Hi all,

I have this code to draw a cube:

Qt Code: 
  1. #-------------------------------------------------
  2. #
  3. # Project created by QtCreator 2012-05-28T13:03:04
  4. #
  5. #-------------------------------------------------
  6.  
  7. QT       += core gui opengl
  8.  
  9. TARGET = opengl
  10. TEMPLATE = app
  11.  
  12.  
  13. SOURCES += main.cpp \
  14.     cube.cpp
  15.  
  16. HEADERS  += cube.h
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Qt Code: 
  1. #include <QtGui/QApplication>
  2. #include "cube.h"
  3.  
  4. int main(int argc, char *argv[])
  5. {
  6.     QApplication app(argc, argv);
  7.     if (!QGLFormat::hasOpenGL())
  8.         qFatal("This system has no OpenGL support");
  9.     Cube cube;
  10.     cube.resize(300, 300);
  11.     cube.show();
  12.     return app.exec();
  13. }
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Qt Code: 
  1. #ifndef GLWIDGET_H
  2. #define GLWIDGET_H
  3.  
  4. #include <QGLWidget>
  5. #include <QMouseEvent>
  6.  
  7. class Cube : public QGLWidget
  8. {
  9. public:
  10.     Cube(QWidget *parent = 0);
  11. protected:
  12.     void initializeGL();
  13.     void resizeGL(int width, int height);
  14.     void paintGL();
  15.     void mousePressEvent(QMouseEvent *event);
  16.     void mouseMoveEvent(QMouseEvent *event);
  17.     void mouseDoubleClickEvent(QMouseEvent *event);
  18. private:
  19.     void draw();
  20.     int faceAtPosition(const QPoint &pos);
  21.     GLfloat rotationX;
  22.     GLfloat rotationY;
  23.     GLfloat rotationZ;
  24.     QColor faceColors[6];
  25.     QPoint lastPos;
  26. };
  27.  
  28. #endif // GLWIDGET_H
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Qt Code: 
  1. #include "cube.h"
  2. #include <QColorDialog>
  3. #include <GL/glu.h>
  4.  
  5. Cube::Cube(QWidget *parent)
  6. : QGLWidget(parent)
  7. {
  8.     setFormat(QGLFormat(QGL::DoubleBuffer | QGL::DepthBuffer));
  9.     rotationX = 0;
  10.     rotationY = 0;
  11.     rotationZ = 0;
  12.     faceColors[0] = Qt::red;
  13.     faceColors[1] = Qt::green;
  14.     faceColors[2] = Qt::blue;
  15.     faceColors[3] = Qt::cyan;
  16.     faceColors[4] = Qt::yellow;
  17.     faceColors[5] = Qt::magenta;
  18. }
  19.  
  20. void Cube::initializeGL()
  21. {
  22.     qglClearColor(Qt::black);
  23.     glShadeModel(GL_FLAT);
  24.     glEnable(GL_DEPTH_TEST);
  25.     glEnable(GL_CULL_FACE);
  26. }
  27.  
  28. void Cube::resizeGL(int width, int height)
  29. {
  30.     glViewport(0, 0, width, height);
  31.     glMatrixMode(GL_PROJECTION);
  32.     glLoadIdentity();
  33.     GLfloat x = (GLfloat)width / height;
  34.     glFrustum(-x, x, -1.0, 1.0, 4.0, 15.0);
  35.     glMatrixMode(GL_MODELVIEW);
  36. }
  37.  
  38. void Cube::paintGL()
  39. {
  40.     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  41.     draw();
  42. }
  43.  
  44. void Cube::draw()
  45. {
  46.     static const GLfloat coords[6] [4] [3] = {
  47.         { { +1.0, -1.0, +1.0 }, { +1.0, -1.0, -1.0 },
  48.         { +1.0, +1.0, -1.0 }, { +1.0, +1.0, +1.0 } },
  49.         { { -1.0, -1.0, -1.0 }, { -1.0, -1.0, +1.0 },
  50.         { -1.0, +1.0, +1.0 }, { -1.0, +1.0, -1.0 } },
  51.         { { +1.0, -1.0, -1.0 }, { -1.0, -1.0, -1.0 },
