Performance Regression: In iOS 18.2 3D rotation in volume rendering is not smooth as compared to iOS 18.1

We as a team of engineers work on an app intended to visualize medical images. The type of situations where the app is used involves time critical decision making for acute clinical conditions. Stability of the app and performance are of utmost importance and can directly help timely treatment action. The app we are developing uses multiple libraries and tools like vtk, webgl, opengl, webkit, gl-matrix etc.

The problem specifically can be described as follows, it has been observed that when 3D volume is rendered in the app and we try to rotate the volume the rotation is slow, unresposive and laggy. Specifically, we have noticed that iOS 18.1 the volume rotation is much smoother as compared to latest iOS 18.2. Eariler, we have faced somewhat similar issue with iOS 17 but it got improved in iOS 18.1. This performance regression is affecting the user experience in our healthcare application.

We have taken reference from the cornerstone.js code and you can reproduce the issue using the following example: https://www.cornerstonejs.org/live-examples/volumeviewport3d

Steps to Reproduce:

  • Load the above mentioned test example on an iPhone running version 18.2 using safari.
  • Perform volume rendering using the provided dataset.
  • Measure the time taken by volume for each rotate or drag action.
  • Repeat the same steps on an iPhone running version 18.1 for comparison.

Additional Information:

  • Device Model Tested:

    • iPhone12, iPhone13, iPhone14
  • iOS Version With Issue:

    • 18.2
    • 18.3(Beta)

I would appreciate any insights or suggestions on how to address this performance regression. If additional information is needed, please let me know.

Thank you.

Performance Regression: In iOS 18.2 3D rotation in volume rendering is not smooth as compared to iOS 18.1
 
 
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