#include "vector.hxx"
+// Given a point p, and a line through p0 with direction vector d,
+// find the closest point (p1) on the line
+void sgClosestPointToLine( sgVec3 p1, const sgVec3 p, const sgVec3 p0,
+ const sgVec3 d ) {
+
+ sgVec3 u, u1;
+
+ // u = p - p0
+ sgSubVec3(u, p, p0);
+
+ // calculate the projection, u1, of u along d.
+ // u1 = ( dot_prod(u, d) / dot_prod(d, d) ) * d;
+ sgScaleVec3( u1, d, sgScalarProductVec3(u,d) / sgScalarProductVec3(d,d) );
+
+ // calculate the point p1 along the line that is closest to p
+ // p0 = p1 + u1
+ sgAddVec3(p1, p0, u1);
+}
+
+
+// Given a point p, and a line through p0 with direction vector d,
+// find the closest point (p1) on the line
+void sgdClosestPointToLine( sgdVec3 p1, const sgdVec3 p, const sgdVec3 p0,
+ const sgdVec3 d ) {
+
+ sgdVec3 u, u1;
+
+ // u = p - p0
+ sgdSubVec3(u, p, p0);
+
+ // calculate the projection, u1, of u along d.
+ // u1 = ( dot_prod(u, d) / dot_prod(d, d) ) * d;
+ double ud = sgdScalarProductVec3(u, d);
+ double dd = sgdScalarProductVec3(d, d);
+ double tmp = ud / dd;
+
+ sgdScaleVec3(u1, d, tmp);;
+
+ // calculate the point p1 along the line that is closest to p
+ // p0 = p1 + u1
+ sgdAddVec3(p1, p0, u1);
+}
+
+
// Given a point p, and a line through p0 with direction vector d,
// find the shortest distance (squared) from the point to the line
-double sgPointLineDistSquared( const sgVec3 p, const sgVec3 p0,
- const sgVec3 d ) {
+double sgClosestPointToLineDistSquared( const sgVec3 p, const sgVec3 p0,
+ const sgVec3 d ) {
sgVec3 u, u1, v;
// Given a point p, and a line through p0 with direction vector d,
// find the shortest distance (squared) from the point to the line
-double sgdPointLineDistSquared( const sgdVec3 p, const sgdVec3 p0,
- const sgdVec3 d ) {
+double sgdClosestPointToLineDistSquared( const sgdVec3 p, const sgdVec3 p0,
+ const sgdVec3 d ) {
sgdVec3 u, u1, v;
- double ud, dd, tmp;
// u = p - p0
sgdSubVec3(u, p, p0);
// calculate the projection, u1, of u along d.
// u1 = ( dot_prod(u, d) / dot_prod(d, d) ) * d;
- ud = sgdScalarProductVec3(u, d);
- dd = sgdScalarProductVec3(d, d);
- tmp = ud / dd;
+ double ud = sgdScalarProductVec3(u, d);
+ double dd = sgdScalarProductVec3(d, d);
+ double tmp = ud / dd;
sgdScaleVec3(u1, d, tmp);;