Merge branch 'master' of github.com:syoyo/tinyobjloader

Issue #74: Added basic diffuse texture support to examples/viewer

README.md

@@ -52,6 +52,7 @@ TinyObjLoader is successfully used in ...
 ### New version(v1.0.x)
 
 * Loading models in Vulkan Tutorial https://vulkan-tutorial.com/Loading_models
+* .obj viewer with Metal https://github.com/middlefeng/NuoModelViewer/tree/master
 * Your project here!
 
 ### Old version(v0.9.x)
@@ -73,6 +74,11 @@ TinyObjLoader is successfully used in ...
 * FireRays SDK https://github.com/GPUOpen-LibrariesAndSDKs/FireRays_SDK
 * parg, tiny C library of various graphics utilities and GL demos https://github.com/prideout/parg
 * Opengl unit of ChronoEngine https://github.com/projectchrono/chrono-opengl
+* Point Based Global Illumination on modern GPU https://pbgi.wordpress.com/code-source/
+* Fast OBJ file importing and parsing in CUDA http://researchonline.jcu.edu.au/42515/1/2015.CVM.OBJCUDA.pdf
+* Sorted Shading for Uni-Directional Pathtracing by Joshua Bainbridge https://nccastaff.bournemouth.ac.uk/jmacey/MastersProjects/MSc15/02Josh/joshua_bainbridge_thesis.pdf
+* GeeXLab http://www.geeks3d.com/hacklab/20160531/geexlab-0-12-0-0-released-for-windows/
+
 
 ## Features
 
@@ -83,6 +89,7 @@ TinyObjLoader is successfully used in ...
 * Material
   * Unknown material attributes are returned as key-value(value is string) map.
 * Crease tag('t'). This is OpenSubdiv specific(not in wavefront .obj specification)
+* PBR material extension for .MTL. Its proposed here: http://exocortex.com/blog/extending_wavefront_mtl_to_support_pbr
 * Callback API for custom loading.
 
 
@@ -90,6 +97,9 @@ TinyObjLoader is successfully used in ...
 
 * [ ] Fix obj_sticker example.
 * [ ] More unit test codes.
+* [ ] Texture options
+* [ ] Normal vector generation
+  * [ ] Support smoothing groups
 
 ## License
 

examples/viewer/viewer.cc

@@ -8,6 +8,7 @@
 #include <cstdlib>
 #include <iostream>
 #include <limits>
+#include <map>
 #include <string>
 #include <vector>
 
@@ -26,12 +27,24 @@
 
 #include "trackball.h"
 
+#define STB_IMAGE_IMPLEMENTATION
+#include "stb_image.h"
+
 #ifdef _WIN32
 #ifdef __cplusplus
 extern "C" {
 #endif
-#include <mmsystem.h>
 #include <windows.h>
+
+#ifdef max
+ #undef max
+#endif
+
+#ifdef min
+ #undef min
+#endif
+
+#include <mmsystem.h>
 #ifdef __cplusplus
 }
 #endif
@@ -112,6 +125,7 @@ class timerutil {
 typedef struct {
   GLuint vb;  // vertex buffer
   int numTriangles;
+  size_t material_id;
 } DrawObject;
 
 std::vector<DrawObject> gDrawObjects;
@@ -163,10 +177,11 @@ void CalcNormal(float N[3], float v0[3], float v1[3], float v2[3]) {
 
 bool LoadObjAndConvert(float bmin[3], float bmax[3],
                        std::vector<DrawObject>* drawObjects,
+                       std::vector<tinyobj::material_t>& materials,
+                       std::map<std::string, GLuint>& textures,
                        const char* filename) {
   tinyobj::attrib_t attrib;
   std::vector<tinyobj::shape_t> shapes;
-  std::vector<tinyobj::material_t> materials;
 
   timerutil tm;
 
@@ -194,11 +209,50 @@ bool LoadObjAndConvert(float bmin[3], float bmax[3],
   printf("# of materials = %d\n", (int)materials.size());
   printf("# of shapes    = %d\n", (int)shapes.size());
 
