doom3-bfg/neo/idlib/geometry/Winding2D.cpp

902 lines
17 KiB
C++

/*
===========================================================================
Doom 3 BFG Edition GPL Source Code
Copyright (C) 1993-2012 id Software LLC, a ZeniMax Media company.
This file is part of the Doom 3 BFG Edition GPL Source Code ("Doom 3 BFG Edition Source Code").
Doom 3 BFG Edition Source Code is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Doom 3 BFG Edition Source Code is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Doom 3 BFG Edition Source Code. If not, see <http://www.gnu.org/licenses/>.
In addition, the Doom 3 BFG Edition Source Code is also subject to certain additional terms. You should have received a copy of these additional terms immediately following the terms and conditions of the GNU General Public License which accompanied the Doom 3 BFG Edition Source Code. If not, please request a copy in writing from id Software at the address below.
If you have questions concerning this license or the applicable additional terms, you may contact in writing id Software LLC, c/o ZeniMax Media Inc., Suite 120, Rockville, Maryland 20850 USA.
===========================================================================
*/
#pragma hdrstop
#include "../precompiled.h"
#include "Winding2D.h"
/*
============
GetAxialBevel
============
*/
bool GetAxialBevel( const idVec3& plane1, const idVec3& plane2, const idVec2& point, idVec3& bevel )
{
if( IEEE_FLT_SIGNBITSET( plane1.x ) ^ IEEE_FLT_SIGNBITSET( plane2.x ) )
{
if( idMath::Fabs( plane1.x ) > 0.1f && idMath::Fabs( plane2.x ) > 0.1f )
{
bevel.x = 0.0f;
if( IEEE_FLT_SIGNBITSET( plane1.y ) )
{
bevel.y = -1.0f;
}
else
{
bevel.y = 1.0f;
}
bevel.z = - ( point.x * bevel.x + point.y * bevel.y );
return true;
}
}
if( IEEE_FLT_SIGNBITSET( plane1.y ) ^ IEEE_FLT_SIGNBITSET( plane2.y ) )
{
if( idMath::Fabs( plane1.y ) > 0.1f && idMath::Fabs( plane2.y ) > 0.1f )
{
bevel.y = 0.0f;
if( IEEE_FLT_SIGNBITSET( plane1.x ) )
{
bevel.x = -1.0f;
}
else
{
bevel.x = 1.0f;
}
bevel.z = - ( point.x * bevel.x + point.y * bevel.y );
return true;
}
}
return false;
}
/*
============
idWinding2D::ExpandForAxialBox
============
*/
void idWinding2D::ExpandForAxialBox( const idVec2 bounds[2] )
{
int i, j, numPlanes;
idVec2 v;
idVec3 planes[MAX_POINTS_ON_WINDING_2D], plane, bevel;
// get planes for the edges and add bevels
for( numPlanes = i = 0; i < numPoints; i++ )
{
j = ( i + 1 ) % numPoints;
if( ( p[j] - p[i] ).LengthSqr() < 0.01f )
{
continue;
}
plane = Plane2DFromPoints( p[i], p[j], true );
if( i )
{
if( GetAxialBevel( planes[numPlanes - 1], plane, p[i], bevel ) )
{
planes[numPlanes++] = bevel;
}
}
assert( numPlanes < MAX_POINTS_ON_WINDING_2D );
planes[numPlanes++] = plane;
}
assert( numPlanes < MAX_POINTS_ON_WINDING_2D && numPlanes > 0 );
if( GetAxialBevel( planes[numPlanes - 1], planes[0], p[0], bevel ) )
{
planes[numPlanes++] = bevel;
}
// expand the planes
for( i = 0; i < numPlanes; i++ )
{
v.x = bounds[ IEEE_FLT_SIGNBITSET( planes[i].x ) ].x;
v.y = bounds[ IEEE_FLT_SIGNBITSET( planes[i].y ) ].y;
planes[i].z += v.x * planes[i].x + v.y * planes[i].y;
