#include "vector.hxx"
+// calculate the projection, p, of u along the direction of d.
+void sgProjection(sgVec3 p, const sgVec3 u, const sgVec3 d){
+ double denom = sgScalarProductVec3(d,d);
+ if (denom == 0.) sgCopyVec3(p, u);
+ else sgScaleVec3(p, d, sgScalarProductVec3(u,d) / denom);
+}
+
+// Same thing, except using double precision
+void sgProjection(sgdVec3 p, const sgdVec3 u, const sgdVec3 d){
+ double denom = sgdScalarProductVec3(d,d);
+ if (denom == 0.) sgdCopyVec3(p, u);
+ else sgdScaleVec3(p, d, sgdScalarProductVec3(u,d) / denom);
+}
+
// 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,
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) );
+ sgProjection(u1, u, d);
// calculate the point p1 along the line that is closest to p
// p0 = p1 + u1
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);;
+ sgProjection(u1, u, d);
// calculate the point p1 along the line that is closest to p
// p0 = p1 + u1
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) );
+ sgProjection(u1, u, d);
// v = u - u1 = vector from closest point on line, p1, to the
// original point, p.
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);;
+ sgProjection(u1, u, d);
// v = u - u1 = vector from closest point on line, p1, to the
// original point, p.