Backface culling with Molehill
Using Flash 11 RC1 with the new Molehill API, I would like to enable backface culling. The beta documentation is pretty vague, but the example implies Molehill wants front-facing triangles to wind counter-clockwise, which is pretty normal.
But when my polygons wind counter-clockwise, I get the exact opposite behavior - in other words, it's as if contrary to its own examples Molehill expects front-facing triangles to wind clockwise. Since the documentation never explicitly states which winding is correct, I am stumped.
I don't want to just flip all my triangles around until it looks right before I am 100% on what Molehill actually wants, since that has a fair chance of hiding a fundamental misunderstanding.
I am using simple perspective pro开发者_如何学Pythonjection (a note regarding .transpose() below: because copyRawDataFrom expects data in column-major order, and I hated the way that looked in code, I decided to just enter it row-major and transpose the matrix afterwards - so sue me :P):
var y:Number = 1.0 / Math.tan(pFOV / 2.0);
var x:Number = y / pAspectRatio;
_projectionMatrix.copyRawDataFrom(new<Number>[
x , 0 , 0 , 0,
0 , y , 0 , 0,
0 , 0 , pFar/(pNear-pFar) , pFar*pNear/(pNear-pFar),
0 , 0 , -1 , 0
]);
_projectionMatrix.transpose();
Any clues?
You can use Context3D.setCulling to change the backface culling in molehill. See: http://help.adobe.com/en_US/FlashPlatform/beta/reference/actionscript/3/flash/display3D/Context3D.html#setCulling()
Which side is front or back depends on your model input data, so trial and error is really yur best bet here. There are only two options :)
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