  52.         { -1.0, +1.0, -1.0 }, { +1.0, +1.0, -1.0 } },
  53.         { { -1.0, -1.0, +1.0 }, { +1.0, -1.0, +1.0 },
  54.         { +1.0, +1.0, +1.0 }, { -1.0, +1.0, +1.0 } },
  55.         { { -1.0, -1.0, -1.0 }, { +1.0, -1.0, -1.0 },
  56.         { +1.0, -1.0, +1.0 }, { -1.0, -1.0, +1.0 } },
  57.         { { -1.0, +1.0, +1.0 }, { +1.0, +1.0, +1.0 },
  58.         { +1.0, +1.0, -1.0 }, { -1.0, +1.0, -1.0 } }
  59.     };
  60.     glMatrixMode(GL_MODELVIEW);
  61.     glLoadIdentity();
  62.     glTranslatef(0.0, 0.0, -10.0);
  63.     glRotatef(rotationX, 1.0, 0.0, 0.0);
  64.     glRotatef(rotationY, 0.0, 1.0, 0.0);
  65.     glRotatef(rotationZ, 0.0, 0.0, 1.0);
  66.     for (int i = 0; i < 6; ++i) {
  67.         glLoadName(i);
  68.         glBegin(GL_QUADS);
  69.         qglColor(faceColors[i]);
  70.         for (int j = 0; j < 4; ++j) {
  71.             glVertex3f(coords[i] [j] [0], coords[i] [j] [1],
  72.             coords[i] [j] [2]);
  73.         }
  74.         glEnd();
  75.     }
  76. }
  77.  
  78. void Cube::mousePressEvent(QMouseEvent *event)
  79. {
  80.     lastPos = event->pos();
  81. }
  82.  
  83. void Cube::mouseMoveEvent(QMouseEvent *event)
  84. {
  85.     GLfloat dx = (GLfloat) (event->x() - lastPos.x()) / width();
  86.     GLfloat dy = (GLfloat) (event->y() - lastPos.y()) / height();
  87.     if (event->buttons() & Qt::LeftButton) {
  88.         rotationX += 180 * dy;
  89.         rotationY += 180 * dx;
  90.         updateGL();
  91.     } else if (event->buttons() & Qt::RightButton) {
  92.         rotationX += 180 * dy;
  93.         rotationZ += 180 * dx;
  94.         updateGL();
  95.     }
  96.     lastPos = event->pos();
  97. }
  98.  
  99. void Cube::mouseDoubleClickEvent(QMouseEvent *event)
  100. {
  101.     int face = faceAtPosition(event->pos());
  102.     if (face != -1) {
  103.         QColor color = QColorDialog::getColor(faceColors[face],
  104.         this);
  105.         if (color.isValid()) {
  106.             faceColors[face] = color;
  107.             updateGL();
  108.         }
  109.     }
  110. }
  111.  
  112. int Cube::faceAtPosition(const QPoint &pos)
  113. {
  114.     const int MaxSize = 512;
  115.     GLuint buffer[MaxSize];
  116.     GLint viewport[4];
  117.     glGetIntegerv(GL_VIEWPORT, viewport);
  118.     glSelectBuffer(MaxSize, buffer);
  119.     glRenderMode(GL_SELECT);
  120.     glInitNames();
  121.     glPushName(0);
  122.     glMatrixMode(GL_PROJECTION);
  123.     glPushMatrix();
  124.     glLoadIdentity();
  125.     gluPickMatrix((GLdouble)pos.x(),
  126.     (GLdouble) (viewport[3] - pos.y()),
  127.     5.0, 5.0, viewport);
  128.     GLfloat x = (GLfloat)width() / height();
  129.     glFrustum(-x, x, -1.0, 1.0, 4.0, 15.0);
  130.     draw();
  131.     glMatrixMode(GL_PROJECTION);
  132.     glPopMatrix();
  133.     if (!glRenderMode(GL_RENDER))
  134.         return -1;
  135.     return buffer[3];
  136. }
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There are any native implementation in Qt C++ that encapsulates all of this to simplify the 3D usage? I think that the above code is a very low level code to draw a cube. I have used Ogre in Qt and it's simplify a bit the 3D usage.

Regards.