That's clearly not the shortest way to resolve the collision :)

(will look into it tomorrow)

There's no reason to test a collision if the source (shape1) is not moving.
One way would be to set a boolean whenever there's a change to x/y/rotation. Not sure if there are other accessors for the user. Will check.

I've used differ very naively in my project, with every tilemap tile having it's own box collider, and with every collision check checking all of these tiles. It's bad - and I'll fix it with a quad tree or something - but the JS export of my project has been working fine, not lagging at all. However, when I export for windows (I'm using Kha) the app can't run, and after just seconds will freeze and close. I think this performance difference is due to differ, as when running the windows build through visual studio, the performance tools reported that 81.53% of my builds CPU time was spent on a differ method.

Feel free to close this if this is outside's of differs control. I totally get that this sort of performance should be expected with what I am doing. I'm just almost curious about why JS does work well, when I expected C++ performance to be higher.

Hi. What is the license for this library?

The best implementation we discussed was a simple custom container that keeps a set of preallocated results.

You'd create one with a fixed size to start, then upon use, it resets each as it populates them. It keeps track of how many are set in the length property, then it can be iterated normally and the length property will correctly reflect the number of valid results, as well as correctly respond to [ ] operator.

This is the last place needing an into argument, which the type of would be this container.

Polygon vs Polygon is ok,

Polygon vs Circle has odd behavior (see test case nme project).

http://dev.underscorediscovery.com/hxcollision

Let's just use something else :)

When using the scaleX and scaleY properties, polygons seems to be incorrectly transformed. When examining transformed vertices of a polygon, it appears that scale transformation is applied for both X and Y, even when only one of the scaleX/Y properties are used.
So, when using myPolygon.scaleX = 0.5; scale is set to {0.5, 1}.
When using myPolygon.scaleY = 0.5; scale is actually set to {0.5, 0.5} but applied to the transformation matrix twice.

Is there a way to split concave polygons into multiple convex polygons to support concave polygons?

Also, like #8, would be best with more than just true or false

Polygon.create([a1, b1, a2, b2...]) and another name for perfect polygon types by number of sides would make more sense.

Triangle.create() could be nice too.

In demo 1 for instance, all I see is
Click to toggle using the polygon, or using the circle. See https://github.com/underscorediscovery/hxcollision for code

nme-application is just a blank square. There are no console errors.

Haxe version: 4.0.5

/Users/dkuffner/games/haxe/celest-hl/.haxelib/differ/1,3,0/differ/shapes/Circle.hx:12: characters 24-34 : radius: Custom property accessor is no longer supported, please use `get`
/Users/dkuffner/games/haxe/celest-hl/.haxelib/differ/1,3,0/differ/shapes/Circle.hx:14: characters 35-56 : transformedRadius: Custom property accessor is no longer supported, please use `get`

as the tile says.

this is just setting it up as normal, nothing has actually been put in apart from imported

I'm using a raycast with infinite turned off, but the raycast is hitting shapes behind me.

For example, I have a square in the middle of the room. If I'm on the right hand side of the square and face left, I hit the outside of the square the the raycast works. If I face right, the raycast now comes in from (what seems like) infinite distance away from the left and hits the square from the left side.

Facing towards the square:
https://dl.dropboxusercontent.com/u/20830426/differ_facingtoward.png
Facing away from the square:
https://dl.dropboxusercontent.com/u/20830426/differ_facingaway.png

It seems like you can replicate this in the github demo by moving the mouse past the raycaster on the left hand side:
https://dl.dropboxusercontent.com/u/20830426/differ_demobug.png

Is this a bug or a settings issue?

Here's an example of the Luxe platformer having its gravity reverted (gravity.set_xyz(0, -800, 0); in Simulation.hx).

The rectangles of the two colliders have exactly the same y-coordinates but appears to block the players movement along the x-axis.
This might be caused by the gravity being applied causing the calculations of the player to be performed in this position -- where he actually would be blocked by the other collider.

Any fix or workaround?

If I set shape.rotation = 45, the shape rotates each time I update the value instead of keeping it at 45º

When a circle shape is positioned at the start of a non-infinite ray, there is no collision detected by testRayVsCircle function. I believe this is non-intentional?