Enable tracing rays with OptiX backend (#1871)

* OptiX ray payload can now be read from and written to using the two payload register pointer method

* changing op to more descriptive name

* small tweak to allow for dumping out intermediate source for cuda targets

* initial trace ray call compiling

* hit attributes now work for float and int types, and vectors thereof

* Hitgroups using structs and arrays now work with optix

Co-authored-by: T. Foley <tfoleyNV@users.noreply.github.com>

1 files changed, 23 insertions, 0 deletions

diff --git a/source/slang/slang-emit-cuda.cpp b/source/slang/slang-emit-cuda.cpp
index 4c430cfa6..0a375cb56 100644
--- a/source/slang/slang-emit-cuda.cpp
+++ b/source/slang/slang-emit-cuda.cpp
@@ -788,6 +788,29 @@ bool CUDASourceEmitter::tryEmitInstExprImpl(IRInst* inst, const EmitOpInfo& inOu
             m_writer->emit(")getOptiXRayPayloadPtr()");
             return true;
         }
+        case kIROp_GetOptiXHitAttribute:
+        {
+            auto typeToFetch = inst->getOperand(0);
+            auto idxInst = as<IRIntLit>(inst->getOperand(1));
+            IRIntegerValue idx = idxInst->getValue();
+            if (typeToFetch->getOp() == kIROp_FloatType) {
+                m_writer->emit("__int_as_float(optixGetAttribute_");
+            }
+            else
+            {
+                m_writer->emit("optixGetAttribute_");
+            }
+            m_writer->emit(idx);
+            if (typeToFetch->getOp() == kIROp_FloatType)
+            {
+                m_writer->emit("())");
+            }
+            else
+            {
+                m_writer->emit("()");
+            }
+            return true;
+        }
         default: break;
     }