gtkradiant/contrib/bobtoolz/DWinding.cpp

/*
BobToolz plugin for GtkRadiant
Copyright (C) 2001 Gordon Biggans

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library 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
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

// DWinding.cpp: implementation of the DWinding class.
//
//////////////////////////////////////////////////////////////////////

#include "StdAfx.h"
#include "DWinding.h"
#include "DPlane.h"
#include "misc.h"

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

DWinding::DWinding()
{
	numpoints = 0;
	p = NULL;
}

DWinding::~DWinding()
{
	if(p)
		delete[] p;
}

//////////////////////////////////////////////////////////////////////
// Implementation
//////////////////////////////////////////////////////////////////////

#define	BOGUS_RANGE	4096

void DWinding::AllocWinding(int points)
{
	numpoints = points;
	if(p)
		delete[] p;
	p = new vec3_t[points];
}

vec_t DWinding::WindingArea()
{
	vec3_t	d1, d2, cross;
	vec_t	total;

	total = 0;
	for (int i = 2; i < numpoints ; i++)
	{
		VectorSubtract (p[i-1], p[0], d1);
		VectorSubtract (p[i], p[0], d2);

		CrossProduct (d1, d2, cross);

		total += 0.5f * VectorLength ( cross );
	}

	return total;
}

void DWinding::RemoveColinearPoints()
{
	vec3_t	p2[MAX_POINTS_ON_WINDING];

	int nump = 0;
	for (int i = 0; i < numpoints; i++)
	{
		int j = (i+1)%numpoints;
		int k = (i+numpoints-1)%numpoints;

		vec3_t	v1, v2;
		VectorSubtract (p[j], p[i], v1);
		VectorSubtract (p[i], p[k], v2);
		VectorNormalize(v1, v1);
		VectorNormalize(v2, v2);

		if (DotProduct(v1, v2) < 0.999)
		{
			VectorCopy (p[i], p2[nump]);
			nump++;
		}
	}

	if (nump == numpoints)
		return;

	AllocWinding(nump);
	memcpy (p, p2, nump*sizeof(vec3_t));
}

DPlane* DWinding::WindingPlane()
{
	DPlane* newPlane = new DPlane(p[0], p[1], p[2], NULL);
	return newPlane;
}

void DWinding::WindingBounds(vec3_t mins, vec3_t maxs)
{
	if(numpoints == 0)
		return;

	VectorCopy(mins, p[0]);
	VectorCopy(maxs, p[0]);

	for (int i = 1; i < numpoints ;i++)
	{
		for (int j = 0; j < 3; j++)
		{
			vec_t v = p[i][j];
			if (v < mins[j])
				mins[j] = v;
			if (v > maxs[j])
				maxs[j] = v;
		}
	}
}

void DWinding::WindingCentre(vec3_t centre)
{
	VectorCopy (vec3_origin, centre);
	for (int i = 0; i < numpoints; i++)
		VectorAdd (p[i], centre, centre);

	float scale = 1.0f/numpoints;
	VectorScale (centre, scale, centre);
}


DWinding* DWinding::CopyWinding()
{
	DWinding* c = new DWinding;
	c->AllocWinding(numpoints);
	memcpy (c->p, p, numpoints*sizeof(vec3_t));
	return c;
}


int DWinding::WindingOnPlaneSide(vec3_t normal, vec_t dist)
{
	bool front = FALSE;
	bool back = FALSE;

	for (int i = 0; i < numpoints; i++)
	{
		vec_t d = DotProduct (p[i], normal) - dist;
		if (d < -ON_EPSILON)
		{
			if (front)
				return SIDE_CROSS;
			back = TRUE;
			continue;
		}
		if (d > ON_EPSILON)
		{
			if (back)
				return SIDE_CROSS;
			front = TRUE;
			continue;
		}
	}

	if (back)
		return SIDE_BACK;
	if (front)
		return SIDE_FRONT;
	return SIDE_ON;
}

void DWinding::CheckWinding()
{
	vec_t	*p1, *p2;
	vec_t	edgedist;
	vec3_t	dir, edgenormal;

	if (numpoints < 3)
		Sys_Printf ("CheckWinding: %i points", numpoints);
	
	vec_t area = WindingArea();
	if (area < 1)
		Sys_Printf ("CheckWinding: %f area", area);

