//--------------------------------------------------------------------------------------------------
/// Transforms the plane with the given homogeneous transformation \a matrix
//--------------------------------------------------------------------------------------------------
void Plane::transform(const Mat4d& matrix)
{
Vec3d n = normal();
Vec3d point = pointInPlane();
n.transformVector(matrix);
point.transformPoint(matrix);
setFromPointAndNormal(point, n);
}
//--------------------------------------------------------------------------------------------------
/// Compute quaternion rotation
///
/// \param oldPosX x coordinate of the last position of the mouse, in the range [-1.0, 1.0]
/// \param oldPosY y coordinate of the last position of the mouse, in the range [-1.0, 1.0]
/// \param newPosX x coordinate of current position of the mouse, in the range [-1.0, 1.0]
/// \param newPosY y coordinate of current position of the mouse, in the range [-1.0, 1.0]
/// \param currViewMatrix Current transformation matrix. The inverse is used when calculating the rotation
/// \param sensitivityFactor Mouse sensitivity factor
///
/// Simulate a track-ball. Project the points onto the virtual trackball, then figure out the axis
/// of rotation. This is a deformed trackball-- is a trackball in the center, but is deformed into a
/// hyperbolic sheet of rotation away from the center.
//--------------------------------------------------------------------------------------------------
Quatd ManipulatorTrackball::trackballRotation(double oldPosX, double oldPosY, double newPosX, double newPosY, const Mat4d& currViewMatrix, double sensitivityFactor)
{
// This particular function was chosen after trying out several variations.
// Implemented by Gavin Bell, lots of ideas from Thant Tessman and the August '88
// issue of Siggraph's "Computer Graphics," pp. 121-129.
// This size should really be based on the distance from the center of rotation to the point on
// the object underneath the mouse. That point would then track the mouse as closely as possible.
const double TRACKBALL_RADIUS = 0.8f;
// Clamp to valid range
oldPosX = Math::clamp(oldPosX, -1.0, 1.0);
oldPosY = Math::clamp(oldPosY, -1.0, 1.0);
newPosX = Math::clamp(newPosX, -1.0, 1.0);
newPosY = Math::clamp(newPosY, -1.0, 1.0);
// First, figure out z-coordinates for projection of P1 and P2 to deformed sphere
Vec3d p1 = projectToSphere(TRACKBALL_RADIUS, oldPosX, oldPosY);
Vec3d p2 = projectToSphere(TRACKBALL_RADIUS, newPosX, newPosY);
// Axis of rotation is the cross product of P1 and P2
Vec3d a = p1 ^ p2;
// Figure out how much to rotate around that axis.
Vec3d d = p1 - p2;
double t = d.length()/(2.0*TRACKBALL_RADIUS);
// Avoid problems with out-of-control values...
t = Math::clamp(t, -1.0, 1.0);
double phi = 2.0*asin(t);
// Scale by sensitivity factor
phi *= sensitivityFactor;
// Use inverted matrix to find rotation axis
Mat4d invMatr = currViewMatrix.getInverted();
a.transformVector(invMatr);
// Get quaternion to be returned by pointer
Quatd quat = Quatd::fromAxisAngle(a, phi);
return quat;
}