+  // Load diffuse textures
+  {
+      for (size_t m = 0; m < materials.size(); m++) {
+          tinyobj::material_t* mp = &materials[m];
+          
+          if (mp->diffuse_texname.length() > 0) {
+              // Only load the texture if it is not already loaded
+              if (textures.find(mp->diffuse_texname) == textures.end()) {
+                  GLuint texture_id;
+                  int w, h;
+                  int comp;
+                  unsigned char* image = stbi_load(mp->diffuse_texname.c_str(), &w, &h, &comp, STBI_default);
+                  if (image == nullptr) {
+                      std::cerr << "Unable to load texture: " << mp->diffuse_texname << std::endl;
+                      exit(1);
+                  }
+                  glGenTextures(1, &texture_id);
+                  glBindTexture(GL_TEXTURE_2D, texture_id);
+                  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+                  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+                  if (comp == 3) {
+                      glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, w, h, 0, GL_RGB, GL_UNSIGNED_BYTE, image);
+                  }
+                  else if (comp == 4) {
+                      glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, image);
+                  }
+                  glBindTexture(GL_TEXTURE_2D, 0);
+                  stbi_image_free(image);
+                  textures.insert(std::make_pair(mp->diffuse_texname, texture_id));
+              }
+          }
+      }
+  }
+
   bmin[0] = bmin[1] = bmin[2] = std::numeric_limits<float>::max();
   bmax[0] = bmax[1] = bmax[2] = -std::numeric_limits<float>::max();
 
   {
     for (size_t s = 0; s < shapes.size(); s++) {
+      size_t current_material_id = 0;
+      if (shapes[s].mesh.material_ids.size() > 0 && shapes[s].mesh.material_ids.size() > s) {
+          // Base case
+          current_material_id = shapes[s].mesh.material_ids[s];
+      }
       DrawObject o;
       std::vector<float> vb;  // pos(3float), normal(3float), color(3float)
       for (size_t f = 0; f < shapes[s].mesh.indices.size() / 3; f++) {
@@ -206,6 +260,32 @@ bool LoadObjAndConvert(float bmin[3], float bmax[3],
         tinyobj::index_t idx1 = shapes[s].mesh.indices[3 * f + 1];
         tinyobj::index_t idx2 = shapes[s].mesh.indices[3 * f + 2];
         
+        current_material_id = shapes[s].mesh.material_ids[f];
+
+        if (current_material_id >= materials.size()) {
+            std::cerr << "Invalid material index: " << current_material_id << std::endl;
+        }
+        
+        float diffuse[3];
+        for (size_t i = 0; i < 3; i++) {
+            diffuse[i] = materials[current_material_id].diffuse[i];
+        }
+        float tc[3][2];
+        if (attrib.texcoords.size() > 0) {
+            assert(attrib.texcoords.size() > 2 * idx0.texcoord_index + 1);
+            assert(attrib.texcoords.size() > 2 * idx1.texcoord_index + 1);
+            assert(attrib.texcoords.size() > 2 * idx2.texcoord_index + 1);
+            tc[0][0] = attrib.texcoords[2 * idx0.texcoord_index];
+            tc[0][1] = 1.0f - attrib.texcoords[2 * idx0.texcoord_index + 1];
+            tc[1][0] = attrib.texcoords[2 * idx1.texcoord_index];
+            tc[1][1] = 1.0f - attrib.texcoords[2 * idx1.texcoord_index + 1];
+            tc[2][0] = attrib.texcoords[2 * idx2.texcoord_index];
+            tc[2][1] = 1.0f - attrib.texcoords[2 * idx2.texcoord_index + 1];
+        } else {
+            std::cerr << "Texcoordinates are not defined" << std::endl;
+            exit(2);
+        }
+
         float v[3][3];
         for (int k = 0; k < 3; k++) {
           int f0 = idx0.vertex_index;
@@ -227,7 +307,6 @@ bool LoadObjAndConvert(float bmin[3], float bmax[3],
         }
 
