examples/opengl/framebufferobject/glwidget.cpp

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  41
  42 #include <QtGui/QImage>
  43 #include "glwidget.h"
  44
  45 #include <math.h>
  46
  47 #ifndef GL_MULTISAMPLE
  48 #define GL_MULTISAMPLE  0x809D
  49 #endif
  50
  51 GLWidget::GLWidget(QWidget *parent)
  52     : QGLWidget(QGLFormat(QGL::SampleBuffers|QGL::AlphaChannel), parent)
  53 {
  54     setWindowTitle(tr("OpenGL framebuffer objects"));
  55     makeCurrent();
  56
  57     if (QGLFramebufferObject::hasOpenGLFramebufferBlit()) {
  58         QGLFramebufferObjectFormat format;
  59         format.setSamples(4);
  60         format.setAttachment(QGLFramebufferObject::CombinedDepthStencil);
  61
  62         render_fbo = new QGLFramebufferObject(512, 512, format);
  63         texture_fbo = new QGLFramebufferObject(512, 512);
  64     } else {
  65         render_fbo = new QGLFramebufferObject(1024, 1024);
  66         texture_fbo = render_fbo;
  67     }
  68
  69     rot_x = rot_y = rot_z = 0.0f;
  70     scale = 0.1f;
  71     anim = new QTimeLine(750, this);
  72     anim->setUpdateInterval(20);
  73     connect(anim, SIGNAL(valueChanged(qreal)), SLOT(animate(qreal)));
  74     connect(anim, SIGNAL(finished()), SLOT(animFinished()));
  75
  76     svg_renderer = new QSvgRenderer(QLatin1String(":/res/bubbles.svg"), this);
  77     connect(svg_renderer, SIGNAL(repaintNeeded()), this, SLOT(draw()));
  78
  79     logo = QImage(":/res/designer.png");
  80     logo = logo.convertToFormat(QImage::Format_ARGB32);
  81
  82     tile_list = glGenLists(1);
  83     glNewList(tile_list, GL_COMPILE);
  84     glBegin(GL_QUADS);
  85     {
  86         glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f, -1.0f,  1.0f);
  87         glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f, -1.0f,  1.0f);
  88         glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f,  1.0f,  1.0f);
  89         glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f,  1.0f,  1.0f);
  90
  91         glTexCoord2f(1.0f, 0.0f); glVertex3f(-1.0f, -1.0f, -1.0f);
  92         glTexCoord2f(1.0f, 1.0f); glVertex3f(-1.0f,  1.0f, -1.0f);
  93         glTexCoord2f(0.0f, 1.0f); glVertex3f( 1.0f,  1.0f, -1.0f);
  94         glTexCoord2f(0.0f, 0.0f); glVertex3f( 1.0f, -1.0f, -1.0f);
  95
  96         glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f,  1.0f, -1.0f);
  97         glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f,  1.0f,  1.0f);
  98         glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f,  1.0f,  1.0f);
  99         glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f,  1.0f, -1.0f);
 100
 101         glTexCoord2f(1.0f, 1.0f); glVertex3f(-1.0f, -1.0f, -1.0f);
 102         glTexCoord2f(0.0f, 1.0f); glVertex3f( 1.0f, -1.0f, -1.0f);
 103         glTexCoord2f(0.0f, 0.0f); glVertex3f( 1.0f, -1.0f,  1.0f);
 104         glTexCoord2f(1.0f, 0.0f); glVertex3f(-1.0f, -1.0f,  1.0f);
 105
 106         glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f, -1.0f, -1.0f);
 107         glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f,  1.0f, -1.0f);
 108         glTexCoord2f(0.0f, 1.0f); glVertex3f( 1.0f,  1.0f,  1.0f);
 109         glTexCoord2f(0.0f, 0.0f); glVertex3f( 1.0f, -1.0f,  1.0f);
 110
 111         glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f, -1.0f, -1.0f);
