Windows pip support

.github/workflows/build-wheels-windows.yml

@@ -0,0 +1,87 @@
+name: Build Wheels (Windows)
+
+on:
+  push:
+    branches: [ master, main ]
+    tags: [ 'v*' ]
+  pull_request:
+    branches: [ master, main ]
+  workflow_dispatch:
+
+jobs:
+  build_wheels:
+    name: Build wheels on ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    timeout-minutes: 90
+    strategy:
+      matrix:
+        os: [windows-latest]
+        python-version: ['3.11', '3.12', '3.13', '3.14']
+
+    steps:
+    - uses: actions/checkout@v6
+      with:
+        submodules: recursive
+
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v6
+      with:
+        python-version: ${{ matrix.python-version }}
+
+    - name: Install CMake (Windows)
+      run: |
+        choco install cmake --installargs 'ADD_CMAKE_TO_PATH=System'
+        refreshenv
+
+    - name: Install build dependencies
+      run: |
+        python -m pip install --upgrade pip
+        python -m pip install build wheel setuptools
+
+    - name: Clone dependencies
+      run: |
+        git clone --single-branch --depth 1 https://github.com/pybind/pybind11.git pybind11
+        git clone -b 20250814.1 --single-branch --depth 1 https://github.com/abseil/abseil-cpp.git open_spiel/abseil-cpp
+        git clone -b master https://github.com/nlohmann/json.git open_spiel/json
+        cd open_spiel/json && git checkout 9cca280a4d0ccf0c08f47a99aa71d1b0e52f8d03 && cd ../..
+        git clone -b master https://github.com/pybind/pybind11_json.git open_spiel/pybind11_json
+        cd open_spiel/pybind11_json && git checkout d0bf434be9d287d73a963ff28745542daf02c08f && cd ../..
+        git clone -b master https://github.com/pybind/pybind11_abseil.git open_spiel/pybind11_abseil
+        cd open_spiel/pybind11_abseil && git checkout 73992b5 && cd ../..
+        git clone -b develop --single-branch --depth 1 https://github.com/jblespiau/dds.git open_spiel/games/bridge/double_dummy_solver
+
+    - name: Build wheel
+      run: |
+        python -m build --wheel --outdir dist/
+        if (!(Test-Path dist/*.whl)) { Write-Error "No wheel file generated"; exit 1 }
+        Get-ChildItem dist/*.whl
+      shell: pwsh
+
+    - name: Test wheel installation
+      run: |
+        $wheel = Get-ChildItem dist/*.whl | Select-Object -First 1
+        python -m pip install $wheel.FullName
+        python -c "import pyspiel; game = pyspiel.load_game('tic_tac_toe'); print('OpenSpiel works! Game:', game.get_type().short_name)"
+      shell: pwsh
+
+    - name: Upload artifacts
+      uses: actions/upload-artifact@v6
+      with:
+        name: wheels-${{ matrix.os }}-py${{ matrix.python-version }}
+        path: dist/*.whl
+
+  upload_pypi:
+    needs: [build_wheels]
+    runs-on: ubuntu-latest
+    if: github.event_name == 'push' && startsWith(github.ref, 'refs/tags/v')
+    steps:
+    - name: Download all artifacts
+      uses: actions/download-artifact@v6
+      with:
+        path: dist
+
+    - name: Publish to PyPI
+      uses: pypa/gh-action-pypi-publish@release/v1
+      with:
+        password: ${{ secrets.PYPI_API_TOKEN }}
+        packages_dir: dist/*/

