OpenGTA/math/obox.cpp
Anonymous Maarten 1ae34ae340 2007-06-14
2015-12-03 01:38:22 +01:00

237 lines
8.1 KiB
C++

/* Derived from code written by Jonathan Kreuzer.
*
* See: http://www.3dkingdoms.com/weekly/weekly.php?a=21
*
* basically the same as bbox.h/.cpp but using coldet math
*
* -- quote from a mail of the author --
*
* You're free to continue using my CBBox code however you want.
* ... [snip] ...
* The only thing I ask is a note about where it came from ( I think
* you said you added a link to the article, so that's fine. )
*
*/
/************************************************************************
* Copyright (c) 2005-2007 tok@openlinux.org.uk *
* *
* 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. *
* *
* Permission is granted to anyone to use this software for any purpose, *
* including commercial applications, and to alter it and redistribute *
* it freely, 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. *
* *
* 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. *
************************************************************************/
#include <cassert>
#include "log.h"
#include "obox.h"
#include "plane.h"
// --------------------------
//
// Oriented Bounding Box Class
//
// --------------------------
//
// Check if a point is in this bounding box
//
bool OBox::isPointInBox(const Vector3D &InP) const
{
// Rotate the point into the box's coordinates
Vector3D P = Transform(InP, m_M.Inverse());
// Now just use an axis-aligned check
if ( fabs(P.x) < m_Extent.x && fabs(P.y) < m_Extent.y && fabs(P.z) < m_Extent.z )
return true;
return false;
}
//
// Check if a sphere overlaps any part of this bounding box
//
bool OBox::isSphereInBox( const Vector3D &InP, float fRadius) const
{
float fDist;
float fDistSq = 0;
Vector3D P = Transform(InP, m_M.Inverse());
// Add distance squared from sphere centerpoint to box for each axis
for ( int i = 0; i < 3; i++ )
{
if ( fabs(P[i]) > m_Extent[i] )
{
fDist = fabs(P[i]) - m_Extent[i];
fDistSq += fDist*fDist;
}
}
return ( fDistSq <= fRadius*fRadius );
}
//
// Check if the bounding box is completely behind a plane( defined by a normal and a point )
//
bool OBox::boxOutsidePlane( const Vector3D &InNorm, const Vector3D &InP ) const
{
// Plane Normal in Box Space
Vector3D Norm = rotateVector(InNorm, m_M.Inverse() );
Norm = Vector3D( fabs( Norm.x ), fabs( Norm.y ), fabs( Norm.z ) );
float Extent = Norm * m_Extent; //Norm.Dot( m_Extent ); // Box Extent along the plane normal
//float Distance = InNorm.Dot( GetCenterPoint() - InP ); // Distance from Box Center to the Plane
float Distance = InNorm * (getCenterPoint() - InP);
// If Box Centerpoint is behind the plane further than its extent, the Box is outside the plane
if ( Distance < -Extent ) return true;
return false;
}
//
// Does the Line (L1, L2) intersect the Box?
//
bool OBox::isLineInBox( const Vector3D& L1, const Vector3D& L2 ) const
{
// Put line in box space
Matrix3D MInv = m_M.Inverse();
Vector3D LB1 = Transform(L1, MInv);
Vector3D LB2 = Transform(L2, MInv);
// Get line midpoint and extent
Vector3D LMid = (LB1 + LB2) * 0.5f;
Vector3D L = (LB1 - LMid);
Vector3D LExt = Vector3D( fabs(L.x), fabs(L.y), fabs(L.z) );
// Use Separating Axis Test
// Separation vector from box center to line center is LMid, since the line is in box space
if ( fabs( LMid.x ) > m_Extent.x + LExt.x ) return false;
if ( fabs( LMid.y ) > m_Extent.y + LExt.y ) return false;
