Unity Ios Touch Input Stuttering

MIT
by JohannesDeml

Bug report for frame jumps and frame freezes on ios with simple touch input

( Crawled 5 minutes ago )
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iOS touch input stuttering

Noticable frame jumps and frame freezes on ios with simple touch input

Project information

Problem

  • Triggering the event system with touches on a dummy button creates frame problems
  • The frame problems are either Frame freezes or frame Jumps
  • boh of them are quite subtle, but noticable once you're trained to see them
  • Frame Jumps (leaving out one frame) seems to be more common than frame freezes (in Unity 5.6 at least)
  • Most significant problems on iPad Pro
  • On GLES3 the problem seems to be less frequent than on Metal

Test Scenario

  • Unity 5.6.0f2
  • XCode 8.3 (8E162)
  • OpenGLES2, OpenGLES3 and Metal graphics API
  • il2CPP
  • Gamma color space

Screenshot v0.2

Results (v0.2)

Lost frames - (Without Tapping / With Tapping)

Metal+Xcode Metal
iPad Pro (0.472 / 6.850) (1.519 / 3.997)
iPhone SE (0.223 / 0.8135) (0.234 / 0.800)
iPhone 6s Plus (0.403 / 1.943) (0.465 / 1.053)

Additional Tests

  • Tested with Unity 5.5.1p1
  • Tested with XCode 8.2.1, 8.3 beta 2

How to reproduce?

  • Clone the project
  • set Build Target to iOS and release, disable development build
  • Build & Run Project
  • Install the app
  • Detach the device from the computer
  • Run once without hitting the Tap! button
  • Run once with hitting the Tap! approximately twice a second
  • Calculate the difference between the two outcomes