From 7bcc1a817ece5e708bd0fe2fd846cfe54c55ba64 Mon Sep 17 00:00:00 2001
From: Simon Kallweit <64953474+skallweitNV@users.noreply.github.com>
Date: Mon, 13 Jan 2025 14:27:44 +0100
Subject: Find OptiX headers (#6071)

* add support for finding OptiX headers

* add documentation

* fix linux path
---
 docs/cuda-target.md | 11 +++++++++++
 1 file changed, 11 insertions(+)

(limited to 'docs')

diff --git a/docs/cuda-target.md b/docs/cuda-target.md
index a80dc59f9..241f253fb 100644
--- a/docs/cuda-target.md
+++ b/docs/cuda-target.md
@@ -301,6 +301,17 @@ There is potential to calculate the lane id using the [numthreads] markup in Sla
 * Intrinsics which only work in pixel shaders
   + QuadXXXX intrinsics
 
+OptiX Support
+=============
+
+Slang supports OptiX for raytracing. To compile raytracing programs, NVRTC must have access to the `optix.h` and dependent files that are typically distributed as part of the OptiX SDK. When Slang detects the use of raytracing in source, it will define `SLANG_CUDA_ENABLE_OPTIX` when `slang-cuda-prelude.h` is included. This will in turn try to include `optix.h`.
+
+Slang tries several mechanisms to locate `optix.h` when NVRTC is initiated. The first mechanism is to look in the include paths that are passed to Slang. If `optix.h` can be found in one of these paths, no more searching will be performed.
+
+If this fails, the default OptiX SDK install locations are searched. On Windows this is `%{PROGRAMDATA}\NVIDIA Corporation\OptiX SDK X.X.X\include`. On Linux this is `${HOME}/NVIDIA-OptiX-SDK-X.X.X-suffix`. 
+
+If OptiX headers cannot be found, compilation will fail.
+
 Limitations
 ===========
 
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