liblesstagcpu.so — LessTag CPU backend (Linux x64)

Linux x86_64 build of the pure-CPU LessTag detector, for DetourLite.dll running on .NET 8 under Linux. Links no OpenCL.

Install

Drop liblesstagcpu.so beside DetourLite.dll. .NET resolves DllImport("lesstagcpu.dll") to liblesstagcpu.so on Linux automatically — do not rename it.

You will normally also want:

• libOpenCvSharpExtern.so (x64 or arm64 variant) from the Other section
• libregcore_gtex_cpu.so if you use GroundTex

Selecting it

Same resolution order as on Windows:

1. the detector's backend setting ("cpu", "cl", "auto")
2. legacy clVer = "cpu"
3. DETOUR_LESSTAG environment variable
4. discovery order — OpenCL first, CPU as the fallback

On a box with no libcllesstag.so, auto lands on the CPU backend by itself.

Build

CMake, from the Detour tree:

cd NativeLibs/clLessTag
cmake -S . -B build-linux -DCMAKE_BUILD_TYPE=Release
cmake --build build-linux -j

Only OpenCL headers are needed (lesstag.h uses cl_* types for struct layout); nothing OpenCL is linked. The header directory defaults to the in-tree tools/opencl_sdk/include and can be overridden with -DLESSTAG_CL_INCLUDE_DIR=.

Identical to the Windows builds

Built from the same sources as lesstagcpu.dll. Fed the same synthesized tag image, this .so, lesstagcpu.dll, and cllesstag.dll's internal CPU path all return the same tag id and the same pose, field for field. Built and verified on gcc 11.4 / Ubuntu 22.04.