[AS3]Array.sortOn not accurate?

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08-01-2007, 02:22 PM
Fall_X

[AS3]Array.sortOn not accurate?

Ok, here's some code I used :

Code:

var transformedSurfaces:Array=surfaces.sortOn("depth",Array.DESCENDING|Array.NUMERIC); for(var i:int=0;i<transformedSurfaces.length;i++) { trace(transformedSurfaces[i].depth); }

And this is the result I got :

Code:

205.44603367212753 182.78833899621128 160.130644320295 138.99973123326004 138.99973123326004 138.99973123326004 138.99973123326004 138.99973123326004 138.99973123326004 114.81525496846251 114.81525496846251 114.81525496846251 92.15756029254628 92.15756029254628 90.63077870366499 90.63077870366499 90.63077870366499 73.72604823403702 69.49986561663002 48.368952529595056 48.36895252959505 48.36895252959505 48.36895252959505 37.47373675257102 37.47373675257102 30.242796788862044 30.242796788862044 24.18447626479752 24.18447626479752 1.5267815888812777 0 0 0 0 0 -24.184476264797524 -24.184476264797524 -24.184476264797524 -42.26182617406994 -42.26182617406994 -46.84217094071377 -48.36895252959505 -48.36895252959505 -48.36895252959505 0 -82.178413468851 -82.178413468851 -82.178413468851 -2.5357095704441965 -8.452365234813989 -89.10399711478371 -90.63077870366499 -90.63077870366499 -21.130913087034973 -31.696369630552457 -132.89260487773493 -132.89260487773493 -137.47294964437876 -138.99973123326006 -138.99973123326006 -138.99973123326006 -157.07708114253245 -172.80919217251602 -172.80919217251602 -172.80919217251602 -181.26155740733 -181.26155740733 -181.26155740733 -205.44603367212753 -223.52338358139994 -228.10372834804377 -263.43997087618095 -263.43997087618095 -263.43997087618095 -271.89233611099496 -271.89233611099496 -271.89233611099496 -314.15416228506496 -362.52311481465995 -362.52311481465995 -362.52311481465995 -362.52311481465995 -362.52311481465995 -362.52311481465995 -404.7849409887299 -495.41571969239493 -495.41571969239493 -495.41571969239493 -495.41571969239493 -495.41571969239493 -495.41571969239493 -495.41571969239493

Note that there's a zero out of place.

I also tried a simple Array.sort(Array.DESCENDING|Array.NUMERIC), and had the toString() function of my objects return the depth field, and that way it was accurate but a lot slower.

So, any ideas?

Thanks.
08-01-2007, 05:43 PM
T1ger

Post the input-array?
08-01-2007, 06:30 PM
AfternoonDelite

Could this be your problem?

Quote:

EXFGHT% said on Jun 16, 2006 at 9:43 PM :

Array.sortOn fails if the field to be sorted on in the underlying Object uses a property getter function, it will only work if the field is stored as a normal var.

from here
08-01-2007, 10:59 PM
Fall_X

Nope, the field is a normal var.

The input var (only the values of the field I'm sorting on) :

Code:

