void Camera::drag(int x, int y)
{
if(!isDragging) return;
currentVector = ProjectToSphere(ScreenToNDC(x, y));
vector3df axis = startVector.crossProduct(currentVector);
float theta = acos(startVector.dotProduct(currentVector));
quaternion delta(axis.x, axis.y, axis.z, -theta);
currentQuat = delta * startQuat;
}
void Camera::Rotate(
int from_x, int from_y, int to_x, int to_y, int width, int height)
{
ElVisFloat from_x_pos =
2.0 * static_cast<ElVisFloat>(from_x) / static_cast<ElVisFloat>(width) -
1.0;
ElVisFloat from_y_pos =
1.0 -
2.0 * static_cast<ElVisFloat>(from_y) / static_cast<ElVisFloat>(height);
ElVisFloat to_x_pos =
2.0 * static_cast<ElVisFloat>(to_x) / static_cast<ElVisFloat>(width) -
1.0;
ElVisFloat to_y_pos =
1.0 -
2.0 * static_cast<ElVisFloat>(to_y) / static_cast<ElVisFloat>(height);
ElVisFloat3 to = ProjectToSphere(from_x_pos, from_y_pos, 0.8);
ElVisFloat3 from = ProjectToSphere(to_x_pos, to_y_pos, .8);
Matrix4x4 m = RotationMatrix(to, from);
Transform(m, true);
OnCameraChanged();
}
void Camera::beginDrag(int x, int y)
{
startVector = ProjectToSphere(ScreenToNDC(x, y));
startQuat = currentQuat;
isDragging = true;
}