	DPlane* wPlane = WindingPlane ();
	int i;
	for (i = 0; i < numpoints; i++)
	{
		p1 = p[i];

		int j;
		for (j = 0; j < 3; j++)
			if (p1[j] > BOGUS_RANGE || p1[j] < -BOGUS_RANGE)
				Sys_Printf ("CheckFace: BUGUS_RANGE: %f", p1[j]);

		j = i + 1 == numpoints ? 0 : i + 1;
		
		// check the point is on the face plane
		vec_t d = DotProduct (p1, wPlane->normal) - wPlane->_d;
		if (d < -ON_EPSILON || d > ON_EPSILON)
			Sys_Printf ("CheckWinding: point off plane");
	
		// check the edge isnt degenerate
		p2 = p[j];
		VectorSubtract (p2, p1, dir);
		
		if (VectorLength (dir) < ON_EPSILON)
			Sys_Printf ("CheckWinding: degenerate edge");
			
		CrossProduct (wPlane->normal, dir, edgenormal);
		VectorNormalize (edgenormal, edgenormal);
		edgedist = DotProduct (p1, edgenormal);
		
		// all other points must be on front side
		for (j = 0 ; j < numpoints ; j++)
		{
			if (j == i)
				continue;

			d = DotProduct (p[j], edgenormal);
			if (d > (edgedist + ON_EPSILON))
				Sys_Printf ("CheckWinding: non-convex");
		}
	}

	delete wPlane;
}

DWinding* DWinding::ReverseWinding()
{
	DWinding* c = new DWinding;
	c->AllocWinding(numpoints);

	for (int i = 0; i < numpoints ; i++)
		VectorCopy (p[numpoints-1-i], c->p[i]);

	return c;
}

bool DWinding::ChopWindingInPlace(DPlane* chopPlane, vec_t epsilon)
{
	vec_t	dists[MAX_POINTS_ON_WINDING+4];
	int		sides[MAX_POINTS_ON_WINDING+4];
	int		counts[3];
	vec_t	*p1, *p2;
	vec3_t	mid;

	counts[0] = counts[1] = counts[2] = 0;

// determine sides for each point
 	int i;
	for (i = 0; i < numpoints; i++)
	{
		vec_t dot = DotProduct (p[i], chopPlane->normal);
		dot -= chopPlane->_d;
		dists[i] = dot;
		
		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 (!counts[0])
	{
		delete this;
		return FALSE;
	}

	if (!counts[1])
		return TRUE;

	int maxpts = numpoints+4;	// cant use counts[0]+2 because
								// of fp grouping errors

	DWinding* f = new DWinding;
	f->AllocWinding(maxpts);
	f->numpoints = 0;
		
	for (i = 0; i < numpoints; i++)
	{
		p1 = p[i];
		
		if (sides[i] == SIDE_ON)
		{
			VectorCopy (p1, f->p[f->numpoints]);
			f->numpoints++;
			continue;
		}
	
		if (sides[i] == SIDE_FRONT)
		{
			VectorCopy (p1, f->p[f->numpoints]);
			f->numpoints++;
		}

		if (sides[i+1] == SIDE_ON || sides[i+1] == sides[i])
			continue;
			
	// generate a split point
		p2 = p[(i+1)%numpoints];
		
		vec_t dot = dists[i] / (dists[i]-dists[i+1]);
		for (int j = 0; j < 3; j++)
		{
			if (chopPlane->normal[j] == 1)
				mid[j] = chopPlane->_d;
			else if (chopPlane->normal[j] == -1)
				mid[j] = -chopPlane->_d;
			else
				mid[j] = p1[j] + dot*(p2[j]-p1[j]);
		}
			
