Method MapForReading

trinityal/dx12/Tr2TextureALDx12.cpp:1485–1550

}

ALResult Tr2TextureAL::MapForReading( const Tr2TextureSubresource& region, bool synchronize, const void*& data, uint32_t& pitch, Tr2RenderContextAL& renderContext )
{
	if( !IsValid() )
	{
		return E_INVALIDCALL;
	}
	if( !renderContext.IsValid() )
	{
		return E_INVALIDARG;
	}
	if( !HasFlag( m_cpuUsage, Tr2CpuUsage::READ ) )
	{
		return E_INVALIDCALL;
	}

	auto texture = GetResourceDx12();

	CComPtr<ID3D12Resource> scratch = m_readScratch;
	if( !scratch )
	{
		auto totalSize = GetRequiredIntermediateSize( texture, 0, 1 );
		auto scratchHeap = HeapDesc( D3D12_HEAP_TYPE_READBACK );
		auto scratchDesc = BufferDesc( totalSize );
		CR_RETURN_HR( m_owner->m_device->CreateCommittedResource(
			&scratchHeap,
			D3D12_HEAP_FLAG_NONE,
			&scratchDesc,
			D3D12_RESOURCE_STATE_COPY_DEST,
			nullptr,
			IID_PPV_ARGS( &scratch ) ) );
	}

	renderContext.ResourceBarrierDx12( Transition( texture, m_defaultState, D3D12_RESOURCE_STATE_COPY_SOURCE ) );
	renderContext.FlushBarriersDx12( texture );

	auto subresource = region.m_startFace * m_desc.GetTrueMipCount() + region.m_startMipLevel;
	D3D12_RESOURCE_DESC desc = texture->GetDesc();
	D3D12_PLACED_SUBRESOURCE_FOOTPRINT layout;
	m_owner->m_device->GetCopyableFootprints( &desc, subresource, 1, 0, &layout, nullptr, nullptr, nullptr );
	layout.Offset = 0;
	D3D12_TEXTURE_COPY_LOCATION Src = { texture, D3D12_TEXTURE_COPY_TYPE_SUBRESOURCE_INDEX, subresource };
	D3D12_TEXTURE_COPY_LOCATION Dst = { scratch, D3D12_TEXTURE_COPY_TYPE_PLACED_FOOTPRINT, layout };

	renderContext.m_commandList->CopyTextureRegion( &Dst, 0, 0, 0, &Src, nullptr );

	renderContext.ResourceBarrierDx12( Transition( texture, D3D12_RESOURCE_STATE_COPY_SOURCE, m_defaultState ) );
	FlushBarriersMaybe( *this, renderContext );

	if( synchronize )
	{
		auto hr = renderContext.FlushAndSyncDx12();
		if( FAILED( hr ) )
		{
			RELEASE_LATER( m_owner, scratch );
			scratch = nullptr;
			return hr;
		}
	}