osg学习（五十三）绘制纹理贴图Texture示例

Posted 2021-09-07 hankern

效果图：

代码：

//osg纹理贴图
    osg::ref_ptr<osg::Geometry> geom = new osg::Geometry;
    osg::ref_ptr<osg::Geode> geode = new osg::Geode;
    geode->addDrawable(geom.get());
    osg::ref_ptr<osg::Vec3Array> vArr = new osg::Vec3Array;
    vArr->push_back(osg::Vec3(-5.0f,0.0f,-5.0f));
    vArr->push_back(osg::Vec3(5.0f,0.0f,-5.0f));
    vArr->push_back(osg::Vec3(5.0f,0.0f,5.0f));
    vArr->push_back(osg::Vec3(-5.0f,0.0f,5.0f));
    geom->setVertexArray(vArr.get());
    geom->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::QUADS,0,4));
    osg::ref_ptr<osg::Vec3Array> nArr = new osg::Vec3Array;
    nArr->push_back(osg::Vec3(0.0, 0.0, 1.0));
    geom->setNormalArray(nArr.get());
    geom->setNormalBinding(osg::Geometry::BIND_OVERALL);
    osg::ref_ptr<osg::Vec4Array> cArr = new osg::Vec4Array;
    cArr->push_back(osg::Vec4(1.0,1.0,1.0,1.0));
    geom->setColorArray(cArr.get());
    geom->setColorBinding(osg::Geometry::BIND_OVERALL);
    osg::ref_ptr<osg::Vec2Array> tArr0 = new osg::Vec2Array;//创建一个 Vec2Array对象以保存纹理单元 0 的纹理坐标
    tArr0->push_back(osg::Vec2(0,0));
    tArr0->push_back(osg::Vec2(0,1));
    tArr0->push_back(osg::Vec2(1,1));
    tArr0->push_back(osg::Vec2(1,0));
    geom->setTexCoordArray(0,tArr0.get());
    osg::StateSet* ss = geode->getOrCreateStateSet();
    ss->setMode( GL_LIGHTING, osg::StateAttribute::OFF | osg::StateAttribute::PROTECTED );
    ss->setRenderingHint( osg::StateSet::TRANSPARENT_BIN );
    //std::string fileName("Images/blueFlowers.png");
    //std::string fileName("Images/clockface.JPG");
    std::string fileName("Images/reflect.rgb");
    osg::ref_ptr<osg::Image> image = osgDB::readImageFile( fileName );
    if (!image.valid())
    {
        osg::notify( osg::FATAL ) << "Unable to load data file Exiting." << std::endl;
        return;
    }
    osg::ref_ptr<osg::Texture2D> tex = new osg::Texture2D;
    tex->setImage(image.get());
    tex->setUnRefImageDataAfterApply( true );
    ss->setTextureAttributeAndModes( 0, tex.get() );
    osg::BlendFunc* bf = new osg::BlendFunc(osg::BlendFunc::SRC_ALPHA, osg::BlendFunc::ONE_MINUS_SRC_ALPHA );
    ss->setAttributeAndModes( bf );
    osg::AlphaFunc* af = new osg::AlphaFunc(osg::AlphaFunc::GREATER, 0.05f );
    ss->setAttributeAndModes( af );