BansheeEngine/CamelotD3D11RenderSystem/Source/CmD3D11HardwareBuffer.cpp

#include "CmD3D11HardwareBuffer.h"
#include "CmD3D11Mappings.h"
#include "CmD3D11Device.h"
#include "CmException.h"
#include "CmDebug.h"

namespace CamelotEngine
{
	D3D11HardwareBuffer::D3D11HardwareBuffer(BufferType btype, UINT32 sizeBytes, HardwareBuffer::Usage usage, 
		D3D11Device& device, bool useSystemMemory, bool streamOut)
		: HardwareBuffer(usage, useSystemMemory),
		mD3DBuffer(0),
		mpTempStagingBuffer(0),
		mUseTempStagingBuffer(false),
		mBufferType(btype),
		mDevice(device)
	{
		mSizeInBytes = sizeBytes;
		mDesc.ByteWidth = static_cast<UINT>(sizeBytes);
		
		mDesc.MiscFlags = 0;

		if (useSystemMemory)
		{
			mDesc.Usage = D3D11_USAGE_STAGING;
			//A D3D11_USAGE_STAGING Resource cannot be bound to any parts of the graphics pipeline, so therefore cannot have any BindFlags bits set.
			mDesc.BindFlags = 0;
			mDesc.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE | D3D11_CPU_ACCESS_READ ;// A D3D11_USAGE_STAGING Resource must have at least one CPUAccessFlag bit set.

		}
		else
		{
			mDesc.Usage = D3D11Mappings::_getUsage(mUsage);
			mDesc.BindFlags = btype == VERTEX_BUFFER ? D3D11_BIND_VERTEX_BUFFER : 
				btype == INDEX_BUFFER  ? D3D11_BIND_INDEX_BUFFER  :
				D3D11_BIND_CONSTANT_BUFFER;
			mDesc.CPUAccessFlags = D3D11Mappings::_getAccessFlags(mUsage); 
		}

		// Check of stream out flag
		if (streamOut && btype != CONSTANT_BUFFER)
		{
			mDesc.BindFlags |= D3D11_BIND_STREAM_OUTPUT;
		}

		// TODO: we can explicitly initialise the buffer contents here if we like
		// not doing this since OGRE doesn't support this model yet
		HRESULT hr = device.getD3D11Device()->CreateBuffer( &mDesc, nullptr, &mD3DBuffer );
		if (FAILED(hr) || mDevice.hasError())
		{
			String msg = device.getErrorDescription();
			CM_EXCEPT(RenderingAPIException, "Cannot create D3D11 buffer: " + msg);
		}
	}

	D3D11HardwareBuffer::~D3D11HardwareBuffer()
	{
		SAFE_RELEASE(mD3DBuffer);
		SAFE_DELETE(mpTempStagingBuffer); // should never be nonzero unless destroyed while locked
	}

	void* D3D11HardwareBuffer::lockImpl(UINT32 offset, 
		UINT32 length, LockOptions options)
	{
		if (length > mSizeInBytes)
			CM_EXCEPT(RenderingAPIException, "Provided length " + toString(length) + " larger than the buffer " + toString(mSizeInBytes) + ".");		

		// Use direct (and faster) Map/Unmap if dynamic write, or a staging read/write
		if((mDesc.Usage == D3D11_USAGE_DYNAMIC && options != HardwareBuffer::HBL_READ_ONLY) || mDesc.Usage == D3D11_USAGE_STAGING)
		{
			D3D11_MAP mapType;

			switch(options)
			{
			case HBL_DISCARD:
				if (mUsage & HardwareBuffer::HBU_DYNAMIC)
				{
					// Map cannot be called with MAP_WRITE access, 
					// because the Resource was created as D3D11_USAGE_DYNAMIC. 
					// D3D11_USAGE_DYNAMIC Resources must use either MAP_WRITE_DISCARD 
					// or MAP_WRITE_NO_OVERWRITE with Map.
					mapType = D3D11_MAP_WRITE_DISCARD;
				}
				else
				{
					// Map cannot be called with MAP_WRITE_DISCARD access, 
					// because the Resource was not created as D3D11_USAGE_DYNAMIC. 
					// D3D11_USAGE_DYNAMIC Resources must use either MAP_WRITE_DISCARD 
					// or MAP_WRITE_NO_OVERWRITE with Map.
					mapType = D3D11_MAP_WRITE;

					LOGWRN("DISCARD lock is only available on dynamic buffers. Falling back to normal write.");
				}
				break;
			case HBL_NO_OVERWRITE:
				if(mBufferType == INDEX_BUFFER || mBufferType == VERTEX_BUFFER)
					mapType = D3D11_MAP_WRITE_NO_OVERWRITE;
				else
				{
					mapType = D3D11_MAP_WRITE;

					LOGWRN("NO_OVERWRITE lock is not available on this (" + toString(mBufferType) + ") buffer type. Falling back to normal write.");
				}
				break;
			case HBL_NORMAL:
				if ((mDesc.CPUAccessFlags & D3D11_CPU_ACCESS_READ) != 0 &&
					(mDesc.CPUAccessFlags & D3D11_CPU_ACCESS_WRITE) != 0)
				{
					mapType = D3D11_MAP_READ_WRITE;
				}
				else if(mDesc.CPUAccessFlags & D3D11_CPU_ACCESS_WRITE)
				{
					mapType = D3D11_MAP_WRITE;
				}
				else
				{
					mapType = D3D11_MAP_READ;
				}
				break;
			case HBL_READ_ONLY:
				mapType = D3D11_MAP_READ;
				break;
			}

