mesh->mName.C_Str() << "\n";
+
+    mOutput << "AttributeBegin\n";
+    aiMaterial* material = mScene->mMaterials[mesh->mMaterialIndex];
+    mOutput << "    NamedMaterial \"" << material->GetName().C_Str() << "\"\n";
+
+    // Handle area lights
+    aiColor3D emission;
+    if (material->Get(AI_MATKEY_COLOR_EMISSIVE, emission) == AI_SUCCESS &&
+        (emission.r > 0 || emission.g > 0 || emission.b > 0))
+        mOutput << "    AreaLightSource \"diffuse\" \"rgb L\" [ " << emission.r <<
+            " " << emission.g << " " << emission.b << " ]\n";
+
+    // Check if any types other than tri
+    if (   (mesh->mPrimitiveTypes & aiPrimitiveType_POINT)
+        || (mesh->mPrimitiveTypes & aiPrimitiveType_LINE)
+        || (mesh->mPrimitiveTypes & aiPrimitiveType_POLYGON)) {
+        std::cerr << "Error: ignoring point / line / polygon mesh " << mesh->mName.C_Str() << ".\n";
+        return;
+    }
+
+    // Alpha mask
+    std::string alpha;
+    aiString opacityTexture;
+    if (material->Get(AI_MATKEY_TEXTURE_OPACITY(0), opacityTexture) == AI_SUCCESS ||
+        material->Get(AI_MATKEY_TEXTURE_DIFFUSE(0), opacityTexture) == AI_SUCCESS) {
+        // material->Get(AI_MATKEY_TEXTURE_BASE_COLOR(0), opacityTexture) == AI_SUCCESS)
+        std::string texName = std::string("alpha:") + CleanTextureFilename(opacityTexture);
+        if (mTextureSet.find(texName) != mTextureSet.end())
+            alpha = std::string("    \"texture alpha\" \"") + texName + "\"\n";
+    } else {
+        float opacity = 1;
+        if (material->Get(AI_MATKEY_OPACITY, opacity) == AI_SUCCESS && opacity < 1)
+            alpha = std::string("    \"float alpha\" [ ") + std::to_string(opacity) + " ]\n";
+    }
+
+    // Output the shape specification
+    mOutput << "Shape \"trianglemesh\"\n" <<
+        alpha <<
+        "    \"integer indices\" [";
+
+    // Start with faces (which hold indices)
+    for (unsigned int i = 0; i < mesh->mNumFaces; i++) {
+        auto face = mesh->mFaces[i];
+        if (face.mNumIndices != 3) throw DeadlyExportError("oh no not a tri!");
+
+        for (unsigned int j = 0; j < face.mNumIndices; j++) {
+            mOutput << face.mIndices[j] << " ";
+        }
+        if ((i % 7) == 6) mOutput << "\n    ";
+    }
+    mOutput << "]\n";
+
+    // Then go to vertices
+    mOutput << "    \"point3 P\" [";
+    for (unsigned int i = 0; i < mesh->mNumVertices; i++) {
+        auto vector = mesh->mVertices[i];
+        mOutput << vector.x << " " << vector.y << " " << vector.z << "  ";
+        if ((i % 4) == 3) mOutput << "\n    ";
+    }
+    mOutput << "]\n";
+
+    // Normals (if present)
+    if (mesh->mNormals) {
+        mOutput << "    \"normal N\" [";
+        for (unsigned int i = 0; i < mesh->mNumVertices; i++) {
+            auto normal = mesh->mNormals[i];
+            mOutput << normal.x << " " << normal.y << " " << normal.z << "  ";
+            if ((i % 4) == 3) mOutput << "\n    ";
+        }
+        mOutput << "]\n";
+    }
+
+    // Tangents (if present)
+    if (mesh->mTangents) {
+        mOutput << "    \"vector3 S\" [";
+        for (unsigned int i = 0; i < mesh->mNumVertices; i++) {
+            auto tangent = mesh->mTangents[i];
+            mOutput << tangent.x << " " << tangent.y << " " << tangent.z << "  ";
+            if ((i % 4) == 3) mOutput << "\n    ";
+        }
+        mOutput << "]\n";
+    }
+
+    // Texture Coords (if present)
+    // Find the first set of 2D texture coordinates..
+    for (int i = 0; i < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++i) {
+        if (mesh->mNumUVComponents[i] == 2) {
+            // assert(mesh->mTextureCoords[i] != nullptr);
+            aiVector3D* uv = mesh->mTextureCoords[i];
+            mOutput << "    \"point2 uv\" [";
+            for (unsigned int j = 0; j < mesh->mNumVertices; ++j) {
+                mOutput << uv[j].x << " " << uv[j].y << " ";
+                if ((j % 6) == 5) mOutput << "\n    ";
+            }
+            mOutput << "]\n";
+            break;
+        }
+    }
+    // TODO: issue warning if there are additional UV sets?
