gtkradiant/contrib/gtkgensurf/face.cpp

/*
GenSurf plugin for GtkRadiant
Copyright (C) 2001 David Hyde, Loki software and qeradiant.com

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
*/

#include <stdlib.h>
#include <math.h>
#include "gensurf.h"

#define MAX_FACES 128    // Maximum number of faces on a brush
#define	MAX_POINTS_ON_WINDING	64
#define	SIDE_FRONT		0
#define	SIDE_ON			2
#define	SIDE_BACK		1
#define	SIDE_CROSS		-2

vec3 vec3_origin = {0,0,0};

void PlaneFromPoints (float *p0, float *p1, float *p2, PLANE *plane)
{
	vec3 t1, t2;
	vec	length;
	
	VectorSubtract (p0, p1, t1);
	VectorSubtract (p2, p1, t2);
	plane->normal[0] = t1[1]*t2[2] - t1[2]*t2[1];
	plane->normal[1] = t1[2]*t2[0] - t1[0]*t2[2];
	plane->normal[2] = t1[0]*t2[1] - t1[1]*t2[0];
	
	length = (vec)(sqrt(plane->normal[0]*plane->normal[0] +
		                plane->normal[1]*plane->normal[1] +
						plane->normal[2]*plane->normal[2]  ));
	if (length == 0)
	{
		VectorClear(plane->normal);
	}
	else
	{
		plane->normal[0] /= length;
		plane->normal[1] /= length;
		plane->normal[2] /= length;
	}
	plane->dist = DotProduct (p0, plane->normal);
}

void VectorMA (vec3 va, vec scale, vec3 vb, vec3 vc)
{
	vc[0] = va[0] + scale*vb[0];
	vc[1] = va[1] + scale*vb[1];
	vc[2] = va[2] + scale*vb[2];
}

void CrossProduct (vec3 v1, vec3 v2, vec3 cross)
{
	cross[0] = v1[1]*v2[2] - v1[2]*v2[1];
	cross[1] = v1[2]*v2[0] - v1[0]*v2[2];
	cross[2] = v1[0]*v2[1] - v1[1]*v2[0];
}

/*
=============
AllocWinding
=============
*/
MY_WINDING	*AllocWinding (int points)
{
	MY_WINDING	*w;
	int			s;

	s = sizeof(vec)*3*points + sizeof(int);
	w = (MY_WINDING*)malloc (s);
	memset (w, 0, s); 
	return w;
}

vec VectorNormalize (vec3 in, vec3 out)
{
	vec	length, ilength;

	length = (vec)(sqrt (in[0]*in[0] + in[1]*in[1] + in[2]*in[2]));
	if (length == 0)
	{
		VectorClear (out);
		return 0;
	}

	ilength = (vec)1.0/length;
	out[0] = in[0]*ilength;
	out[1] = in[1]*ilength;
	out[2] = in[2]*ilength;

	return length;
}

/*
=================
BaseWindingForPlane
=================
*/
MY_WINDING *BaseWindingForPlane (vec3 normal, vec dist)
{
	int		   i, x;
	vec        max, v;
	vec3       org, vright, vup;
	MY_WINDING *w;

// find the major axis

	max = -BOGUS_RANGE;
	x = -1;
	for (i=0 ; i<3; i++)
	{
		v = (vec)(fabs(normal[i]));
		if (v > max)
		{
			x = i;
			max = v;
		}
	}
	if (x==-1) x = 2;
		
	VectorCopy(vec3_origin,vup);
	switch (x)
	{
	case 0:
	case 1:
		vup[2] = 1;
		break;		
	case 2:
		vup[0] = 1;
		break;		
	}

	v = DotProduct (vup, normal);
	VectorMA (vup, -v, normal, vup);
	VectorNormalize (vup, vup);
		
	VectorScale (normal, dist, org);
	
	CrossProduct (vup, normal, vright);
	
	VectorScale (vup, 65536, vup);
	VectorScale (vright, 65536, vright);

// project a really big	axis aligned box onto the plane
	w = AllocWinding (4);
	
	VectorSubtract (org, vright, w->p[0]);
	VectorAdd (w->p[0], vup, w->p[0]);
	
	VectorAdd (org, vright, w->p[1]);
	VectorAdd (w->p[1], vup, w->p[1]);
	
	VectorAdd (org, vright, w->p[2]);
	VectorSubtract (w->p[2], vup, w->p[2]);
	