.github/workflows/wheels.yml

@@ -1,11 +1,10 @@
 # Builds and tests the OpenSpiel wheels using cibuildwheel.
 #
-# Each wheel is built via the manylinux2014 pypa Docker image on Linux and
-# standard MacOS X on 10.15. Each binary wheel is built only for x86_64. Basic
-# API tests are run within the Docker environment that built the wheel. Full
-# tests (tests that use extra dependencies such as PyTorch, JAX, Tensorflow)
-# are tested in the Github Actions CI environment (Ubuntu 20.04 and Mac OS
-# 10.15).
+# Each wheel is built via the manylinux_2_28 pypa Docker image on Linux,
+# standard MacOS X, and Windows using MSVC. Each binary wheel is built for
+# x86_64 (and arm64 where supported). Basic API tests are run within the build
+# environment. Full tests (tests that use extra dependencies such as PyTorch,
+# JAX, Tensorflow) are tested in the Github Actions CI environment.
 name: wheels
 
 on:
@@ -145,3 +144,79 @@ jobs:
             dist/*.tar.gz
             ./wheelhouse/*.whl
 
+  # Windows wheel builds - separate job due to different build process (no cibuildwheel)
+  build_windows_wheels:
+    name: Build wheels on Windows Python ${{ matrix.python-version }}
+    runs-on: windows-latest
+    timeout-minutes: 90
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: ['3.11', '3.12', '3.13', '3.14']
+
+    env:
+      OPEN_SPIEL_BUILDING_WHEEL: ON
+
+    steps:
+      - uses: actions/checkout@v6
+        with:
+          submodules: recursive
+
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v6
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - name: Install CMake
+        run: |
+          choco install cmake --installargs 'ADD_CMAKE_TO_PATH=System' -y
+          refreshenv
+        shell: pwsh
+
+      - name: Install build dependencies
+        run: |
+          python -m pip install --upgrade pip
+          python -m pip install build wheel setuptools
+        shell: pwsh
+
+      - name: Clone dependencies
+        run: |
+          git clone --single-branch --depth 1 https://github.com/pybind/pybind11.git pybind11
+          git clone -b 20250814.1 --single-branch --depth 1 https://github.com/abseil/abseil-cpp.git open_spiel/abseil-cpp
+          git clone -b master https://github.com/nlohmann/json.git open_spiel/json
+          cd open_spiel/json && git checkout 9cca280a4d0ccf0c08f47a99aa71d1b0e52f8d03 && cd ../..
+          git clone -b master https://github.com/pybind/pybind11_json.git open_spiel/pybind11_json
+          cd open_spiel/pybind11_json && git checkout d0bf434be9d287d73a963ff28745542daf02c08f && cd ../..
+          git clone -b master https://github.com/pybind/pybind11_abseil.git open_spiel/pybind11_abseil
+          cd open_spiel/pybind11_abseil && git checkout 73992b5 && cd ../..
+          git clone -b develop --single-branch --depth 1 https://github.com/jblespiau/dds.git open_spiel/games/bridge/double_dummy_solver
+        shell: pwsh
+
+      - name: Build wheel
+        run: |
+          python -m build --wheel --outdir dist/
+          if (!(Test-Path dist/*.whl)) { Write-Error "No wheel file generated"; exit 1 }
+          Get-ChildItem dist/*.whl
+        shell: pwsh
+
+      - name: Test wheel installation
+        run: |
+          $wheel = Get-ChildItem dist/*.whl | Select-Object -First 1
+          python -m pip install $wheel.FullName
+          python -c "import pyspiel; game = pyspiel.load_game('tic_tac_toe'); print('OpenSpiel works! Game:', game.get_type().short_name)"
+        shell: pwsh
+
+      # Note: Windows tests are currently less thorough than Linux/macOS tests.
+      # TODO: Improve Windows test coverage in future iterations.
+      - name: Run basic tests
+        run: |
+          python -c "import pyspiel; print('Registered games:', len(pyspiel.registered_names()))"
+          python -c "import pyspiel; g = pyspiel.load_game('kuhn_poker'); print('Kuhn poker loaded successfully')"
+          python -c "import pyspiel; g = pyspiel.load_game('leduc_poker'); print('Leduc poker loaded successfully')"
+        shell: pwsh
+
+      - name: Upload artifacts
+        uses: actions/upload-artifact@v6
+        with:
+          name: wheels-windows-py${{ matrix.python-version }}
+          path: dist/*.whl

