obj.cpp: don't use memory-mapped I/O on windows

mitsuba-renderer · Nov 21, 2022 · 28660f3 · 28660f3
1 parent 56ea910
commit 28660f3
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Showing 2 changed files with 22 additions and 8 deletions.
diff --git a/ext/drjit b/ext/drjit
diff --git a/src/shapes/obj.cpp b/src/shapes/obj.cpp
@@ -1,5 +1,6 @@
 #include <mitsuba/render/mesh.h>
 #include <mitsuba/core/fresolver.h>
+#include <mitsuba/core/fstream.h>
 #include <mitsuba/core/properties.h>
 #include <mitsuba/core/mmap.h>
 #include <mitsuba/core/util.h>
@@ -8,6 +9,7 @@
 
 #include <array>
 
+
 NAMESPACE_BEGIN(mitsuba)
 
 /**!
@@ -148,8 +150,8 @@ class OBJMesh final : public Mesh<Float, Spectrum> {
            Enabled by default, for consistence with the Mitsuba 1 behavior. */
         bool flip_tex_coords = props.get<bool>("flip_tex_coords", true);
 
-        auto fs = Thread::thread()->file_resolver();
-        fs::path file_path = fs->resolve(props.string("filename"));
+        auto fr = Thread::thread()->file_resolver();
+        fs::path file_path = fr->resolve(props.string("filename"));
         m_name = file_path.filename().string();
 
 
@@ -162,7 +164,6 @@ class OBJMesh final : public Mesh<Float, Spectrum> {
         if (!fs::exists(file_path))
             fail("file not found");
 
-        ref<MemoryMappedFile> mmap = new MemoryMappedFile(file_path);
         ScopedPhase phase(ProfilerPhase::LoadGeometry);
 
         using ScalarIndex3 = std::array<ScalarIndex, 3>;
@@ -180,7 +181,23 @@ class OBJMesh final : public Mesh<Float, Spectrum> {
         std::vector<ScalarIndex3> triangles;
         std::vector<VertexBinding> vertex_map;
 
-        size_t vertex_guess = mmap->size() / 100;
+ #if !defined(_WIN32)
+        ref<MemoryMappedFile> mmap = new MemoryMappedFile(file_path);
+        size_t file_size           = mmap->size();
+        const char *ptr            = (const char *) mmap->data();
+#else
+        // Memory-mapped IO performs surprisingly poorly on Windows
+        ref<FileStream> fs = new FileStream(file_path);
+        size_t file_size = fs->size();
+        std::unique_ptr<char[]> tmp(new char[file_size]);
+        fs->read(tmp.get(), file_size);
+        const char *ptr = tmp.get();
+#endif
+
+        size_t vertex_guess = file_size / 100;
+        const char *eof     = ptr + file_size;
+        char buf[1025];
+
         vertices.reserve(vertex_guess);
         normals.reserve(vertex_guess);
         texcoords.reserve(vertex_guess);
@@ -189,9 +206,6 @@ class OBJMesh final : public Mesh<Float, Spectrum> {
 
         ScalarIndex vertex_ctr = 0;
 
-        const char *ptr = (const char *) mmap->data();
-        const char *eof = ptr + mmap->size();
-        char buf[1025];
         Timer timer;
 
         while (ptr < eof) {