title: sampler value of texture from DisparityFloat16 pixel format on iOS OpenGLES
body: <p>I want to use depthDataMap as a texture from iPhoneX true depth camera on my OpenGLES project. Have downloaded some Swift samples, it seems that depthMap can be created and sampled as a float texture on Metal. But on OpenGLES, the only way to create a depth texture from depth buffer is,</p>
  
  <pre><code>glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, depthWidth, depthHeight, 0, GL_DEPTH_COMPONENT, GL_UNSIGNED_SHORT, CVPixelBufferGetBaseAddress(depthBuffer));
  </code></pre>
  
  <p>The sample value is different from the value exported as CIImage from DisparityFloat16 pixel type. The value is much lower, and not a linear scale compared to the CIImage. </p>
  
  <p>This is sampled value in OpenGLES
  <a href="https://i.stack.imgur.com/jqlAm.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/jqlAm.jpg" alt="enter image description here"></a></p>
  
  <p>This is via code: CIImage *image = [CIImage imageWithCVImageBuffer:depthData.depthDataMap];</p>
  
  <p><a href="https://i.stack.imgur.com/9itqR.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/9itqR.jpg" alt="enter image description here"></a></p>
  
  <p>Does anyone have the same issue?</p>