}
// get intersection points of the planes
for( numPoints = i = 0; i < numPlanes; i++ )
{
if( Plane2DIntersection( planes[( i + numPlanes - 1 ) % numPlanes], planes[i], p[numPoints] ) )
{
numPoints++;
}
}
}
/*
============
idWinding2D::Expand
============
*/
void idWinding2D::Expand( const float d )
{
int i;
idVec2 edgeNormals[MAX_POINTS_ON_WINDING_2D];
for( i = 0; i < numPoints; i++ )
{
idVec2& start = p[i];
idVec2& end = p[( i + 1 ) % numPoints];
edgeNormals[i].x = start.y - end.y;
edgeNormals[i].y = end.x - start.x;
edgeNormals[i].Normalize();
edgeNormals[i] *= d;
}
for( i = 0; i < numPoints; i++ )
{
p[i] += edgeNormals[i] + edgeNormals[( i + numPoints - 1 ) % numPoints];
}
}
/*
=============
idWinding2D::Split
=============
*/
int idWinding2D::Split( const idVec3& plane, const float epsilon, idWinding2D** front, idWinding2D** back ) const
{
float dists[MAX_POINTS_ON_WINDING_2D];
byte sides[MAX_POINTS_ON_WINDING_2D];
int counts[3];
float dot;
int i, j;
const idVec2* p1, *p2;
idVec2 mid;
idWinding2D* f;
idWinding2D* b;
int maxpts;
counts[0] = counts[1] = counts[2] = 0;
// determine sides for each point
for( i = 0; i < numPoints; i++ )
{
dists[i] = dot = plane.x * p[i].x + plane.y * p[i].y + plane.z;
if( dot > epsilon )
{
sides[i] = SIDE_FRONT;
}
else if( dot < -epsilon )
{
sides[i] = SIDE_BACK;
}
else
{
sides[i] = SIDE_ON;
}
counts[sides[i]]++;
}
sides[i] = sides[0];
dists[i] = dists[0];
*front = *back = NULL;
// if nothing at the front of the clipping plane
if( !counts[SIDE_FRONT] )
{
*back = Copy();
return SIDE_BACK;
}
// if nothing at the back of the clipping plane
if( !counts[SIDE_BACK] )
{
*front = Copy();
return SIDE_FRONT;
}
maxpts = numPoints + 4; // cant use counts[0]+2 because of fp grouping errors
*front = f = new( TAG_IDLIB_WINDING ) idWinding2D;
*back = b = new( TAG_IDLIB_WINDING ) idWinding2D;
for( i = 0; i < numPoints; i++ )
{
p1 = &p[i];
if( sides[i] == SIDE_ON )
{
f->p[f->numPoints] = *p1;
f->numPoints++;
b->p[b->numPoints] = *p1;
b->numPoints++;
continue;
}
if( sides[i] == SIDE_FRONT )
{
f->p[f->numPoints] = *p1;
f->numPoints++;
}
if( sides[i] == SIDE_BACK )
{
b->p[b->numPoints] = *p1;
b->numPoints++;
}
if( sides[i + 1] == SIDE_ON || sides[i + 1] == sides[i] )
{
continue;
}
// generate a split point
p2 = &p[( i + 1 ) % numPoints];
// always calculate the split going from the same side
// or minor epsilon issues can happen
if( sides[i] == SIDE_FRONT )
{
dot = dists[i] / ( dists[i] - dists[i + 1] );
for( j = 0; j < 2; j++ )
{
// avoid round off error when possible
if( plane[j] == 1.0f )
{
mid[j] = plane.z;
}
else if( plane[j] == -1.0f )
{
mid[j] = -plane.z;
}
else
{
mid[j] = ( *p1 )[j] + dot * ( ( *p2 )[j] - ( *p1 )[j] );
}
}
}
else
{
dot = dists[i + 1] / ( dists[i + 1] - dists[i] );
for( j = 0; j < 2; j++ )
{
// avoid round off error when possible
if( plane[j] == 1.0f )
{
mid[j] = plane.z;
}
else if( plane[j] == -1.0f )
{
mid[j] = -plane.z;
}
else
{
mid[j] = ( *p2 )[j] + dot * ( ( *p1 )[j] - ( *p2 )[j] );
}
}
}
f->p[f->numPoints] = mid;
f->numPoints++;
b->p[b->numPoints] = mid;
b->numPoints++;
}
