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    How to draw 3d line(x,y,z)

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    • W
      webadana last edited by

      i can draw the 2d line and i want to draw 3d (x,y,z) dimension for graph the math equation..

      Where i should start ?
      there is some explanation
      http://www.digitalfanatics.org/projects/qt_tutorial/chapter14.html

      but it is too complex.. i need to draw just line on (x,y,z) dimention..

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      • H
        hakan last edited by

        to draw on 3D you have to learn some basics. then things will get easier. The link which you have given seems good. Just try to implement examples then you'll see how easy to draw a 3d line.

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        • Z
          ZapB last edited by

          This simple app should get you started with drawing lines in 3D using OpenGL and Qt. I suggest you also have a read through the QGLWidget docs and get yourself a good book on OpenGL programming. I can recommend the OpenGL Superbible.

          == main.cpp ==
          @
          #include <QtGui/QApplication>
          #include "lines.h"

          int main(int argc, char *argv[])
          {
          QApplication a(argc, argv);
          Lines w;
          w.show();
          return a.exec();
          }
          @

          == lines.h ==
          @
          #ifndef LINES_H
          #define LINES_H

          #include <QGLWidget>
          #include <QVector2D>

          const float pi = 3.141592653f;
          const float twoPi = 2.0f * pi;
          const float piBy2 = 0.5f * pi;
          const float degToRad = pi / 180.0f;
          const float radToDeg = 180.0f / pi;

          class Lines : public QGLWidget
          {
          Q_OBJECT

          public:
          Lines( QWidget* parent = 0 );

          protected:
          virtual void initializeGL();
          virtual void resizeGL( int w, int h );
          virtual void paintGL();

          virtual void keyPressEvent( QKeyEvent* e );
          

          private:
          float m_theta; /< Rotation about x-axis */
          float m_phi; /
          < Rotation about y-axis */
          float m_aspectRatio;
          QVector2D m_lineWidthRange;
          float m_lineWidthStep;
          float m_lineWidth;
          };

          #endif // LINES_H
          @

          == lines.cpp ==
          @
          #include "lines.h"

          #include <QCoreApplication>
          #include <QDebug>
          #include <QKeyEvent>

          #include <math.h>

          Lines::Lines( QWidget* parent )
          : QGLWidget( parent ),
          m_theta( 0.0f ),
          m_phi( 0.0f ),
          m_aspectRatio( 1.0 ),
          m_lineWidthRange(),
          m_lineWidthStep( 0.0f ),
          m_lineWidth( 1.0f )
          {
          }

          void Lines::initializeGL()
          {
          // Set the clear color to black
          glClearColor( 0.0f, 0.0f, 0.0f, 1.0f );

          // Set the drawing color to green
          glColor3f( 0.0f, 1.0f, 0.0f );
          
          // Query some info about supported point sizes
          glGetFloatv( GL_LINE_WIDTH_RANGE, reinterpret_cast<float*>( &m_lineWidthRange ) );
          glGetFloatv( GL_LINE_WIDTH_GRANULARITY, &m_lineWidthStep );
          
          qDebug() << "Point size range:" << m_lineWidthRange;
          qDebug() << "Point size step:" << m_lineWidthStep;
          
          m_lineWidth = m_lineWidthRange.x();
          

          }

          void Lines::resizeGL( int w, int h )
          {
          // Prevent a divde by zero
          if ( h == 0 )
          h = 1;

          // Set the viewport to window dimensions
          glViewport( 0, 0, w, h );
          
          // reset the coordinate system
          glMatrixMode( GL_PROJECTION );
          glLoadIdentity();
          
          // Establish the clipping volume by setting up an orthographic projection
          double range = 100.0;
          m_aspectRatio = double( w ) / double( h );
          if ( w <=h )
              glOrtho( -range, range, -range / m_aspectRatio, range / m_aspectRatio, range, -range );
          else
              glOrtho( -range * m_aspectRatio, range * m_aspectRatio, -range, range, range, -range );
          
          glMatrixMode( GL_MODELVIEW );
          glLoadIdentity();
          

          }

          void Lines::paintGL()
          {
          // Clear the buffer with the current clearing color
          glClear( GL_COLOR_BUFFER_BIT );

          // Set drawing colour to red
          glColor3f( 1.0f, 0.0f, 0.0f );
          
          // Save matrix state and do the custom rotation
          glPushMatrix();
          glRotatef( m_theta, 1.0f, 0.0f, 0.0f );
          glRotatef( m_phi,   0.0f, 1.0f, 0.0f );
          
          // Draw some Lines in a helix
          glLineWidth( m_lineWidth );
          glBegin( GL_LINE_STRIP );
          float z = -50.0f;
          float angle = 0.0f;
          for ( angle = 0.0f; angle <= twoPi * 3.0f; angle += 0.1f, z += 0.5f )
          {
              float x = 50.0 * sin( angle );
              float y = 50.0 * cos( angle );
              glVertex3f( x, y, z );
          }
          glEnd();
          
          // Restore the matrix state
          glPopMatrix();
          

          }

          void Lines::keyPressEvent( QKeyEvent* e )
          {
          switch ( e->key() )
          {
          case Qt::Key_Escape:
          QCoreApplication::instance()->quit();
          break;

              case Qt::Key_Left:
                  m_phi += 1.0f;
                  updateGL();
                  break;
          
              case Qt::Key_Right:
                  m_phi -= 1.0f;
                  updateGL();
                  break;
          
              case Qt::Key_Up:
                  m_theta += 1.0f;
                  updateGL();
                  break;
          
              case Qt::Key_Down:
                  m_theta -= 1.0f;
                  updateGL();
                  break;
          
              case Qt::Key_Plus:
                  m_lineWidth = qMin( m_lineWidth + m_lineWidthStep, float( m_lineWidthRange.y() ) );
                  qDebug() << "m_lineWidth =" << m_lineWidth;
                  updateGL();
                  break;
          
              case Qt::Key_Minus:
                  m_lineWidth = qMax( m_lineWidth - m_lineWidthStep, float( m_lineWidthRange.x() ) );
                  qDebug() << "m_lineWidth =" << m_lineWidth;
                  updateGL();
                  break;
          
              default:
                  QGLWidget::keyPressEvent( e );
          }
          

          }
          @

          Nokia Certified Qt Specialist
          Interested in hearing about Qt related work

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          • W
            webadana last edited by

            @ZapB thank you very much... its awesome :)
            @hakan ayrıca teşekkür ederim hakan bey yorumunuz için.

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            • Z
              ZapB last edited by

              No problem. Good luck with OpenGL it is good fun although it can be confusing and frustrating to start with when you spend a long time coding something only to be presented with an empty window ;-)

              Nokia Certified Qt Specialist
              Interested in hearing about Qt related work

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