glwidget.cpp Example File
opengl/overpainting/glwidget.cpp
/****************************************************************************
**
** Copyright (C) 2006-2006 Trolltech AS. All rights reserved.
**
** This file is part of the documentation of the Qt Toolkit.
**
** This file may be used under the terms of the GNU General Public
** License version 2.0 as published by the Free Software Foundation
** and appearing in the file LICENSE.GPL included in the packaging of
** this file. Please review the following information to ensure GNU
** General Public Licensing requirements will be met:
** http://www.trolltech.com/products/qt/opensource.html
**
** If you are unsure which license is appropriate for your use, please
** review the following information:
** http://www.trolltech.com/products/qt/licensing.html or contact the
** sales department at sales@trolltech.com.
**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
**
****************************************************************************/
#include <QtGui>
#include <QtOpenGL>
#include <stdlib.h>
#include <math.h>
#include "bubble.h"
#include "glwidget.h"
GLWidget::GLWidget(QWidget *parent)
: QGLWidget(QGLFormat(QGL::SampleBuffers), parent)
{
QTime midnight(0, 0, 0);
srand(midnight.secsTo(QTime::currentTime()));
object = 0;
xRot = 0;
yRot = 0;
zRot = 0;
trolltechGreen = QColor::fromCmykF(0.40, 0.0, 1.0, 0.0);
trolltechPurple = QColor::fromCmykF(0.39, 0.39, 0.0, 0.0);
animationTimer.setSingleShot(false);
connect(&animationTimer, SIGNAL(timeout()), this, SLOT(animate()));
animationTimer.start(25);
setAttribute(Qt::WA_NoSystemBackground);
setMinimumSize(200, 200);
setWindowTitle(tr("Overpainting a Scene"));
}
GLWidget::~GLWidget()
{
makeCurrent();
glDeleteLists(object, 1);
}
void GLWidget::setXRotation(int angle)
{
normalizeAngle(&angle);
if (angle != xRot) {
xRot = angle;
emit xRotationChanged(angle);
}
}
void GLWidget::setYRotation(int angle)
{
normalizeAngle(&angle);
if (angle != yRot) {
yRot = angle;
emit yRotationChanged(angle);
}
}
void GLWidget::setZRotation(int angle)
{
normalizeAngle(&angle);
if (angle != zRot) {
zRot = angle;
emit zRotationChanged(angle);
}
}
void GLWidget::initializeGL()
{
object = makeObject();
}
void GLWidget::mousePressEvent(QMouseEvent *event)
{
lastPos = event->pos();
}
void GLWidget::mouseMoveEvent(QMouseEvent *event)
{
int dx = event->x() - lastPos.x();
int dy = event->y() - lastPos.y();
if (event->buttons() & Qt::LeftButton) {
setXRotation(xRot + 8 * dy);
setYRotation(yRot + 8 * dx);
} else if (event->buttons() & Qt::RightButton) {
setXRotation(xRot + 8 * dy);
setZRotation(zRot + 8 * dx);
}
lastPos = event->pos();
}
void GLWidget::paintEvent(QPaintEvent *event)
{
QPainter painter;
painter.begin(this);
painter.setRenderHint(QPainter::Antialiasing);
glPushAttrib(GL_ALL_ATTRIB_BITS);
glMatrixMode(GL_PROJECTION);
glPushMatrix();
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
qglClearColor(trolltechPurple.dark());
glShadeModel(GL_SMOOTH);
glEnable(GL_DEPTH_TEST);
glEnable(GL_CULL_FACE);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
static GLfloat lightPosition[4] = { 0.5, 5.0, 7.0, 1.0 };
glLightfv(GL_LIGHT0, GL_POSITION, lightPosition);
resizeGL(width(), height());
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
glTranslated(0.0, 0.0, -10.0);
glRotated(xRot / 16.0, 1.0, 0.0, 0.0);
glRotated(yRot / 16.0, 0.0, 1.0, 0.0);
glRotated(zRot / 16.0, 0.0, 0.0, 1.0);
glCallList(object);
glPopAttrib();
glMatrixMode(GL_MODELVIEW);
glPopMatrix();
glMatrixMode(GL_PROJECTION);
glPopMatrix();
glDisable(GL_CULL_FACE); // ### not required if begin() also does it
foreach (Bubble *bubble, bubbles) {
if (bubble->rect().intersects(event->rect()))
bubble->drawBubble(&painter);
}
painter.drawImage((width() - image.width())/2, 0, image);
painter.end();
}
void GLWidget::resizeGL(int width, int height)
{
int side = qMin(width, height);
