1 files changed, 166 insertions, 0 deletions
diff --git a/examples/callback_api/main.cc b/examples/callback_api/main.cc
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+++ b/examples/callback_api/main.cc
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+//
+// An example of how to use callback API.
+// This example is minimum and incomplete. Just showing the usage of callback
+// API.
+// You need to implement your own Mesh data struct constrution based on this
+// example in practical.
+//
+#define TINYOBJLOADER_IMPLEMENTATION
+#include "tiny_obj_loader.h"
+
+#include <cassert>
+#include <cstdio>
+#include <cstdlib>
+#include <fstream>
+#include <iostream>
+#include <sstream>
+
+typedef struct {
+  std::vector<float> vertices;
+  std::vector<float> normals;
+  std::vector<float> texcoords;
+  std::vector<int> v_indices;
+  std::vector<int> vn_indices;
+  std::vector<int> vt_indices;
+
+  std::vector<tinyobj::material_t> materials;
+
+} MyMesh;
+
+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 (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) {
+  MyMesh *mesh = reinterpret_cast<MyMesh *>(user_data);
+  printf("vn[%ld] = %f, %f, %f\n", mesh->normals.size() / 3, x, y, z);
+
+  mesh->normals.push_back(x);
+  mesh->normals.push_back(y);
+  mesh->normals.push_back(z);
+}
+
+void texcoord_cb(void *user_data, float x, float y, float z) {
+  MyMesh *mesh = reinterpret_cast<MyMesh *>(user_data);
+  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) {
+  // NOTE: the value of each index is raw value.
+  // For example, the application must manually adjust the index with offset
+  // (e.g. v_indices.size()) when the value is negative(whic means relative
+  // index).
+  // Also, the first index starts with 1, not 0.
+  // See fixIndex() function in tiny_obj_loader.h for details.
+  // Also, 0 is set for the index value which
+  // does not exist in .obj
+  MyMesh *mesh = reinterpret_cast<MyMesh *>(user_data);
+
+  for (int i = 0; i < num_indices; i++) {
+    tinyobj::index_t idx = indices[i];
+    printf("idx[%ld] = %d, %d, %d\n", mesh->v_indices.size(), idx.vertex_index,
+           idx.normal_index, idx.texcoord_index);
+
+    if (idx.vertex_index != 0) {
+      mesh->v_indices.push_back(idx.vertex_index);
+    }
+    if (idx.normal_index != 0) {
+      mesh->vn_indices.push_back(idx.normal_index);
+    }
+    if (idx.texcoord_index != 0) {
+      mesh->vt_indices.push_back(idx.texcoord_index);
+    }
+  }
+}
+
+void usemtl_cb(void *user_data, const char *name, int material_idx) {
+  MyMesh *mesh = reinterpret_cast<MyMesh *>(user_data);
+  if ((material_idx > -1) && (material_idx < mesh->materials.size())) {
+    printf("usemtl. material id = %d(name = %s)\n", material_idx,
+           mesh->materials[material_idx].name.c_str());
+  } else {
+    printf("usemtl. name = %s\n", name);
+  }
+}
+
+void mtllib_cb(void *user_data, const tinyobj::material_t *materials,
+               int num_materials) {
+  MyMesh *mesh = reinterpret_cast<MyMesh *>(user_data);
+  printf("mtllib. # of materials = %d\n", num_materials);
+
+  for (int i = 0; i < num_materials; i++) {
+    mesh->materials.push_back(materials[i]);
+  }
+}
+
+void group_cb(void *user_data, const char **names, int num_names) {
+  // MyMesh *mesh = reinterpret_cast<MyMesh*>(user_data);
+  printf("group : name = \n");
+
+  for (int i = 0; i < num_names; i++) {
+    printf("  %s\n", names[i]);
+  }
+}
+
+void object_cb(void *user_data, const char *name) {
+  // MyMesh *mesh = reinterpret_cast<MyMesh*>(user_data);
+  printf("object : name = %s\n", name);
+}
+
+int main(int argc, char **argv) {
+  tinyobj::callback_t cb;
+  cb.vertex_cb = vertex_cb;
+  cb.normal_cb = normal_cb;
+  cb.texcoord_cb = texcoord_cb;
+  cb.index_cb = index_cb;
+  cb.usemtl_cb = usemtl_cb;
+  cb.mtllib_cb = mtllib_cb;
+  cb.group_cb = group_cb;
+  cb.object_cb = object_cb;
+
+  MyMesh mesh;
+  std::string err;
+  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;
+    return EXIT_FAILURE;
+  }
+
+  tinyobj::MaterialFileReader mtlReader("../../models/");
+
+  bool ret = tinyobj::LoadObjWithCallback(ifs, cb, &mesh, &mtlReader, &err);
+
+  if (!err.empty()) {
+    std::cerr << err << std::endl;
+  }
+
+  if (!ret) {
+    std::cerr << "Failed to parse .obj" << std::endl;
+    return EXIT_FAILURE;
+  }
+
+  printf("# of vertices         = %ld\n", mesh.vertices.size() / 3);
+  printf("# of normals          = %ld\n", mesh.normals.size() / 3);
+  printf("# of texcoords        = %ld\n", mesh.texcoords.size() / 2);
+  printf("# of vertex indices   = %ld\n", mesh.v_indices.size());
+  printf("# of normal indices   = %ld\n", mesh.vn_indices.size());
+  printf("# of texcoord indices   = %ld\n", mesh.vt_indices.size());
+  printf("# of materials = %ld\n", mesh.materials.size());
+
+  return EXIT_SUCCESS;
+}