From 75e64cd47a1217f4200bfcb2c65c5c1ccc196dbf Mon Sep 17 00:00:00 2001
From: Syoyo Fujita <syoyo@lighttransport.com>
Date: Wed, 27 Jul 2016 16:16:51 +0900
Subject: [PATCH] Support parsing `w` element of vertex coordinate, and also
 third element of texture coordinates. Fixes #88.

---
 examples/callback_api/main.cc | 16 +++++++++++-----
 tiny_obj_loader.h             | 36 ++++++++++++++++++++---------------
 2 files changed, 32 insertions(+), 20 deletions(-)

diff --git a/examples/callback_api/main.cc b/examples/callback_api/main.cc
index 44ec62f..97b8867 100644
--- a/examples/callback_api/main.cc
+++ b/examples/callback_api/main.cc
@@ -27,13 +27,14 @@ typedef struct {
 
 } MyMesh;
 
-void vertex_cb(void *user_data, float x, float y, float z) {
+void vertex_cb(void *user_data, float x, float y, float z, float w) {
   MyMesh *mesh = reinterpret_cast<MyMesh *>(user_data);
-  printf("v[%ld] = %f, %f, %f\n", mesh->vertices.size() / 3, x, y, z);
+  printf("v[%ld] = %f, %f, %f (w %f)\n", mesh->vertices.size() / 3, x, y, z, w);
 
   mesh->vertices.push_back(x);
   mesh->vertices.push_back(y);
   mesh->vertices.push_back(z);
+  // Discard w
 }
 
 void normal_cb(void *user_data, float x, float y, float z) {
@@ -45,12 +46,13 @@ void normal_cb(void *user_data, float x, float y, float z) {
   mesh->normals.push_back(z);
 }
 
-void texcoord_cb(void *user_data, float x, float y) {
+void texcoord_cb(void *user_data, float x, float y, float z) {
   MyMesh *mesh = reinterpret_cast<MyMesh *>(user_data);
-  printf("vt[%ld] = %f, %f\n", mesh->texcoords.size() / 2, x, y);
+  printf("vt[%ld] = %f, %f, %f\n", mesh->texcoords.size() / 3, x, y, z);
 
   mesh->texcoords.push_back(x);
   mesh->texcoords.push_back(y);
+  mesh->texcoords.push_back(z);
 }
 
 void index_cb(void *user_data, tinyobj::index_t *indices, int num_indices) {
@@ -128,7 +130,11 @@ int main(int argc, char **argv) {
 
   MyMesh mesh;
   std::string err;
-  std::ifstream ifs("../../models/cornell_box.obj");
+  std::string filename = "../../models/cornell_box.obj";
+  if (argc > 1) {
+    filename = std::string(argv[1]);
+  }
+  std::ifstream ifs(filename.c_str());
 
   if (ifs.fail()) {
     std::cerr << "file not found." << std::endl;
diff --git a/tiny_obj_loader.h b/tiny_obj_loader.h
index 4f79f42..d9b8148 100644
--- a/tiny_obj_loader.h
+++ b/tiny_obj_loader.h
@@ -148,9 +148,12 @@ typedef struct {
 } attrib_t;
 
 typedef struct callback_t_ {
-  void (*vertex_cb)(void *user_data, float x, float y, float z);
+  // W is optional and set to 1 if there is no `w` item in `v` line
+  void (*vertex_cb)(void *user_data, float x, float y, float z, float w);
   void (*normal_cb)(void *user_data, float x, float y, float z);
-  void (*texcoord_cb)(void *user_data, float x, float y);
+
+  // y and z are optional and set to 0 if there is no `y` and/or `z` item(s) in `vt` line.
+  void (*texcoord_cb)(void *user_data, float x, float y, float z);
 
   // called per 'f' line. num_indices is the number of face indices(e.g. 3 for
   // triangle, 4 for quad)
@@ -443,18 +446,13 @@ fail:
   return false;
 }
 
-static inline float parseFloat(const char **token) {
+static inline float parseFloat(const char **token, double default_value = 0.0) {
   (*token) += strspn((*token), " \t");
-#ifdef TINY_OBJ_LOADER_OLD_FLOAT_PARSER
-  float f = static_cast<float>(atof(*token));
-  (*token) += strcspn((*token), " \t\r");
-#else
   const char *end = (*token) + strcspn((*token), " \t\r");
-  double val = 0.0;
+  double val = default_value;
   tryParseDouble((*token), end, &val);
   float f = static_cast<float>(val);
   (*token) = end;
-#endif
   return f;
 }
 
@@ -470,6 +468,14 @@ static inline void parseFloat3(float *x, float *y, float *z,
   (*z) = parseFloat(token);
 }
 
+static inline void parseV(float *x, float *y, float *z, float *w,
+                          const char **token) {
+  (*x) = parseFloat(token);
+  (*y) = parseFloat(token);
+  (*z) = parseFloat(token);
+  (*w) = parseFloat(token, 1.0);
+}
+
 static tag_sizes parseTagTriple(const char **token) {
   tag_sizes ts;
 
@@ -1348,10 +1354,10 @@ bool LoadObjWithCallback(void *user_data, const callback_t &callback,
     // vertex
     if (token[0] == 'v' && IS_SPACE((token[1]))) {
       token += 2;
-      float x, y, z;
-      parseFloat3(&x, &y, &z, &token);
+      float x, y, z, w; // w is optional. default = 1.0
+      parseV(&x, &y, &z, &w, &token);
       if (callback.vertex_cb) {
-        callback.vertex_cb(user_data, x, y, z);
+        callback.vertex_cb(user_data, x, y, z, w);
       }
       continue;
     }
@@ -1370,10 +1376,10 @@ bool LoadObjWithCallback(void *user_data, const callback_t &callback,
     // texcoord
     if (token[0] == 'v' && token[1] == 't' && IS_SPACE((token[2]))) {
       token += 3;
-      float x, y;
-      parseFloat2(&x, &y, &token);
+      float x, y, z; // y and z are optional. default = 0.0
+      parseFloat3(&x, &y, &z, &token);
       if (callback.texcoord_cb) {
-        callback.texcoord_cb(user_data, x, y);
+        callback.texcoord_cb(user_data, x, y, z);
       }
       continue;
     }