+
+    mOutput << "AttributeEnd\n";
+}
+
+void PbrtExporter::WriteInstanceDefinition(int i) {
+    aiMesh* mesh = mScene->mMeshes[i];
+
+    mOutput << "ObjectBegin \"";
+    if (mesh->mName == aiString(""))
+        mOutput << "mesh_" << i+1 << "\"\n";
+    else
+        mOutput << mesh->mName.C_Str() << "_" << i+1 << "\"\n";
+
+    WriteMesh(mesh);
+
+    mOutput << "ObjectEnd\n";
+}
+
+void PbrtExporter::WriteGeometricObjects(aiNode* node, aiMatrix4x4 worldFromObject,
+                                         std::map<int, int> &meshUses) {
+    // Sometimes interior nodes have degenerate matrices??
+    if (node->mTransformation.Determinant() != 0)
+        worldFromObject = worldFromObject * node->mTransformation;
+
+    if (node->mNumMeshes > 0) {
+        mOutput << "AttributeBegin\n";
+
+        mOutput << "  Transform [ " << TransformAsString(worldFromObject) << "]\n";
+
+        for (unsigned int i = 0; i < node->mNumMeshes; i++) {
+            aiMesh* mesh = mScene->mMeshes[node->mMeshes[i]];
+            if (meshUses[node->mMeshes[i]] == 1) {
+                // If it's only used once in the scene, emit it directly as
+                // a triangle mesh.
+                mOutput << "  # " << mesh->mName.C_Str();
+                WriteMesh(mesh);
+            } else {
+                // If it's used multiple times, there will be an object
+                // instance for it, so emit a reference to that.
+                mOutput << "  ObjectInstance \"";
+                if (mesh->mName == aiString(""))
+                    mOutput << "mesh_" << node->mMeshes[i] + 1 << "\"\n";
+                else
+                    mOutput << mesh->mName.C_Str() << "_" << node->mMeshes[i] + 1 << "\"\n";
+            }
+        }
+        mOutput << "AttributeEnd\n\n";
+    }
+
+    // Recurse through children
+    for (unsigned int i = 0; i < node->mNumChildren; i++) {
+        WriteGeometricObjects(node->mChildren[i], worldFromObject, meshUses);
+    }
+}
+
+#endif // ASSIMP_BUILD_NO_PBRT_EXPORTER
+#endif // ASSIMP_BUILD_NO_EXPORT

code/Pbrt/PbrtExporter.h

@@ -0,0 +1,135 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2020, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+copyright notice, this list of conditions and the
+following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the
+following disclaimer in the documentation and/or other
+materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+contributors may be used to endorse or promote products
+derived from this software without specific prior
+written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file PbrtExporter.h
+* Declares the exporter class to write a scene to a pbrt file
+*/
+#ifndef AI_PBRTEXPORTER_H_INC
+#define AI_PBRTEXPORTER_H_INC
+
+#ifndef ASSIMP_BUILD_NO_PBRT_EXPORTER
+
+#include <assimp/types.h>
+#include <assimp/StreamWriter.h>
+#include <assimp/Exceptional.h>
+
+#include <map>
+#include <set>
+#include <string>
+#include <sstream>
+
+struct aiScene;
+struct aiNode;
+struct aiMaterial;
+struct aiMesh;
+
+namespace Assimp {
+
+class IOSystem;
+class IOStream;
+class ExportProperties;
+
+// ---------------------------------------------------------------------
+/** Helper class to export a given scene to a Pbrt file. */
+// ---------------------------------------------------------------------
+class PbrtExporter
+{
+public:
+    /// Constructor for a specific scene to export
+    PbrtExporter(const aiScene* pScene, IOSystem* pIOSystem,
+        const std::string path, const std::string file);
+
+    /// Destructor
+    virtual ~PbrtExporter();
+
+private:
+    // the scene to export
+    const aiScene* mScene;
+
+    /// Stringstream to write all output into
+    std::stringstream mOutput;
+
+    /// The IOSystem for output
+    IOSystem* mIOSystem;
+
+    /// Path of the directory where the scene will be exported
+    const std::string mPath;
+
+    /// Name of the file (without extension) where the scene will be exported
+    const std::string mFile;
+
+private:
+    //  A private set to keep track of which textures have been declared
+    std::set<std::string> mTextureSet;
+
+    aiMatrix4x4 GetNodeTransform(const aiString& name) const;
+    static std::string TransformAsString(const aiMatrix4x4& m);
+
+    static std::string RemoveSuffix(std::string filename);
+    std::string CleanTextureFilename(const aiString &f, bool rewriteExtension = true) const;
+
+    void WriteMetaData();
+
+    void WriteWorldDefinition();
+
+    void WriteCameras();
+    void WriteCamera(int i);
+
+    void WriteLights();
+
+    void WriteTextures();
+    static bool TextureHasAlphaMask(const std::string &filename);
+
+    void WriteMaterials();
+    void WriteMaterial(int i);
+
+    void WriteMesh(aiMesh* mesh);
+
+    void WriteInstanceDefinition(int i);
+    void WriteGeometricObjects(aiNode* node, aiMatrix4x4 parentTransform,
+                               std::map<int, int> &meshUses);
+};
+
+} // namespace Assimp
+
+#endif // ASSIMP_BUILD_NO_PBRT_EXPORTER
+
+#endif // AI_PBRTEXPORTER_H_INC