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Comprehensive documentation and working C++ examples for OpenUSD's Crate (USDC binary) format implementation. Documentation (crate-impl.md, 1249 lines): - Complete binary format specification with diagrams - File layout: Bootstrap, Value Data, Structural Sections, TOC - Key data structures: ValueRep (8 bytes), Spec, Field, TimeSamples - Type system: All 60 supported types documented - Reading implementation: 3 ByteStream backends (mmap/pread/asset) - Writing implementation: Packing, deduplication, async I/O - Compression: Integer/float/LZ4 algorithms detailed - Deduplication: 3-level system (structural/per-type/time arrays) - Version history: 13 versions (0.0.1 to 0.13.0) - Optimizations: Zero-copy arrays, parallel construction, etc. - Performance: Read/write speeds, memory usage, file sizes - Security: Bounds checking, recursion protection, validation C++ Examples (aousd/crate/): Three working programs demonstrating OpenUSD C++ API: 1. crate_reader (157 KB) - Read .usdc/.usda files - Traverse prim hierarchy - Display attributes and TimeSamples - Works with any USD file 2. crate_writer (329 KB) - Create animated USD scenes - Write TimeSamples for animation - Animated transforms and colors - Simple and complex scene modes 3. crate_internal_api (169 KB) - Inspect binary format (magic, version, TOC) - Analyze TimeSamples (uniform/non-uniform sampling) - Compare format sizes (ASCII vs binary) - Low-level format introspection Build Systems: - Makefile: Simple, fast Unix builds - CMake: Cross-platform, IDE integration - build.sh: Convenience wrapper script - Both monolithic and standard USD linking - Links against no-python OpenUSD builds Documentation: - README.md: Complete build/usage instructions - EXAMPLES_OUTPUT.md: Actual program outputs - Full API usage examples - Troubleshooting guide Verified Working: - Compiles with C++17 - Links against libusd_ms.so (monolithic) - Creates/reads .usdc files successfully - Binary format inspection working - TimeSamples encoding/decoding functional File sizes: ~660 KB total (all 3 programs) Binary compression: 50-60% smaller than ASCII 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
122 lines
3.4 KiB
CMake
122 lines
3.4 KiB
CMake
cmake_minimum_required(VERSION 3.12)
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project(USDCrateExamples CXX)
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set(CMAKE_CXX_STANDARD 17)
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set(CMAKE_CXX_STANDARD_REQUIRED ON)
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# Option to use monolithic build
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option(USE_MONOLITHIC_USD "Use monolithic USD library (libusd_ms)" OFF)
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# Find USD installation
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# Set USD_ROOT to your OpenUSD installation directory
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if(NOT DEFINED USD_ROOT)
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if(USE_MONOLITHIC_USD)
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set(USD_ROOT "${CMAKE_CURRENT_SOURCE_DIR}/../dist_nopython_monolithic"
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CACHE PATH "USD installation directory (monolithic)")
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else()
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set(USD_ROOT "${CMAKE_CURRENT_SOURCE_DIR}/../dist_nopython"
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CACHE PATH "USD installation directory")
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endif()
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endif()
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message(STATUS "USD_ROOT: ${USD_ROOT}")
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message(STATUS "USE_MONOLITHIC_USD: ${USE_MONOLITHIC_USD}")
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# Check if USD installation exists
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if(NOT EXISTS "${USD_ROOT}")
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message(FATAL_ERROR "USD installation not found at: ${USD_ROOT}\n"
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"Please build OpenUSD first or set USD_ROOT")
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endif()
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# USD include directories
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include_directories(${USD_ROOT}/include)
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# USD library directory
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link_directories(${USD_ROOT}/lib)
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# Platform-specific settings
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if(UNIX AND NOT APPLE)
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# Linux
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set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-deprecated")
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# Add rpath for runtime library loading
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set(CMAKE_INSTALL_RPATH "${USD_ROOT}/lib")
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set(CMAKE_BUILD_RPATH "${USD_ROOT}/lib")
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endif()
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# Define USD libraries based on build type
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if(USE_MONOLITHIC_USD)
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# Monolithic build - single library
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set(USD_LIBRARIES
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usd_ms
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tbb
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)
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message(STATUS "Using monolithic USD library: libusd_ms")
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else()
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# Standard build - multiple libraries
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set(USD_LIBRARIES
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# Core USD libraries
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usd
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usdGeom
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sdf
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tf
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vt
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gf
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ar
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arch
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plug
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trace
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work
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# TBB for threading
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tbb
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)
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message(STATUS "Using standard USD libraries")
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endif()
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# Print found libraries
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message(STATUS "USD libraries: ${USD_LIBRARIES}")
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# Common function to create executable
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function(add_usd_executable target source)
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add_executable(${target} ${source})
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target_link_libraries(${target}
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${USD_LIBRARIES}
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${CMAKE_DL_LIBS}
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pthread
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)
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# Set RPATH
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set_target_properties(${target} PROPERTIES
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BUILD_RPATH "${USD_ROOT}/lib"
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INSTALL_RPATH "${USD_ROOT}/lib"
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)
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message(STATUS "Added executable: ${target}")
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endfunction()
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# Build executables
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add_usd_executable(crate_reader src/crate_reader.cpp)
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add_usd_executable(crate_writer src/crate_writer.cpp)
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add_usd_executable(crate_internal_api src/crate_internal_api.cpp)
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# Install targets
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install(TARGETS crate_reader crate_writer crate_internal_api
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RUNTIME DESTINATION bin)
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# Print summary
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message(STATUS "")
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message(STATUS "========================================")
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message(STATUS "USD Crate Examples Configuration")
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message(STATUS "========================================")
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message(STATUS " Build type: ${CMAKE_BUILD_TYPE}")
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message(STATUS " USD root: ${USD_ROOT}")
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message(STATUS " Monolithic: ${USE_MONOLITHIC_USD}")
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message(STATUS " Compiler: ${CMAKE_CXX_COMPILER}")
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message(STATUS " C++ Standard: ${CMAKE_CXX_STANDARD}")
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message(STATUS "")
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message(STATUS "Targets:")
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message(STATUS " - crate_reader")
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message(STATUS " - crate_writer")
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message(STATUS " - crate_internal_api")
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message(STATUS "========================================")
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