fix bugs introduced to example 24, the overflow submit Xfer & compute strategy fot messed up

Author: devsh

include/nbl/asset/ICPUImage.h

@@ -202,7 +202,7 @@ class NBL_API2 ICPUImage final : public IImage, public IPreHashed
 		inline ICPUImage(const SCreationParams& _params) : IImage(_params) {}
 		virtual ~ICPUImage() = default;
 
-		inline IAsset* getDependant_impl(const size_t ix) override {return buffer.get();}
+		inline IAsset* getDependant_impl(const size_t ix) override {return nullptr;}
 
 		inline void discardContent_impl() override
 		{

include/nbl/video/IDeviceMemoryAllocation.h

@@ -22,7 +22,7 @@ TO COPY BETWEEN MEMORY ALLOCATIONS you need to have them bound to
 one or two IGPUBuffers and execute IVideoDriver::copyBuffer between them.
 We only support persistently mapped buffers with ARB_buffer_storage.
 Please don't ask us to support Buffer Orphaning. */
-class IDeviceMemoryAllocation : public virtual core::IReferenceCounted
+class NBL_API2 IDeviceMemoryAllocation : public virtual core::IReferenceCounted
 {
     public:
         //! Access flags for how the application plans to use mapped memory (if any)

src/nbl/video/utilities/CAssetConverter.cpp

@@ -4003,20 +4003,27 @@ ISemaphore::future_t<IQueue::RESULT> CAssetConverter::convert_impl(SReserveResul
 				// there might be some QFOT releases from transfer to compute which need to happen before we execute Compute
 				auto drain = [&]()->bool
 				{
-					if (item.recomputeMips && transferBarriers.empty())
-						return drainCompute()==IQueue::RESULT::SUCCESS;
-					else if (pipelineBarrier(xferCmdBuf,{.memBarriers={},.bufBarriers={},.imgBarriers=transferBarriers},"Recording QFOT Release from Transfer Queue Familye after overflow failed"))
+					// Transfer and Compute barriers get recorded for image individually (see the TODO why its horrible)
+					// so we only need to worry about QFOTs for current image if they even exist
+					if (item.recomputeMips && !transferBarriers.empty())
 					{
-						if (drainBoth()!=IQueue::RESULT::SUCCESS)
+						// so now we need a immeidate QFOT Release cause we already recorded some compute mipmapping for current image
+						if (pipelineBarrier(xferCmdBuf,{.memBarriers={},.bufBarriers={},.imgBarriers=transferBarriers},"Recording QFOT Release from Transfer Queue Family after overflow failed"))
+						{
+							// a transfer microsubmit just for QFOT Release will need to be performed before Compute
+							if (drainBoth()!=IQueue::RESULT::SUCCESS)
+								return false;
+							transferBarriers.clear();
+						}
+						else
+						{
+							markFailureInStaging("Image QFOT Pipeline Barrier",item.canonical,image,pFoundHash);
 							return false;
-						transferBarriers.clear();
-					}
-					else
-					{
-						markFailureInStaging("Image QFOT Pipeline Barrier",item.canonical,image,pFoundHash);
-						return false;
+						}
+						return true;
 					}
-					return true;
+					else // Transfer just got submitted due to staging buffer overflow, compute has all the data required to start
+						return drainCompute()==IQueue::RESULT::SUCCESS;
 				};
 				//
 				using layout_t = IGPUImage::LAYOUT;