在OGRE中画图元 rendering your own stuff
http://www.4ucode.com/Study/Topic/1489492
http://blog.csdn.net/zhuxiaoyang2000/article/details/6326315
ManualObject* manual = mSceneMgr->createManualObject("manual");
manual->begin("BaseWhiteNoLighting", RenderOperation::OT_LINE_STRIP);
manual->position(-100.0, -100.0, 0.0); // start position
manual->position( 100.0, -100.0, 0.0); // draw first line
manual->position( 100.0, 100.0, 0.0);
manual->position(-100.0, 100.0, 0.0);
manual->position(-100.0, -100.0, 0.0); // draw fourth line
manual->end();
mSceneMgr->getRootSceneNode()->createChildSceneNode()->attachObject(manual);