Posted: 13 May 2013
Released v1.2.1 update for Freeform Backgammon. This minor update includes a fix for rendering checkers on older GPUs.
Thanks to Amazon for finding and reporting the bug this release fixes. The Amazon test process for the v1.2.0 release failed a test case with a "User Interface Distortion" bug. The bug report included this description (on a first-generation Kindle fire):
- Install and Launch the app.
- Tap on red coins.
- All the coins turns to white.
While this description is pretty broad and imprecise, I am glad that Amazon and not a (paying) customer found this.
After figuring out which GPU the older Kindles have (the Imagination PowerVR) then borrowing a friend's Kindle Fire, and then some googling I found a very useful hint.
The "fix" is to just make shader code more robust in the cases where the
shader tries to return early (via a discard or return) inside an if.
Thankfully these fixes are a good idea anyway (the
single-instruction-multiple-data nature of fragment shaders means its
always good to minimize conditional control flow).