return SIDE_CROSS;
}
/*
============
idWinding2D::ClipInPlace
============
*/
bool idWinding2D::ClipInPlace( const idVec3& plane, const float epsilon, const bool keepOn )
{
int i, j, maxpts, newNumPoints;
int sides[MAX_POINTS_ON_WINDING_2D + 1], counts[3];
float dot, dists[MAX_POINTS_ON_WINDING_2D + 1];
idVec2* p1, *p2, mid, newPoints[MAX_POINTS_ON_WINDING_2D + 4];
counts[SIDE_FRONT] = counts[SIDE_BACK] = counts[SIDE_ON] = 0;
for( i = 0; i < numPoints; i++ )
{
dists[i] = dot = plane.x * p[i].x + plane.y * p[i].y + plane.z;
if( dot > epsilon )
{
sides[i] = SIDE_FRONT;
}
else if( dot < -epsilon )
{
sides[i] = SIDE_BACK;
}
else
{
sides[i] = SIDE_ON;
}
counts[sides[i]]++;
}
sides[i] = sides[0];
dists[i] = dists[0];
// if the winding is on the plane and we should keep it
if( keepOn && !counts[SIDE_FRONT] && !counts[SIDE_BACK] )
{
return true;
}
if( !counts[SIDE_FRONT] )
{
numPoints = 0;
return false;
}
if( !counts[SIDE_BACK] )
{
return true;
}
maxpts = numPoints + 4; // cant use counts[0]+2 because of fp grouping errors
newNumPoints = 0;
for( i = 0; i < numPoints; i++ )
{
p1 = &p[i];
if( newNumPoints + 1 > maxpts )
{
return true; // can't split -- fall back to original
}
if( sides[i] == SIDE_ON )
{
newPoints[newNumPoints] = *p1;
newNumPoints++;
continue;
}
if( sides[i] == SIDE_FRONT )
{
newPoints[newNumPoints] = *p1;
newNumPoints++;
}
if( sides[i + 1] == SIDE_ON || sides[i + 1] == sides[i] )
{
continue;
}
if( newNumPoints + 1 > maxpts )
{
return true; // can't split -- fall back to original
}
// generate a split point
p2 = &p[( i + 1 ) % numPoints];
dot = dists[i] / ( dists[i] - dists[i + 1] );
for( j = 0; j < 2; j++ )
{
// avoid round off error when possible
if( plane[j] == 1.0f )
{
mid[j] = plane.z;
}
else if( plane[j] == -1.0f )
{
mid[j] = -plane.z;
}
else
{
mid[j] = ( *p1 )[j] + dot * ( ( *p2 )[j] - ( *p1 )[j] );
}
}
newPoints[newNumPoints] = mid;
newNumPoints++;
}
if( newNumPoints >= MAX_POINTS_ON_WINDING_2D )
{
return true;
}
numPoints = newNumPoints;
memcpy( p, newPoints, newNumPoints * sizeof( idVec2 ) );
return true;
}
/*
=============
idWinding2D::Copy
=============
*/
idWinding2D* idWinding2D::Copy() const
{
idWinding2D* w;
w = new( TAG_IDLIB_WINDING ) idWinding2D;
w->numPoints = numPoints;
memcpy( w->p, p, numPoints * sizeof( p[0] ) );
return w;
}
/*
=============
idWinding2D::Reverse
=============
*/
idWinding2D* idWinding2D::Reverse() const
{
idWinding2D* w;
int i;
w = new( TAG_IDLIB_WINDING ) idWinding2D;
w->numPoints = numPoints;
for( i = 0; i < numPoints; i++ )
{
w->p[ numPoints - i - 1 ] = p[i];
}
return w;
}
/*
============
idWinding2D::GetArea
============
*/
float idWinding2D::GetArea() const
{
int i;
idVec2 d1, d2;
float total;
total = 0.0f;
for( i = 2; i < numPoints; i++ )
{
d1 = p[i - 1] - p[0];
d2 = p[i] - p[0];
total += d1.x * d2.y - d1.y * d2.x;
}
return total * 0.5f;
}
/*
============
idWinding2D::GetCenter
============
*/
idVec2 idWinding2D::GetCenter() const
{
int i;
idVec2 center;
center.Zero();
for( i = 0; i < numPoints; i++ )
{
center += p[i];
}
center *= ( 1.0f / numPoints );
return center;
}
/*
============