glViewport((width - side) / 2, (height - side) / 2, side, side);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(-0.5, +0.5, +0.5, -0.5, 4.0, 15.0);
glMatrixMode(GL_MODELVIEW);
formatInstructions(width, height);
}
void GLWidget::showEvent(QShowEvent *event)
{
Q_UNUSED(event);
createBubbles(20 - bubbles.count());
}
QSize GLWidget::sizeHint() const
{
return QSize(400, 400);
}
GLuint GLWidget::makeObject()
{
GLuint list = glGenLists(1);
glNewList(list, GL_COMPILE);
glEnable(GL_NORMALIZE);
glBegin(GL_QUADS);
static GLfloat logoDiffuseColor[4] = {trolltechGreen.red()/255.0,
trolltechGreen.green()/255.0,
trolltechGreen.blue()/255.0, 1.0};
glMaterialfv(GL_FRONT, GL_DIFFUSE, logoDiffuseColor);
GLdouble x1 = +0.06;
GLdouble y1 = -0.14;
GLdouble x2 = +0.14;
GLdouble y2 = -0.06;
GLdouble x3 = +0.08;
GLdouble y3 = +0.00;
GLdouble x4 = +0.30;
GLdouble y4 = +0.22;
quad(x1, y1, x2, y2, y2, x2, y1, x1);
quad(x3, y3, x4, y4, y4, x4, y3, x3);
extrude(x1, y1, x2, y2);
extrude(x2, y2, y2, x2);
extrude(y2, x2, y1, x1);
extrude(y1, x1, x1, y1);
extrude(x3, y3, x4, y4);
extrude(x4, y4, y4, x4);
extrude(y4, x4, y3, x3);
const double Pi = 3.14159265358979323846;
const int NumSectors = 200;
for (int i = 0; i < NumSectors; ++i) {
double angle1 = (i * 2 * Pi) / NumSectors;
GLdouble x5 = 0.30 * sin(angle1);
GLdouble y5 = 0.30 * cos(angle1);
GLdouble x6 = 0.20 * sin(angle1);
GLdouble y6 = 0.20 * cos(angle1);
double angle2 = ((i + 1) * 2 * Pi) / NumSectors;
GLdouble x7 = 0.20 * sin(angle2);
GLdouble y7 = 0.20 * cos(angle2);
GLdouble x8 = 0.30 * sin(angle2);
GLdouble y8 = 0.30 * cos(angle2);
quad(x5, y5, x6, y6, x7, y7, x8, y8);
extrude(x6, y6, x7, y7);
extrude(x8, y8, x5, y5);
}
glEnd();
glEndList();
return list;
}
void GLWidget::quad(GLdouble x1, GLdouble y1, GLdouble x2, GLdouble y2,
GLdouble x3, GLdouble y3, GLdouble x4, GLdouble y4)
{
glNormal3d(0.0, 0.0, -1.0);
glVertex3d(x1, y1, -0.05);
glVertex3d(x2, y2, -0.05);
glVertex3d(x3, y3, -0.05);
glVertex3d(x4, y4, -0.05);
glNormal3d(0.0, 0.0, 1.0);
glVertex3d(x4, y4, +0.05);
glVertex3d(x3, y3, +0.05);
glVertex3d(x2, y2, +0.05);
glVertex3d(x1, y1, +0.05);
}
void GLWidget::extrude(GLdouble x1, GLdouble y1, GLdouble x2, GLdouble y2)
{
qglColor(trolltechGreen.dark(250 + int(100 * x1)));
glNormal3d((x1 + x2)/2.0, (y1 + y2)/2.0, 0.0);
glVertex3d(x1, y1, +0.05);
glVertex3d(x2, y2, +0.05);
glVertex3d(x2, y2, -0.05);
glVertex3d(x1, y1, -0.05);
}
void GLWidget::normalizeAngle(int *angle)
{
while (*angle < 0)
*angle += 360 * 16;
while (*angle > 360 * 16)
*angle -= 360 * 16;
}
void GLWidget::createBubbles(int number)
{
for (int i = 0; i < number; ++i) {
QPointF position(width()*(0.1 + (0.8*rand()/(RAND_MAX+1.0))),
height()*(0.1 + (0.8*rand()/(RAND_MAX+1.0))));
qreal radius = qMin(width(), height())*(0.0125 + 0.0875*rand()/(RAND_MAX+1.0));
QPointF velocity(width()*0.0125*(-0.5 + rand()/(RAND_MAX+1.0)),
height()*0.0125*(-0.5 + rand()/(RAND_MAX+1.0)));
bubbles.append(new Bubble(position, radius, velocity));
}
}
void GLWidget::animate()
{
QMutableListIterator<Bubble*> iter(bubbles);
while (iter.hasNext()) {
Bubble *bubble = iter.next();
update(bubble->rect().toRect());
bubble->move(rect());
update(bubble->rect().toRect());
}
}
void GLWidget::formatInstructions(int width, int height)
{
QString text = tr("Click and drag with the left mouse button "
"to rotate the Qt logo.");
QFontMetrics metrics = QFontMetrics(font());
int border = qMax(4, metrics.leading());
QRect rect = metrics.boundingRect(0, 0, width - 2*border, int(height*0.125),
Qt::AlignCenter | Qt::TextWordWrap, text);
image = QImage(width, rect.height() + 2*border, QImage::Format_ARGB32_Premultiplied);
image.fill(qRgba(0, 0, 0, 127));
QPainter painter;
painter.begin(&image);
painter.setRenderHint(QPainter::TextAntialiasing);
painter.setPen(Qt::white);
painter.drawText((width - rect.width())/2, border,
rect.width(), rect.height(),
Qt::AlignCenter | Qt::TextWordWrap, text);
painter.end();
}
