From becfce6709e592ff7b4091bb6771925ace64d0d7 Mon Sep 17 00:00:00 2001
From: mattijs <mattijs@hunt.opencfd.co.uk>
Date: Fri, 3 Apr 2009 13:56:17 +0100
Subject: [PATCH] intersection
---
.../searchableSurface/searchableCylinder.C | 238 ++++++++++++++----
.../searchableSurface/searchableCylinder.H | 2 +
2 files changed, 190 insertions(+), 50 deletions(-)
diff --git a/src/meshTools/searchableSurface/searchableCylinder.C b/src/meshTools/searchableSurface/searchableCylinder.C
index e2b8426f1fe..fcaa42194aa 100644
--- a/src/meshTools/searchableSurface/searchableCylinder.C
+++ b/src/meshTools/searchableSurface/searchableCylinder.C
@@ -105,6 +105,13 @@ Foam::pointIndexHit Foam::searchableCylinder::findNearest
}
+Foam::scalar Foam::searchableCylinder::radius2(const point& pt) const
+{
+ const vector x = (pt-point1_) ^ unitDir_;
+ return x&x;
+}
+
+
// From http://www.gamedev.net/community/forums/topic.asp?topic_id=467789 -
// intersection of cylinder with ray
void Foam::searchableCylinder::findLineAll
@@ -118,13 +125,91 @@ void Foam::searchableCylinder::findLineAll
near.setMiss();
far.setMiss();
- // Line as P = start + t*V
- const vector V(end-start);
+ vector point1Start(start-point1_);
+ vector point2Start(start-point2_);
+ vector point1End(end-point1_);
+
+ // Quick rejection of complete vector outside endcaps
+ scalar s1 = point1Start&unitDir_;
+ scalar s2 = point1End&unitDir_;
+
+ if ((s1 < 0 && s2 < 0) || (s1 > magDir_ && s2 > magDir_))
+ {
+ return;
+ }
+
+ // Line as P = start+t*V where V is unit vector and t=[0..mag(end-start)]
+ vector V(end-start);
+ scalar magV = mag(V);
+ if (magV < ROOTVSMALL)
+ {
+ return;
+ }
+ V /= magV;
+
+
+ // We now get the nearest intersections to start. This can either be
+ // the intersection with the end plane or with the cylinder side.
+
+ // Get the two points (expressed in t) on the end planes. This is to
+ // clip any cylinder intersection against.
+ scalar tPoint1;
+ scalar tPoint2;
+
+ // Maintain the two intersections with the endcaps
+ scalar tNear = VGREAT;
+ scalar tFar = VGREAT;
+
+ {
+ scalar s = (V&unitDir_);
+ if (mag(s) > VSMALL)
+ {
+ tPoint1 = -s1/s;
+ tPoint2 = -(point2Start&unitDir_)/s;
+ if (tPoint2 < tPoint1)
+ {
+ Swap(tPoint1, tPoint2);
+ }
+ if (tPoint1 > magV || tPoint2 < 0)
+ {
+ return;
+ }
+
+ // See if the points on the endcaps are actually inside the cylinder
+ if (tPoint1 >= 0 && tPoint1 <= magV)
+ {
+ if (radius2(start+tPoint1*V) <= sqr(radius_))
+ {
+ tNear = tPoint1;
+ }
+ }
+ if (tPoint2 >= 0 && tPoint2 <= magV)
+ {
+ if (radius2(start+tPoint2*V) <= sqr(radius_))
+ {
+ // Check if already have a near hit from point1
+ if (tNear <= 1)
+ {
+ tFar = tPoint2;
+ }
+ else
+ {
+ tNear = tPoint2;
+ }
+ }
+ }
+ }
+ else
+ {
+ // Vector perpendicular to cylinder. Check for outside already done
+ // above so just set tpoint to allow all.
+ tPoint1 = -VGREAT;
+ tPoint2 = VGREAT;
+ }
+ }
-//Pout<< "point1:" << point1_ << " point2:" << point2_
-// << " start:" << start << " end:" << end << endl;
- const vector x = (start-point1_) ^ unitDir_;
+ const vector x = point1Start ^ unitDir_;
const vector y = V ^ unitDir_;
const scalar d = sqr(radius_);
@@ -135,11 +220,12 @@ void Foam::searchableCylinder::findLineAll
const scalar disc = b*b-4*a*c;
-//Pout<< "a:" << a << " b:" << b << " c:" << c << " disc:" << disc
-// << endl;
+ scalar t1 = -VGREAT;
+ scalar t2 = VGREAT;
if (disc < 0)
{
+ // Fully outside
return;
}
else if (disc < ROOTVSMALL)
@@ -147,12 +233,40 @@ void Foam::searchableCylinder::findLineAll
// Single solution
if (mag(a) > ROOTVSMALL)
{
- scalar t = -b/(2*a);
- if (t >= 0 && t <= 1)
+ t1 = -b/(2*a);
+
+ //Pout<< "single solution t:" << t1
+ // << " for start:" << start << " end:" << end
+ // << " c:" << c << endl;
+
+ if (t1 >= 0 && t1 <= magV && t1 >= tPoint1 && t1 <= tPoint2)
+ {
+ // valid. Insert sorted.