 112         glTexCoord2f(1.0f, 0.0f); glVertex3f(-1.0f, -1.0f,  1.0f);
 113         glTexCoord2f(1.0f, 1.0f); glVertex3f(-1.0f,  1.0f,  1.0f);
 114         glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f,  1.0f, -1.0f);
 115     }
 116     glEnd();
 117     glEndList();
 118
 119     wave = new GLfloat[logo.width()*logo.height()];
 120     memset(wave, 0, logo.width()*logo.height());
 121     startTimer(30); // wave timer
 122 }
 123
 124 GLWidget::~GLWidget()
 125 {
 126     delete[] wave;
 127     glDeleteLists(tile_list, 1);
 128     delete texture_fbo;
 129     if (render_fbo != texture_fbo)
 130         delete render_fbo;
 131 }
 132
 133 void GLWidget::paintEvent(QPaintEvent *)
 134 {
 135     draw();
 136 }
 137
 138 void GLWidget::draw()
 139 {
 140     QPainter p(this); // used for text overlay
 141
 142     // save the GL state set for QPainter
 143     saveGLState();
 144
 145     // render the 'bubbles.svg' file into our framebuffer object
 146     QPainter fbo_painter(render_fbo);
 147     svg_renderer->render(&fbo_painter);
 148     fbo_painter.end();
 149
 150     if (render_fbo != texture_fbo) {
 151         QRect rect(0, 0, render_fbo->width(), render_fbo->height());
 152         QGLFramebufferObject::blitFramebuffer(texture_fbo, rect,
 153                                               render_fbo, rect);
 154     }
 155
 156     // draw into the GL widget
 157     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 158     glMatrixMode(GL_PROJECTION);
 159     glLoadIdentity();
 160     glFrustum(-1, 1, -1, 1, 10, 100);
 161     glTranslatef(0.0f, 0.0f, -15.0f);
 162     glMatrixMode(GL_MODELVIEW);
 163     glLoadIdentity();
 164     glViewport(0, 0, width(), height());
 165     glEnable(GL_BLEND);
 166     glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 167
 168     glBindTexture(GL_TEXTURE_2D, texture_fbo->texture());
 169     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 170     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 171     glEnable(GL_TEXTURE_2D);
 172     glEnable(GL_MULTISAMPLE);
 173     glEnable(GL_CULL_FACE);
 174
 175     // draw background
 176     glPushMatrix();
 177     glScalef(1.7f, 1.7f, 1.7f);
 178     glColor4f(1.0f, 1.0f, 1.0f, 1.0f);
 179     glCallList(tile_list);
 180     glPopMatrix();
 181
 182     const int w = logo.width();
 183     const int h = logo.height();
 184
 185     glRotatef(rot_x, 1.0f, 0.0f, 0.0f);
 186     glRotatef(rot_y, 0.0f, 1.0f, 0.0f);
 187     glRotatef(rot_z, 0.0f, 0.0f, 1.0f);
 188     glScalef(scale/w, scale/w, scale/w);
 189
 190     glDepthFunc(GL_LESS);
 191     glEnable(GL_DEPTH_TEST);
 192     // draw the Qt icon
 193     glTranslatef(-w+1, -h+1, 0.0f);
 194     for (int y=h-1; y>=0; --y) {
 195         uint *p = (uint*) logo.scanLine(y);
 196         uint *end = p + w;
 197         int  x = 0;
 198         while (p < end) {
 199             glColor4ub(qRed(*p), qGreen(*p), qBlue(*p), uchar(qAlpha(*p)*.9));
 200             glTranslatef(0.0f, 0.0f, wave[y*w+x]);
 201             if (qAlpha(*p) > 128)
 202                 glCallList(tile_list);
 203             glTranslatef(0.0f, 0.0f, -wave[y*w+x]);
 204             glTranslatef(2.0f, 0.0f, 0.0f);
 205             ++x;
 206             ++p;
 207         }
 208         glTranslatef(-w*2.0f, 2.0f, 0.0f);
 209     }
 210
 211     // restore the GL state that QPainter expects
 212     restoreGLState();
