osg渲染一个房子的四壁（有纹理）

/* -*-c++-*- Copyright (C) 2009 Wang Rui <wangray84 at gmail dot com>
 * OpenSceneGraph Engine Book - Design and Implementation
 * How to create a geometric house
*/

#include <osg/Texture2D>
#include <osg/Geometry>
#include <osg/Geode>
#include <osgDB/ReadFile>
#include <osgUtil/SmoothingVisitor>
#include <osgViewer/Viewer>

osg::Drawable* createHouseWall()
{
    // House vertices
    osg::ref_ptr<osg::Vec3Array> vertices = new osg::Vec3Array;
    //前面
    vertices->push_back( osg::Vec3( 0.0, 0.0, 4.0) );  // 0
    vertices->push_back( osg::Vec3( 0.0, 0.0, 0.0) );  // 1
    vertices->push_back( osg::Vec3( 6.0, 0.0, 4.0) );  // 2
    vertices->push_back( osg::Vec3( 6.0, 0.0, 0.0) );  // 3
    //右面
    vertices->push_back( osg::Vec3( 6.0, 4.0, 4.0) );  // 4
    vertices->push_back( osg::Vec3( 6.0, 4.0, 0.0) );  // 5
    //后面
    vertices->push_back( osg::Vec3( 0.0, 4.0, 4.0) );  // 6
    vertices->push_back( osg::Vec3( 0.0, 4.0, 0.0) );  // 7
    //左面
    vertices->push_back( osg::Vec3( 0.0, 0.0, 4.0) );  // 8
    vertices->push_back( osg::Vec3( 0.0, 0.0, 0.0) );  // 9
    
    // House normals
    osg::ref_ptr<osg::Vec3Array> normals = new osg::Vec3Array( 10 );
    //左前
    (*normals)[0].set(-1.0,1.0, 0.0 );
    (*normals)[1].set(-1.0,1.0, 0.0 );
    //右前
   // (*normals)[2].set( 1.0,-1.0, 0.0 );
   // (*normals)[3].set( 1.0,-1.0, 0.0 );
    //右后
    (*normals)[4].set( 1.0, 1.0, 0.0 );
    (*normals)[5].set( 1.0, 1.0, 0.0 );
    //左后
    //(*normals)[6].set(-1.0, 1.0, 0.0 );
    //(*normals)[7].set(-1.0, 1.0, 0.0 );
    //左前
    //(*normals)[8].set(-1.0,-1.0, 0.0 );
    //(*normals)[9].set(-1.0,-1.0, 0.0 );
    
    // House texture coordinates
    osg::ref_ptr<osg::Vec2Array> texcoords = new osg::Vec2Array( 10 );
    //前面的左0.3
    (*texcoords)[0].set( 0.0, 1.0 );
    (*texcoords)[1].set( 0.0, 0.0 );
    (*texcoords)[2].set( 0.3, 1.0 );
    (*texcoords)[3].set( 0.3, 0.0 );

    //右面0.2
    (*texcoords)[4].set( 0.5, 1.0 );
    (*texcoords)[5].set( 0.5, 0.0 );

    //后面0.3
    (*texcoords)[6].set( 0.8, 1.0 );
    (*texcoords)[7].set( 0.8, 0.0 );
    //左边0.2
    (*texcoords)[8].set( 1.0, 1.0 );
    (*texcoords)[9].set( 1.0, 0.0 );
    
    // Create wall geometry
    osg::ref_ptr<osg::Geometry> houseWall = new osg::Geometry;
    houseWall->setVertexArray( vertices.get() );
    houseWall->setTexCoordArray( 0, texcoords.get() );
    houseWall->setNormalArray( normals.get() );
    houseWall->setNormalBinding( osg::Geometry::BIND_PER_VERTEX );
    houseWall->addPrimitiveSet( new osg::DrawArrays(osg::DrawArrays::QUAD_STRIP, 0, 10) );
    
    houseWall->getOrCreateStateSet()->setTextureAttributeAndModes( 0,
        new osg::Texture2D(osgDB::readImageFile("C:\wall.png")) );
    return houseWall.release();
}

int main( int argc, char** argv )
{
    osg::ref_ptr<osg::Geode> geode = new osg::Geode;
    geode->addDrawable( createHouseWall() );
   // geode->addDrawable( createHouseRoof() );
    
    osgViewer::Viewer viewer;
    viewer.setSceneData( geode.get() );
    return viewer.run();
}

