/*! Compute a force based on a mass attached to the cursor
* and add this force to the global cursor force. */
void OscCursorCHAI::addCursorMassForce()
{
double timestep = simulation()->timestep();
// if no mass, just update the mass position
if (m_mass.m_value <= 0) {
m_massVel = (m_pCursor->m_deviceGlobalPos - m_massPos) / timestep;
m_massPos = m_pCursor->m_deviceGlobalPos;
return;
}
double k=10; // stiffness of mass-spring
double b=0.001;//2*sqrt(k*m_mass.m_value); // critical damping
cVector3d posdiff(m_pCursor->m_deviceGlobalPos - m_massPos);
cVector3d springVel((posdiff - m_lastPosDiff)/timestep);
m_lastPosDiff = posdiff;
cVector3d veldiff(m_pCursor->m_deviceGlobalVel - m_massVel);
cVector3d force(-k*posdiff - b*springVel);
m_massPos += m_massVel*timestep;
m_massVel -= force/m_mass.m_value*timestep;
m_pCursor->m_lastComputedGlobalForce += force*10;
}
static void
sel_extend(pos selpoint)
{
if (term.selected) {
if (!term.sel_rect) {
/*
* For normal selection, we extend by moving
* whichever end of the current selection is closer
* to the mouse.
*/
if (posdiff(selpoint, term.sel_start) <
posdiff(term.sel_end, term.sel_start) / 2) {
term.sel_anchor = term.sel_end;
decpos(term.sel_anchor);
}
else
term.sel_anchor = term.sel_start;
}
else {
/*
* For rectangular selection, we have a choice of
* _four_ places to put sel_anchor and selpoint: the
* four corners of the selection.
*/
term.sel_anchor.x =
selpoint.x * 2 < term.sel_start.x + term.sel_end.x
? term.sel_end.x - 1
: term.sel_start.x;
term.sel_anchor.y =
selpoint.y * 2 < term.sel_start.y + term.sel_end.y
? term.sel_end.y
: term.sel_start.y;
}
}
else
term.sel_anchor = selpoint;
sel_drag(selpoint);
}