source: pacpusframework/branches/2.0-beta1/include/extlib/qwtplot3d/qwt3d_openglhelper.h@ 89

#ifndef __openglhelper_2003_06_06_15_49__
#define __openglhelper_2003_06_06_15_49__

#include "qglobal.h"

#if QT_VERSION < 0x040000
#   include <qgl.h>
#else
#   include <QtOpenGL/qgl.h>
#endif

#include <GL/glu.h>

namespace Qwt3D
{

#ifndef QWT3D_NOT_FOR_DOXYGEN

class GLStateBewarer
{
public:
        
        GLStateBewarer(GLenum what, bool on, bool persist=false)
        {
                state_ = what;
                stateval_ = glIsEnabled(what);  
                if (on)
                        turnOn(persist);
                else
                        turnOff(persist);
        }

        ~GLStateBewarer() 
        {
                if (stateval_)
                        glEnable(state_);
                else
                        glDisable(state_);
        }
        
        void turnOn(bool persist = false)
        {
                glEnable(state_);
                if (persist)
                        stateval_ = true;
        }
        
        void turnOff(bool persist = false)
        {
                glDisable(state_);
                if (persist)
                        stateval_ = false;
        }


private:
        
        GLenum state_;
        bool stateval_;

};

inline const GLubyte* gl_error()
{
        GLenum errcode;
        const GLubyte* err = 0;
        
        if ((errcode = glGetError()) != GL_NO_ERROR)
        {
                err = gluErrorString(errcode);
        }
        return err;
}

inline  void SaveGlDeleteLists(GLuint& lstidx, GLsizei range)
{
        if (glIsList(lstidx))
                glDeleteLists(lstidx, range);
        lstidx = 0;
}

//! get OpenGL transformation matrices
/**
        Don't rely on (use) this in display lists !
        \param modelMatrix should be a GLdouble[16]
        \param projMatrix should be a GLdouble[16]
        \param viewport should be a GLint[4]
*/
inline void getMatrices(GLdouble* modelMatrix, GLdouble* projMatrix, GLint* viewport)
{
        glGetIntegerv(GL_VIEWPORT, viewport);
        glGetDoublev(GL_MODELVIEW_MATRIX,       modelMatrix);
        glGetDoublev(GL_PROJECTION_MATRIX,      projMatrix);
}

//! simplified glut routine (glUnProject): windows coordinates_p --> object coordinates_p 
/**
        Don't rely on (use) this in display lists !
*/
inline bool ViewPort2World(double& objx, double& objy, double& objz, double winx, double winy, double winz)
{
        GLdouble modelMatrix[16];
  GLdouble projMatrix[16];
  GLint viewport[4];

        getMatrices(modelMatrix, projMatrix, viewport);
        int res = gluUnProject(winx, winy, winz, modelMatrix, projMatrix, viewport, &objx, &objy, &objz);

        return (res == GL_FALSE) ? false : true;
}

//! simplified glut routine (glProject): object coordinates_p --> windows coordinates_p 
/**
        Don't rely on (use) this in display lists !
*/
inline bool World2ViewPort(double& winx, double& winy, double& winz, double objx, double objy, double objz )
{
        GLdouble modelMatrix[16];
  GLdouble projMatrix[16];
  GLint viewport[4];

        getMatrices(modelMatrix, projMatrix, viewport);
        int res = gluProject(objx, objy, objz, modelMatrix, projMatrix, viewport, &winx, &winy, &winz);

        return (res == GL_FALSE) ? false : true;
}


#endif // QWT3D_NOT_FOR_DOXYGEN

} // ns

#endif