README.md

@@ -33,6 +33,7 @@ To try OpenSpiel in Google Colaboratory, please refer to `open_spiel/colabs` sub
 Please choose among the following options:
 
 *   [Installing OpenSpiel](docs/install.md)
+*   [Windows Installation](docs/windows.md)
 *   [Introduction to OpenSpiel](docs/intro.md)
 *   [API Overview and First Example](docs/concepts.md)
 *   [API Reference](docs/api_reference.md)

__init__.py

@@ -0,0 +1,10 @@
+"""
+OpenSpiel: A Framework for Reinforcement Learning in Games.
+
+OpenSpiel is a collection of environments and algorithms for research in general
+reinforcement learning and search/planning in games.
+"""
+
+import pyspiel
+
+__all__ = ["pyspiel"]

docs/windows.md

@@ -1,18 +1,97 @@
 # OpenSpiel Installation on Windows
 
-OpenSpiel has limited support on Windows and is not being regularly tested,
-which means support could break at any time. This may change in the future, but
-for now please be aware that Windows support is experimental. Please report any
-bugs or problems you encounter.
+OpenSpiel now has official support for Windows with pre-built binary wheels
+available on PyPI. Windows wheels are built and tested automatically via GitHub
+Actions CI for Python 3.11, 3.12, and 3.13.
 
-OpenSpiel has limited support on Windows and is not being regularly tested,
-which means support could break at any time. This may change in the future
-(contributions are welcome), with Github Actions supporting
-[windows workers](https://docs.github.com/en/actions/using-github-hosted-runners/customizing-github-hosted-runners#installing-software-on-windows-runners!),
-but for now please be aware that Windows support is experimental. Please report
-any bugs or problems you encounter.
+> **Note:** Windows support is currently experimental. If you encounter any
+> issues, please [open an issue](https://github.com/deepmind/open_spiel/issues)
+> on GitHub so we can improve the Windows experience.
 
-## Option 1: Windows Installation using Visual Studio Community Edition
+## Option 1: Quick Installation using pip (Recommended)
+
+The easiest way to install OpenSpiel on Windows is using pip:
+
+```bash
+pip install open-spiel
+```
+
+### Optional dependencies
+For additional features like visualization and machine learning:
+```bash
+pip install open-spiel[full]
+```
+
+### Verification
+
+Test your installation:
+```python
+import pyspiel
+
+# Create a simple game
+game = pyspiel.load_game("tic_tac_toe")
+state = game.new_initial_state()
+print("OpenSpiel is working!")
+```
+
+### Building from Source
+
+If you need to build from source or contribute to the project:
+
+#### Prerequisites
+- **Python 3.11+** (get from [python.org](https://python.org))
+- **Git** (get from [git-scm.com](https://git-scm.com))
+- **CMake 3.15+** (get from [cmake.org](https://cmake.org))
+- **Visual Studio 2019 or later** with C++ development tools
+
+#### Build Steps
+1. Clone the repository:
+   ```bash
+   git clone https://github.com/deepmind/open_spiel.git
+   cd open_spiel
+   ```
+
+2. Build the wheel:
+   ```bash
+   python -m pip wheel . --no-deps -w dist
+   ```
+
+3. Install the built wheel:
+   ```bash
+   pip install dist/open_spiel-*.whl
+   ```
+
+### Troubleshooting
+
+**"CMake not found"**
+- Install CMake from [cmake.org](https://cmake.org) and add it to your PATH
+
+**"Git not found"**  
+- Install Git from [git-scm.com](https://git-scm.com) and add it to your PATH
+
+**"MSVC compiler not found"**
+- Install Visual Studio Community with C++ development tools
+- Or install "Microsoft C++ Build Tools"
+
+**"Import pyspiel failed"**
+- Make sure you installed the package: `pip install open-spiel`
+- Try reinstalling: `pip uninstall open-spiel && pip install open-spiel`
+
+### Development Installation
+```bash
+git clone https://github.com/deepmind/open_spiel.git
+cd open_spiel
+pip install -e .
+```
+
+### Using with Conda
+```bash
+conda create -n openspiel python=3.11
+conda activate openspiel
+pip install open-spiel
+```
+
+## Option 2: Windows Installation using Visual Studio Community Edition
 
