WSL 2 support, bump nanobind & drjit versions

Author: wjakob

docs/index.rst

@@ -35,6 +35,11 @@ This command will also install :monosp:`Dr.Jit` on your system if not already av
 See the :ref:`developer guide <sec-compiling>` for complete instructions on building
 from the git source tree.
 
+When using the `Windows Subsystem for Linux 2 (WSL2)
+<https://learn.microsoft.com/en-us/windows/wsl/compare-versions#whats-new-in-wsl-2>`__,
+you must follow the :ref:`linked instructions <optix-wsl2>` to enable hardware-accelerated
+ray tracing on NVIDIA GPUs.
+
 Requirements
 ^^^^^^^^^^^^
 
@@ -149,5 +154,6 @@ When using Mitsuba 3 in academic projects, please cite:
     :hidden:
 
     src/gallery
+    src/optix_setup
     release_notes
     zz_bibliography

docs/src/developer_guide.rst

@@ -63,4 +63,4 @@ Going further
     developer_guide/documentation
     developer_guide/variants_cpp
     developer_guide/writing_plugin
-    developer_guide/testing
+    developer_guide/testing

docs/src/optix_setup.rst

@@ -0,0 +1,63 @@
+.. _optix-wsl2:
+
+Mitsuba on WSL 2
+----------------
+
+Mitsuba uses the `NVIDIA OptiX
+<https://developer.nvidia.com/rtx/ray-tracing/optix>`__ framework for
+hardware-accelerated ray tracing. While OptiX is not yet officially supported
+on the `Windows Subsystem for Linux 2 (WSL 2)
+<https://learn.microsoft.com/en-us/windows/wsl/compare-versions#whats-new-in-wsl-2>`__,
+it *is* possible to get it to run in practice. The following instructions are
+based on an NVIDIA `forum post by @dhart
+<https://forums.developer.nvidia.com/t/problem-running-optix-7-6-in-wsl/239355/8>`__
+Use them at your own risk.
+
+- Determine your driver version using the ``nvidia-smi`` command. This is a number
+  such as ``560.94`` shown in the middle of the first row.
+
+- Go to the `NVIDA driver webpage <https://www.nvidia.com/en-us/drivers>`__ to
+  download a similar driver version for Linux (64 bit). You may have to click on
+  the "New feature branch" tab to find newer driver versions.
+
+- Following this step, you should have file named
+  ``NVIDIA-Linux-x86_64-*.run``. Move it to your WSL home directory but *do
+  not install it*. Instead, merely extract its contents within a WSL session using
+  the following command:
+
+.. code-block:: console
+
+   $ bash NVIDIA-Linux-x86_64-*.run -x --target driver
+
+Create a symbolic link that exposes the already installed CUDA driver to runtime loading:
+
+.. code-block:: console
+
+   $ ln -s /usr/lib/wsl/lib/libcuda.so /usr/lib/x86_64-linux-gnu/
+
+Next, copy-paste and run the following command:
+
+.. code-block:: console
+
+   $ mkdir driver-dist && cp driver/libnvoptix.so.* driver-dist/libnvoptix.so.1 && cp driver/libnvidia-ptxjitcompiler.so.* driver-dist/libnvidia-ptxjitcompiler.so.1 && cp driver/libnvidia-rtcore.so.* driver-dist && cp driver/libnvidia-gpucomp.so.* driver-dist && cp driver/nvoptix.bin driver-dist && explorer.exe driver-dist && explorer.exe "C:\Windows\System32\lxss\lib"
+
+This will open two Explorer windows: one to a system path containing internal
+WSL driver files (``C:\Windows\System32\lxss\lib``), and another to a newly
+created ``driver-dist`` directory containing files that need to be copied to
+``C:\Windows\System32\lxss\lib``. Perform this copy manually using Explorer and
+overwrite existing files if present. It will warn you that this is dangerous,
+and you will need to give permission.
+
+Close all WSL windows, and enter the following command in a ``cmd.exe`` or
+PowerShell session:
+
+.. code-block:: pwsh-session
+
+   C:\Users\...> wsl --shutdown
+
+Following this, OptiX should be usable within WSL.
+
+.. warning::
+
+   Using CUDA and OptiX through WSL degrades performance. Please do not collect
+   performance data within WSL, since the results will not be representative.