DirectX Managed code question

John Olbert

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Oct 31, 2003, 6:27:31 PM10/31/03

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I have been using the DirectX9 Managed Code Sdk with
the .NET Ide to create a program that plots data as a
surface using the--

"device.DrawPrimitives(PrimitiveType.TriangleStrip,
0,mjNumTriangles);"

approach. Works fine except for the fact that when you
cause the surface to rotate by changing the
Transform.World--

"device.Transform.World = Matrix.RotationAxis(new Vector3
((float)Math.Cos(Environment.TickCount / 5000.0f),1,(float)
Math.Sin(Environment.TickCount / 5000.0f)),
Environment.TickCount / 7000.0f );"

Depending on which angle of viewing that you start from
you will get random open spaces in the surfaces that open
and close. They look like thin slits, occassionally with
pointed ends. The shape of these "rips" varies over all
the place. Note that they are true opennings. You can see
though them.

I have tried various things with the lighting. Also have
varied the speed of the rotation. Nothing resolves the
problem.

I added single step code that allows rotation by 10
degree's around any of the X,Y, Z axis. You get the same
effect. For some positions of the camera you do not get
these effects but for most you do.

We really find the DirectX9 Managed very powerful and
would like to resolve this problem.

Please note if this is the wrong newsgroup could you
indicate the correct one.

Thanks.

--John Olbert
John....@perkinelmer.com

Michael

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Oct 31, 2003, 7:23:47 PM10/31/03

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did you clear the z-buffer? i could think that you forgotten to clear the
z-buffer. so some parts are visible and some aren't.

Michael

Graham Ambrose

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Nov 1, 2003, 12:28:16 PM11/1/03

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have you tried setting culling to None.
direct3d dose not draw faces that are facing away from the camera by default
to speed up rendering and it sounds to me that as you are rotating your
'surface' some of the faces are being culled.

"John Olbert" <anon...@discussions.microsoft.com> wrote in message
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John Olbert

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Nov 3, 2003, 6:39:09 PM11/3/03

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Yes I did try that.

Any other possibilities come to mind?

By the way am I in the right newsgroup?

Thanks.

--John

>.
>

John Olbert

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Nov 3, 2003, 6:55:20 PM11/3/03

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I can send a Word doc that shows two screen shots, one as
it should be and one with the "rips". It is 46kb in size.

Is there a way I can send it into this thread.

I tried pasting the images to this text box but they would
not paste.

Thanks.

--John Olbert
javo...@snet.net

>.
>

John Olbert

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Nov 3, 2003, 6:54:28 PM11/3/03

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Yes I did. It did not resolve the problelm.

I can send a Word doc that shows two screen shots, one as
it should be and one with the "rips". It is 46kb in size.

Is there a way I can send it into this thread.

I tried pasting the images to this text box but they would
not paste.

Thanks.

--John

>.
>

Graham Ambrose

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Nov 7, 2003, 11:50:55 AM11/7/03

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if you want to send me the word file I will have a look at it my email
address is below. (you take out the bits that say *NoSpamThanks* I have to
put them in to stop the viruses)

*NoSpamThanks*graham*NoSpamThanks*@*NoSpamThanks*ambroseMail.co.uk*NoSpamTha
nks*

as far as i know this is the right news group.

"John Olbert" <anon...@discussions.microsoft.com> wrote in message

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