add arg-parser

CMakeLists.txt

@@ -370,6 +370,7 @@ if(TINYUSDZ_WITH_PYTHON)
 endif()
 
 set(TINYUSDZ_SOURCES
+    ${PROJECT_SOURCE_DIR}/src/arg-parser.cc
     ${PROJECT_SOURCE_DIR}/src/asset-resolution.cc
     ${PROJECT_SOURCE_DIR}/src/tinyusdz.cc
     ${PROJECT_SOURCE_DIR}/src/xform.cc
@@ -1257,6 +1258,10 @@ if(TINYUSDZ_BUILD_EXAMPLES)
   if (TINYUSDZ_WITH_TYDRA)
     add_subdirectory(examples/tydra_api)
     add_subdirectory(examples/tydra_to_renderscene)
+
+    if (TINYUSDZ_WITH_MCP_SERVER)
+      add_subdirectory(examples/mcp_server)
+    endif()
   endif ()
 
   add_subdirectory(examples/api_tutorial)

examples/mcp_server/CMakeLists.txt

@@ -0,0 +1,14 @@
+# Assume this cmake is called from tinyusdz root(../../)
+set(EXAMPLE_TARGET "mcp_server")
+
+set(EXAMPLE_SOURCES
+    example-mcp-server.cc
+    )
+
+add_executable(${EXAMPLE_TARGET} ${EXAMPLE_SOURCES})
+add_sanitizers(${EXAMPLE_TARGET})
+
+target_include_directories(${EXAMPLE_TARGET} PRIVATE ${PROJECT_SOURCE_DIR}/src)
+target_link_libraries(${EXAMPLE_TARGET} tinyusdz_static)
+
+set_target_properties(${EXAMPLE_TARGET} PROPERTIES RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}")

examples/mcp_server/example-mcp-server.cc

@@ -0,0 +1,14 @@
+#include <iostream>
+
+#include "tydra/mcp-server.hh"
+#include "arg-parser.hh"
+
+int main(int argc, char **argv) {
+
+#if !defined(TINYUSDZ_WITH_MCP_SERVER)
+  std::cerr << "TinyUSDZ is not built with `TINYUSDZ_WITH_MCP_SERVER` cmake option)" << "\n";
+#endif
+
+  return 0;
+
+}

src/arg-parser.cc

@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: MIT
+// Copyright 2025 - Present, Light Transport Entertainment, Inc.
+//
+#include "arg-parser.hh"
+#include "str-util.hh"
+
+namespace tinyusdz {
+namespace argparser {
+
+ArgParser::ArgParser() {}
+
+void ArgParser::add_option(const std::string& name, bool has_value, const std::string& help) {
+    Option opt;
+    opt.name = name;
+    opt.has_value = has_value;
+    opt.is_set = false;
+    opt.value = "";
+    opt.help = help;
+    options_[name] = opt;
+}
+
+bool ArgParser::parse(int argc, char** argv) {
+    positional_args_.clear();
+    for (int i = 1; i < argc; ++i) {
+        std::string arg = argv[i];
+        if (arg.size() > 0 && arg[0] == '-') {
+            // Option
+            auto it = options_.find(arg);
+            if (it == options_.end()) {
+                // Unknown option
+                return false;
+            }
+            it->second.is_set = true;
+            if (it->second.has_value) {
+                if (i + 1 < argc) {
+                    it->second.value = argv[i + 1];
+                    ++i;
+                } else {
+                    // Missing value
+                    return false;
+                }
+            }
+        } else {
+            // Positional argument
+            positional_args_.push_back(arg);
+        }
+    }
+    return true;
+}
+
+bool ArgParser::is_set(const std::string& name) const {
+    auto it = options_.find(name);
+    if (it != options_.end()) {
+        return it->second.is_set;
+    }
+    return false;
+}
+
+bool ArgParser::get(const std::string& name, std::string& value) const {
+    auto it = options_.find(name);
+    if (it != options_.end() && it->second.is_set && it->second.has_value) {
+        value = it->second.value;
+        return true;
+    }
+    return false;
+}
+
+bool ArgParser::get(const std::string& name, double& value) const {
+    auto it = options_.find(name);
+    if (it != options_.end() && it->second.is_set && it->second.has_value) {
+        double d = tinyusdz::atof(it->second.value.c_str());
+        value = d;
+        return true;
+    }
+    return false;
+}
+
+const std::vector<std::string>& ArgParser::positional() const {
+    return positional_args_;
+}
+
+void ArgParser::print_help() const {
+    for (const auto& kv : options_) {
+        const auto& opt = kv.second;
+        std::string value_hint = opt.has_value ? " <value>" : "";
+        printf("  %s%s\n      %s\n", opt.name.c_str(), value_hint.c_str(), opt.help.c_str());
+    }
+}
+
+} // namespace argparser
+} // namespace tinyusdz

src/arg-parser.hh

@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: MIT
+// Copyright 2025 - Present, Light Transport Entertainment, Inc.
+//
+// Simple arg parser.
+//
+#pragma once
+#include <string>
+#include <vector>
+#include <map>
+
+namespace tinyusdz {
+namespace argparser {
+
+struct Option {
+    std::string name;
+    std::string value;
+    bool has_value;
+    bool is_set;
+    std::string help; // Help string for the option
+};
+
+class ArgParser {
+public:
+    ArgParser();
+
+    // Register an option (e.g., "--input") with help string
+    void add_option(const std::string& name, bool has_value, const std::string& help = "");
+
+    // Parse argc/argv. Returns true on success, false on error.
+    bool parse(int argc, char** argv);
+
+    // Check if option is set
+    bool is_set(const std::string& name) const;
+
+    // Get value for option. Returns true if found, false otherwise.
+    bool get(const std::string& name, std::string& value) const;
+
+    // Get value for option as double. Returns true if found and conversion succeeds, false otherwise.
+    bool get(const std::string& name, double& value) const;
+
+    // Get positional arguments (non-option arguments)
+    const std::vector<std::string>& positional() const;
+
+    // Print help for all options
+    void print_help() const;
+
+private:
+    std::map<std::string, Option> options_;
+    std::vector<std::string> positional_args_;
+};
+
+} // namespace argparser
+} // namespace tinyusdz

src/str-util.cc

@@ -707,4 +707,14 @@ std::string makeIdentifierValid(const std::string &str, bool is_utf8) {
   return s;
 }
 
+double atof(const char *p) {
+  // TODO: Use from_chars
+  return std::atof(p);
+}
+
+double atof(const std::string &s) {
+  return atof(s.c_str());
+}
+
+
 }  // namespace tinyusdz

src/str-util.hh

@@ -395,4 +395,9 @@ inline std::string join(const std::string& sep, It& v)
 }
 #endif
 
+// Simple atof replacement
+// Returns qNaN for invalid input.
+double atof(const char *s);
+double atof(const std::string &s);
+
 }  // namespace tinyusdz