D3D: Fixed D3D validation error during EFB to texture copy

Texture was being bound as a render target while still being set as a shader resource.
D3D automatically unbinds the SRV in this case and generates a validation error.
The fix is to manually unbind SRV, render into it and then re-bind to old slots.

Source/Core/VideoBackends/D3D/D3DState.cpp

@@ -199,6 +199,22 @@ void StateManager::Apply()
 	m_dirtyFlags = 0;
 }
 
+u32 StateManager::UnsetTexture(ID3D11ShaderResourceView* srv)
+{
+	u32 mask = 0;
+
+	for (u32 index = 0; index < 8; ++index)
+	{
+		if (m_current.textures[index] == srv)
+		{
+			SetTexture(index, nullptr);
+			mask |= 1 << index;
+		}
+	}
+
+	return mask;
+}
+
 }  // namespace D3D
 
 ID3D11SamplerState* StateCache::Get(SamplerState state)

Source/Core/VideoBackends/D3D/D3DState.h

@@ -234,6 +234,9 @@ public:
 		}
 	}
 
+	// removes currently set texture from all slots, returns mask of previously bound slots
+	u32 StateManager::UnsetTexture(ID3D11ShaderResourceView* srv);
+
 	// call this immediately before any drawing operation or to explicitly apply pending resource state changes
 	void Apply();
 

Source/Core/VideoBackends/D3D/TextureCache.cpp

@@ -156,6 +156,10 @@ void TextureCache::TCacheEntry::FromRenderTarget(u32 dstAddr, unsigned int dstFo
 		else
 			D3D::SetPointCopySampler();
 
+		// if texture is currently in use, it needs to be temporarily unset
+		u32 textureSlotMask = D3D::stateman->UnsetTexture(texture->GetSRV());
+		D3D::stateman->Apply();
+
 		D3D::context->OMSetRenderTargets(1, &texture->GetRTV(), nullptr);
 
 		// Create texture copy
@@ -168,6 +172,15 @@ void TextureCache::TCacheEntry::FromRenderTarget(u32 dstAddr, unsigned int dstFo
 		D3D::context->OMSetRenderTargets(1, &FramebufferManager::GetEFBColorTexture()->GetRTV(), FramebufferManager::GetEFBDepthTexture()->GetDSV());
 
 		g_renderer->RestoreAPIState();
+
+		// Restore old texture in all previously used slots, if any
+		while (textureSlotMask)
+		{
+			unsigned long index;
+			_BitScanForward(&index, textureSlotMask);
+			D3D::stateman->SetTexture(index, texture->GetSRV());
+			textureSlotMask &= ~(1 << index);
+		}
 	}
 
 	if (!g_ActiveConfig.bCopyEFBToTexture)