#ifndef MYPANEL_H#define MYPANEL_H#include "QtGui"#include <QGLWidget>#include "ui_mypanel.h"class MyPanel : public QGLWidget{Q_OBJECTpublic:MyPanel(QWidget *parent = 0);~MyPanel();protected:virtual void mouseMoveEvent(QMouseEvent *event);virtual void mousePressEvent(QMouseEvent *event);virtual void wheelEvent(QWheelEvent *event);virtual void paintEvent(QPaintEvent* event);private:Ui::MyPanel ui;void createGradient();void createGLObject();void drawBackground(QPainter * painter);void drawCube();void drawLegend(QPainter* painter);GLuint glObject;QRadialGradient gradient;GLfloat xrot;GLfloat yrot;GLfloat zrot;GLfloat scaling;QPoint lastPos;};#endif // MYPANEL_H
#include <cmath>#include "mypanel.h"#ifndef GL_MULTISAMPLE#define GL_MULTISAMPLE 0x809D#endifMyPanel::MyPanel(QWidget *parent): QGLWidget(parent){//setFormat(QGLFormat(QGL::SampleBuffers));xrot = -38.0;yrot = -58.0;zrot = 0.0;scaling = 1.0;setAutoBufferSwap(false);setAutoFillBackground(false);createGradient();createGLObject();}MyPanel::~MyPanel(){makeCurrent();glDeleteLists(glObject, 1);}void MyPanel::paintEvent(QPaintEvent *e){QPainter painter(this); //painter.begin(this);drawBackground(&painter);painter.end();//painter.beginNativePainting();drawCube();//painter.endNativePainting();painter.begin(this);drawLegend(&painter);painter.end();swapBuffers();}void MyPanel::mousePressEvent(QMouseEvent *e){lastPos = e->pos();}void MyPanel::mouseMoveEvent(QMouseEvent *e){GLfloat dx = GLfloat(e->x() - lastPos.x()) / width();GLfloat dy = GLfloat(e->y() - lastPos.y()) / height();if (e->buttons() & Qt::LeftButton) {xrot += 180 * dy;yrot += 180 * dx;update();} else if (e->buttons() & Qt::RightButton) {xrot += 180 * dy;zrot += 180 * dx;update();}lastPos = e->pos();}void MyPanel::wheelEvent(QWheelEvent *e){double numDegrees = -e->delta() / 8.0;double numSteps = numDegrees / 15.0;scaling *= std::pow(1.125, numSteps);update();}void MyPanel::createGradient(){gradient.setCoordinateMode(QGradient::ObjectBoundingMode);gradient.setCenter(0.45, 0.50);gradient.setFocalPoint(0.40, 0.45);gradient.setColorAt(0.0, QColor(105, 146, 182));gradient.setColorAt(0.4, QColor(81, 113, 150));gradient.setColorAt(0.8, QColor(16, 56, 121));}void MyPanel::createGLObject(){ static const GLfloat vertex_list[8][3] = {{-1.0, -1.0, 1.0},{1.0, -1.0, 1.0},{1.0, 1.0, 1.0},{-1.0, 1.0, 1.0},{-1.0, -1.0, -1.0},{1.0, -1.0, -1.0},{1.0, 1.0, -1.0},{-1.0, 1.0, -1.0}};static const int vertex_index_list1[6] = {6, 7, 5, 4, 1, 0};static const int vertex_index_list2[10] = {2, 6, 5, 1, 2, 3, 7, 4, 0, 3};makeCurrent();glShadeModel(GL_FLAT);glObject = glGenLists(1);glNewList(glObject, GL_COMPILE); {qglColor(QColor(255, 239, 191));glLineWidth(1.0);glBegin(GL_LINES); {for (int i = 0; i < 6; i++)glVertex3fv(vertex_list[vertex_index_list1[i]]);} glEnd();glBegin(GL_LINE_LOOP); {for (int i = 0; i < 10; i++)glVertex3fv(vertex_list[vertex_index_list2[i]]);} glEnd();} glEndList();}void MyPanel::drawBackground(QPainter *painter){painter->setPen(Qt::NoPen);painter->setBrush(gradient);painter->drawRect(rect());}void MyPanel::drawCube(){//glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);glPushAttrib(GL_ALL_ATTRIB_BITS);glMatrixMode(GL_PROJECTION);glPushMatrix(); {glLoadIdentity();GLfloat x = 3.0 * GLfloat(width()) / height();glOrtho(-x, x, -3.0, 3.0, 4.0, 15.0);glMatrixMode(GL_MODELVIEW);glPushMatrix(); {glLoadIdentity();glTranslatef(0.0, 0.0, -10.0);glScalef(scaling, scaling, scaling);glRotatef(xrot, 1.0, 0.0, 0.0);glRotatef(yrot, 0.0, 1.0, 0.0);glRotatef(zrot, 0.0, 0.0, 1.0);glEnable(GL_MULTISAMPLE);glCallList(glObject);setFont(QFont("Times", 24));qglColor(QColor(255, 223, 127));renderText(1.0, 1.0, 1.0, QChar('a'));renderText(-1.0, 1.0, 1.0, QChar('e'));renderText(1.0, 1.0, -1.0, QChar('o'));renderText(-1.0, 1.0, -1.0, QChar(0x00F6));renderText(1.0, -1.0, 1.0, QChar(0x0131));renderText(-1.0, -1.0, 1.0, QChar('i'));renderText(1.0, -1.0, -1.0, QChar('u'));renderText(-1.0, -1.0, -1.0, QChar(0x00FC));glMatrixMode(GL_MODELVIEW);//切换到模型视图} glPopMatrix();glMatrixMode(GL_PROJECTION);//切换到投影视图} glPopMatrix();glPopAttrib(); }void MyPanel::drawLegend(QPainter *painter){const int Margin = 11;const int Padding = 6;QTextDocument textDocument;textDocument.setDefaultStyleSheet("* { color: #FFEFEF }");textDocument.setHtml("<h4 align=\"center\">Vowel Categories</h4>""<p align=\"center\"><table width=\"100%\">""<tr><td>Open:<td>a<td>e<td>o<td>ö""<tr><td>Close:<td>ı<td>i<td>u<td>ü""<tr><td>Front:<td>e<td>i<td>ö<td>ü""<tr><td>Back:<td>a<td>ı<td>o<td>u""<tr><td>Round:<td>o<td>ö<td>u<td>ü""<tr><td>Unround:<td>a<td>e<td>ı<td>i""</table>");textDocument.setTextWidth(textDocument.size().width());QRect rect(QPoint(0, 0), textDocument.size().toSize() + QSize(2 * Padding, 2 * Padding));painter->translate(width() - rect.width() - Margin, height() - rect.height() - Margin);painter->setPen(QColor(255, 239, 239));painter->setBrush(QColor(255, 0, 0, 31));painter->drawRect(rect);painter->translate(Padding, Padding);textDocument.drawContents(painter);}上面是C++ Gui Programming with Qt4第20章第二个示例代码，注意构造函数中的setFormat函数会导致程序崩溃，可能是书中用的Qt版本比较旧，我现在用的是Qt4.7.0,构造函数还需要添加两个函数
setAutoBufferSwap(false);
setAutoFillBackground(false);在调用drawCube之前需要禁用painter,否则会无法绘制立方体。
