- do not use persistent buffers for models as it is a limited resource where each consumes a vkDeviceMemory object

src/rendering/vulkan/system/vk_buffers.cpp

@@ -110,15 +110,29 @@ void VKBuffer::Unmap()
 
 void *VKBuffer::Lock(unsigned int size)
 {
-	SetData(size, nullptr, false);
-	if (!mPersistent)
+	if (!mBuffer)
+	{
+		// The model mesh loaders lock multiple non-persistent buffers at the same time. This is not allowed in vulkan.
+		// VkDeviceMemory can only be mapped once and multiple non-persistent buffers may come from the same device memory object.
+		mStaticUpload.Resize(size);
+		map = mStaticUpload.Data();
+	}
+	else if (!mPersistent)
+	{
 		map = mBuffer->Map(0, size);
+	}
 	return map;
 }
 
 void VKBuffer::Unlock()
 {
-	if (!mPersistent)
+	if (!mBuffer)
+	{
+		map = nullptr;
+		SetData(mStaticUpload.Size(), mStaticUpload.Data(), true);
+		mStaticUpload.Clear();
+	}
+	else if (!mPersistent)
 	{
 		mBuffer->Unmap();
 		map = nullptr;

src/rendering/vulkan/system/vk_buffers.h

@@ -2,6 +2,7 @@
 
 #include "hwrenderer/data/buffers.h"
 #include "vk_objects.h"
+#include "utility/tarray.h"
 
 #ifdef _MSC_VER
 // silence bogus warning C4250: 'VKVertexBuffer': inherits 'VKBuffer::VKBuffer::SetData' via dominance
@@ -28,6 +29,7 @@ public:
 	std::unique_ptr<VulkanBuffer> mBuffer;
 	std::unique_ptr<VulkanBuffer> mStaging;
 	bool mPersistent = false;
+	TArray<uint8_t> mStaticUpload;
 };
 
 class VKVertexBuffer : public IVertexBuffer, public VKBuffer