From 09962210177be8680c4f859e6a33a775a15908a2 Mon Sep 17 00:00:00 2001
From: Jan Honsbrok <jan.honsbrok@gmail.com>
Date: Wed, 5 Nov 2025 08:24:41 +0100
Subject: [PATCH] fix: write textures to folder of PBRT file (#6099)

* fix: write textures to folder of PBRT file
---
 code/Pbrt/PbrtExporter.cpp | 20 +++++++++++++-------
 code/Pbrt/PbrtExporter.h   |  5 ++++-
 2 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/code/Pbrt/PbrtExporter.cpp b/code/Pbrt/PbrtExporter.cpp
index 07bf1f056..0cc30e668 100644
--- a/code/Pbrt/PbrtExporter.cpp
+++ b/code/Pbrt/PbrtExporter.cpp
@@ -93,17 +93,22 @@ void ExportScenePbrt(const char *pFile, IOSystem *pIOSystem, const aiScene *pSce
         const ExportProperties *) {
     std::string path = DefaultIOSystem::absolutePath(std::string(pFile));
     std::string file = DefaultIOSystem::completeBaseName(std::string(pFile));
+    std::string texturesPath = path;
+    if (!texturesPath.empty()) {
+        texturesPath+=pIOSystem->getOsSeparator(); 
+    }
+    texturesPath+="textures";
     
     // initialize the exporter
-    PbrtExporter exporter(pScene, pIOSystem, path, file);
+    PbrtExporter exporter(pScene, pIOSystem, path, file, texturesPath);
 }
 
 } // end of namespace Assimp
 
-static void create_embedded_textures_folder(const aiScene *scene, IOSystem *pIOSystem) {
+static void create_embedded_textures_folder(const aiScene *scene, IOSystem *pIOSystem, const std::string &texturesPath) {
     if (scene->mNumTextures > 0) {
-        if (!pIOSystem->Exists("textures")) {
-            if (!pIOSystem->CreateDirectory("textures")) {
+        if (!pIOSystem->Exists(texturesPath)) {
+            if (!pIOSystem->CreateDirectory(texturesPath)) {
                 throw DeadlyExportError("Could not create textures/ directory.");
             }
         }
@@ -112,11 +117,12 @@ static void create_embedded_textures_folder(const aiScene *scene, IOSystem *pIOS
 
 PbrtExporter::PbrtExporter(
         const aiScene *pScene, IOSystem *pIOSystem,
-        const std::string &path, const std::string &file) :
+        const std::string &path, const std::string &file, const std::string &texturesPath) :
         mScene(pScene),
         mIOSystem(pIOSystem),
         mPath(path),
         mFile(file),
+        mTexturesPath(texturesPath),
         mRootTransform(
             // rotates the (already left-handed) CRS -90 degrees around the x axis in order to
             // make +Z 'up' and +Y 'towards viewer', as in default in pbrt
@@ -134,7 +140,7 @@ PbrtExporter::PbrtExporter(
     ) * mRootTransform;
 
     // Export embedded textures.
-    create_embedded_textures_folder(mScene, mIOSystem);
+    create_embedded_textures_folder(mScene, mIOSystem, mTexturesPath);
 
     for (unsigned int i = 0; i < mScene->mNumTextures; ++i) {
         aiTexture* tex = mScene->mTextures[i];
@@ -684,7 +690,7 @@ std::string PbrtExporter::CleanTextureFilename(const aiString &f, bool rewriteEx
     }
 
     // Expect all textures in textures
-    fn = std::string("textures") + mIOSystem->getOsSeparator() + fn;
+    fn = mTexturesPath + mIOSystem->getOsSeparator() + fn;
 
     // Rewrite extension for unsupported file formats.
     if (rewriteExtension) {
diff --git a/code/Pbrt/PbrtExporter.h b/code/Pbrt/PbrtExporter.h
index 71a906e87..bc596e5d2 100644
--- a/code/Pbrt/PbrtExporter.h
+++ b/code/Pbrt/PbrtExporter.h
@@ -74,7 +74,7 @@ class PbrtExporter {
 public:
     /// Constructor for a specific scene to export
     PbrtExporter(const aiScene *pScene, IOSystem *pIOSystem,
-            const std::string &path, const std::string &file);
+            const std::string &path, const std::string &file, const std::string &texturesPath);
 
     /// Destructor
     virtual ~PbrtExporter() = default;
@@ -114,6 +114,9 @@ private:
     /// Name of the file (without extension) where the scene will be exported
     const std::string mFile;
 
+    /// Path of the textures directory (inlcuding seperator)
+    const std::string mTexturesPath;
+
     //  A private set to keep track of which textures have been declared
     std::set<std::string> mTextureSet;