aas_gsubdiv.c

quakeIII源码这个不用我多说吧

/*
===========================================================================
Copyright (C) 1999-2005 Id Software, Inc.

This file is part of Quake III Arena source code.

Quake III Arena 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 2 of the License,
or (at your option) any later version.

Quake III Arena 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 Foobar; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
===========================================================================
*/

#include "qbsp.h"
#include "../botlib/aasfile.h"
#include "aas_create.h"
#include "aas_store.h"
#include "aas_cfg.h"

#define FACECLIP_EPSILON			0.2
#define FACE_EPSILON					1.0

int numgravitationalsubdivisions = 0;
int numladdersubdivisions = 0;

//NOTE: only do gravitational subdivision BEFORE area merging!!!!!!!
//			because the bsp tree isn't refreshes like with ladder subdivision

//===========================================================================
// NOTE: the original face is invalid after splitting
//
// Parameter:				-
// Returns:					-
// Changes Globals:		-
//===========================================================================
void AAS_SplitFace(tmp_face_t *face, vec3_t normal, float dist,
							tmp_face_t **frontface, tmp_face_t **backface)
{
	winding_t *frontw, *backw;

	//
	*frontface = *backface = NULL;

	ClipWindingEpsilon(face->winding, normal, dist, FACECLIP_EPSILON, &frontw, &backw);

#ifdef DEBUG
	//
	if (frontw)
	{
		if (WindingIsTiny(frontw))
		{
			Log_Write("AAS_SplitFace: tiny back face\r\n");
			FreeWinding(frontw);
			frontw = NULL;
		} //end if
	} //end if
	if (backw)
	{
		if (WindingIsTiny(backw))
		{
			Log_Write("AAS_SplitFace: tiny back face\r\n");
			FreeWinding(backw);
			backw = NULL;
		} //end if
	} //end if
#endif //DEBUG
	//if the winding was split
	if (frontw)
	{
		//check bounds
		(*frontface) = AAS_AllocTmpFace();
		(*frontface)->planenum = face->planenum;
		(*frontface)->winding = frontw;
		(*frontface)->faceflags = face->faceflags;
	} //end if
	if (backw)
	{
		//check bounds
		(*backface) = AAS_AllocTmpFace();
		(*backface)->planenum = face->planenum;
		(*backface)->winding = backw;
		(*backface)->faceflags = face->faceflags;
	} //end if
} //end of the function AAS_SplitFace
//===========================================================================
//
// Parameter:				-
// Returns:					-
// Changes Globals:		-
//===========================================================================
winding_t *AAS_SplitWinding(tmp_area_t *tmparea, int planenum)
{
	tmp_face_t *face;
	plane_t *plane;
	int side;
	winding_t *splitwinding;

	//
	plane = &mapplanes[planenum];
	//create a split winding, first base winding for plane
	splitwinding = BaseWindingForPlane(plane->normal, plane->dist);
	//chop with all the faces of the area
	for (face = tmparea->tmpfaces; face && splitwinding; face = face->next[side])
	{
		//side of the face the original area was on
		side = face->frontarea != tmparea;
		plane = &mapplanes[face->planenum ^ side];
		ChopWindingInPlace(&splitwinding, plane->normal, plane->dist, 0); // PLANESIDE_EPSILON);
	} //end for
	return splitwinding;
} //end of the function AAS_SplitWinding
//===========================================================================
//
// Parameter:				-
// Returns:					-
// Changes Globals:		-
//===========================================================================
int AAS_TestSplitPlane(tmp_area_t *tmparea, vec3_t normal, float dist,
							int *facesplits, int *groundsplits, int *epsilonfaces)
{
	int j, side, front, back, planenum;
	float d, d_front, d_back;
	tmp_face_t *face;
	winding_t *w;

	*facesplits = *groundsplits = *epsilonfaces = 0;

	planenum = FindFloatPlane(normal, dist);

	w = AAS_SplitWinding(tmparea, planenum);
	if (!w) return false;
	FreeWinding(w);
	//
	for (face = tmparea->tmpfaces; face; face = face->next[side])
	{
		//side of the face the area is on
		side = face->frontarea != tmparea;

		if ((face->planenum & ~1) == (planenum & ~1))
		{
			Log_Print("AAS_TestSplitPlane: tried face plane as splitter\n");
			return false;
		} //end if
		w = face->winding;
		//reset distance at front and back side of plane
		d_front = d_back = 0;
		//reset front and back flags
		front = back = 0;
		for (j = 0; j < w->numpoints; j++)
		{
			d = DotProduct(w->p[j], normal) - dist;
			if (d > d_front) d_front = d;
			if (d < d_back) d_back = d;

			if (d > 0.4) // PLANESIDE_EPSILON)
				front = 1;
			if (d < -0.4) // PLANESIDE_EPSILON)
				back = 1;
		} //end for
		//check for an epsilon face
		if ( (d_front > FACECLIP_EPSILON && d_front < FACE_EPSILON)
			|| (d_back < -FACECLIP_EPSILON && d_back > -FACE_EPSILON) )
		{
			(*epsilonfaces)++;
		} //end if
		//if the face has points at both sides of the plane
		if (front && back)
		{
			(*facesplits)++;
			if (face->faceflags & FACE_GROUND)
			{
				(*groundsplits)++;
			} //end if
		} //end if
	} //end for
	return true;
} //end of the function AAS_TestSplitPlane
//===========================================================================
//
// Parameter:				-
// Returns:					-
// Changes Globals:		-
//===========================================================================
void AAS_SplitArea(tmp_area_t *tmparea, int planenum, tmp_area_t **frontarea, tmp_area_t **backarea)
{
	int side;
	tmp_area_t *facefrontarea, *facebackarea, *faceotherarea;
	tmp_face_t *face, *frontface, *backface, *splitface, *nextface;
	winding_t *splitwinding;
	plane_t *splitplane;