         float n[3][3];
-
         if (attrib.normals.size() > 0) {
           int f0 = idx0.normal_index;
           int f1 = idx1.normal_index;
@@ -258,8 +337,14 @@ bool LoadObjAndConvert(float bmin[3], float bmax[3],
           vb.push_back(n[k][0]);
           vb.push_back(n[k][1]);
           vb.push_back(n[k][2]);
-          // Use normal as color.
+          // Combine normal and diffuse to get color.
-          float c[3] = {n[k][0], n[k][1], n[k][2]};
+          float normal_factor = 0.2;
+          float diffuse_factor = 1 - normal_factor;
+          float c[3] = {
+              n[k][0] * normal_factor + diffuse[0] * diffuse_factor,
+              n[k][1] * normal_factor + diffuse[1] * diffuse_factor,
+              n[k][2] * normal_factor + diffuse[2] * diffuse_factor
+          };
           float len2 = c[0] * c[0] + c[1] * c[1] + c[2] * c[2];
           if (len2 > 0.0f) {
             float len = sqrtf(len2);
@@ -271,17 +356,21 @@ bool LoadObjAndConvert(float bmin[3], float bmax[3],
           vb.push_back(c[0] * 0.5 + 0.5);
           vb.push_back(c[1] * 0.5 + 0.5);
           vb.push_back(c[2] * 0.5 + 0.5);
+          
+          vb.push_back(tc[k][0]);
+          vb.push_back(tc[k][1]);
         }
       }
 
       o.vb = 0;
       o.numTriangles = 0;
+      o.material_id = current_material_id;
       if (vb.size() > 0) {
         glGenBuffers(1, &o.vb);
         glBindBuffer(GL_ARRAY_BUFFER, o.vb);
         glBufferData(GL_ARRAY_BUFFER, vb.size() * sizeof(float), &vb.at(0),
                      GL_STATIC_DRAW);
-        o.numTriangles = vb.size() / 9 / 3;
+        o.numTriangles = vb.size() / (3 + 3 + 3 + 2) * 3;
         printf("shape[%d] # of triangles = %d\n", static_cast<int>(s),
                o.numTriangles);
       }
@@ -395,13 +484,13 @@ void motionFunc(GLFWwindow* window, double mouse_x, double mouse_y) {
   prevMouseY = mouse_y;
 }
 
-void Draw(const std::vector<DrawObject>& drawObjects) {
+void Draw(const std::vector<DrawObject>& drawObjects, std::vector<tinyobj::material_t>& materials, std::map<std::string, GLuint>& textures) {
   glPolygonMode(GL_FRONT, GL_FILL);
   glPolygonMode(GL_BACK, GL_FILL);
 
   glEnable(GL_POLYGON_OFFSET_FILL);
   glPolygonOffset(1.0, 1.0);
-  glColor3f(1.0f, 1.0f, 1.0f);
+  GLsizei stride = (3 + 3 + 3 + 2) * sizeof(float);
   for (size_t i = 0; i < drawObjects.size(); i++) {
     DrawObject o = drawObjects[i];
     if (o.vb < 1) {
@@ -412,12 +501,20 @@ void Draw(const std::vector<DrawObject>& drawObjects) {
     glEnableClientState(GL_VERTEX_ARRAY);
     glEnableClientState(GL_NORMAL_ARRAY);
     glEnableClientState(GL_COLOR_ARRAY);
-    glVertexPointer(3, GL_FLOAT, 36, (const void*)0);
+    glEnableClientState(GL_TEXTURE_COORD_ARRAY);
-    glNormalPointer(GL_FLOAT, 36, (const void*)(sizeof(float) * 3));
+
-    glColorPointer(3, GL_FLOAT, 36, (const void*)(sizeof(float) * 6));
+    std::string diffuse_texname = materials[o.material_id].diffuse_texname;
+    if (diffuse_texname.length() > 0) {
+        glBindTexture(GL_TEXTURE_2D, textures[diffuse_texname]);
+    }
+    glVertexPointer(3, GL_FLOAT, stride, (const void*)0);
+    glNormalPointer(GL_FLOAT, stride, (const void*)(sizeof(float) * 3));
+    glColorPointer(3, GL_FLOAT, stride, (const void*)(sizeof(float) * 6));
+    glTexCoordPointer(2, GL_FLOAT, stride, (const void*)(sizeof(float) * 9));
 
     glDrawArrays(GL_TRIANGLES, 0, 3 * o.numTriangles);
     CheckErrors("drawarrays");
+    glBindTexture(GL_TEXTURE_2D, 0);
   }
 
