No24-DrawCallback(OSG利用DrawCallback实现动画效果)

#include <QApplication> #include <osg/Node> #include <osg/Group> #include <osg/Geode> #include <osg/Geometry> #include <osg/Texture2D> #include <osg/StateSet> #include <osg/PositionAttitudeTransform> #include <osgViewer/Viewer> #include <osgDB/ReadFile> #include <osgParticle/PrecipitationEffect> // 雨雪效果 #include <osg/MatrixTransform> // 粒子效果 #include <osgParticle/PrecipitationEffect> #include <osgParticle/Particle> #include <osgParticle/LinearInterpolator> #include <osgParticle/ParticleSystem> #include <osgParticle/RandomRateCounter> #include <osgParticle/PointPlacer> #include <osgParticle/RadialShooter> #include <osgParticle/ModularEmitter> #include <osgParticle/ParticleSystemUpdater> #include <osgParticle/ModularProgram> #include <osgUtil/Optimizer> #include <osgUtil/Simplifier> #include <osgParticle/FireEffect> // 雾 #include <osg/Fog> #include <osgDB/ReadFile> #include <osgViewer/Viewer> #include <osg/StateSet> #include <osg/StateAttribute> #include <osgViewer/ViewerEventHandlers> #include <osgWidget/ViewerEventHandlers> // #include <QDebug> class MyDrawCallback : public osg::Drawable::DrawCallback { public: void drawImplementation(osg::RenderInfo &renderInfo, const osg::Drawable *drawable) const { static double dColor = 0;//颜色 glColor3f(dColor, 0, 0); glBegin(GL_TRIANGLES);//在OSG中画一个opengl三角形 glVertex3f(0.0, 0.0, -2.0); glVertex3f(0.2, 0.0, -2.0); glVertex3f(0.0, 0.4, -2.0); glEnd(); dColor += 0.01;//颜色渐变 if (dColor > 1.0) { dColor = 0.0; } } }; int main(int argc, char *argv[]) { osgViewer::Viewer viewer; osg::Geometry* geometry = new osg::Geometry; //此处一定要把显示列表设置为false, //否则DrawCallback的drawImplementation()函数只会调用一次，而不是在画一帧时都动态更新opengl图形 geometry->setUseDisplayList(false); geometry->setDrawCallback(new MyDrawCallback);//Drawable设置动态更新opengl图形 osg::Geode* geode = new osg::Geode; geode->addDrawable(geometry); geode->getOrCreateStateSet()->setMode(GL_LIGHTING, osg::StateAttribute::OFF); osg::Group* group = new osg::Group; group->addChild(geode); viewer.setSceneData(group); viewer.setUpViewInWindow(35, 35, 500, 500); // return viewer.run(); osg::Matrix mt; mt.makeIdentity(); while (!viewer.done()) { viewer.getCamera()->setViewMatrix(mt); viewer.frame(); } }