[osg-users] Texture wrapping for a geometry object

Dominic Stalder dominic.stalder at bluewin.ch
Mon Nov 23 01:09:26 PST 2009


Hi Robert

thanks a lot, I got it from this mailing list message:

http://www.mail-archive.com/osg-users@openscenegraph.net/msg11209.html

I will try the texture coordinates scaling. But just for interesting, 
how would the texture matrix work, do you have some basic code snippet?

Regards
Dominic

Robert Osfield schrieb:
> Hi Dominc,
>
> I don't know where you might have got the impression that you can't
> set up texture repeats with geometry - you just using texture
> coordinates beyond the 0.0 to 1.0 range and you'll get repeats.
> Another way is to use a texture matrix to up the tex coords from 0.0
> to 1.0 range to what you want.
>
> Robert.
>
> On Sun, Nov 22, 2009 at 3:28 PM, Dominic Stalder
> <dominic.stalder at bluewin.ch> wrote:
>   
>> Hi there
>>
>> I would like to wrap (repeated) my texture image on a geometry object. I
>> read somewhere, that this is not possible directly on the geometry, but how
>> can I do it otherwise? Here is my code:
>>
>>   /*
>>    * creates the ground geometry
>>    */
>>   // creates the vertices array
>>   ref_ptr<Vec3Array> verticesGround = new Vec3Array;
>>   verticesGround->push_back(Vec3(-WORLD_INFINITY, 0.0, -WORLD_INFINITY)); //
>> back left
>>   verticesGround->push_back(Vec3(WORLD_INFINITY, 0.0, -WORLD_INFINITY));  //
>> back right
>>   verticesGround->push_back(Vec3(WORLD_INFINITY, 0.0, WORLD_INFINITY));   //
>> front right
>>   verticesGround->push_back(Vec3(-WORLD_INFINITY, 0.0, WORLD_INFINITY));  //
>> front left
>>     // creates the normal array
>>   ref_ptr<Vec3Array> normalsGround = new Vec3Array;
>>   normalsGround->push_back(Vec3(0.0, 1.0, 0.0));
>>     // creates the texture coordinates array
>>   ref_ptr<Vec2Array> texCoordGround = new Vec2Array;
>>   texCoordGround->push_back(Vec2(0.0, 0.0));
>>   texCoordGround->push_back(Vec2(1.0, 0.0));
>>   texCoordGround->push_back(Vec2(1.0, 1.0));
>>   texCoordGround->push_back(Vec2(0.0, 1.0));
>>     // loads the texture image
>>   ref_ptr<Image> imgGrass =
>> osgDB::readImageFile(Utilities::filePath("res/osg/grass.png").toStdString());
>>     // attaches the image to the texture
>>   ref_ptr<Texture2D> texGround = new Texture2D;
>>   texGround->setDataVariance(Object::DYNAMIC);
>>   texGround->setWrap(Texture::WRAP_S, Texture::REPEAT);
>>   texGround->setWrap(Texture::WRAP_T, Texture::REPEAT);
>>   texGround->setImage(imgGrass.get());
>>     // releases the image after applying
>>   texGround->setUnRefImageDataAfterApply(true);
>>     // creates the geometry
>>   ref_ptr<Geometry> geomGround = new Geometry;
>>   geomGround->setVertexArray(verticesGround.get());
>>   geomGround->setNormalArray(normalsGround.get());
>>   geomGround->setTexCoordArray(0, texCoordGround.get());
>>
>>   // adds the primitive set to the geometry
>>   geomGround->addPrimitiveSet(new DrawArrays(PrimitiveSet::QUADS, 0, 4));
>>     // enables all the necessary states for the ground geometry node
>>   ref_ptr<StateSet> stateGroundGeometry = geomGround->getOrCreateStateSet();
>>   stateGroundGeometry->setTextureAttributeAndModes(0, texGround.get(),
>> StateAttribute::ON);
>>
>>   // creates the geode
>>   ref_ptr<Geode> geoGround = new Geode;
>>   geoGround->addDrawable(geomGround.get());
>>
>> Thanks a lot in advance!
>>
>> Best regards
>> Dominic
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>> osg-users at lists.openscenegraph.org
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>>
>>     
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