   // draw wireframe
@@ -436,8 +533,11 @@ void Draw(const std::vector<DrawObject>& drawObjects) {
     glEnableClientState(GL_VERTEX_ARRAY);
     glEnableClientState(GL_NORMAL_ARRAY);
     glDisableClientState(GL_COLOR_ARRAY);
-    glVertexPointer(3, GL_FLOAT, 36, (const void*)0);
+    glDisableClientState(GL_TEXTURE_COORD_ARRAY);
-    glNormalPointer(GL_FLOAT, 36, (const void*)(sizeof(float) * 3));
+    glVertexPointer(3, GL_FLOAT, stride, (const void*)0);
+    glNormalPointer(GL_FLOAT, stride, (const void*)(sizeof(float) * 3));
+    glColorPointer(3, GL_FLOAT, stride, (const void*)(sizeof(float) * 6));
+    glTexCoordPointer(2, GL_FLOAT, stride, (const void*)(sizeof(float) * 9));
 
     glDrawArrays(GL_TRIANGLES, 0, 3 * o.numTriangles);
     CheckErrors("drawarrays");
@@ -498,7 +598,9 @@ int main(int argc, char** argv) {
   reshapeFunc(window, width, height);
 
   float bmin[3], bmax[3];
-  if (false == LoadObjAndConvert(bmin, bmax, &gDrawObjects, argv[1])) {
+  std::vector<tinyobj::material_t> materials;
+  std::map<std::string, GLuint> textures;
+  if (false == LoadObjAndConvert(bmin, bmax, &gDrawObjects, materials, textures, argv[1])) {
     return -1;
   }
 
@@ -516,6 +618,7 @@ int main(int argc, char** argv) {
     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 
     glEnable(GL_DEPTH_TEST);
+    glEnable(GL_TEXTURE_2D);
 
     // camera & rotate
     glMatrixMode(GL_MODELVIEW);
@@ -533,7 +636,7 @@ int main(int argc, char** argv) {
     glTranslatef(-0.5 * (bmax[0] + bmin[0]), -0.5 * (bmax[1] + bmin[1]),
                  -0.5 * (bmax[2] + bmin[2]));
 
-    Draw(gDrawObjects);
+    Draw(gDrawObjects, materials, textures);
 
     glfwSwapBuffers(window);
   }

experimental/README.md

@@ -0,0 +1,5 @@
+Experimental code for .obj loader.
+
+* Multi-threaded optimized parser : tinyobj_loader_opt.h
+* zstd compressed .obj support. `--with-zstd` premake option.
+* gzip compressed .obj support. `--with-zlib` premake option.

experimental/premake4.lua

@@ -3,6 +3,11 @@ newoption {
    description = "Build with zlib."
 }
 
+newoption {
+   trigger     = "with-zstd",
+   description = "Build with ZStandard compression."
+}
+
 solution "objview"
 	-- location ( "build" )
 	configurations { "Release", "Debug" }
@@ -23,6 +28,15 @@ solution "objview"
 		links { 'z' }
 	end	
 
+	if _OPTIONS['with-zstd'] then
+		print("with-zstd")
+		defines { 'ENABLE_ZSTD' }
+		-- Set path to zstd installed dir.
+		includedirs { '$$HOME/local/include' }
+		libdirs { '$$HOME/local/lib' }
+		links { 'zstd' }
+	end	
+
 	-- Uncomment if you want address sanitizer(gcc/clang only)
 	--buildoptions { "-fsanitize=address" }
 	--linkoptions { "-fsanitize=address" }

experimental/viewer.cc

@@ -16,6 +16,10 @@
 #include <zlib.h>
 #endif
 
+#if defined(ENABLE_ZSTD)
+#include <zstd.h>
+#endif
+
 #include <GL/glew.h>
 
 #ifdef __APPLE__
@@ -182,6 +186,71 @@ bool gz_load(std::vector<char>* buf, const char* filename)
 #endif
 }
 
