Vulkan: fixed issues with max vertex in acceleration structures

Author: TheMostDiligent

Graphics/GraphicsEngineVulkan/src/BottomLevelASVkImpl.cpp

@@ -66,13 +66,16 @@ BottomLevelASVkImpl::BottomLevelASVkImpl(IReferenceCounters*      pRefCounters,
                 dst.sType        = VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_GEOMETRY_KHR;
                 dst.pNext        = nullptr;
                 dst.geometryType = VK_GEOMETRY_TYPE_TRIANGLES_KHR;
-                dst.flags        = VkGeometryFlagsKHR(0);
-
-                tri.sType                       = VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_GEOMETRY_TRIANGLES_DATA_KHR;
-                tri.pNext                       = nullptr;
-                tri.vertexFormat                = TypeToVkFormat(src.VertexValueType, src.VertexComponentCount, src.VertexValueType < VT_FLOAT16);
-                tri.maxVertex                   = src.MaxVertexCount;
-                tri.indexType                   = TypeToVkIndexType(src.IndexType);
+                dst.flags        = 0;
+
+                tri.sType        = VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_GEOMETRY_TRIANGLES_DATA_KHR;
+                tri.pNext        = nullptr;
+                tri.vertexFormat = TypeToVkFormat(src.VertexValueType, src.VertexComponentCount, src.VertexValueType < VT_FLOAT16);
+                // maxVertex is the number of vertices in vertexData minus one.
+                VERIFY(src.MaxVertexCount > 0, "MaxVertexCount must be greater than 0");
+                tri.maxVertex = src.MaxVertexCount - 1;
+                tri.indexType = TypeToVkIndexType(src.IndexType);
+                // Non-null address indicates that non-null transform data will be provided to the build command.
                 tri.transformData.deviceAddress = src.AllowsTransforms ? 1 : 0;
                 MaxPrimitiveCounts[i]           = src.MaxPrimitiveCount;
 

Graphics/GraphicsEngineVulkan/src/DeviceContextVkImpl.cpp

@@ -3434,9 +3434,11 @@ void DeviceContextVkImpl::BuildBLAS(const BuildBLASAttribs& Attribs)
             auto* const pVB = ClassPtrCast<BufferVkImpl>(SrcTris.pVertexBuffer);
 
             // vertex format in SrcTris may be undefined, so use vertex format from description
-            vkTris.vertexFormat             = TypeToVkFormat(TriDesc.VertexValueType, TriDesc.VertexComponentCount, TriDesc.VertexValueType < VT_FLOAT16);
-            vkTris.vertexStride             = SrcTris.VertexStride;
-            vkTris.maxVertex                = SrcTris.VertexCount;
+            vkTris.vertexFormat = TypeToVkFormat(TriDesc.VertexValueType, TriDesc.VertexComponentCount, TriDesc.VertexValueType < VT_FLOAT16);
+            vkTris.vertexStride = SrcTris.VertexStride;
+            // maxVertex is the number of vertices in vertexData minus one.
+            VERIFY(SrcTris.VertexCount > 0, "Vertex count must be greater than 0");
+            vkTris.maxVertex                = SrcTris.VertexCount - 1;
             vkTris.vertexData.deviceAddress = pVB->GetVkDeviceAddress() + SrcTris.VertexOffset;
 
             // geometry.triangles.vertexData.deviceAddress must be aligned to the size in bytes of the smallest component of the format in vertexFormat