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Fix atan2 implementation to behave like Javascript Math.atan2#683

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Fix atan2 implementation to behave like Javascript Math.atan2#683

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ted-piotrowski commentedMar 23, 2021

Previous implementation returned values in -PI/2 to PI/2 range even though Javascript returns in -PI to PI range
Add unit tests covering edge cases

Fixes#647

Previously the following cases failed:

Math.atan2(1, 0);Math.atan2(-1,0);Math.atan(0,-1);

According toMDNMath.atan2(y, x) returns a value between -PI and PI. According toOpenGLatan(y / x) returns a value between -PI/2 and PI/2 whileatan(y, x) returns a value between -PI and PI.

The main fix was to change theatan signature to take(y, x) instead of(y / x) and then to handle the casesMath.atan2(-1, 0),Math.atan2(1, 0),Math.atan(0, 0) because in OpenGLatan is undefined whenx = 0 but defined in Javascript.

Note:atan arguments are passedy first and thenx. This caused me some confusion at first.

Fix atan2 implementation to behave like Javascript Math.atan2

c30d85b

- Previous implementation returned values in -PI/2 to PI/2 range even though Javascript returns in -PI to PI range- Add unit tests covering edge cases