我正在尝试使用轨迹球旋转 opengl 场景。我遇到的问题是我的旋转方向与我在屏幕上的滑动方向相反。这是代码片段。
prevPoint.y = viewPortHeight - prevPoint.y;
currentPoint.y = viewPortHeight - currentPoint.y;
prevPoint.x = prevPoint.x - centerx;
prevPoint.y = prevPoint.y - centery;
currentPoint.x = currentPoint.x - centerx;
currentPoint.y = currentPoint.y - centery;
double angle=0;
if (prevPoint.x == currentPoint.x && prevPoint.y == currentPoint.y) {
return;
}
double d, z, radius = viewPortHeight * 0.5;
if(viewPortWidth > viewPortHeight) {
radius = viewPortHeight * 0.5f;
} else {
radius = viewPortWidth * 0.5f;
}
d = (prevPoint.x * prevPoint.x + prevPoint.y * prevPoint.y);
if (d <= radius * radius * 0.5 ) { /* Inside sphere */
z = sqrt(radius*radius - d);
} else { /* On hyperbola */
z = (radius * radius * 0.5) / sqrt(d);
}
Vector refVector1(prevPoint.x,prevPoint.y,z);
refVector1.normalize();
d = (currentPoint.x * currentPoint.x + currentPoint.y * currentPoint.y);
if (d <= radius * radius * 0.5 ) { /* Inside sphere */
z = sqrt(radius*radius - d);
} else { /* On hyperbola */
z = (radius * radius * 0.5) / sqrt(d);
}
Vector refVector2(currentPoint.x,currentPoint.y,z);
refVector2.normalize();
Vector axisOfRotation = refVector1.cross(refVector2);
axisOfRotation.normalize();
angle = acos(refVector1*refVector2);