idWinding2D::GetRadius
============
*/
float idWinding2D::GetRadius( const idVec2& center ) const
{
int i;
float radius, r;
idVec2 dir;
radius = 0.0f;
for( i = 0; i < numPoints; i++ )
{
dir = p[i] - center;
r = dir * dir;
if( r > radius )
{
radius = r;
}
}
return idMath::Sqrt( radius );
}
/*
============
idWinding2D::GetBounds
============
*/
void idWinding2D::GetBounds( idVec2 bounds[2] ) const
{
int i;
if( !numPoints )
{
bounds[0].x = bounds[0].y = idMath::INFINITY;
bounds[1].x = bounds[1].y = -idMath::INFINITY;
return;
}
bounds[0] = bounds[1] = p[0];
for( i = 1; i < numPoints; i++ )
{
if( p[i].x < bounds[0].x )
{
bounds[0].x = p[i].x;
}
else if( p[i].x > bounds[1].x )
{
bounds[1].x = p[i].x;
}
if( p[i].y < bounds[0].y )
{
bounds[0].y = p[i].y;
}
else if( p[i].y > bounds[1].y )
{
bounds[1].y = p[i].y;
}
}
}
/*
=============
idWinding2D::IsTiny
=============
*/
#define EDGE_LENGTH 0.2f
bool idWinding2D::IsTiny() const
{
int i;
float len;
idVec2 delta;
int edges;
edges = 0;
for( i = 0; i < numPoints; i++ )
{
delta = p[( i + 1 ) % numPoints] - p[i];
len = delta.Length();
if( len > EDGE_LENGTH )
{
if( ++edges == 3 )
{
return false;
}
}
}
return true;
}
/*
=============
idWinding2D::IsHuge
=============
*/
bool idWinding2D::IsHuge() const
{
int i, j;
for( i = 0; i < numPoints; i++ )
{
for( j = 0; j < 2; j++ )
{
if( p[i][j] <= MIN_WORLD_COORD || p[i][j] >= MAX_WORLD_COORD )
{
return true;
}
}
}
return false;
}
/*
=============
idWinding2D::Print
=============
*/
void idWinding2D::Print() const
{
int i;
for( i = 0; i < numPoints; i++ )
{
idLib::common->Printf( "(%5.1f, %5.1f)\n", p[i][0], p[i][1] );
}
}
/*
=============
idWinding2D::PlaneDistance
=============
*/
float idWinding2D::PlaneDistance( const idVec3& plane ) const
{
int i;
float d, min, max;
min = idMath::INFINITY;
max = -min;
for( i = 0; i < numPoints; i++ )
{
d = plane.x * p[i].x + plane.y * p[i].y + plane.z;
if( d < min )
{
min = d;
if( IEEE_FLT_SIGNBITSET( min ) & IEEE_FLT_SIGNBITNOTSET( max ) )
{
return 0.0f;
}
}
if( d > max )
{
max = d;
if( IEEE_FLT_SIGNBITSET( min ) & IEEE_FLT_SIGNBITNOTSET( max ) )
{
return 0.0f;
}
}
}
if( IEEE_FLT_SIGNBITNOTSET( min ) )
{
return min;
}
if( IEEE_FLT_SIGNBITSET( max ) )
{
return max;
}
return 0.0f;
}
/*
=============
idWinding2D::PlaneSide
=============
*/
int idWinding2D::PlaneSide( const idVec3& plane, const float epsilon ) const
{
bool front, back;
int i;
float d;
front = false;
back = false;
for( i = 0; i < numPoints; i++ )
{
d = plane.x * p[i].x + plane.y * p[i].y + plane.z;
if( d < -epsilon )
{
if( front )
{
return SIDE_CROSS;
}
back = true;
continue;
}
else if( d > epsilon )
{
if( back )
{
return SIDE_CROSS;
}
front = true;
continue;
}
}
if( back )
{
return SIDE_BACK;
}
if( front )
{
return SIDE_FRONT;
}
return SIDE_ON;
}
/*
============
idWinding2D::PointInside
============
*/
bool idWinding2D::PointInside( const idVec2& point, const float epsilon ) const
{
int i;
float d;
idVec3 plane;
for( i = 0; i < numPoints; i++ )
{
plane = Plane2DFromPoints( p[i], p[( i + 1 ) % numPoints] );
d = plane.x * point.x + plane.y * point.y + plane.z;
if( d > epsilon )