 This option will describe how to install and use OpenSpiel on Windows 10 via
 [Visual Studio Community Edition](https://visualstudio.microsoft.com/vs/community/).
@@ -28,7 +107,7 @@ You will need to have the following dependencies installed:
 *   [CMake](https://cmake.org/download/)
 *   [git](https://gitforwindows.org/)
 *   [Python](https://www.python.org/downloads/windows/). Note: get the latest
-    3.9 release as OpenSpiel has not been tested on 3.10 yet. Also, tick the box
+    3.11 or newer release. Tick the box
     during installation to ensure Python executable is in your path.
 *   Recommended: Windows Terminal / Powershell.
 
@@ -85,7 +164,7 @@ pip install numpy
 For a complete list, depending on what you will use, see
 [python_extra_deps.sh](https://github.com/deepmind/open_spiel/blob/master/open_spiel/scripts/python_extra_deps.sh).
 
-## Option 2: Windows Installation using Windows Subsystem for Linux (WSL)
+## Option 3: Windows Installation using Windows Subsystem for Linux (WSL)
 
 This section describes the installation steps to get OpenSpiel running in a
 Windows 10 environment using Windows Subsystem for Linux (WSL). Note that WSL

open_spiel/CMakeLists.txt

@@ -206,7 +206,7 @@ include_directories (pybind11_json/include)
 add_library(open_spiel_core OBJECT ${OPEN_SPIEL_CORE_FILES})
 target_include_directories (
   open_spiel_core PUBLIC ${CMAKE_CURRENT_SOURCE_DIR} abseil-cpp)
-link_libraries(open_spiel_core
+target_link_libraries(open_spiel_core
   absl::algorithm
   absl::flags
   absl::flags_parse
@@ -218,6 +218,7 @@ link_libraries(open_spiel_core
   absl::time
 )
 
+
 # Just the minimal base library: no games.
 set (OPEN_SPIEL_CORE_OBJECTS $<TARGET_OBJECTS:open_spiel_core>)
 

open_spiel/games/crazy_eights/crazy_eights.cc

@@ -315,7 +315,7 @@ void CrazyEightsState::WriteObservationTensor(Player player,
   SPIEL_CHECK_GE(player, 0);
   SPIEL_CHECK_LT(player, num_players_);
 
-  absl::c_fill(values, 0.);
+  absl::c_fill(values, 0.0f);
   if (phase_ == Phase::kDeal) return;
 
   for (int card = 0; card < kNumCards; ++card) {

open_spiel/games/dou_dizhu/dou_dizhu.cc

@@ -216,7 +216,7 @@ void DouDizhuState::WriteObservationTensor(Player player,
   SPIEL_CHECK_GE(player, 0);
   SPIEL_CHECK_LT(player, num_players_);
 
-  absl::c_fill(values, 0.);
+  absl::c_fill(values, 0.0f);
   if (phase_ == Phase::kDeal) return;
   auto values_iterator = values.begin();
   const int played_deck_base = (kNumRanks - 2) * (kNumSuits + 1) + 2 * 2;

open_spiel/games/lines_of_action/lines_of_action.cc

@@ -76,9 +76,12 @@ Player CellStateToPlayer(CellState cell_state) {
       return 0;
     case CellState::kWhite:
       return 1;
+    default:
+      return kInvalidPlayer;
   }
 }
 
+
 CellState PlayerToCellState(Player player) {
   switch (player) {
     case 0:

open_spiel/games/tarok/contracts.cc

@@ -79,6 +79,7 @@ std::string ContractNameToString(const ContractName& contract_name) {
     case ContractName::kNotSelected:
       return "Not selected";
   }
+  SpielFatalError("Unknown contract name");
 }
 
 }  // namespace tarok