It’s difficult to control model with mouse to me. I define the 4-dimension matrix of projection, camera, and model, and the mvp matrix is :
$$mvp = projection * camera * model$$
In the mouse movement event loop, I rotate the camera matrix like:
$$camera.rotate(dy, glm::vec3(1.0f, 0.0f, 0.0f))$$
$$camera.rotate(dx, glm::vec3(0.0f, 1.0f, 0.0f))$$
and then I re-calculate the mvp. But the model does not rotate in the direction of the mouse.
This is my code:
void GLWidget::mouseMoveEvent(QMouseEvent *event)
{
float dx = static_cast<int>(event->localPos().x() - m_lastPos.x());
float dy = static_cast<int>(event->localPos().y() - m_lastPos.y());
// m_camera.setToIdentity();
// m_camera.translate(0.0f, 0.0f, -500.0f);
// m_camera.rotate(45, QVector3D(1.0f, 0.0f, 0.0f));
// m_camera.rotate(-45, QVector3D(0.0f, 1.0f, 0.0f));
if (event->buttons() & Qt::LeftButton)
{
m_camera.rotate(dy, QVector3D(1.0f, 0.0f, 0.0f));//m_camera rotate δθ
m_camera.rotate(dx, QVector3D(0.0f, 1.0f, 0.0f));
mvp = m_proj * m_camera * m_model;
}
update();
}