/*
#ifdef AW_DEBUG
	int facesplits, groundsplits, epsilonface;
	Log_Print("\n----------------------\n");
	Log_Print("splitting area %d\n", areanum);
	Log_Print("with normal = \'%f %f %f\', dist = %f\n", normal[0], normal[1], normal[2], dist);
	AAS_TestSplitPlane(areanum, normal, dist,
										&facesplits, &groundsplits, &epsilonface);
	Log_Print("face splits = %d\nground splits = %d\n", facesplits, groundsplits);
	if (epsilonface) Log_Print("aaahh epsilon face\n");
#endif //AW_DEBUG*/
	//the original area

	AAS_FlipAreaFaces(tmparea);
	AAS_CheckArea(tmparea);
	//
	splitplane = &mapplanes[planenum];
/*	//create a split winding, first base winding for plane
	splitwinding = BaseWindingForPlane(splitplane->normal, splitplane->dist);
	//chop with all the faces of the area
	for (face = tmparea->tmpfaces; face && splitwinding; face = face->next[side])
	{
		//side of the face the original area was on
		side = face->frontarea != tmparea->areanum;
		plane = &mapplanes[face->planenum ^ side];
		ChopWindingInPlace(&splitwinding, plane->normal, plane->dist, 0); // PLANESIDE_EPSILON);
	} //end for*/
	splitwinding = AAS_SplitWinding(tmparea, planenum);
	if (!splitwinding)
	{
/*
#ifdef DEBUG
		AAS_TestSplitPlane(areanum, normal, dist,
											&facesplits, &groundsplits, &epsilonface);
		Log_Print("\nface splits = %d\nground splits = %d\n", facesplits, groundsplits);
		if (epsilonface) Log_Print("aaahh epsilon face\n");
#endif //DEBUG*/
		Error("AAS_SplitArea: no split winding when splitting area %d\n", tmparea->areanum);
	} //end if
	//create a split face
	splitface = AAS_AllocTmpFace();
	//get the map plane
	splitface->planenum = planenum;
	//store the split winding
	splitface->winding = splitwinding;
	//the new front area
	(*frontarea) = AAS_AllocTmpArea();
	(*frontarea)->presencetype = tmparea->presencetype;
	(*frontarea)->contents = tmparea->contents;
	(*frontarea)->modelnum = tmparea->modelnum;
	(*frontarea)->tmpfaces = NULL;
	//the new back area
	(*backarea) = AAS_AllocTmpArea();
	(*backarea)->presencetype = tmparea->presencetype;
	(*backarea)->contents = tmparea->contents;
	(*backarea)->modelnum = tmparea->modelnum;
	(*backarea)->tmpfaces = NULL;
	//add the split face to the new areas
	AAS_AddFaceSideToArea(splitface, 0, (*frontarea));
	AAS_AddFaceSideToArea(splitface, 1, (*backarea));

	//split all the faces of the original area
	for (face = tmparea->tmpfaces; face; face = nextface)
	{
		//side of the face the original area was on
		side = face->frontarea != tmparea;
		//next face of the original area
		nextface = face->next[side];
		//front area of the face
		facefrontarea = face->frontarea;
		//back area of the face
		facebackarea = face->backarea;
		//remove the face from both the front and back areas
		if (facefrontarea) AAS_RemoveFaceFromArea(face, facefrontarea);
		if (facebackarea) AAS_RemoveFaceFromArea(face, facebackarea);
		//split the face
		AAS_SplitFace(face, splitplane->normal, splitplane->dist, &frontface, &backface);
		//free the original face
		AAS_FreeTmpFace(face);
		//get the number of the area at the other side of the face
		if (side) faceotherarea = facefrontarea;
		else faceotherarea = facebackarea;
		//if there is an area at the other side of the original face
		if (faceotherarea)
		{
			if (frontface) AAS_AddFaceSideToArea(frontface, !side, faceotherarea);
			if (backface) AAS_AddFaceSideToArea(backface, !side, faceotherarea);
		} //end if
		//add the front and back part left after splitting the original face to the new areas
		if (frontface) AAS_AddFaceSideToArea(frontface, side, (*frontarea));
		if (backface) AAS_AddFaceSideToArea(backface, side, (*backarea));
	} //end for

	if (!(*frontarea)->tmpfaces) Log_Print("AAS_SplitArea: front area without faces\n");
	if (!(*backarea)->tmpfaces) Log_Print("AAS_SplitArea: back area without faces\n");

	tmparea->invalid = true;
/*
#ifdef AW_DEBUG
	for (i = 0, face = frontarea->tmpfaces; face; face = face->next[side])
	{
		side = face->frontarea != frontarea->areanum;
		i++;
	} //end for
	Log_Print("created front area %d with %d faces\n", frontarea->areanum, i);

	for (i = 0, face = backarea->tmpfaces; face; face = face->next[side])
	{
		side = face->frontarea != backarea->areanum;
		i++;
	} //end for
	Log_Print("created back area %d with %d faces\n", backarea->areanum, i);
#endif //AW_DEBUG*/

	AAS_FlipAreaFaces((*frontarea));
	AAS_FlipAreaFaces((*backarea));
	//
	AAS_CheckArea((*frontarea));
	AAS_CheckArea((*backarea));
} //end of the function AAS_SplitArea
//===========================================================================
//
// Parameter:				-
// Returns:					-
// Changes Globals:		-
//===========================================================================
int AAS_FindBestAreaSplitPlane(tmp_area_t *tmparea, vec3_t normal, float *dist)
{
	int side1, side2;