FadeText

/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield 
 *
 * This library is open source and may be redistributed and/or modified under  
 * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or 
 * (at your option) any later version.  The full license is in LICENSE file
 * included with this distribution, and on the openscenegraph.org website.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
 * OpenSceneGraph Public License for more details.
*/

#ifndef OSGTEXT_FADETEXT
#define OSGTEXT_FADETEXT 1

#include <osgText/Text>

namespace osgText {


class OSGTEXT_EXPORT FadeText : public osgText::Text
{
public:

    FadeText();
    FadeText(const Text& text,const osg::CopyOp& copyop=osg::CopyOp::SHALLOW_COPY);

    META_Object(osgText,FadeText)


    /** Set the speed that the alpha value changes as the text is occluded or becomes visible.*/
    void setFadeSpeed(float fadeSpeed) { _fadeSpeed = fadeSpeed; }

    /** Get the speed that the alpha value changes.*/
    float getFadeSpeed() const { return _fadeSpeed; }

    /** Draw the text.*/
    virtual void drawImplementation(osg::RenderInfo& renderInfo) const;

protected:

    virtual ~FadeText() {}

    void init();
  
    struct FadeTextUpdateCallback;
    friend struct FadeTextUpdateCallback;

    typedef std::map<osg::View*, osg::Vec4 > ViewBlendColourMap;
    
    ViewBlendColourMap& getViewBlendColourMap() { return _viewBlendColourMap; }
    const ViewBlendColourMap& getViewBlendColourMap() const { return _viewBlendColourMap; }

    float _fadeSpeed;
    
    mutable ViewBlendColourMap _viewBlendColourMap;
};

}


#endif