Sprite animation using QPainter:
You can download the "sprites-cat-running.png" sprite sheet here: https://plnkr.co/edit/zjYT0KTfj50MejT9?preview
main.cpp
#include <QtWidgets/QApplication>
#include <QtWidgets/QWidget>
#include <QtGui/QPainter>
#include <QtGui/QImage>
#include <QtCore/QTimer>
#include <QtCore/QElapsedTimer>
#include <QtCore/QDebug>
#define N_FRAMES 8
class Window : public QWidget
{
Q_OBJECT
public:
Window()
{
setWindowTitle("Qt C++");
resize(512, 256);
// Download a sprite sheet here:
// https://plnkr.co/edit/zjYT0KTfj50MejT9?preview
m_spriteSheet.load(":/Sprites/sprites-cat-running.png");
int index = 0;
for (int i = 0; i < 2; i++ )
{
for (int j = 0; j < 4; j++)
{
m_frames[index] = QPoint(j * m_sw, i * m_sh);
qDebug() << m_frames[index];
index++;
}
}
connect(&m_timer, &QTimer::timeout, this, &Window::animationLoop);
m_timer.start(1000.f/60.f);
m_elapsedTimer.start();
}
private:
QTimer m_timer;
QElapsedTimer m_elapsedTimer;
float m_deltaTime;
float m_animationTime = 0.f;
const float m_animationSpeed = 100.f;
QImage m_spriteSheet;
QPoint m_frames[N_FRAMES];
int m_frameIndex = 0;
int m_x, m_y;
const int m_sw = 512, m_sh = 256; // Source image width and height
private slots:
void animationLoop()
{
m_deltaTime = m_elapsedTimer.elapsed();
m_elapsedTimer.restart();
m_animationTime += m_deltaTime;
if (m_animationTime > m_animationSpeed)
{
m_animationTime = 0;
m_x = m_frames[m_frameIndex].x();
m_y = m_frames[m_frameIndex].y();
m_frameIndex++;
if (m_frameIndex >= N_FRAMES)
{
m_frameIndex = 0;
}
}
update();
}
private:
void paintEvent(QPaintEvent *event)
{
Q_UNUSED(event);
QPainter qp(this);
qp.drawImage(0, 0, m_spriteSheet, m_x, m_y, m_sw, m_sh);
}
};
#include "main.moc"
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
Window w;
w.show();
return a.exec();
}
a302b780-34ce-4ae6-9219-ad76c844ee66.gif
