Fixed ray-tracing tests on Vulkan

Author: TheMostDiligent

Graphics/GraphicsEngine/interface/PipelineState.h

@@ -1,5 +1,5 @@
 /*
- *  Copyright 2019-2024 Diligent Graphics LLC
+ *  Copyright 2019-2025 Diligent Graphics LLC
  *  Copyright 2015-2019 Egor Yusov
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
@@ -510,8 +510,11 @@ struct RayTracingPipelineDesc
     /// Shader record size plus shader group size (32 bytes) must not exceed 4096 bytes.
     Uint16  ShaderRecordSize   DEFAULT_INITIALIZER(0);
 
-    /// Number of recursive calls of TraceRay() in HLSL or traceRay() in GLSL.
-    /// Zero means no tracing of rays at all, only ray-gen shader will be executed.
+    /// Number of recursive calls of TraceRay() in HLSL or traceRayEXT() in GLSL.
+    /// Shaders directly invoked from the API always have a recursion depth of 0; each
+    /// shader executed by the trace ray instruction has a recursion depth one higher than
+    /// the recursion depth of the shader which invoked it. Applications must not invoke a
+    /// shader with a recursion depth greater than the value of MaxRecursionDepth.
     /// See DeviceProperties::MaxRayTracingRecursionDepth.
     Uint8   MaxRecursionDepth  DEFAULT_INITIALIZER(0);
 

Tests/DiligentCoreAPITest/src/RayTracingTest.cpp

@@ -1,5 +1,5 @@
 /*
- *  Copyright 2019-2022 Diligent Graphics LLC
+ *  Copyright 2019-2025 Diligent Graphics LLC
  *  Copyright 2015-2019 Egor Yusov
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
@@ -1634,6 +1634,7 @@ TEST_P(RT5, InlineRayTracing_RayTracingPSO)
     PSOCreateInfo.pGeneralShaders    = GeneralShaders;
     PSOCreateInfo.GeneralShaderCount = _countof(GeneralShaders);
 
+    // The hardware does not need a recursion stack to jump among separate programs - everything is inlined in the same shader invocation.
     PSOCreateInfo.RayTracingPipeline.MaxRecursionDepth       = 0;
     PSOCreateInfo.PSODesc.ResourceLayout.DefaultVariableType = SHADER_RESOURCE_VARIABLE_TYPE_MUTABLE;
 

Tests/DiligentCoreAPITest/src/Vulkan/RayTracingReferenceVk.cpp

@@ -1,5 +1,5 @@
 /*
- *  Copyright 2019-2024 Diligent Graphics LLC
+ *  Copyright 2019-2025 Diligent Graphics LLC
  *  Copyright 2015-2019 Egor Yusov
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
@@ -274,7 +274,7 @@ void InitializeRTContext(RTContext& Ctx, ISwapChain* pSwapChain, PSOCtorType&& P
         PipelineCI.pStages                      = Helper.Stages.data();
         PipelineCI.groupCount                   = static_cast<Uint32>(Helper.Groups.size());
         PipelineCI.pGroups                      = Helper.Groups.data();
-        PipelineCI.maxPipelineRayRecursionDepth = 0;
+        PipelineCI.maxPipelineRayRecursionDepth = 1;
         PipelineCI.layout                       = Ctx.vkLayout;
 
         res = vkCreateRayTracingPipelinesKHR(Ctx.vkDevice, VK_NULL_HANDLE, VK_NULL_HANDLE, 1, &PipelineCI, nullptr, &Ctx.vkPipeline);