[Bf-cycles] uv coordinates in Cycles standalone

[Guillaume Rouault]

After reflection, It's dumb of me to think that the error comes from source
code. It definitely comes from my python code :
I was able to render correctly the example object you gave me 'uv_cube.xml'

Guillaume

On Thu, Dec 10, 2015 at 12:45 PM, Guillaume Rouault <
guillaume.rouault.fx at gmail.com> wrote:

> Thank you guys for your answers, I wanted some infos, and I have plenty of
> them now ^^ .
> I am trying to code a exporter from Houdini to Cycles Standalone. I use
> python to do that in houdini 15.
> The fact is , I am really bad at C++ and after several hours of reading
> the source code, my head hurts a little ^^ .
>
> indeed a lot of infos in cycles_xml.cpp
> I adapted my export script to try and mimic the way mesh is computed.
>
>  in the part of the code you mentionned
> https://developer.blender.org/diffusion/C/browse/master/src/app/cycles_xml.cpp;65ff373f0c71c043dd7b5632580501f1fc4bea7e$982
>
> Is it normal that the variable 'index_offset' stays at 0 ?
> Shouldn't it be incremented at every iteration ?
>
> Guillaume
>
> On Thu, Dec 10, 2015 at 6:42 AM, Nathan Letwory <nathan at mcneel.com> wrote:
>
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>> I haven't actually tested this in the C++ standalone version, but only
>> in my C# CCSycles tester, but check out
>>
>> https://github.com/jesterKing/CCSycles/blob/master/tests/objects/uv_cube
>> .xml
>> <https://github.com/jesterKing/CCSycles/blob/master/tests/objects/uv_cube.xml>
>>
>> You'll have to add a texture coordinate input node and connect it to
>> the image texture node (vector). That should have your shader use UV
>> coordinates from the mesh data.
>>
>> UV coordinates are per triangle (you can double-check here:
>> https://developer.blender.org/diffusion/C/browse/master/src/app/cycles_x
>> ml.cpp;65ff373f0c71c043dd7b5632580501f1fc4bea7e$982)
>>
>> Here a custom RhinoCycles material using XML with a texture coordinate
>> input node:
>> https://github.com/mcneel/RhinoCycles/blob/master/Materials/BrickWithChe
>> ckeredMortar.cs
>>
>> And here for the C#-way of creating nodes in RhinoCycles where I set
>> projection and mappings
>> https://github.com/mcneel/RhinoCycles/blob/master/RenderEngine.Utils.cs#
>> L131
>> <https://github.com/mcneel/RhinoCycles/blob/master/RenderEngine.Utils.cs#L131>
>> - - in this function the last else block is probably the most
>> interesting, since here I connect the UV output from texture
>> coordinate input node :)
>>
>> Hope that helps,
>>
>> /Nathan
>>
>> On 09/12/2015 23:42, Guillaume Rouault wrote:
>> >
>> > I couldn't find a file named blender_mesh.cpp in the sources I
>> > have. And I think it would mainly give me some infos on how to
>> > format the mesh in the xml object file. but my main issue, I think,
>> > is at the shader level in the scene xml file, using the standalone
>> > XML API . How do I force the shader to use uv coordinates provided
>> > on the mesh ?
>> >
>> > Now that I think of it, there are no examples using uv mapped
>> > objects in the /examples folder, at least nothing using coordinates
>> > generated during modeling.  Is it even supported at this stage in
>> > the standalone version ?
>> >
>> > Guillaume
>> >
>> > On Wed, Dec 9, 2015 at 10:19 PM, Mohamed Sakr <3dsakr at gmail.com
>> > <mailto:3dsakr at gmail.com>> wrote:
>> >
>> > in blender_mesh.cpp, find attr_create_uv_map() function and see
>> > how they create UVs
>> >
>> > On Wed, Dec 9, 2015 at 10:26 PM, Guillaume Rouault
>> > <guillaume.rouault.fx at gmail.com
>> > <mailto:guillaume.rouault.fx at gmail.com>> wrote:
>> >
>> > Hi,
>> >
>> > I can't find any infos on uv coordinates for cycles standalone. As
>> > of now, I haven't been able to render an object with the correct
>> > uvs. I can see a texture, but it's mapped to every triangle on the
>> > mesh.
>> >
>> > I searched the xml api , and came up with that setup :
>> >
>> >
>> > *<!-- floor shader-->* *<shader name="floor" >* *<diffuse_bsdf
>> > name="diffuse" roughness="0.05" color="1.0, 1.0, 1.0" />*
>> > *<glossy_bsdf name="glossy" roughness="0.05" color="0.2, 0.2, 0.2"
>> > />* * * *<texture_coordinate name="uv" />* *<image_texture
>> > name="tex" src="./maps/aaa.jpg" />* *<add_closure name="mix" />*
>> > *<fresnel name="fresnel" />* *<connect from="fresnel fac"
>> > to="glossy color" />* * * *<connect from="uv uv" to="tex vector"
>> > />* *<connect from="tex color" to="diffuse color" />* * * * *
>> > *<connect from="diffuse bsdf" to="mix closure1" />* *<connect
>> > from="glossy bsdf" to="mix closure2" />* *<connect from="mix
>> > closure" to="output surface" />* *</shader>* * * * * Am I on the
>> > right path ? * * Are there any examples or infos on uvs somewhere
>> > ? Actually, on my meshes,  I don't even know if I have to export uv
>> > coords as vector2  (uv) , or vector3 (uvw) ? * * * * *Guillaume*
>>
>>
>> - --
>> Nathan Letwory
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