Sprite Kit physics is not deterministic

Originator:jamesnorton
Number:rdar://17893385 Date Originated:01-Aug-2014
Status:open Resolved:
Product:iOS Product Version:iOS 7.0.6
Classification:bug Reproducible:yes
 
Summary:
Repeated runs of a physics simulation using the Sprite Kit physics API give different results despite identical initial conditions.

Steps to Reproduce:
1. Create a simple physics simulation involving many falling blocks, balls, etc.
2. Run the simulation repeatedly using identical initial conditions.
3. Compare final screen shots from each run which show different final positions for simulation objects.

Expected Results:
Repeated runs of a physics simulation with identical initial conditions should always produce the same final output.

Actual Results:
Each run of the simulation produces noticeably different results. The more objects involved, the greater the difference.

Comments


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