		VectorCopy (mid, f->p[f->numpoints]);
		f->numpoints++;
	}
	
	if (f->numpoints > maxpts)
		Sys_Printf ("ClipWinding: points exceeded estimate");
	if (f->numpoints > MAX_POINTS_ON_WINDING)
		Sys_Printf ("ClipWinding: MAX_POINTS_ON_WINDING");

	delete[] p;
	p = f->p;
	f->p = NULL;
	delete f;
	return TRUE;
}

void DWinding::ClipWindingEpsilon(DPlane* chopPlane, vec_t epsilon, DWinding **front, DWinding **back)
{
	vec_t	dists[MAX_POINTS_ON_WINDING+4];
	int		sides[MAX_POINTS_ON_WINDING+4];
	int		counts[3];
	vec_t	*p1, *p2;
	vec3_t	mid;
	
	counts[0] = counts[1] = counts[2] = 0;

// determine sides for each point
 	int i;
	for (i = 0; i < numpoints; i++)
	{
		vec_t dot = -chopPlane->DistanceToPoint(p[i]);
		dists[i] = dot;
		
		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 (!counts[0])
	{
		*back = CopyWinding();
		return;
	}
	if (!counts[1])
	{
		*front = CopyWinding();
		return;
	}

	int maxpts = numpoints+4;	// cant use counts[0]+2 because
								// of fp grouping errors

	DWinding* f = new DWinding;
	DWinding* b = new DWinding;

	f->AllocWinding(maxpts);
	f->numpoints = 0;

	b->AllocWinding(maxpts);
	b->numpoints = 0;
		
	*front = f;
	*back = b;

	for (i = 0; i < numpoints ; i++)
	{
		p1 = p[i];
		
		if (sides[i] == SIDE_ON)
		{
			VectorCopy (p1, f->p[f->numpoints]);
			f->numpoints++;
			VectorCopy (p1, b->p[b->numpoints]);
			b->numpoints++;
			continue;
		}
	
		if (sides[i] == SIDE_FRONT)
		{
			VectorCopy (p1, f->p[f->numpoints]);
			f->numpoints++;
		}
		if (sides[i] == SIDE_BACK)
		{
			VectorCopy (p1, b->p[b->numpoints]);
			b->numpoints++;
		}

		if (sides[i+1] == SIDE_ON || sides[i+1] == sides[i])
			continue;
			
	// generate a split point
		p2 = p[(i+1)%numpoints];
		
		vec_t dot = dists[i] / (dists[i]-dists[i+1]);
		for (int j = 0; j < 3; j++)
		{
			if (chopPlane->normal[j] == 1)
				mid[j] = chopPlane->_d;
			else if (chopPlane->normal[j] == -1)
				mid[j] = -chopPlane->_d;
			else
				mid[j] = p1[j] + dot*(p2[j]-p1[j]);
		}
			
		VectorCopy (mid, f->p[f->numpoints]);
		f->numpoints++;
		VectorCopy (mid, b->p[b->numpoints]);
		b->numpoints++;
	}
	
	if (f->numpoints > maxpts || b->numpoints > maxpts)
		Sys_Printf ("ClipWinding: points exceeded estimate");
	if (f->numpoints > MAX_POINTS_ON_WINDING || b->numpoints > MAX_POINTS_ON_WINDING)
		Sys_Printf ("ClipWinding: MAX_POINTS_ON_WINDING");
}

bool DWinding::ChopWinding(DPlane* chopPlane)
{
	DWinding *f, *b;

	ClipWindingEpsilon (chopPlane, (float)ON_EPSILON, &f, &b);

	if (b)
		delete (b);


	if(!f)
	{
		delete this;
		return FALSE;
	}

	delete[] p;
	p = f->p;
	f->p = NULL;
	numpoints = f->numpoints;
	delete f;

	return TRUE;
}