Alghost Mar 13
Claire Blackshaw
My best strange bug was animations glitching out on a Wii title which was in dev pre launch. Animations glitches appeared seemingly randomly though only repo with multiple local players. No solid repo until someone noticed it was related to multiple controllers active and amount of audio played
Mar 13 at 2:02pmWeb
Show threadClaire BlackshawMar 13

Older hardware had less registers and fixed function pipelines have a matrix stack. Most commonly used by the render system for skinning and transforms but also the audio HW.

The remote audio has a much higher than frame sample rate and depends on HW interrupts which don't show up in the debugger

Show threadClaire BlackshawMar 13
Turns out if you had enough animation you were using the full stack and enough audio playing through the controller speaker then it used all of the matrix stack but only correctly restored the bottom 6. Meaning memory scribble randomly on the top of the stack.
Show threadClaire BlackshawMar 13

This was HW/SDK issue we highlighted prior to launch with easy repo project but it couldn't be fixed due to a 1st party title not hitting frame target if fixed supplied due to perf cost.

Our fix was to limit audio playback in multiple local player situations to avoid it needing full stack.