Real Cylinder3D::closestPoint(const Point3D& pt,Point3D& closest) const
{
Real h = dot(pt-center,axis);
if(h < 0) {
Circle3D c;
getBase(c);
return c.closestPoint(pt,closest);
}
else if (h > height) {
Circle3D c;
getCap(c);
return c.closestPoint(pt,closest);
}
else {
Vector3 vperp = (pt-center) - h*axis;
Real rv = vperp.norm();
if(rv <= radius) {
//inside cylinder
closest = pt;
return 0;
}
else {
closest = center + axis*h + vperp*(radius/rv);
return rv - radius;
}
}
}
bool Cylinder3D::intersects(const Line3D& line,Real* tmin,Real* tmax) const
{
Real axistmin,axistmax;
//quick reject - infinite cylinder
Vector3 src=line.source-center;
const Vector3& dir=line.direction;
assert(FuzzyEquals(axis.normSquared(),One));
//quadratic equation
Real a,b,c;
Real dv,sv;
dv = dir.dot(axis);
sv = src.dot(axis);
a=dir.normSquared()-Sqr(dv);
b=Two*(dir.dot(src)-sv*dv);
c=src.normSquared()-Sqr(sv)-Sqr(radius);
int nroots=quadratic(a,b,c,axistmin,axistmax);
//TODO: if the line is contained within the cylinder, ignore this
if(nroots == 0) return false;
else if(nroots == 1) axistmax=axistmin;
else if(nroots == 2) {
if(axistmin > axistmax) std::swap(axistmin,axistmax);
}
else if(nroots == -1) return false;
else return false; //what case is this?
//projection of intersection pts on the cyl axis
Real axisumin,axisumax;
Vector3 temp;
line.eval(axistmin,temp); axisumin = axis.dot(temp-center);
line.eval(axistmax,temp); axisumax = axis.dot(temp-center);
//now check the caps
Real tc;
Circle3D cir;
if(axisumin < 0) { //hits a cap first
if(dv > 0) //line points along axis
getBase(cir);
else //line points against axis
getCap(cir);
if(!cir.intersects(line,&tc)) return false;
axistmin = tc;
}
if(axisumin > height) { //hits a cap last
if(dv > 0) //line points along axis
getCap(cir);
else //line points against axis
getBase(cir);
if(!cir.intersects(line,&tc)) return false;
axistmax = tc;
}
//if(axistmin > axistmax) return false;
if(tmin) *tmin=axistmin;
if(tmax) *tmax=axistmax;
return true;
}
bool Circle3D::boundaryIntersects(const Sphere3D& s) const
{
//slice the ball along the plane of the circle, check for circle-disk intersection
Plane3D p;
Circle3D cs;
getPlane(p);
if(!cs.setIntersection(s,p)) return false;
return Sphere3D::ballSphereIntersect(cs.center,cs.radius,center,radius);
}
void Cylinder3D::getAABB(AABB3D& aabb) const
{
Circle3D c;
getBase(c);
c.getAABB(aabb);
if(axis.x > 0) aabb.bmax.x += axis.x*height;
else aabb.bmin.x -= axis.x*height;
if(axis.y > 0) aabb.bmax.y += axis.y*height;
else aabb.bmin.y -= axis.y*height;
if(axis.z > 0) aabb.bmax.z += axis.z*height;
else aabb.bmin.z -= axis.z*height;
}
bool BallCircleCollision(const Sphere3D& a, const Circle3D& b)
{
return b.boundaryIntersects(a);
}
bool TransformWidget::Hover(int x,int y,Camera::Viewport& viewport,double& distance)
{
Real globalScale = 1.0;
if(scaleToScreen) {
float sx,sy,sz;
viewport.project(T.t,sx,sy,sz);
globalScale = sz/viewport.scale;
}
distance = Inf;
int oldHoverItem = hoverItem;
hoverItem = -1;
Ray3D r;
viewport.getClickSource(x,y,r.source);
viewport.getClickVector(x,y,r.direction);
//check origin
if(enableTranslation && enableOriginTranslation) {
Sphere3D s;
s.center = T.t;
s.radius = originRadius*globalScale;
Real tmin,tmax;
if(s.intersects(r,&tmin,&tmax)) {
distance = tmin;
hoverItem = 0;
}
}
//check translation axes
for(int i=0;i<3;i++) {
if(!enableTranslation) break;
if(!enableTranslationAxes[i]) continue;
Line3D axisLine;
axisLine.source = T.t;
axisLine.direction = Vector3(T.R.col(i));
Real t,u;
axisLine.closestPoint(r,t,u);
t = Clamp(t,0.0,axisLength*globalScale);
u = Clamp(u,0.0,Inf);
Vector3 paxis,pray;
axisLine.eval(t,paxis);
r.eval(u,pray);
if(paxis.distanceSquared(pray) <= Sqr(axisRadius*globalScale)) {
if(u < distance) {
distance = u;
hoverItem = 1+i;
}
}
}
if(enableRotation) {
//check rotation rings
Circle3D c;
c.center = T.t;
for(int i=0;i<3;i++) {
if(!enableRotationAxes[i]) continue;
c.axis = Vector3(T.R.col(i));
c.radius = ringOuterRadius*globalScale;
Real t;
if(c.intersects(r,&t) && t >= 0) {
c.radius = ringInnerRadius*globalScale;
if(!c.intersects(r,NULL)) {
if(t < distance) {
distance = t;
hoverItem = i+4;
}
}
}
}
}
if(enableRotation && enableOuterRingRotation) {
//check outer ring
Circle3D c;
c.center = T.t;
viewport.getViewVector(c.axis);
c.radius = (ringOuterRadius+arrowHeight)*globalScale;
Real t;
if(c.intersects(r,&t) && t >= 0) {
c.radius = (ringInnerRadius+arrowHeight)*globalScale;
if(!c.intersects(r,NULL)) {
if(t < distance) {
distance = t;
hoverItem = 7;
}
}
}
clickAxis = c.axis;
}
if(hoverItem != oldHoverItem) Refresh();
r.eval(distance,hoverPos);
return hoverItem != -1;
}