			if(D3D11Mappings::isMappingRead(mapType) && (mDesc.CPUAccessFlags & D3D11_CPU_ACCESS_READ) == 0)
				CM_EXCEPT(RenderingAPIException, "Trying to read a buffer, but buffer wasn't created with a read access flag.");

			if(D3D11Mappings::isMappingWrite(mapType) && (mDesc.CPUAccessFlags & D3D11_CPU_ACCESS_WRITE) == 0)
				CM_EXCEPT(RenderingAPIException, "Trying to write to a buffer, but buffer wasn't created with a write access flag.");

			void * pRet = NULL;
			D3D11_MAPPED_SUBRESOURCE mappedSubResource;
			mappedSubResource.pData = NULL;
			mDevice.clearErrors();
			HRESULT hr = mDevice.getImmediateContext()->Map(mD3DBuffer, 0, mapType, 0, &mappedSubResource);
			if (FAILED(hr) || mDevice.hasError())
			{
				String msg = mDevice.getErrorDescription();
				CM_EXCEPT(RenderingAPIException, "Error calling Map: " + msg);
			}

			pRet = static_cast<void*>(static_cast<char*>(mappedSubResource.pData) + offset);

			return pRet;
		}
		else // Otherwise create a staging buffer to do all read/write operations on. Usually try to avoid this.
		{
			mUseTempStagingBuffer = true;
			if (!mpTempStagingBuffer)
			{
				// create another buffer instance but use system memory
				mpTempStagingBuffer = new D3D11HardwareBuffer(mBufferType, 
					mSizeInBytes, mUsage, mDevice, true, false);
			}

			// schedule a copy to the staging
			if (options != HBL_DISCARD)
				mpTempStagingBuffer->copyData(*this, 0, 0, mSizeInBytes, true);

			// register whether we'll need to upload on unlock
			mStagingUploadNeeded = (options != HBL_READ_ONLY);

			return mpTempStagingBuffer->lock(offset, length, options);
		}
	}

	void D3D11HardwareBuffer::unlockImpl(void)
	{
		if (mUseTempStagingBuffer)
		{
			mUseTempStagingBuffer = false;

			// ok, we locked the staging buffer
			mpTempStagingBuffer->unlock();

			// copy data if needed
			// this is async but driver should keep reference
			if (mStagingUploadNeeded)
				copyData(*mpTempStagingBuffer, 0, 0, mSizeInBytes, true);

			// delete
			// not that efficient, but we should not be locking often
			SAFE_DELETE(mpTempStagingBuffer);
		}
		else
		{
			// unmap
			mDevice.getImmediateContext()->Unmap(mD3DBuffer, 0);
		}
	}

	void D3D11HardwareBuffer::copyData(HardwareBuffer& srcBuffer, UINT32 srcOffset, 
		UINT32 dstOffset, UINT32 length, bool discardWholeBuffer)
	{
		// If we're copying same-size buffers in their entirety...
		if (srcOffset == 0 && dstOffset == 0 &&
			length == mSizeInBytes && mSizeInBytes == srcBuffer.getSizeInBytes())
		{
			// schedule hardware buffer copy
			mDevice.getImmediateContext()->CopyResource(mD3DBuffer, static_cast<D3D11HardwareBuffer&>(srcBuffer).getD3DBuffer());
			if (mDevice.hasError())
			{
				String errorDescription = mDevice.getErrorDescription();
				CM_EXCEPT(RenderingAPIException, "Cannot copy D3D11 resource\nError Description:" + errorDescription);
			}
		}
		else
		{
			// copy subregion
			D3D11_BOX srcBox;
			srcBox.left = (UINT)srcOffset;
			srcBox.right = (UINT)srcOffset + length;
			srcBox.top = 0;
			srcBox.bottom = 1;
			srcBox.front = 0;
			srcBox.back = 1;

			mDevice.getImmediateContext()->CopySubresourceRegion(mD3DBuffer, 0, (UINT)dstOffset, 0, 0, 
				static_cast<D3D11HardwareBuffer&>(srcBuffer).getD3DBuffer(), 0, &srcBox);
			if (mDevice.hasError())
			{
				String errorDescription = mDevice.getErrorDescription();
				CM_EXCEPT(RenderingAPIException, "Cannot copy D3D11 subresource region\nError Description:" + errorDescription);
			}
		}
	}

	void D3D11HardwareBuffer::readData(UINT32 offset, UINT32 length, void* pDest)
	{
		// There is no functional interface in D3D, just do via manual 
		// lock, copy & unlock
		void* pSrc = this->lock(offset, length, HardwareBuffer::HBL_READ_ONLY);
		memcpy(pDest, pSrc, length);
		this->unlock();
	}

	void D3D11HardwareBuffer::writeData(UINT32 offset, UINT32 length, 
		const void* pSource, bool discardWholeBuffer)
	{
		if(mDesc.Usage == D3D11_USAGE_DYNAMIC || mDesc.Usage == D3D11_USAGE_STAGING)
		{
			void* pDst = this->lock(offset, length, 
				discardWholeBuffer ? HardwareBuffer::HBL_DISCARD : HardwareBuffer::HBL_NORMAL);
			memcpy(pDst, pSource, length);
			this->unlock();
		}
		else if(mDesc.Usage == D3D11_USAGE_DEFAULT)
		{
			mDevice.getImmediateContext()->UpdateSubresource(mD3DBuffer, 0, nullptr, pSource, offset, length);
		}
		else
		{
			CM_EXCEPT(RenderingAPIException, "Trying to write into a buffer with unsupported usage: " + toString(mDesc.Usage));
		}
	}
}