/* OpenSceneGraph example, osgtext.
*
*  Permission is hereby granted, free of charge, to any person obtaining a copy
*  of this software and associated documentation files (the "Software"), to deal
*  in the Software without restriction, including without limitation the rights
*  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
*  copies of the Software, and to permit persons to whom the Software is
*  furnished to do so, subject to the following conditions:
*
*  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
*  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
*  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
*  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
*  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
*  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
*  THE SOFTWARE.
*/

#include <osgDB/ReadFile>
#include <osgDB/WriteFile>

#include <osgGA/StateSetManipulator>
#include <osgViewer/Viewer>
#include <osgViewer/ViewerEventHandlers>

#include <osg/Camera>

#include <osgText/Font>
#include <osgText/Text>

class UpdateText : public osgGA::GUIEventHandler
{
public:
  UpdateText(osgText::Text* left, osgText::Text* right)
    : left_(left), right_(right), flipText_(false)
  {
  }

  virtual bool handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& aa, osg::Object*, osg::NodeVisitor*)
  {
    if (ea.getEventType() == ea.FRAME)
    {
      static const int INIT_X = 10;
      static const int INIT_Y = 100;

      osg::BoundingBox bb1 = left_->getBoundingBox();

      // Alternate the Y to get new positions every frame
      int newY = INIT_Y;
      if (flipText_)
        newY += 10.f;
      flipText_ = !flipText_;

      left_->setPosition(osg::Vec3f(INIT_X, newY, 0.f));
      int newX = (bb1.xMax() - bb1.xMin()) + 50 + INIT_X;
      right_->setPosition(osg::Vec3f(newX, newY, 0.f));
    }
    return false;
  }
private:
  osg::ref_ptr<osgText::Text> left_;
  osg::ref_ptr<osgText::Text> right_;
  bool flipText_;
};


int main(int argc, char** argv)
{
    osg::ArgumentParser arguments(&argc, argv);

    // construct the viewer.
    osgViewer::Viewer viewer(arguments);

    // create the hud.
    osg::Camera* camera = new osg::Camera;
    camera->setReferenceFrame(osg::Transform::ABSOLUTE_RF);
    camera->setProjectionMatrixAsOrtho2D(0, 1280, 0, 1024);
    camera->setViewMatrix(osg::Matrix::identity());
    camera->setClearMask(GL_DEPTH_BUFFER_BIT);
    camera->getOrCreateStateSet()->setMode(GL_LIGHTING, osg::StateAttribute::OFF);

    viewer.setSceneData(camera);

    osgText::Text* left = new osgText::Text;
    left->setFont("fonts/arialbd.ttf");
    left->setText("Left");
    left->setDataVariance(osg::Object::DYNAMIC);
    left->setBackdropType(osgText::Text::DROP_SHADOW_BOTTOM_RIGHT);
    camera->addChild(left);

    osgText::Text* right = new osgText::Text;
    right->setFont("fonts/arialbd.ttf");
    right->setText("Right");
    right->setDataVariance(osg::Object::DYNAMIC);
    right->setBackdropType(osgText::Text::DROP_SHADOW_BOTTOM_RIGHT);
    camera->addChild(right);

    viewer.addEventHandler(new UpdateText(left, right));
    viewer.addEventHandler(new osgGA::StateSetManipulator(viewer.getCamera()->getOrCreateStateSet()));
    viewer.addEventHandler(new osgViewer::StatsHandler());

    viewer.run();

    return 0;
}