Comments on: FlatShadeMaterial.doubleSided does not seem to work as expected

By: Petar Zaharinov

Petar Zaharinov — Wed, 10 Dec 2008 10:45:25 +0000

flicker solution:
I am not sure if it is the best fix, but the flicker can be removed by adding below the line
zAngle = zd * 0xff;
the following line:
if (zAngle == 0) {zAngle = 1}

By: Al

Al — Tue, 27 May 2008 05:57:42 +0000

Seems LightMaps.getFlatMapArray returns an array of length 255, instead of 256.

change LighMaps.getFlatMapArray to look like this (it returns 256 colors):

public static function getFlatMapArray(lightColor:int, ambientColor:int, specularLevel:int):Array
{
var array:Array = new Array();
var tempmap:BitmapData = new BitmapData(256,1,false,0);
var s:Sprite = new Sprite();
var m:Matrix = new Matrix();
m.createGradientBox(256,1,0,0,0)
s.graphics.beginGradientFill(GradientType.LINEAR, [lightColor,ambientColor],[1,1],[0,255],m);
s.graphics.drawRect(0,0,256,1);
s.graphics.endFill();
tempmap.draw(s);

var i:int = 256;
while(–i > -1){
array.push(tempmap.getPixel(i,0));
}

return array;
}

Should probably lodge this with papervision team…

By: Al

Al — Tue, 27 May 2008 03:33:57 +0000

If you look at lines 46/47 the dot product is scaled by 255 (0xFF) and then used to look up a color in the _colors array (see line 30 for that). Do a trace on zAngle and you should be able to figure out wtf is going on….

By: Joshua Mostafa

Joshua Mostafa — Tue, 27 May 2008 02:16:57 +0000

Thanks for the quickfix! Nice one, I will try that out.

Yes that flicker is annoying isn’t it. I see it also.

By: Al

Al — Tue, 27 May 2008 01:49:17 +0000

Think your right…

Looking at lines 42 and 43 of FlatShadeMaterial….

42 does a dot-product of the face normal with the light
43 checks to see if light is ‘behind’ if it is clamps the dot to 0

quick fix is to change line 43 to:
if(zd < 0){zd = -zd;};

That seems to work. Might want to put in the doubleSided check.

Also, is it just me or does it flicker black when normal is aligned with the light?