+#ifdef ENABLE_ZSTD
+static off_t fsize_X(const char *filename)
+{
+    struct stat st;
+    if (stat(filename, &st) == 0) return st.st_size;
+    /* error */
+    printf("stat: %s : %s \n", filename, strerror(errno));
+    exit(1);
+}
+
+static FILE* fopen_X(const char *filename, const char *instruction)
+{
+    FILE* const inFile = fopen(filename, instruction);
+    if (inFile) return inFile;
+    /* error */
+    printf("fopen: %s : %s \n", filename, strerror(errno));
+    exit(2);
+}
+
+static void* malloc_X(size_t size)
+{
+    void* const buff = malloc(size);
+    if (buff) return buff;
+    /* error */
+    printf("malloc: %s \n", strerror(errno));
+    exit(3);
+}
+#endif
+
+bool zstd_load(std::vector<char>* buf, const char* filename)
+{
+#ifdef ENABLE_ZSTD
+    off_t const buffSize = fsize_X(filename);
+    FILE* const inFile = fopen_X(filename, "rb");
+    void* const buffer = malloc_X(buffSize);
+    size_t const readSize = fread(buffer, 1, buffSize, inFile);
+    if (readSize != (size_t)buffSize) {
+        printf("fread: %s : %s \n", filename, strerror(errno));
+        exit(4);
+    }
+    fclose(inFile);
+
+    unsigned long long const rSize = ZSTD_getDecompressedSize(buffer, buffSize);
+    if (rSize==0) {
+        printf("%s : original size unknown \n", filename);
+        exit(5);
+    }
+
+    buf->resize(rSize);
+
+    size_t const dSize = ZSTD_decompress(buf->data(), rSize, buffer, buffSize);
+
+    if (dSize != rSize) {
+        printf("error decoding %s : %s \n", filename, ZSTD_getErrorName(dSize));
+        exit(7);
+    }
+
+    free(buffer);
+
+    return true;
+#else
+  return false;
+#endif
+}
+
 const char* get_file_data(size_t *len, const char* filename)
 {
 
@@ -204,6 +273,20 @@ const char* get_file_data(size_t *len, const char* filename)
       data_len = buf.size();
     }
 
+  } else if (strcmp(ext, ".zst") == 0) {
+    printf("zstd\n");
+    // Zstandard data.
+
+    std::vector<char> buf;
+    bool ret = zstd_load(&buf, filename);
+
+    if (ret) {
+      char *p = static_cast<char*>(malloc(buf.size() + 1));  // @fixme { implement deleter }
+      memcpy(p, &buf.at(0), buf.size());
+      p[buf.size()] = '\0';
+      data = p;
+      data_len = buf.size();
+    }
   } else {
     
     data = mmap_file(&data_len, filename);
@@ -220,13 +303,22 @@ bool LoadObjAndConvert(float bmin[3], float bmax[3], const char* filename, int n
   std::vector<tinyobj_opt::shape_t> shapes;
   std::vector<tinyobj_opt::material_t> materials;
 
+  auto load_t_begin = std::chrono::high_resolution_clock::now();
   size_t data_len = 0;
   const char* data = get_file_data(&data_len, filename);
   if (data == nullptr) {
+    printf("failed to load file\n");
     exit(-1);
     return false;
   }
-  printf("filesize: %d\n", (int)data_len);
+  auto load_t_end = std::chrono::high_resolution_clock::now();
+  std::chrono::duration<double, std::milli> load_ms = load_t_end - load_t_begin;
+  if (verbose) {
+    std::cout << "filesize: " << data_len << std::endl;
+    std::cout << "load time: " << load_ms.count() << " [msecs]" << std::endl;
+  }
+
+
   tinyobj_opt::LoadOption option;
   option.req_num_threads = num_threads;
   option.verbose = verbose;
@@ -534,6 +626,7 @@ int main(int argc, char **argv)
     size_t data_len = 0;
     const char* data = get_file_data(&data_len, argv[1]);
     if (data == nullptr) {
+      printf("failed to load file\n");
       exit(-1);
       return false;
     }

models/usemtl-issue-104.obj

@@ -0,0 +1,30 @@
+# cornell_box.obj and cornell_box.mtl are grabbed from Intel's embree project.
+# original cornell box data
+  # comment
+
+# empty line including some space
+   
+
+mtllib cornell_box.mtl
+
+o floor
+v 552.8 0.0   0.0
+v 0.0   0.0   0.0
+v 0.0   0.0 559.2
+v 549.6 0.0 559.2
+
+v 130.0 0.0  65.0
+v  82.0 0.0 225.0
+v 240.0 0.0 272.0
+v 290.0 0.0 114.0
+
+v 423.0 0.0 247.0
+v 265.0 0.0 296.0
+v 314.0 0.0 456.0
+v 472.0 0.0 406.0
+
+f 1 2 3 4 
+f 8 7 6 5
+f 12 11 10 9
+
+usemtl white