	VectorSubtract (org, vright, w->p[3]);
	VectorSubtract (w->p[3], vup, w->p[3]);
	
	w->numpoints = 4;
	
	return w;	
}

void FreeWinding (MY_WINDING *w)
{
	if (*(unsigned *)w == 0xdeaddead)
//		Error ("FreeWinding: freed a freed winding");
		return;
	*(unsigned *)w = 0xdeaddead;

	free (w);
}

/*
=============
ChopWindingInPlace
=============
*/
void ChopWindingInPlace (MY_WINDING **inout, vec3 normal, vec dist, vec epsilon)
{
	MY_WINDING *in;
	vec        dists[MAX_POINTS_ON_WINDING+4];
	int        sides[MAX_POINTS_ON_WINDING+4];
	int        counts[3];
	static vec dot;		// VC 4.2 optimizer bug if not static
	int        i, j;
	vec        *p1, *p2;
	vec3       mid;
	MY_WINDING *f;
	int        maxpts;

	in = *inout;
	counts[0] = counts[1] = counts[2] = 0;

// determine sides for each point
	for (i=0 ; i<in->numpoints ; i++)
	{
		dot = DotProduct (in->p[i], normal);
		dot -= dist;
		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])
	{
		FreeWinding(in);
		*inout = NULL;
		return;
	}
	if (!counts[1])
		return;		// inout stays the same

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

	f = AllocWinding (maxpts);
		
	for (i=0 ; i<in->numpoints ; i++)
	{
		p1 = in->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 = in->p[(i+1)%in->numpoints];
		
		dot = dists[i] / (dists[i]-dists[i+1]);
		for (j=0 ; j<3 ; j++)
		{	// avoid round off error when possible
			if (normal[j] == 1)
				mid[j] = dist;
			else if (normal[j] == -1)
				mid[j] = -dist;
			else
				mid[j] = p1[j] + dot*(p2[j]-p1[j]);
		}
			
		VectorCopy (mid, f->p[f->numpoints]);
		f->numpoints++;
	}
	
//	if (f->numpoints > maxpts)
//		Error ("ClipWinding: points exceeded estimate");
//	if (f->numpoints > MAX_POINTS_ON_WINDING)
//		Error ("ClipWinding: MAX_POINTS_ON_WINDING");

	FreeWinding(in);
	*inout = f;
}

void UseFaceBounds()
{
	LPVOID       vp;
	float        Dot, BestDot;
	float		 planepts[3][3];
	int          BestFace;
	int          i, j;
	int          NumFaces;
	vec3         SurfNormal;
	vec3         vmin,vmax;
	_QERFaceData *QERFaceData;
	PLANE        plane[MAX_FACES*2];
	PLANE        pface;
	MY_WINDING   *w;

	switch(Plane)
	{
	case PLANE_XY1:
		SurfNormal[0] = 0.0;
		SurfNormal[1] = 0.0;
		SurfNormal[2] =-1.0;
		break;
	case PLANE_XZ0:
		SurfNormal[0] = 0.0;
		SurfNormal[1] = 1.0;
		SurfNormal[2] = 0.0;
		break;
	case PLANE_XZ1:
		SurfNormal[0] = 0.0;
		SurfNormal[1] =-1.0;
		SurfNormal[2] = 0.0;
		break;
	case PLANE_YZ0:
		SurfNormal[0] = 1.0;
		SurfNormal[1] = 0.0;
		SurfNormal[2] = 0.0;
		break;
	case PLANE_YZ1:
		SurfNormal[0] =-1.0;
		SurfNormal[1] = 0.0;
		SurfNormal[2] = 0.0;
		break;
	default:
		SurfNormal[0] = 0.0;
		SurfNormal[1] = 0.0;
		SurfNormal[2] = 1.0;
	}

	i  = g_FuncTable.m_pfnAllocateSelectedBrushHandles();
	vp = g_FuncTable.m_pfnGetSelectedBrushHandle(0);
	NumFaces = g_FuncTable.m_pfnGetFaceCount(vp);

	BestFace = -1;
	BestDot  = 0.0;

	for(i=0; i<NumFaces; i++)
	{
		QERFaceData = g_FuncTable.m_pfnGetFaceData(vp,i);
		planepts[0][0] = QERFaceData->m_v1[0];
		planepts[0][1] = QERFaceData->m_v1[1];
		planepts[0][2] = QERFaceData->m_v1[2];
		planepts[1][0] = QERFaceData->m_v2[0];
		planepts[1][1] = QERFaceData->m_v2[1];
		planepts[1][2] = QERFaceData->m_v2[2];
		planepts[2][0] = QERFaceData->m_v3[0];
		planepts[2][1] = QERFaceData->m_v3[1];
		planepts[2][2] = QERFaceData->m_v3[2];

