glbox.cpp Example File

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  **
  ** Copyright (C) 2015 The Qt Company Ltd.
  ** Contact: http://www.qt.io/licensing/
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  ** This file is part of the examples of the Qt Toolkit.
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  /****************************************************************************
  **
  ** This is a simple QGLWidget displaying an openGL wireframe box
  **
  ** The OpenGL code is mostly borrowed from Brian Pauls "spin" example
  ** in the Mesa distribution
  **
  ****************************************************************************/

  #include "glbox.h"
  #include <QAxAggregated>
  #include <QUuid>
  #include <objsafe.h>

  #if defined(Q_CC_MSVC)
  #pragma warning(disable:4305) // init: truncation from const double to float
  #endif

  /*!
    Create a GLBox widget
  */

  GLBox::GLBox( QWidget* parent, const char* name )
      : QGLWidget( parent )
  {
      xRot = yRot = zRot = 0.0;           // default object rotation
      scale = 1.25;                       // default object scale
      object = 0;
  }

  /*!
    Release allocated resources
  */

  GLBox::~GLBox()
  {
      makeCurrent();

      if (object)
          glDeleteLists( object, 1 );
  }

  /*!
    Paint the box. The actual openGL commands for drawing the box are
    performed here.
  */

  void GLBox::paintGL()
  {
      glClear( GL_COLOR_BUFFER_BIT );

      glLoadIdentity();
      glTranslatef( 0.0, 0.0, -10.0 );
      glScalef( scale, scale, scale );

      glRotatef( xRot, 1.0, 0.0, 0.0 );
      glRotatef( yRot, 0.0, 1.0, 0.0 );
      glRotatef( zRot, 0.0, 0.0, 1.0 );

      glCallList( object );
  }

  /*!
    Set up the OpenGL rendering state, and define display list
  */

  void GLBox::initializeGL()
  {
      initializeOpenGLFunctions();

      qglClearColor(Qt::black);           // Let OpenGL clear to black
      object = makeObject();              // Generate an OpenGL display list
      glShadeModel( GL_FLAT );
  }

  /*!
    Set up the OpenGL view port, matrix mode, etc.
  */

  void GLBox::resizeGL( int w, int h )
  {
      glViewport( 0, 0, (GLint)w, (GLint)h );
      glMatrixMode( GL_PROJECTION );
      glLoadIdentity();
      glFrustum( -1.0, 1.0, -1.0, 1.0, 5.0, 15.0 );
      glMatrixMode( GL_MODELVIEW );
  }

  /*!
    Generate an OpenGL display list for the object to be shown, i.e. the box
  */

  GLuint GLBox::makeObject()
  {
      GLuint list;

      list = glGenLists( 1 );

      glNewList( list, GL_COMPILE );

      qglColor(Qt::white);                      // Shorthand for glColor3f or glIndex

      glLineWidth( 2.0 );

      glBegin( GL_LINE_LOOP );
      glVertex3f(  1.0,  0.5, -0.4 );
      glVertex3f(  1.0, -0.5, -0.4 );
      glVertex3f( -1.0, -0.5, -0.4 );
      glVertex3f( -1.0,  0.5, -0.4 );
      glEnd();

      glBegin( GL_LINE_LOOP );
      glVertex3f(  1.0,  0.5, 0.4 );
      glVertex3f(  1.0, -0.5, 0.4 );
      glVertex3f( -1.0, -0.5, 0.4 );
      glVertex3f( -1.0,  0.5, 0.4 );
      glEnd();

      glBegin( GL_LINES );
      glVertex3f(  1.0,  0.5, -0.4 );   glVertex3f(  1.0,  0.5, 0.4 );
      glVertex3f(  1.0, -0.5, -0.4 );   glVertex3f(  1.0, -0.5, 0.4 );
      glVertex3f( -1.0, -0.5, -0.4 );   glVertex3f( -1.0, -0.5, 0.4 );
      glVertex3f( -1.0,  0.5, -0.4 );   glVertex3f( -1.0,  0.5, 0.4 );
      glEnd();

      glEndList();

      return list;
  }

  /*!
    Set the rotation angle of the object to \e degrees around the X axis.
  */

  void GLBox::setXRotation( int degrees )
  {
      xRot = (GLfloat)(degrees % 360);
      updateGL();
  }

  /*!
    Set the rotation angle of the object to \e degrees around the Y axis.
  */

  void GLBox::setYRotation( int degrees )
  {
      yRot = (GLfloat)(degrees % 360);
      updateGL();
  }

  /*!
    Set the rotation angle of the object to \e degrees around the Z axis.
  */

  void GLBox::setZRotation( int degrees )
  {
      zRot = (GLfloat)(degrees % 360);
      updateGL();
  }

  class ObjectSafetyImpl : public QAxAggregated,
                           public IObjectSafety
  {
  public:
      ObjectSafetyImpl() {}

      long queryInterface( const QUuid &iid, void **iface )
      {
          *iface = 0;
          if ( iid == IID_IObjectSafety )
              *iface = (IObjectSafety*)this;
          else
              return E_NOINTERFACE;

          AddRef();
          return S_OK;
      }

      QAXAGG_IUNKNOWN;

      HRESULT WINAPI GetInterfaceSafetyOptions( REFIID riid, DWORD *pdwSupportedOptions, DWORD *pdwEnabledOptions )
      {
          *pdwSupportedOptions = INTERFACESAFE_FOR_UNTRUSTED_DATA | INTERFACESAFE_FOR_UNTRUSTED_CALLER;
          *pdwEnabledOptions = INTERFACESAFE_FOR_UNTRUSTED_DATA | INTERFACESAFE_FOR_UNTRUSTED_CALLER;
          return S_OK;
      }
      HRESULT WINAPI SetInterfaceSafetyOptions( REFIID riid, DWORD pdwSupportedOptions, DWORD pdwEnabledOptions )
      {
          return S_OK;
      }
  };

  QAxAggregated *GLBox::createAggregate()
  {
      return new ObjectSafetyImpl();
  }