tests/tester.cc

@@ -184,6 +184,48 @@ TestLoadObj(
   return true;
 }
 
+static bool
+TestLoadObjFromPreopenedFile(
+  const char* filename,
+  const char* basepath = NULL,
+  bool readMaterials = true,
+  bool triangulate = true)
+{
+  std::string fullFilename = std::string(basepath) + filename;
+  std::cout << "Loading " << fullFilename << std::endl;
+
+  std::ifstream fileStream(fullFilename.c_str());
+
+  if (!fileStream) {
+    std::cerr << "Could not find specified file: " << fullFilename << std::endl;
+    return false;
+  }
+
+  tinyobj::MaterialStreamReader materialStreamReader(fileStream);
+  tinyobj::MaterialStreamReader* materialReader = readMaterials
+    ? &materialStreamReader
+    : NULL;
+
+  tinyobj::attrib_t attrib;
+  std::vector<tinyobj::shape_t> shapes;
+  std::vector<tinyobj::material_t> materials;
+
+  std::string err;
+  bool ret = tinyobj::LoadObj(&attrib, &shapes, &materials, &err, &fileStream, materialReader);
+
+  if (!err.empty()) {
+    std::cerr << err << std::endl;
+  }
+
+  if (!ret) {
+    printf("Failed to load/parse .obj.\n");
+    return false;
+  }
+
+  std::cout << "Loaded material count: " << materials.size() << "\n";
+
+  return true;
+}
 
 static bool
 TestStreamLoadObj()
@@ -351,6 +393,16 @@ TEST_CASE("stream_load", "[Stream]") {
     REQUIRE(true == TestStreamLoadObj());
 }
 
+TEST_CASE("stream_load_from_file_skipping_materials", "[Stream]") {
+  REQUIRE(true == TestLoadObjFromPreopenedFile(
+    "../models/pbr-mat-ext.obj", gMtlBasePath, /*readMaterials*/false, /*triangulate*/false));
+}
+
+TEST_CASE("stream_load_from_file_with_materials", "[Stream]") {
+  REQUIRE(true == TestLoadObjFromPreopenedFile(
+    "../models/pbr-mat-ext.obj", gMtlBasePath, /*readMaterials*/true, /*triangulate*/false));
+}
+
 TEST_CASE("trailing_whitespace_in_mtl", "[Issue92]") {
   tinyobj::attrib_t attrib;
   std::vector<tinyobj::shape_t> shapes;
@@ -402,6 +454,7 @@ TEST_CASE("transmittance_filter_Tf", "[Issue95-Tf]") {
   REQUIRE(0.2 == Approx(materials[0].transmittance[1]));
   REQUIRE(0.3 == Approx(materials[0].transmittance[2]));
 }
+
 TEST_CASE("transmittance_filter_Kt", "[Issue95-Kt]") {
   tinyobj::attrib_t attrib;
   std::vector<tinyobj::shape_t> shapes;
@@ -420,6 +473,21 @@ TEST_CASE("transmittance_filter_Kt", "[Issue95-Kt]") {
   REQUIRE(0.3 == Approx(materials[0].transmittance[2]));
 }
 
+TEST_CASE("usemtl_at_last_line", "[Issue104]") {
+  tinyobj::attrib_t attrib;
+  std::vector<tinyobj::shape_t> shapes;
+  std::vector<tinyobj::material_t> materials;
+
+  std::string err;
+  bool ret = tinyobj::LoadObj(&attrib, &shapes, &materials, &err, "../models/usemtl-issue-104.obj", gMtlBasePath);
+
+  if (!err.empty()) {
+    std::cerr << err << std::endl;
+  }
+  REQUIRE(true == ret);
+  REQUIRE(1 == shapes.size());
+}
+
 #if 0
 int
 main(

tiny_obj_loader.h

@@ -23,6 +23,7 @@ THE SOFTWARE.
 */
 
 //
+// version 1.0.1 : Fixes a shape is lost if obj ends with a 'usemtl'(#104)
 // version 1.0.0 : Change data structure. Change license from BSD to MIT.
 //
 
@@ -91,7 +92,7 @@ typedef struct {
   std::vector<std::string> stringValues;
 } tag_t;
 
-// Index struct to support differnt indices for vtx/normal/texcoord.
+// Index struct to support different indices for vtx/normal/texcoord.
 // -1 means not used.
 typedef struct {
   int vertex_index;
@@ -179,6 +180,19 @@ class MaterialFileReader : public MaterialReader {
   std::string m_mtlBasePath;
 };
 
