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#include "mandelbrot.h"
#include<QtGui/QPainter>
#include<QtGui/QImage>
#include<QtGui/QMouseEvent>
#include<QtCore/QTime>
void MandelbrotWidget::resizeEvent(QResizeEvent *)
{
if(size < width() * height())
{
std::cout << "reallocate buffer" << std::endl;
size = width() * height();
if(buffer) delete[]buffer;
buffer = new unsigned char[4*size];
}
}
void MandelbrotWidget::paintEvent(QPaintEvent *)
{
QTime time;
time.start();
int alignedWidth = (width()/packetSize)*packetSize;
real yradius = xradius * height() / width();
vector2 start(center.x() - xradius, center.y() - yradius);
vector2 step(2*xradius/width(), 2*yradius/height());
int pix = 0, total_iter = 0;
static float max_speed = 0;
for(int y = 0; y < height(); y++)
{
// for each pixel, we're going to do the iteration z := z^2 + c where z and c are complex numbers,
// starting with z = c = complex coord of the pixel. pzi and pzr denote the real and imaginary parts of z.
// pci and pcr denote the real and imaginary parts of c.
packet pzi_start, pci_start;
for(int i = 0; i < packetSize; i++) pzi_start[i] = pci_start[i] = start.y() + y * step.y();
for(int x = 0; x < alignedWidth; x += packetSize, pix += packetSize)
{
packet pcr, pci = pci_start, pzr, pzi = pzi_start, pzr_buf;
for(int i = 0; i < packetSize; i++) pzr[i] = pcr[i] = start.x() + (x+i) * step.x();
// do the iterations. Every 4 iterations we check for divergence, in which case we can stop iterating.
int j;
for(j = 0; j < iter/4 && (pzr.cwiseAbs2() + pzi.cwiseAbs2()).eval().minCoeff() < 4; j++)
{
total_iter += 4 * packetSize;
for(int i = 0; i < 4; i++)
{
pzr_buf = pzr;
pzr = pzr.cwiseAbs2() - pzi.cwiseAbs2() + pcr;
pzi = 2 * pzr_buf.cwiseProduct(pzi) + pci;
}
}
// compute arbitrary pixel colors
packet pblue, pgreen;
if(j == iter/4)
{
packet pampl = (pzr.cwiseAbs2() + pzi.cwiseAbs2());
pblue = real(510) * (packet::constant(0.1) + pampl).cwiseInverse().cwiseMin(packet::ones());
pgreen = real(2550) * (packet::constant(10) + pampl).cwiseInverse().cwiseMin(packet::constant(0.1));
}
else pblue = pgreen = packet::zero();
for(int i = 0; i < packetSize; i++)
{
buffer[4*(pix+i)] = (unsigned char)(pblue[i]);
buffer[4*(pix+i)+1] = (unsigned char)(pgreen[i]);
buffer[4*(pix+i)+2] = 0;
}
}
// if the width is not a multiple of packetSize, fill the remainder in black
for(int x = alignedWidth; x < width(); x++, pix++)
buffer[4*pix] = buffer[4*pix+1] = buffer[4*pix+2] = 0;
}
int elapsed = time.elapsed();
float speed = elapsed ? float(total_iter)*1000/elapsed : 0;
max_speed = std::max(max_speed, speed);
std::cout << elapsed << " ms elapsed, "
<< total_iter << " iters, "
<< speed << " iters/s (max " << max_speed << ")" << std::endl;
QImage image(buffer, width(), height(), QImage::Format_RGB32);
QPainter painter(this);
painter.drawImage(QPointF(0,0), image);
}
void MandelbrotWidget::mousePressEvent(QMouseEvent *event)
{
if( event->buttons() & Qt::LeftButton )
{
lastpos = event->pos();
real yradius = xradius * height() / width();
center = vector2(center.x() + (event->pos().x() - width()/2) * xradius * 2 / width(),
center.y() + (event->pos().y() - height()/2) * yradius * 2 / height());
update();
}
}
void MandelbrotWidget::mouseMoveEvent(QMouseEvent *event)
{
QPoint delta = event->pos() - lastpos;
lastpos = event->pos();
if( event->buttons() & Qt::LeftButton )
{
real t = 1 + 3 * real(delta.y()) / height();
if(t < 0.5) t = 0.5;
if(t > 2) t = 2;
xradius *= t;
update();
}
}
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
MandelbrotWidget w;
w.show();
return app.exec();
}
#include "mandelbrot.moc"
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