-2.816829376715345 -9.389431255717817 -23.473578139294542 -35.21036720894181 34.19799306009999 23.68865115012508 -488.4209527080526 -353.1790371435708 -264.88427785767806 -176.5895185717854 -155.9157170681336 -135.2419155644818 -46.94715627858908 88.29475928589271 108.96856078954451 129.64236229319633 -488.4209527080526 -353.1790371435708 -255.49484660196026 -197.2633200754372 -176.5895185717854 -88.2947592858927 0 20.673801503651806 41.34760300730362 129.64236229319633 -488.4209527080526 -353.1790371435708 -255.49484660196026 -129.6423622931963 -167.20008731606757 -41.34760300730362 -78.90532803017489 -20.67380150365181 0 64.82118114659816 108.96856078954451 129.64236229319633 -488.4209527080526 -353.1790371435708 -255.49484660196026 -129.6423622931963 -167.20008731606757 -41.34760300730362 -78.90532803017489 -20.67380150365181 0 20.673801503651806 41.34760300730362 129.64236229319633 -488.4209527080526 -353.1790371435708 -264.88427785767806 -129.6423622931963 -167.20008731606757 -41.34760300730362 -78.90532803017489 -20.67380150365181 0 88.29475928589271 108.96856078954451 129.64236229319633 -488.4209527080526 -353.1790371435708 -264.88427785767806 -176.5895185717854 -88.2947592858927 0 88.29475928589271 153.11594043249087 197.2633200754372 -488.4209527080526 -400.1261934221599 -311.83143413626715 -223.53667485037448 -135.2419155644818 -46.94715627858908 41.34760300730362 129.64236229319633 34.19799306009999 69.51589677445708 23.68865115012508 0

It's quite important that I find a way to fix this - when Im' using sort (in combination with toString()) I'm getting 40 fps, if I use sortOn I'm getting 110 fps. It's for my isometric engine thingie. Until now I've settled with the sort-approach, but off course speed is important here.
08-02-2007, 12:01 AM
mr_malee

something must be wrong with your depth var because mine works:

Code:

var i:int = 500; var sortArray:Array = []; while(--i >= 0){ var depth:Number = Math.random() * 1000 - 500; var ob:Object = {} if(Math.random() < .05) depth = 0; ob.depth = depth; sortArray.push(ob); } var transformArray:Array = sortArray.sortOn("depth", Array.NUMERIC | Array.DESCENDING); for(i = 0; i<transformArray.length; i++){ trace(transformArray[i].depth) }
08-02-2007, 12:08 AM
Fall_X

I'm guessing it's some floating point accuracy problem.

I managed to work around it by adding a number to the depth of my "sprites" (ie the objects that don't have to be skewed in the iso engine). My player character was always at coordinate 0,0,0 (in camera space), and it was flickering, ie sometimes it was underneath the tile he was standing on, and sometimes he was above it. If the difference between it's depth and the tile he was on was very small, the sort sometimes put them in the wrong order, but by increasing it's depth slightly, it works.

Strange though, because it worked with the normal sort method.
08-02-2007, 12:10 AM
renderhjs

otherwise you could write your own bubblesort function- can´t be so difficult
08-02-2007, 12:17 AM
Fall_X

Yeah I've done that some years ago (in C if I'm not mistaking), but it can't be as fast as a native function.
08-02-2007, 12:17 AM
AfternoonDelite

Quote:

Originally Posted by renderhjs

otherwise you could write your own bubblesort function- can´t be so difficult

mergesort would probably be your best bet if you're looking for efficiency.

A simple google search should lead you to the right direction, if you need to implement your own.

I was looking on google.. but I'm not really sure how to find how the methods are implemented in AS3.

I know that in Java.. the sort method.. uses mergesort.. and in order to do something like 'sorton'.. you just have to implement a Comparable interface and change the method to how you want to compare the objects.

And I know in PHP and PERL, you can also customize how arrays are compared through the sort method.

Not sure if that's possible in AS3.
08-02-2007, 12:23 AM
mr_malee

http://linux.wku.edu/~lamonml/algor/sort/sort.html

has source code too ;)

hmmm, me thinks a package is in order here :D
08-02-2007, 01:58 AM
BlinkOk

what is the numeric value for the character "0"?
10-29-2008, 12:51 AM
Ray Beez

Could it be because you forgot the spaces? IE:

surfaces.sortOn("depth",Array.DESCENDING | Array.NUMERIC)
10-29-2008, 02:48 AM
BlinkOk

hehe. i would say a day late and a dollar short but it's a lot longer than that lol
10-29-2008, 04:31 PM
Ray Beez

That's what she said
10-29-2008, 04:34 PM
BlinkOk

har har lmao!