if ( fabs( LMid.z ) > m_Extent.z + LExt.z ) return false;
// Crossproducts of line and each axis
if ( fabs( LMid.y * L.z - LMid.z * L.y) > (m_Extent.y * LExt.z + m_Extent.z * LExt.y) ) return false;
if ( fabs( LMid.x * L.z - LMid.z * L.x) > (m_Extent.x * LExt.z + m_Extent.z * LExt.x) ) return false;
if ( fabs( LMid.x * L.y - LMid.y * L.x) > (m_Extent.x * LExt.y + m_Extent.y * LExt.x) ) return false;
// No separating axis, the line intersects
return true;
}
void OBox::lineCrossBox(const Vector3D& L1, const Vector3D& L2, Vector3D & isecLocal) const {
// Put line in box space
Matrix3D MInv = m_M.Inverse();
Vector3D LB1 = Transform(L1, MInv);
Vector3D LB2 = Transform(L2, MInv);
float small_t = 2.0f;
Vector3D p_copy(0, 0, 0);
//i = 0: -x,-z <-> -x,z
//i = 1: -x,-z <-> x,-z
//i = 2: x,-z, <-> x,z
//i = 3: -x,z <-> x,z
for (int i = 0; i < 4; i++) {
Vector3D s1((i <= 1 || i == 3 ? -m_Extent.x : m_Extent.x), 0, (i < 3 ? -m_Extent.z : m_Extent.z));
Vector3D s2((i == 0 ? -m_Extent.x : m_Extent.x), 0, (i == 1 ? -m_Extent.z : m_Extent.z));
Vector3D p;
float dt = Math::intersection_segments(s1, s2, LB1, LB2, p);
if ((dt >= 0.0f) && (dt < small_t)) {
p_copy = p;
small_t = dt;
}
}
if (small_t >= 0.0f && small_t <= 1.0f) {
isecLocal = p_copy;
return;
}
ERROR << "Did not find intersection when OBB says there is one :-(" << std::endl;
isecLocal = L1;
}
//
// Returns a 3x3 rotation matrix as vectors
//
inline void OBox::getInvRot( Vector3D *pvRot ) const
{
pvRot[0] = Vector3D( m_M.m[0][0], m_M.m[0][1], m_M.m[0][2] );
pvRot[1] = Vector3D( m_M.m[1][0], m_M.m[1][1], m_M.m[1][2] );
pvRot[2] = Vector3D( m_M.m[2][0], m_M.m[2][1], m_M.m[2][2] );
}
//
// Check if any part of a box is inside any part of another box
// Uses the separating axis test.
//
bool OBox::isBoxInBox( OBox &BBox ) const
{
Vector3D SizeA = m_Extent;
Vector3D SizeB = BBox.m_Extent;
Vector3D RotA[3], RotB[3];
getInvRot( RotA );
BBox.getInvRot( RotB );
float R[3][3]; // Rotation from B to A
float AR[3][3]; // absolute values of R matrix, to use with box extents
float ExtentA, ExtentB, Separation;
int i, k;
// Calculate B to A rotation matrix
for( i = 0; i < 3; i++ )
for( k = 0; k < 3; k++ )
{
R[i][k] = RotA[i] * RotB[k];
AR[i][k] = fabs(R[i][k]);
}
// Vector separating the centers of Box B and of Box A
Vector3D vSepWS = BBox.getCenterPoint() - getCenterPoint();
// Rotated into Box A's coordinates
Vector3D vSepA( vSepWS * RotA[0], vSepWS * RotA[1], vSepWS * RotA[2] );
// Test if any of A's basis vectors separate the box
for( i = 0; i < 3; i++ )
{
ExtentA = SizeA[i];
ExtentB = SizeB * Vector3D( AR[i][0], AR[i][1], AR[i][2] );
Separation = fabs( vSepA[i] );
if( Separation > ExtentA + ExtentB ) return false;
}
// Test if any of B's basis vectors separate the box
for( k = 0; k < 3; k++ )
{
ExtentA = SizeA * Vector3D( AR[0][k], AR[1][k], AR[2][k] );
ExtentB = SizeB[k];
Separation = fabs( vSepA * Vector3D(R[0][k],R[1][k],R[2][k]) );
if( Separation > ExtentA + ExtentB ) return false;
}
// Now test Cross Products of each basis vector combination ( A[i], B[k] )
for( i=0 ; i<3 ; i++ )
for( k=0 ; k<3 ; k++ )
{
int i1 = (i+1)%3, i2 = (i+2)%3;
int k1 = (k+1)%3, k2 = (k+2)%3;
ExtentA = SizeA[i1] * AR[i2][k] + SizeA[i2] * AR[i1][k];
ExtentB = SizeB[k1] * AR[i][k2] + SizeB[k2] * AR[i][k1];
Separation = fabs( vSepA[i2] * R[i1][k] - vSepA[i1] * R[i2][k] );
if( Separation > ExtentA + ExtentB ) return false;
}
// No separating axis found, the boxes overlap
return true;
}