react-native/ReactAndroid
Krzysztof Magiera b60a8dc6b9 Fix rotation matrix decomposition.
Summary:
This PR fixes an issue with rotation decomposition matrix on android.

The issue can be illustrated with this sample code https://snack.expo.io/r1SHEJpVb

It surfaces when we have non-zero rotation in Y or X axis and when rotation Z is greater than 90deg or less than -90deg. In that case the decomposition code doesn't give a valid output and as a result the view gets rotated by 180deg in Z axis.

You may want to run the code linked above on android and iOS to see the difference. Basically the example app renders first image rotated only by 89deg and the next one by 91deg. As a result you should see the second view being pivoted just slightly more than the first image. Apparently on android the second image is completely flipped:

iOS:
![screen shot 2017-07-07 at 12 40 30](https://user-images.githubusercontent.com/726445/27954719-7cf6d02c-6311-11e7-9104-5c3cc8e9b9c1.png)

Android:
![screen shot 2017-07-07 at 12 41 21](https://user-images.githubusercontent.com/726445/27954737-981f57e8-6311-11e7-8c72-af1824426c30.png)

The bug seemed to be caused by the code that decomposes the matrix into axis angles. It seems like that whole code has been overly complicated and we've been converting matrix first into quaternion just to extract angles. Whereas it is sufficient to extract angles directly from rotation matrix as described here: http://nghiaho.com/?page_id=846

This formula produces way simpler code and also gives correct result in the aforementioned case, so I decided not to debug quaternion code any further.

sidenote: New formula's y angle output range is now -90 to 90deg hence changes in tests.
Closes https://github.com/facebook/react-native/pull/14888

Reviewed By: astreet

Differential Revision: D5414006

Pulled By: shergin

fbshipit-source-id: 2e0a68cf4b2a9e32f10f6bfff2d484867a337fa3
2017-07-17 18:34:32 -07:00
..
libs Apply auto-formatter for BUCK files in fbandroid. 2017-02-27 14:04:56 -08:00
src Fix rotation matrix decomposition. 2017-07-17 18:34:32 -07:00
.npmignore
DEFS Fix oss build 2017-06-06 08:30:50 -07:00
DevExperience.md
README.md
build.gradle Update OSS Fresco dependency 2017-07-12 07:54:09 -07:00
gradle.properties fixed mockito version 2016-10-04 10:43:35 -07:00
release.gradle Circle CI releases now work with Java 8 2016-10-28 07:58:52 -07:00

README.md

Building React Native for Android

See the docs on the website.

Running tests

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