{
return false;
}
}
return true;
}
/*
============
idWinding2D::LineIntersection
============
*/
bool idWinding2D::LineIntersection( const idVec2& start, const idVec2& end ) const
{
int i, numEdges;
int sides[MAX_POINTS_ON_WINDING_2D + 1], counts[3];
float d1, d2, epsilon = 0.1f;
idVec3 plane, edges[2];
counts[SIDE_FRONT] = counts[SIDE_BACK] = counts[SIDE_ON] = 0;
plane = Plane2DFromPoints( start, end );
for( i = 0; i < numPoints; i++ )
{
d1 = plane.x * p[i].x + plane.y * p[i].y + plane.z;
if( d1 > epsilon )
{
sides[i] = SIDE_FRONT;
}
else if( d1 < -epsilon )
{
sides[i] = SIDE_BACK;
}
else
{
sides[i] = SIDE_ON;
}
counts[sides[i]]++;
}
sides[i] = sides[0];
if( !counts[SIDE_FRONT] )
{
return false;
}
if( !counts[SIDE_BACK] )
{
return false;
}
numEdges = 0;
for( i = 0; i < numPoints; i++ )
{
if( sides[i] != sides[i + 1] && sides[i + 1] != SIDE_ON )
{
edges[numEdges++] = Plane2DFromPoints( p[i], p[( i + 1 ) % numPoints] );
if( numEdges >= 2 )
{
break;
}
}
}
if( numEdges < 2 )
{
return false;
}
d1 = edges[0].x * start.x + edges[0].y * start.y + edges[0].z;
d2 = edges[0].x * end.x + edges[0].y * end.y + edges[0].z;
if( IEEE_FLT_SIGNBITNOTSET( d1 ) & IEEE_FLT_SIGNBITNOTSET( d2 ) )
{
return false;
}
d1 = edges[1].x * start.x + edges[1].y * start.y + edges[1].z;
d2 = edges[1].x * end.x + edges[1].y * end.y + edges[1].z;
if( IEEE_FLT_SIGNBITNOTSET( d1 ) & IEEE_FLT_SIGNBITNOTSET( d2 ) )
{
return false;
}
return true;
}
/*
============
idWinding2D::RayIntersection
============
*/
bool idWinding2D::RayIntersection( const idVec2& start, const idVec2& dir, float& scale1, float& scale2, int* edgeNums ) const
{
int i, numEdges, localEdgeNums[2];
int sides[MAX_POINTS_ON_WINDING_2D + 1], counts[3];
float d1, d2, epsilon = 0.1f;
idVec3 plane, edges[2];
scale1 = scale2 = 0.0f;
counts[SIDE_FRONT] = counts[SIDE_BACK] = counts[SIDE_ON] = 0;
plane = Plane2DFromVecs( start, dir );
for( i = 0; i < numPoints; i++ )
{
d1 = plane.x * p[i].x + plane.y * p[i].y + plane.z;
if( d1 > epsilon )
{
sides[i] = SIDE_FRONT;
}
else if( d1 < -epsilon )
{
sides[i] = SIDE_BACK;
}
else
{
sides[i] = SIDE_ON;
}
counts[sides[i]]++;
}
sides[i] = sides[0];
if( !counts[SIDE_FRONT] )
{
return false;
}
if( !counts[SIDE_BACK] )
{
return false;
}
numEdges = 0;
for( i = 0; i < numPoints; i++ )
{
if( sides[i] != sides[i + 1] && sides[i + 1] != SIDE_ON )
{
localEdgeNums[numEdges] = i;
edges[numEdges++] = Plane2DFromPoints( p[i], p[( i + 1 ) % numPoints] );
if( numEdges >= 2 )
{
break;
}
}
}
if( numEdges < 2 )
{
return false;
}
d1 = edges[0].x * start.x + edges[0].y * start.y + edges[0].z;
d2 = - ( edges[0].x * dir.x + edges[0].y * dir.y );
if( d2 == 0.0f )
{
return false;
}
scale1 = d1 / d2;
d1 = edges[1].x * start.x + edges[1].y * start.y + edges[1].z;
d2 = - ( edges[1].x * dir.x + edges[1].y * dir.y );
if( d2 == 0.0f )
{
return false;
}
scale2 = d1 / d2;
if( idMath::Fabs( scale1 ) > idMath::Fabs( scale2 ) )
{
SwapValues( scale1, scale2 );
SwapValues( localEdgeNums[0], localEdgeNums[1] );
}
if( edgeNums )
{
edgeNums[0] = localEdgeNums[0];
edgeNums[1] = localEdgeNums[1];
}
return true;
}