Thanks for the suggestion Guy, I've not looked at lightmap shaders in XSI
yet. I'll check out the docs on them when I get a sec. I take it that they
provide the shader with the final tessellated geometry?
I'm still interested to know what I'm doing wrong in the geo shader if you
or anyone else has any ideas, but it sounds like the lightshader's probably
the way to go.
Thanks for your help.
-----Original Message-----
From: owner-xsi(at)Softimage.COM [mailto:owner-xsi(at)Softimage.COM] On Behalf Of
Guy Rabiller
Sent: 10 January 2007 01:54
To: XSI(at)Softimage.COM
Subject: Re: Getting displaced geometry in a geometry shader?
Did you considere the use of lightmap shaders for this. From my pov this
approach replace the 'old' geometry shader + tesselate way.
What do you think ?
--
guy rabiller | 3d technical director (at) LaMaison
Andy Nicholas a écrit :
> Hi Guy,
>
> I'm trying to write a tool to emulate Maya's "Convert displacement to
> polygons" tool. I just need to dump out the triangles to a file so
> that I can load it back in later to create the actual displaced mesh in
the scene.
>
> Andy
>
> -----Original Message-----
> From: owner-xsi(at)Softimage.COM [mailto:owner-xsi(at)Softimage.COM] On
> Behalf Of Guy Rabiller
> Sent: 09 January 2007 17:43
> To: XSI(at)Softimage.COM
> Subject: Re: Getting displaced geometry in a geometry shader?
>
>
> Hi Andy,
>
> is it to precompute some kind of illumination datas or to place other
> instances/geometries according to this tesselated geometry ?
>
> --
> guy rabiller | 3d technical director (at) LaMaison
>
>
> Andy Nicholas a écrit :
>
>> Hi,
>>
>> This is kinda aimed at Halfdan since I know you helped someone else
>> on a similar topic a while back, but if anyone else (Alan?) knows
>> something on this, I'm all ears.
>>
>> I'm trying to use a geometry shader to get hold of the displaced
>> vertex and triangle list of an object in the scene that's been
>> displaced with a texture. So I figured that I need to call
>> "mi_geoshader_tesselate()" on an object so that Mental Ray will go
>> away and give me the subdivided/displaced geometry that I need. As
>> yet though, I've had no success. Every time I pass an object tag to
>> mi_geoshader_tesselate(), it crashes on me.
>>
>> From what I can tell, I don't think that I'm passing the correct
>> object tag to the routine. There seem to be a lot of different
>> objects around, and the docs are less than clear on what I should be
>> passing to mi_geoshader_tesselate().
>>
>> Once I extract the instance object from the input parameters, I think
>> I've figured that I have the following object hierarchy in the
>> database (ignoring instance type objects).
>>
>> miScene_Group
>> |
>> Kid[0]
>> |___ miScene_Object (type = miOBJECT_PLACEHOLDER)
>> |
>> |__ geo.placeholder_list.object---> miBox
>> object
>>
>>
>> If I pass any of the above object's tags to "mi_geoshader_tesselate()"
>> then XSI will crash, unless I pass the miBox's object tag, in which
>> case it doesn't crash but I get no leaves returned.
>>
>> What am I doing wrong here! Is it possible to get displaced geometry?
>> What's contained in the miBox structure - there seem to be some
>> geometry information, but I'm guessing that it's not subdivided or
>> displaced?
>>
>> Thanks
>>
>> Andy
>>
>>
>>
>>
>>
>>
>>
>
>
>
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