windows: build fixes and docs

BUILD_WINDOWS.md

@@ -0,0 +1,43 @@
+# Windows (MSVC) Build Guide
+
+This project can be built with CMake on Windows using MSVC. The steps below
+use a clean out-of-source build directory (`build_clean`) and force fetching
+fmt/spdlog to avoid conflicts with system or Anaconda-provided versions.
+
+## Prerequisites
+
+- Visual Studio 2022 Build Tools (MSVC toolchain + CMake)
+- Git
+
+Tip: run these commands from a "x64 Native Tools Command Prompt for VS 2022"
+or a PowerShell that has MSVC tools on PATH.
+
+## Configure
+
+```powershell
+cmake -S . -B build_clean -DLIBOCULUS_FETCH_DEPS=ON -DLIBOCULUS_FORCE_FETCH_DEPS=ON
+```
+
+## Build
+
+```powershell
+cmake --build build_clean --config Debug --target occlient
+```
+
+## Outputs
+
+- Executable: `build_clean\bin\Debug\occlient.exe`
+- Library: `build_clean\lib\Debug\oculus.lib` (static on MSVC)
+
+## Run (example)
+
+```powershell
+.\build_clean\bin\Debug\occlient.exe -i "F:\Projects\liboculus\test\data\three_pings_8bit.raw" -v -o "F:\Projects\liboculus\test\data\out.raw"
+```
+
+## Troubleshooting
+
+- If CMake links against the wrong fmt/spdlog (e.g., Anaconda), use a fresh
+  build directory and keep `LIBOCULUS_FORCE_FETCH_DEPS=ON`.
+- If `build_clean` cannot be deleted, close Visual Studio or any process that
+  is holding files under `build_clean\.vs`.

CMakeLists.txt

@@ -3,7 +3,9 @@ project(liboculus)
 
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
-add_compile_options(-std=c++17)
+if(NOT MSVC)
+    add_compile_options(-std=c++17)
+endif()
 
 # == Code common to all builds =======================================
 list(APPEND CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)

README.md

@@ -57,6 +57,12 @@ make
 
 Note the `CMakelists.txt` attempts to auto-detect ROS.  Cmake build should be done in a session where ROS has not been loaded.
 
+### Windows (MSVC)
+
+See `BUILD_WINDOWS.md` for a repeatable Windows build flow that uses a clean
+out-of-source directory and forces fetching fmt/spdlog to avoid version
+conflicts.
+
 ## Logging
 
 > [!NOTE] [fips](http://floooh.github.io/fips/) support has been removed from this version.

build_clean/ALL_BUILD.vcxproj.filters

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="17.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup>
+    <CustomBuild Include="F:\Projects\liboculus\CMakeLists.txt" />
+  </ItemGroup>
+  <ItemGroup>
+  </ItemGroup>
+</Project>