所用的纹理：
　　

运行效果(为了观察法线对灯光的影响，注释掉30行到40行相应的代码。改掉左前的法线方向，其影响是房子的里面亮了，如下图)：

　　

运行效果(没有纹理)：

　　

带有环境光、散射光，指定光源位置，有多个纹理

效果：

　　

代码实现：

/* -*-c++-*- Copyright (C) 2009 Wang Rui <wangray84 at gmail dot com>
 * OpenSceneGraph Engine Book - Design and Implementation
 * How to create a geometric house
*/

#include <osg/Texture2D>
#include <osg/Geometry>
#include <osg/Geode>
#include <osgDB/ReadFile>
#include <osgUtil/SmoothingVisitor>
#include <osgViewer/Viewer>
#include <osg/PositionAttitudeTransform>
#include <osg/MatrixTransform>
//回调函数，让其不断的旋转
class RotateCallback : public osg::NodeCallback
{
public:
    RotateCallback() : _rotateZ(0.0) {}

    virtual void operator()( osg::Node* node, osg::NodeVisitor* nv )
    {
        osg::PositionAttitudeTransform* pat = dynamic_cast<osg::PositionAttitudeTransform*>( node );
        if ( pat )
        {
            osg::Quat quat( osg::DegreesToRadians(_rotateZ), osg::Z_AXIS );
            pat->setAttitude( quat );
            _rotateZ += 1.0;
        }
        traverse( node, nv );//访问器的下一个节点
    }

protected:
    double _rotateZ;
};
//向场景中添加光源
osg::ref_ptr<osg::Group> createLight(osg::ref_ptr<osg::Node> node)
{
    osg::ref_ptr<osg::Group> lightRoot= new osg::Group();
    //lightRoot->addChild(node);

    //开启光照
    osg::ref_ptr<osg::StateSet> stateset = new osg::StateSet();
    stateset = lightRoot->getOrCreateStateSet();
    stateset->setMode(GL_LIGHTING,osg::StateAttribute::ON);
    stateset->setMode(GL_LIGHT0,osg::StateAttribute::ON);

    //创建一个Light对象
    osg::ref_ptr<osg::Light> light = new osg::Light();
    light->setLightNum(0);
    //设置方向
    light->setDirection(osg::Vec3(0.0f,1.0f,-1.0f));
    //设置位置
    light->setPosition(osg::Vec4(0,-10,8,1.0f));
    //设置环境光的颜色
    light->setAmbient(osg::Vec4(0.1f,0.1f,0.1f,1.0f));
    //设置散射光的颜色
    light->setDiffuse(osg::Vec4(1.0f,1.0f,1.0f,1.0f));

     ////设置恒衰减指数
     //light->setConstantAttenuation(1.0f);
     ////设置线形衰减指数
     //light->setLinearAttenuation(0.0f);
     ////设置二次方衰减指数
     //light->setQuadraticAttenuation(0.0f);

    //创建光源
    osg::ref_ptr<osg::LightSource> lightSource = new osg::LightSource();
    lightSource->setLight(light.get());

    lightRoot->addChild(lightSource.get());

    return lightRoot.get() ;
}
osg::Drawable* createHouseWall()
{
    // House vertices
    osg::ref_ptr<osg::Vec3Array> vertices = new osg::Vec3Array;
    //前面
    vertices->push_back( osg::Vec3( 0.0, 0.0, 4.0) );  // 0
    vertices->push_back( osg::Vec3( 0.0, 0.0, 0.0) );  // 1
    vertices->push_back( osg::Vec3( 4.0, 0.0, 4.0) );  // 2
    vertices->push_back( osg::Vec3( 4.0, 0.0, 0.0) );  // 3
    //右面
    vertices->push_back( osg::Vec3( 4.0, 4.0, 4.0) );  // 4
    vertices->push_back( osg::Vec3( 4.0, 4.0, 0.0) );  // 5
    //后面
    vertices->push_back( osg::Vec3( 0.0, 4.0, 4.0) );  // 6
    vertices->push_back( osg::Vec3( 0.0, 4.0, 0.0) );  // 7
    //左面
    vertices->push_back( osg::Vec3( 0.0, 0.0, 4.0) );  // 8
    vertices->push_back( osg::Vec3( 0.0, 0.0, 0.0) );  // 9
    
