通过上篇文章，我们了解了在视频图像从kinect开发包传输到应用程序之前的一系列初始化工作，那么这篇文章主要来叙述，如何将一帧图像数据获取到，并显示出来的。

更新窗口是在Run函数消息处理中，当KinectSDK触发了m_hNextDepthFrameEvent之后，上层收到这个Event就调用Update函数去更新窗口了。关键代码如下图，Run函数的全部代码也可以从上一篇博文中找到：

Update函数：

void CDepthBasics::Update(){	if (NULL == m_pNuiSensor)  // 如果pNuiSensor为空，那说明设备还没有初始化	{		return;	}	// 继续判断m_hNextDepthFrameEvent是否有消息，其实这个判断这里可以去掉，但是考虑鲁棒性，还是留着吧	if ( WAIT_OBJECT_0 == WaitForSingleObject(m_hNextDepthFrameEvent, 0) )	{		ProcessDepth();  // 处理	}}

update函数做了一些错误处理，真正的更新窗口的代码在ProcessDepth中，接下来看ProcessDepth函数

void CDepthBasics::ProcessDepth(){	HRESULT hr;	NUI_IMAGE_FRAME imageFrame;	// 通过kinect对象，从m_pDepthStreamHandle中获取图像数据，还记得m_pDepthStreamHandle么，是在初始化kinect设备时创建的深度图流	// 在这里调用这个代码的意义是：将一帧深度图，保存在imageFrame中	hr = m_pNuiSensor->NuiImageStreamGetNextFrame(m_pDepthStreamHandle, 0, &imageFrame);	if (FAILED(hr))	{		return;	}	BOOL nearMode;	INuiFrameTexture* pTexture;	// Get the depth image pixel texture，通过imageFrame把数据转化成纹理	hr = m_pNuiSensor->NuiImageFrameGetDepthImagePixelFrameTexture(		m_pDepthStreamHandle, &imageFrame, &nearMode, &pTexture);	if (FAILED(hr))	{		goto ReleaseFrame;	}	NUI_LOCKED_RECT LockedRect;	// Lock the frame data so the Kinect knows not to modify it while we're reading it，锁定数据	pTexture->LockRect(0, &LockedRect, NULL, 0);	// Make sure we've received valid data	if (LockedRect.Pitch != 0)	{		// Get the min and max reliable depth for the current frame		int minDepth = (nearMode ? NUI_IMAGE_DEPTH_MINIMUM_NEAR_MODE : NUI_IMAGE_DEPTH_MINIMUM) >> NUI_IMAGE_PLAYER_INDEX_SHIFT;		int maxDepth = (nearMode ? NUI_IMAGE_DEPTH_MAXIMUM_NEAR_MODE : NUI_IMAGE_DEPTH_MAXIMUM) >> NUI_IMAGE_PLAYER_INDEX_SHIFT;		// 将m_depthRGBX的首地址保存在rgbrun，方便赋值		BYTE * rgbrun = m_depthRGBX;		const NUI_DEPTH_IMAGE_PIXEL * pBufferRun = reinterpret_cast
    
     (LockedRect.pBits);		// end pixel is start + width*height - 1		const NUI_DEPTH_IMAGE_PIXEL * pBufferEnd = pBufferRun + (cDepthWidth * cDepthHeight);		// 对m_depthRGBX也就是rgbrun赋值		while ( pBufferRun < pBufferEnd )		{			// discard the portion of the depth that contains only the player index			USHORT depth = pBufferRun->depth;			// To convert to a byte, we're discarding the most-significant			// rather than least-significant bits.			// We're preserving detail, although the intensity will "wrap."			// Values outside the reliable depth range are mapped to 0 (black).			// Note: Using conditionals in this loop could degrade performance.			// Consider using a lookup table instead when writing production code.			BYTE intensity = static_cast
     
      (depth >= minDepth && depth <= maxDepth ? depth % 256 : 0);			// Write out blue byte			*(rgbrun++) = intensity;			// Write out green byte			*(rgbrun++) = intensity;			// Write out red byte			*(rgbrun++) = intensity;			// We're outputting BGR, the last byte in the 32 bits is unused so skip it			// If we were outputting BGRA, we would write alpha here.			++rgbrun;			// Increment our index into the Kinect's depth buffer			++pBufferRun;		}		// Draw the data with Direct2D 最后将m_depthRGBX保存的图片，显示在窗口上		m_pDrawDepth->Draw(m_depthRGBX, cDepthWidth * cDepthHeight * cBytesPerPixel);	}	// We're done with the texture so unlock it，解锁和释放纹理	pTexture->UnlockRect(0);	pTexture->Release();ReleaseFrame:	// Release the frame  释放帧	m_pNuiSensor->NuiImageStreamReleaseFrame(m_pDepthStreamHandle, &imageFrame);}
     
    

从以上代码可以看到处理Depth数据的流程，获取一个深度图帧，然后经过转换成RGB格式，最后通过ImageRenderer::Draw函数将其画出来。但是ImageRenderer的功能和Kinect关系不大，不是我们学习的重点，因此我们可以先忽略它。那么深度图的获取详细过程就到这里，在下一篇文章中，我们来总结一下这两篇文章所提到的一些Kinect SDK中的函数，并详细了解熟悉这些函数的参数，更进一步的学习Kinect SDK。