Add initial files for CPU raycasting of USD model example using NanoRT

CMakeLists.txt

@@ -1182,6 +1182,7 @@ if(TINYUSDZ_BUILD_EXAMPLES)
   add_subdirectory(examples/api_tutorial)
   add_subdirectory(examples/file_format)
   add_subdirectory(examples/asset_resolution)
+  add_subdirectory(examples/traycast)
   #if (TINYUSDZ_WITH_JSON)
   #  add_subdirectory(examples/usd_to_json)
   #endif()

examples/traycast/CMakeLists.txt

@@ -0,0 +1,15 @@
+# Assume this cmake is called from tinyusdz root(../../)
+set(EXAMPLE_TARGET "traycast")
+
+set(TINYUSDZ_TRENDER_SOURCES
+    traycast-main.cc
+    )
+
+add_executable(${EXAMPLE_TARGET} ${TINYUSDZ_TRENDER_SOURCES})
+add_sanitizers(${EXAMPLE_TARGET})
+
+target_include_directories(${EXAMPLE_TARGET} PRIVATE ${PROJECT_SOURCE_DIR}/src)
+target_include_directories(${EXAMPLE_TARGET} PRIVATE ${PROJECT_SOURCE_DIR}/examples/common)
+target_link_libraries(${EXAMPLE_TARGET} tinyusdz_static)
+
+set_target_properties(${EXAMPLE_TARGET} PROPERTIES RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}")

examples/traycast/README.md

@@ -0,0 +1 @@
+Simple command line raycasting rendering of USD model.

examples/traycast/traycast-main.cc

@@ -0,0 +1,165 @@
+// SPDX-License-Identifier: Apache 2.0
+// Copyright 2022-Present Light Transport Entertainment Inc.
+
+//
+// Command-line tool to convert USD Stage to RenderScene(glTF-like data
+// structure)
+//
+#include <algorithm>
+#include <iostream>
+#include <sstream>
+#include <fstream>
+
+// clang-format off
+// <tinyusdz>/examples/common
+#include "nanort.h"
+
+#include "io-util.hh"
+#include "str-util.hh"
+#include "pprinter.hh"
+#include "prim-pprint.hh"
+#include "tinyusdz.hh"
+#include "tydra/render-data.hh"
+#include "tydra/scene-access.hh"
+#include "tydra/shader-network.hh"
+#include "tydra/obj-export.hh"
+#include "tydra/usd-export.hh"
+#include "usdShade.hh"
+#include "value-pprint.hh"
+#include "value-types.hh"
+
+// clang-format on
+
+static std::string GetFileExtension(const std::string &filename) {
+  if (filename.find_last_of('.') != std::string::npos)
+    return filename.substr(filename.find_last_of('.') + 1);
+  return "";
+}
+
+static std::string str_tolower(std::string s) {
+  std::transform(s.begin(), s.end(), s.begin(),
+                 [](unsigned char c) { return std::tolower(c); });
+  return s;
+}
+
+int main(int argc, char **argv) {
+  if (argc < 2) {
+    std::cout << "Usage: " << argv[0] << " input.usd [OPTIONS].\n";
+    std::cout << "\n\nOptions\n\n";
+    std::cout << "  --timecode VALUE: Specify timecode value(e.g. 3.14)\n";
+    std::cout << "  --debug: Do some debug logging\n";
+    std::cout << "  --notri: Do not triangulate mesh\n";
+    return EXIT_FAILURE;
+  }
+
+  // When Xform, Mesh, Material, etc. have time-varying values,
+  // values are evaluated at `timecode` time(except for animation values in SkelAnimation)
+  double timecode = tinyusdz::value::TimeCode::Default();
+
+  bool debug = false;
+  bool triangulate = true;
+  std::string filepath;
+  for (int i = 1; i < argc; i++) {
+    if (strcmp(argv[i], "--notri") == 0) {
+      triangulate = false;
+    } else if (strcmp(argv[i], "--debug") == 0) {
+      debug = false;
+    } else if (strcmp(argv[i], "--timecode") == 0) {
+      if ((i + 1) >= argc) {
+        std::cerr << "arg is missing for --timecode flag.\n";
+        return -1;
+      }
+      timecode = std::stod(argv[i+1]);
+      std::cout << "Use timecode: " << timecode << "\n";
+      i++;
+    } else {
+      filepath = argv[i];
+    }
+  }
+
+  std::string warn;
+  std::string err;
+
+  std::string ext = str_tolower(GetFileExtension(filepath));
+
+  tinyusdz::Stage stage;
+  bool is_usdz = false;
+
+  bool ret = tinyusdz::LoadUSDFromFile(filepath, &stage, &warn, &err);
+
+  if (!warn.empty()) {
+    std::cerr << "WARN : " << warn << "\n";
+  }
+
+  if (!ret) {
+    std::cerr << "Failed to load USD file: " << filepath << "\n";
+    std::cerr << "Error: " << err << "\n";
+    return EXIT_FAILURE;
+  }
+
+  is_usdz = tinyusdz::IsUSDZ(filepath);
+
+
+  // RenderScene: Scene graph object which is suited for GL/Vulkan renderer
+  tinyusdz::tydra::RenderScene render_scene;
+  tinyusdz::tydra::RenderSceneConverter converter;
+  tinyusdz::tydra::RenderSceneConverterEnv env(stage);
+
+  std::cout << "Triangulate : " << (triangulate ? "true" : "false") << "\n";
+  env.mesh_config.triangulate = triangulate;
+  env.mesh_config.build_vertex_indices = false;
+
+  // Add base directory of .usd file to search path.
+  std::string usd_basedir = tinyusdz::io::GetBaseDir(filepath);
+  std::cout << "Add seach path: " << usd_basedir << "\n";
+
+
+  tinyusdz::USDZAsset usdz_asset;
+  if (is_usdz) {
+    // Setup AssetResolutionResolver to read a asset(file) from memory.
+    if (!tinyusdz::ReadUSDZAssetInfoFromFile(filepath, &usdz_asset, &warn, &err)) {
+      std::cerr << "Failed to read USDZ assetInfo from file: " << err << "\n";
+      exit(-1);
+    }
+    if (warn.size()) {
+      std::cout << warn << "\n";
+    }
+
+    tinyusdz::AssetResolutionResolver arr;
+
+    // NOTE: Pointer address of usdz_asset must be valid until the call of RenderSceneConverter::ConvertToRenderScene.
+    if (!tinyusdz::SetupUSDZAssetResolution(arr, &usdz_asset)) {
+      std::cerr << "Failed to setup AssetResolution for USDZ asset\n";
+      exit(-1);
+    };
+
+    env.asset_resolver = arr;
+
+  } else {
+    env.set_search_paths({usd_basedir});
+
+    // TODO: Add example to set user-defined AssetResolutionResolver
+    // AssetResolutionResolver arr;
+    // ...
+    // env.asset_resolver(arr);
+  }
+
+  env.timecode = timecode;
+  ret = converter.ConvertToRenderScene(env, &render_scene);
+  if (!ret) {
+    std::cerr << "Failed to convert USD Stage to RenderScene: \n" << converter.GetError() << "\n";
+    return EXIT_FAILURE;
+  }
+
+  if (converter.GetWarning().size()) {
+    std::cout << "ConvertToRenderScene warn: " << converter.GetWarning() << "\n";
+  }
+
+  if (debug) {
+    std::cout << DumpRenderScene(render_scene) << "\n";
+  }
+
+  // TODO: Do raytracing
+
+  return EXIT_SUCCESS;
+}