+class MaterialStreamReader : public MaterialReader {
+ public:
+  explicit MaterialStreamReader(std::istream &inStream)
+      : m_inStream(inStream) {}
+  virtual ~MaterialStreamReader() {}
+  virtual bool operator()(const std::string &matId,
+                          std::vector<material_t> *materials,
+                          std::map<std::string, int> *matMap, std::string *err);
+
+ private:
+  std::istream &m_inStream;
+};
+
 /// Loads .obj from a file.
 /// 'attrib', 'shapes' and 'materials' will be filled with parsed shape data
 /// 'shapes' will be filled with parsed shape data
@@ -209,7 +223,7 @@ bool LoadObjWithCallback(std::istream &inStream, const callback_t &callback,
 /// Returns warning and error message into `err`
 bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
              std::vector<material_t> *materials, std::string *err,
-             std::istream *inStream, MaterialReader *readMatFn,
+             std::istream *inStream, MaterialReader *readMatFn = NULL,
              bool triangulate = true);
 
 /// Loads materials into std::map
@@ -1010,6 +1024,22 @@ bool MaterialFileReader::operator()(const std::string &matId,
   return true;
 }
 
+bool MaterialStreamReader::operator()(const std::string &matId,
+                                      std::vector<material_t> *materials,
+                                      std::map<std::string, int> *matMap,
+                                      std::string *err) {
+  LoadMtl(matMap, materials, &m_inStream);
+  if (!m_inStream) {
+    std::stringstream ss;
+    ss << "WARN: Material stream in error state."
+       << " Created a default material.";
+    if (err) {
+      (*err) += ss.str();
+    }
+  }
+  return true;
+}
+
 bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
              std::vector<material_t> *materials, std::string *err,
              const char *filename, const char *mtl_basepath,
@@ -1042,7 +1072,8 @@ bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
 
 bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
              std::vector<material_t> *materials, std::string *err,
-             std::istream *inStream, MaterialReader *readMatFn,
+             std::istream *inStream,
+             MaterialReader *readMatFn /*= NULL*/,
              bool triangulate) {
   std::stringstream errss;
 
@@ -1161,7 +1192,9 @@ bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
       }
 
       if (newMaterialId != material) {
-        // Create per-face material
+        // Create per-face material. Thus we don't add `shape` to `shapes` at
+        // this time.
+        // just clear `faceGroup` after `exportFaceGroupToShape()` call.
         exportFaceGroupToShape(&shape, faceGroup, tags, material, name,
                                triangulate);
         faceGroup.clear();
@@ -1173,23 +1206,25 @@ bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
 
     // load mtl
     if ((0 == strncmp(token, "mtllib", 6)) && IS_SPACE((token[6]))) {
-      char namebuf[TINYOBJ_SSCANF_BUFFER_SIZE];
+      if (readMatFn) {
-      token += 7;
+        char namebuf[TINYOBJ_SSCANF_BUFFER_SIZE];
+        token += 7;
 #ifdef _MSC_VER
-      sscanf_s(token, "%s", namebuf, (unsigned)_countof(namebuf));
+        sscanf_s(token, "%s", namebuf, (unsigned)_countof(namebuf));
 #else
-      sscanf(token, "%s", namebuf);
+        sscanf(token, "%s", namebuf);
 #endif
 
-      std::string err_mtl;
+        std::string err_mtl;
-      bool ok = (*readMatFn)(namebuf, materials, &material_map, &err_mtl);
+        bool ok = (*readMatFn)(namebuf, materials, &material_map, &err_mtl);
-      if (err) {
+        if (err) {
-        (*err) += err_mtl;
+          (*err) += err_mtl;
-      }
+        }
 
-      if (!ok) {
+        if (!ok) {
-        faceGroup.clear();  // for safety
+          faceGroup.clear();  // for safety
-        return false;
+          return false;
+        }
       }
 
       continue;
@@ -1307,7 +1342,11 @@ bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
 
   bool ret = exportFaceGroupToShape(&shape, faceGroup, tags, material, name,
                                     triangulate);
-  if (ret) {
+  // exportFaceGroupToShape return false when `usemtl` is called in the last
+  // line.
+  // we also add `shape` to `shapes` when `shape.mesh` has already some
+  // faces(indices)
+  if (ret || shape.mesh.indices.size()) {
     shapes->push_back(shape);
   }
   faceGroup.clear();  // for safety