 213
 214     // draw the overlayed text using QPainter
 215     p.setPen(QColor(197, 197, 197, 157));
 216     p.setBrush(QColor(197, 197, 197, 127));
 217     p.drawRect(QRect(0, 0, width(), 50));
 218     p.setPen(Qt::black);
 219     p.setBrush(Qt::NoBrush);
 220     const QString str1(tr("A simple OpenGL framebuffer object example."));
 221     const QString str2(tr("Use the mouse wheel to zoom, press buttons and move mouse to rotate, double-click to flip."));
 222     QFontMetrics fm(p.font());
 223     p.drawText(width()/2 - fm.width(str1)/2, 20, str1);
 224     p.drawText(width()/2 - fm.width(str2)/2, 20 + fm.lineSpacing(), str2);
 225 }
 226
 227 void GLWidget::mousePressEvent(QMouseEvent *e)
 228 {
 229     anchor = e->pos();
 230 }
 231
 232 void GLWidget::mouseMoveEvent(QMouseEvent *e)
 233 {
 234     QPoint diff = e->pos() - anchor;
 235     if (e->buttons() & Qt::LeftButton) {
 236         rot_x += diff.y()/5.0f;
 237         rot_y += diff.x()/5.0f;
 238     } else if (e->buttons() & Qt::RightButton) {
 239         rot_z += diff.x()/5.0f;
 240     }
 241
 242     anchor = e->pos();
 243     draw();
 244 }
 245
 246 void GLWidget::wheelEvent(QWheelEvent *e)
 247 {
 248     e->delta() > 0 ? scale += scale*0.1f : scale -= scale*0.1f;
 249     draw();
 250 }
 251
 252 void GLWidget::mouseDoubleClickEvent(QMouseEvent *)
 253 {
 254     anim->start();
 255 }
 256
 257 void GLWidget::animate(qreal val)
 258 {
 259     rot_y = val * 180;
 260     draw();
 261 }
 262
 263 void GLWidget::animFinished()
 264 {
 265     if (anim->direction() == QTimeLine::Forward)
 266         anim->setDirection(QTimeLine::Backward);
 267     else
 268         anim->setDirection(QTimeLine::Forward);
 269 }
 270
 271 void GLWidget::saveGLState()
 272 {
 273     glPushAttrib(GL_ALL_ATTRIB_BITS);
 274     glMatrixMode(GL_PROJECTION);
 275     glPushMatrix();
 276     glMatrixMode(GL_MODELVIEW);
 277     glPushMatrix();
 278 }
 279
 280 void GLWidget::restoreGLState()
 281 {
 282     glMatrixMode(GL_PROJECTION);
 283     glPopMatrix();
 284     glMatrixMode(GL_MODELVIEW);
 285     glPopMatrix();
 286     glPopAttrib();
 287 }
 288
 289 #define PI 3.14159
 290
 291 void GLWidget::timerEvent(QTimerEvent *)
 292 {
 293     if (QApplication::mouseButtons() != 0)
 294         return;
 295
 296     static bool scale_in = true;
 297
 298     if (scale_in && scale > 35.0f)
 299         scale_in = false;
 300     else if (!scale_in && scale < .5f)
 301         scale_in = true;
 302
 303     scale = scale_in ? scale + scale*0.01f : scale-scale*0.01f;
 304     rot_z += 0.3f;
 305     rot_x += 0.1f;
 306
 307     int dx, dy; // disturbance point
 308     float s, v, W, t;
 309     int i, j;
 310     static float wt[128][128];
 311     const int width = logo.width();
 312     const int AMP = 5;
 313
 314     dx = dy = width >> 1;
 315
 316     W = .3f;
 317     v = -4; // wave speed
 318
 319     for (i = 0; i < width; ++i) {
 320         for ( j = 0; j < width; ++j) {
 321             s = sqrt((double) ((j - dx) * (j - dx) + (i - dy) * (i - dy)));
 322             wt[i][j] += 0.1f;
 323             t = s / v;
 324             if (s != 0)
 325                 wave[i*width + j] = AMP * sin(2 * PI * W * (wt[i][j] + t)) / (0.2*(s + 2));
 326             else
 327                 wave[i*width + j] = AMP * sin(2 * PI * W * (wt[i][j] + t));
 328         }
 329     }
 330 }