		PlaneFromPoints (planepts[0], planepts[1], planepts[2], &plane[2*i]);
		VectorSubtract (vec3_origin, plane[2*i].normal, plane[2*i+1].normal);
		plane[2*i+1].dist = -plane[2*i].dist;

		Dot = DotProduct(plane[2*i].normal,SurfNormal);
		if(Dot > BestDot)
		{
			BestDot  = Dot;
			BestFace = i;
			if(strlen(QERFaceData->m_TextureName))
				strcpy(Texture[Game][0],QERFaceData->m_TextureName);
		}
	}
	for(i=0; i<NumFaces; i++)
	{
		if(i==BestFace) continue;
		QERFaceData = g_FuncTable.m_pfnGetFaceData(vp,i);
		if(strlen(QERFaceData->m_TextureName))
		{
			if(strcmp(Texture[Game][0],QERFaceData->m_TextureName))
				strcpy(Texture[Game][1],QERFaceData->m_TextureName);
		}
	}


	g_FuncTable.m_pfnReleaseSelectedBrushHandles();

	w = BaseWindingForPlane (plane[BestFace*2].normal, plane[BestFace*2].dist);

	for (i=0 ; i<NumFaces && w; i++)
	{
		if (BestFace == i)
			continue;
		ChopWindingInPlace (&w, plane[i*2+1].normal, plane[i*2+1].dist, 0);
	}
	if(!w) return;

	// Get bounding box for this face
	vmin[0] = vmax[0] = w->p[0][0];
	vmin[1] = vmax[1] = w->p[0][1];
	vmin[2] = vmax[2] = w->p[0][2];
	for(j=1; j<w->numpoints; j++)
	{
		vmin[0] = min(vmin[0],w->p[j][0]);
		vmin[1] = min(vmin[1],w->p[j][1]);
		vmin[2] = min(vmin[2],w->p[j][2]);
		vmax[0] = max(vmax[0],w->p[j][0]);
		vmax[1] = max(vmax[1],w->p[j][1]);
		vmax[2] = max(vmax[2],w->p[j][2]);
	}

	FreeWinding(w);

	VectorCopy(plane[BestFace*2].normal,pface.normal);
	pface.dist = plane[BestFace*2].dist;
	switch(Plane)
	{
	case PLANE_XZ0:
	case PLANE_XZ1:
		if(pface.normal[1] == 0.) return;
		Hll = vmin[0];
		Hur = vmax[0];
		Vll = vmin[2];
		Vur = vmax[2];
		Z00 = (pface.dist - pface.normal[0]*Hll - pface.normal[2]*Vll)/pface.normal[1];
		Z01 = (pface.dist - pface.normal[0]*Hll - pface.normal[2]*Vur)/pface.normal[1];
		Z10 = (pface.dist - pface.normal[0]*Hur - pface.normal[2]*Vll)/pface.normal[1];
		Z11 = (pface.dist - pface.normal[0]*Hur - pface.normal[2]*Vur)/pface.normal[1];
		break;
	case PLANE_YZ0:
	case PLANE_YZ1:
		if(pface.normal[0] == 0.) return;
		Hll = vmin[1];
		Hur = vmax[1];
		Vll = vmin[2];
		Vur = vmax[2];
		Z00 = (pface.dist - pface.normal[1]*Hll - pface.normal[2]*Vll)/pface.normal[0];
		Z01 = (pface.dist - pface.normal[1]*Hll - pface.normal[2]*Vur)/pface.normal[0];
		Z10 = (pface.dist - pface.normal[1]*Hur - pface.normal[2]*Vll)/pface.normal[0];
		Z11 = (pface.dist - pface.normal[1]*Hur - pface.normal[2]*Vur)/pface.normal[0];
		break;
	default:
		if(pface.normal[2] == 0.) return;
		Hll = vmin[0];
		Hur = vmax[0];
		Vll = vmin[1];
		Vur = vmax[1];
		Z00 = (pface.dist - pface.normal[0]*Hll - pface.normal[1]*Vll)/pface.normal[2];
		Z01 = (pface.dist - pface.normal[0]*Hll - pface.normal[1]*Vur)/pface.normal[2];
		Z10 = (pface.dist - pface.normal[0]*Hur - pface.normal[1]*Vll)/pface.normal[2];
		Z11 = (pface.dist - pface.normal[0]*Hur - pface.normal[1]*Vur)/pface.normal[2];
	}
}