    // House normals
    osg::ref_ptr<osg::Vec3Array> normals = new osg::Vec3Array( 10 );
    //左前
    (*normals)[0].set(-1.0,-1.0, 0.0 );
    (*normals)[1].set(-1.0,-1.0, 0.0 );
    //右前
    (*normals)[2].set( 1.0,-1.0, 0.0 );
    (*normals)[3].set( 1.0,-1.0, 0.0 );
    //右后
    (*normals)[4].set( 1.0, 1.0, 0.0 );
    (*normals)[5].set( 1.0, 1.0, 0.0 );
    //左后
    (*normals)[6].set(-1.0, 1.0, 0.0 );
    (*normals)[7].set(-1.0, 1.0, 0.0 );
    //左前
    (*normals)[8].set(-1.0,-1.0, 0.0 );
    (*normals)[9].set(-1.0,-1.0, 0.0 );
    
    // House texture coordinates
    osg::ref_ptr<osg::Vec2Array> texcoords = new osg::Vec2Array( 10 );
    //前面的左0.3
    (*texcoords)[0].set( 0.0, 1.0 );
    (*texcoords)[1].set( 0.0, 0.0 );
    (*texcoords)[2].set( 1.0, 1.0 );
    (*texcoords)[3].set( 1.0, 0.0 );

    //右面0.2
    /*   (*texcoords)[4].set( 0.0, 1.0 );
    (*texcoords)[5].set( 0.0, 0.0 );

    //后面0.3
    (*texcoords)[6].set( 1.0, 1.0 );
    (*texcoords)[7].set( 1.0, 0.0 );
    //左边0.2
    (*texcoords)[8].set( 0.0, 1.0 );
    (*texcoords)[9].set( 0.0, 0.0 );*/

    // House texture coordinates
    osg::ref_ptr<osg::Vec2Array> texcoords2 = new osg::Vec2Array( 10 );


      //右面0.2

    (*texcoords2)[4].set( 0.0, 1.0 );
    (*texcoords2)[5].set( 0.0, 0.0 );
    

    //后面0.3
    (*texcoords2)[6].set( 1.0, 1.0 );
    (*texcoords2)[7].set( 1.0, 0.0 );
    //左边0.2
    (*texcoords2)[8].set( 0.0, 1.0 );
    (*texcoords2)[9].set( 0.0, 0.0 );

    
    // Create wall geometry
    osg::ref_ptr<osg::Geometry> houseWall = new osg::Geometry;
    houseWall->setVertexArray( vertices.get() );
    houseWall->setTexCoordArray( 0, texcoords.get() );
     houseWall->setTexCoordArray( 1, texcoords2.get() );
    houseWall->setNormalArray( normals.get() );
    houseWall->setNormalBinding( osg::Geometry::BIND_PER_VERTEX );
    houseWall->addPrimitiveSet( new osg::DrawArrays(osg::DrawArrays::QUAD_STRIP, 0, 10) );
    
    houseWall->getOrCreateStateSet()->setTextureAttributeAndModes( 0,new osg::Texture2D(osgDB::readImageFile("C:\22.jpg")) );

     houseWall->getOrCreateStateSet()->setTextureAttributeAndModes( 1,new osg::Texture2D(osgDB::readImageFile("C:\55.jpg")) );

    return houseWall.release();
}

int main( int argc, char** argv )
{

    osg::Group *root = new osg::Group;
    osg::ref_ptr<osg::Geode> geode = new osg::Geode;
    geode->addDrawable( createHouseWall() );
    

    osg::ref_ptr<osg::PositionAttitudeTransform> pat = new osg::PositionAttitudeTransform;
    pat->addChild( geode );
    pat->setUpdateCallback( new RotateCallback );

    root->addChild(pat);
    root->addChild(createLight(geode.get()));
    osgViewer::Viewer viewer;
    viewer.setUpViewInWindow(20,20,400,400);
    viewer.setSceneData(root);
    return viewer.run();
}