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Differential D8762 Diff 28333 extern/bullet2/src/LinearMath/btGrahamScan2dConvexHull.h

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extern/bullet2/src/LinearMath/btGrahamScan2dConvexHull.h

/* /*
Bullet Continuous Collision Detection and Physics Library Bullet Continuous Collision Detection and Physics Library
Copyright (c) 2011 Advanced Micro Devices, Inc. http://bulletphysics.org Copyright (c) 2011 Advanced Micro Devices, Inc. http://bulletphysics.org
This software is provided 'as-is', without any express or implied warranty. This software is provided 'as-is', without any express or implied warranty.
In no event will the authors be held liable for any damages arising from the use of this software. In no event will the authors be held liable for any damages arising from the use of this software.
Permission is granted to anyone to use this software for any purpose, Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it freely, including commercial applications, and to alter it and redistribute it freely,
subject to the following restrictions: subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required. 1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software. 2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution. 3. This notice may not be removed or altered from any source distribution.
*/ */
#ifndef GRAHAM_SCAN_2D_CONVEX_HULL_H #ifndef GRAHAM_SCAN_2D_CONVEX_HULL_H
#define GRAHAM_SCAN_2D_CONVEX_HULL_H #define GRAHAM_SCAN_2D_CONVEX_HULL_H
#include "btVector3.h" #include "btVector3.h"
#include "btAlignedObjectArray.h" #include "btAlignedObjectArray.h"
struct GrahamVector3 : public btVector3 struct GrahamVector3 : public btVector3
{ {
GrahamVector3(const btVector3& org, int orgIndex) GrahamVector3(const btVector3& org, int orgIndex)
:btVector3(org), : btVector3(org),
m_orgIndex(orgIndex) m_orgIndex(orgIndex)
{ {
} }
btScalar m_angle; btScalar m_angle;
int m_orgIndex; int m_orgIndex;
}; };
struct btAngleCompareFunc
struct btAngleCompareFunc { {
btVector3 m_anchor; btVector3 m_anchor;
btAngleCompareFunc(const btVector3& anchor) btAngleCompareFunc(const btVector3& anchor)
: m_anchor(anchor) : m_anchor(anchor)
{ {
} }
bool operator()(const GrahamVector3& a, const GrahamVector3& b) const { bool operator()(const GrahamVector3& a, const GrahamVector3& b) const
{
if (a.m_angle != b.m_angle) if (a.m_angle != b.m_angle)
return a.m_angle < b.m_angle; return a.m_angle < b.m_angle;
else else
{ {
btScalar al = (a-m_anchor).length2(); btScalar al = (a - m_anchor).length2();
btScalar bl = (b-m_anchor).length2(); btScalar bl = (b - m_anchor).length2();
if (al != bl) if (al != bl)
return al < bl; return al < bl;
else else
{ {
return a.m_orgIndex < b.m_orgIndex; return a.m_orgIndex < b.m_orgIndex;
} }
} }
} }
}; };
inline void GrahamScanConvexHull2D(btAlignedObjectArray<GrahamVector3>& originalPoints, btAlignedObjectArray<GrahamVector3>& hull, const btVector3& normalAxis) inline void GrahamScanConvexHull2D(btAlignedObjectArray<GrahamVector3>& originalPoints, btAlignedObjectArray<GrahamVector3>& hull, const btVector3& normalAxis)
{ {
btVector3 axis0,axis1; btVector3 axis0, axis1;
btPlaneSpace1(normalAxis,axis0,axis1); btPlaneSpace1(normalAxis, axis0, axis1);
if (originalPoints.size()<=1) if (originalPoints.size() <= 1)
{ {
for (int i=0;i<originalPoints.size();i++) for (int i = 0; i < originalPoints.size(); i++)
hull.push_back(originalPoints[0]); hull.push_back(originalPoints[0]);
return; return;
} }
//step1 : find anchor point with smallest projection on axis0 and move it to first location //step1 : find anchor point with smallest projection on axis0 and move it to first location
for (int i=0;i<originalPoints.size();i++) for (int i = 0; i < originalPoints.size(); i++)
{ {
// const btVector3& left = originalPoints[i]; // const btVector3& left = originalPoints[i];
// const btVector3& right = originalPoints[0]; // const btVector3& right = originalPoints[0];
btScalar projL = originalPoints[i].dot(axis0); btScalar projL = originalPoints[i].dot(axis0);
btScalar projR = originalPoints[0].dot(axis0); btScalar projR = originalPoints[0].dot(axis0);
if (projL < projR) if (projL < projR)
{ {
originalPoints.swap(0,i); originalPoints.swap(0, i);
} }
} }
//also precompute angles //also precompute angles
originalPoints[0].m_angle = -1e30f; originalPoints[0].m_angle = -1e30f;
for (int i=1;i<originalPoints.size();i++) for (int i = 1; i < originalPoints.size(); i++)
{ {
btVector3 ar = originalPoints[i]-originalPoints[0]; btVector3 ar = originalPoints[i] - originalPoints[0];
btScalar ar1 = axis1.dot(ar); btScalar ar1 = axis1.dot(ar);
btScalar ar0 = axis0.dot(ar); btScalar ar0 = axis0.dot(ar);
if( ar1*ar1+ar0*ar0 < FLT_EPSILON ) if (ar1 * ar1 + ar0 * ar0 < FLT_EPSILON)
{ {
originalPoints[i].m_angle = 0.0f; originalPoints[i].m_angle = 0.0f;
} }
else else
{ {
originalPoints[i].m_angle = btAtan2Fast(ar1, ar0); originalPoints[i].m_angle = btAtan2Fast(ar1, ar0);
} }
} }
//step 2: sort all points, based on 'angle' with this anchor //step 2: sort all points, based on 'angle' with this anchor
btAngleCompareFunc comp(originalPoints[0]); btAngleCompareFunc comp(originalPoints[0]);
originalPoints.quickSortInternal(comp,1,originalPoints.size()-1); originalPoints.quickSortInternal(comp, 1, originalPoints.size() - 1);
int i; int i;
for (i = 0; i<2; i++) for (i = 0; i < 2; i++)
hull.push_back(originalPoints[i]); hull.push_back(originalPoints[i]);
//step 3: keep all 'convex' points and discard concave points (using back tracking) //step 3: keep all 'convex' points and discard concave points (using back tracking)
for (; i != originalPoints.size(); i++) for (; i != originalPoints.size(); i++)
{ {
bool isConvex = false; bool isConvex = false;
while (!isConvex&& hull.size()>1) { while (!isConvex && hull.size() > 1)
{
btVector3& a = hull[hull.size()-2]; btVector3& a = hull[hull.size() - 2];
btVector3& b = hull[hull.size()-1]; btVector3& b = hull[hull.size() - 1];
isConvex = btCross(a-b,a-originalPoints[i]).dot(normalAxis)> 0; isConvex = btCross(a - b, a - originalPoints[i]).dot(normalAxis) > 0;
if (!isConvex) if (!isConvex)
hull.pop_back(); hull.pop_back();
else else
hull.push_back(originalPoints[i]); hull.push_back(originalPoints[i]);
} }
if( hull.size() == 1 ) if (hull.size() == 1)
{ {
hull.push_back( originalPoints[i] ); hull.push_back(originalPoints[i]);
} }
} }
} }
#endif //GRAHAM_SCAN_2D_CONVEX_HULL_H #endif //GRAHAM_SCAN_2D_CONVEX_HULL_H