+ if (t1 < tNear)
+ {
+ tFar = tNear;
+ tNear = t1;
+ }
+ else if (t1 < tFar)
+ {
+ tFar = t1;
+ }
+ }
+ else
{
- near.setPoint(start + t*V);
- near.setHit();
- near.setIndex(0);
+ return;
+ }
+ }
+ else
+ {
+ // Aligned with axis. Check if outside radius
+ //Pout<< "small discriminant:" << disc
+ // << " for start:" << start << " end:" << end
+ // << " magV:" << magV
+ // << " c:" << c << endl;
+ if (c > 0)
+ {
+ return;
}
}
}
@@ -162,41 +276,79 @@ void Foam::searchableCylinder::findLineAll
{
scalar sqrtDisc = sqrt(disc);
- scalar t1 = (-b + sqrtDisc)/2*a;
- scalar t2 = (-b - sqrtDisc)/2*a;
+ t1 = (-b - sqrtDisc)/(2*a);
+ t2 = (-b + sqrtDisc)/(2*a);
+ if (t2 < t1)
+ {
+ Swap(t1, t2);
+ }
- if (t1 < t2)
+ if (t1 >= 0 && t1 <= magV && t1 >= tPoint1 && t1 <= tPoint2)
{
- if (t1 >= 0 && t1 <= 1)
+ // valid. Insert sorted.
+ if (t1 < tNear)
{
- near.setPoint(start + t1*V);
- near.setHit();
- near.setIndex(0);
+ tFar = tNear;
+ tNear = t1;
}
- if (t2 >= 0 && t2 <= 1)
+ else if (t1 < tFar)
{
- far.setPoint(start + t2*V);
- far.setHit();
- far.setIndex(0);
+ tFar = t1;
}
}
- else
+ if (t2 >= 0 && t2 <= magV && t2 >= tPoint1 && t2 <= tPoint2)
{
- if (t2 >= 0 && t2 <= 1)
+ // valid. Insert sorted.
+ if (t2 < tNear)
{
- near.setPoint(start + t2*V);
- near.setHit();
- near.setIndex(0);
+ tFar = tNear;
+ tNear = t2;
}
- if (t1 >= 0 && t1 <= 1)
+ else if (t2 < tFar)
{
- far.setPoint(start + t1*V);
- far.setHit();
- far.setIndex(0);
+ tFar = t2;
}
}
+ //Pout<< "two solutions t1:" << t1 << " t2:" << t2
+ // << " for start:" << start << " end:" << end
+ // << " magV:" << magV
+ // << " c:" << c << endl;
+ }
+ else
+ {
+ // Aligned with axis. Check if outside radius
+ //Pout<< "large discriminant:" << disc
+ // << " small a:" << a
+ // << " for start:" << start << " end:" << end
+ // << " magV:" << magV
+ // << " c:" << c << endl;
+ if (c > 0)
+ {
+ return;
+ }
+ }
+ }
+
+ // Check tNear, tFar
+ if (tNear >= 0 && tNear <= magV)
+ {
+ near.setPoint(start+tNear*V);
+ near.setHit();
+ near.setIndex(0);
+
+ if (tFar <= magV)
+ {
+ far.setPoint(start+tFar*V);
+ far.setHit();
+ far.setIndex(0);
}
}
+ else if (tFar >= 0 && tFar <= magV)
+ {
+ near.setPoint(start+tFar*V);
+ near.setHit();
+ near.setIndex(0);
+ }
}
@@ -216,13 +368,7 @@ Foam::searchableCylinder::searchableCylinder
magDir_(mag(point2_-point1_)),
unitDir_((point2_-point1_)/magDir_),
radius_(radius)
-{
- Pout<< "point1_:" << point1_ << endl;
- Pout<< "point2_:" << point2_ << endl;
- Pout<< "magDir_:" << magDir_ << endl;
- Pout<< "unitDir_:" << unitDir_ << endl;
- Pout<< "radius_:" << radius_ << endl;
-}
+{}
Foam::searchableCylinder::searchableCylinder
@@ -237,13 +383,7 @@ Foam::searchableCylinder::searchableCylinder
magDir_(mag(point2_-point1_)),
unitDir_((point2_-point1_)/magDir_),
radius_(readScalar(dict.lookup("radius")))
-{
- Pout<< "point1_:" << point1_ << endl;
- Pout<< "point2_:" << point2_ << endl;
- Pout<< "magDir_:" << magDir_ << endl;
- Pout<< "unitDir_:" << unitDir_ << endl;
- Pout<< "radius_:" << radius_ << endl;
-}
+{}
// * * * * * * * * * * * * * * * * Destructor * * * * * * * * * * * * * * * //
@@ -290,11 +430,10 @@ void Foam::searchableCylinder::findLine
{
info.setSize(start.size());
- pointIndexHit b;
-
forAll(start, i)
{
// Pick nearest intersection. If none intersected take second one.
+ pointIndexHit b;
findLineAll(start[i], end[i], info[i], b);
if (!info[i].hit() && b.hit())
{
@@ -313,11 +452,10 @@ void Foam::searchableCylinder::findLineAny
{
info.setSize(start.size());
- pointIndexHit b;
-
forAll(start, i)
{
// Discard far intersection
+ pointIndexHit b;
findLineAll(start[i], end[i], info[i], b);
if (!info[i].hit() && b.hit())
{
diff --git a/src/meshTools/searchableSurface/searchableCylinder.H b/src/meshTools/searchableSurface/searchableCylinder.H
index 55ee0354ddd..cae0f058db2 100644
--- a/src/meshTools/searchableSurface/searchableCylinder.H
+++ b/src/meshTools/searchableSurface/searchableCylinder.H
@@ -86,6 +86,8 @@ private:
const scalar nearestDistSqr
) const;
+ scalar radius2(const point& pt) const;
+
//- Find intersection with cylinder
void findLineAll
(
--
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