sv_world.c

3D 游戏界的大牛人 John Carmack 终于放出了 Q3 的源代码

/*
===========================================================================
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
===========================================================================
*/
// world.c -- world query functions

#include "server.h"

/*
================
SV_ClipHandleForEntity

Returns a headnode that can be used for testing or clipping to a
given entity.  If the entity is a bsp model, the headnode will
be returned, otherwise a custom box tree will be constructed.
================
*/
clipHandle_t SV_ClipHandleForEntity( const sharedEntity_t *ent ) {
	if ( ent->r.bmodel ) {
		// explicit hulls in the BSP model
		return CM_InlineModel( ent->s.modelindex );
	}
	if ( ent->r.svFlags & SVF_CAPSULE ) {
		// create a temp capsule from bounding box sizes
		return CM_TempBoxModel( ent->r.mins, ent->r.maxs, qtrue );
	}

	// create a temp tree from bounding box sizes
	return CM_TempBoxModel( ent->r.mins, ent->r.maxs, qfalse );
}



/*
===============================================================================

ENTITY CHECKING

To avoid linearly searching through lists of entities during environment testing,
the world is carved up with an evenly spaced, axially aligned bsp tree.  Entities
are kept in chains either at the final leafs, or at the first node that splits
them, which prevents having to deal with multiple fragments of a single entity.

===============================================================================
*/

typedef struct worldSector_s {
	int		axis;		// -1 = leaf node
	float	dist;
	struct worldSector_s	*children[2];
	svEntity_t	*entities;
} worldSector_t;

#define	AREA_DEPTH	4
#define	AREA_NODES	64

worldSector_t	sv_worldSectors[AREA_NODES];
int			sv_numworldSectors;


/*
===============
SV_SectorList_f
===============
*/
void SV_SectorList_f( void ) {
	int				i, c;
	worldSector_t	*sec;
	svEntity_t		*ent;

	for ( i = 0 ; i < AREA_NODES ; i++ ) {
		sec = &sv_worldSectors[i];

		c = 0;
		for ( ent = sec->entities ; ent ; ent = ent->nextEntityInWorldSector ) {
			c++;
		}
		Com_Printf( "sector %i: %i entities\n", i, c );
	}
}

/*
===============
SV_CreateworldSector

Builds a uniformly subdivided tree for the given world size
===============
*/
worldSector_t *SV_CreateworldSector( int depth, vec3_t mins, vec3_t maxs ) {
	worldSector_t	*anode;
	vec3_t		size;
	vec3_t		mins1, maxs1, mins2, maxs2;

	anode = &sv_worldSectors[sv_numworldSectors];
	sv_numworldSectors++;

	if (depth == AREA_DEPTH) {
		anode->axis = -1;
		anode->children[0] = anode->children[1] = NULL;
		return anode;
	}
	
	VectorSubtract (maxs, mins, size);
	if (size[0] > size[1]) {
		anode->axis = 0;
	} else {
		anode->axis = 1;
	}

	anode->dist = 0.5 * (maxs[anode->axis] + mins[anode->axis]);
	VectorCopy (mins, mins1);	
	VectorCopy (mins, mins2);	
	VectorCopy (maxs, maxs1);	
	VectorCopy (maxs, maxs2);	
	
	maxs1[anode->axis] = mins2[anode->axis] = anode->dist;
	
	anode->children[0] = SV_CreateworldSector (depth+1, mins2, maxs2);
	anode->children[1] = SV_CreateworldSector (depth+1, mins1, maxs1);

	return anode;
}

/*
===============
SV_ClearWorld

===============
*/
void SV_ClearWorld( void ) {
	clipHandle_t	h;
	vec3_t			mins, maxs;

	Com_Memset( sv_worldSectors, 0, sizeof(sv_worldSectors) );
	sv_numworldSectors = 0;

	// get world map bounds
	h = CM_InlineModel( 0 );
	CM_ModelBounds( h, mins, maxs );
	SV_CreateworldSector( 0, mins, maxs );
}


/*
===============
SV_UnlinkEntity

===============
*/
void SV_UnlinkEntity( sharedEntity_t *gEnt ) {
	svEntity_t		*ent;
	svEntity_t		*scan;
	worldSector_t	*ws;

	ent = SV_SvEntityForGentity( gEnt );

	gEnt->r.linked = qfalse;

	ws = ent->worldSector;
	if ( !ws ) {
		return;		// not linked in anywhere
	}
	ent->worldSector = NULL;

	if ( ws->entities == ent ) {
		ws->entities = ent->nextEntityInWorldSector;
		return;
	}

	for ( scan = ws->entities ; scan ; scan = scan->nextEntityInWorldSector ) {
		if ( scan->nextEntityInWorldSector == ent ) {
			scan->nextEntityInWorldSector = ent->nextEntityInWorldSector;
			return;
		}
	}

	Com_Printf( "WARNING: SV_UnlinkEntity: not found in worldSector\n" );
}


/*
===============
SV_LinkEntity

===============
*/
#define MAX_TOTAL_ENT_LEAFS		128
void SV_LinkEntity( sharedEntity_t *gEnt ) {
	worldSector_t	*node;
	int			leafs[MAX_TOTAL_ENT_LEAFS];
	int			cluster;
	int			num_leafs;
	int			i, j, k;
	int			area;
	int			lastLeaf;
	float		*origin, *angles;
	svEntity_t	*ent;

	ent = SV_SvEntityForGentity( gEnt );

	if ( ent->worldSector ) {
		SV_UnlinkEntity( gEnt );	// unlink from old position
	}

	// encode the size into the entityState_t for client prediction
	if ( gEnt->r.bmodel ) {
		gEnt->s.solid = SOLID_BMODEL;		// a solid_box will never create this value
	} else if ( gEnt->r.contents & ( CONTENTS_SOLID | CONTENTS_BODY ) ) {
		// assume that x/y are equal and symetric
		i = gEnt->r.maxs[0];
		if (i<1)
			i = 1;
		if (i>255)
			i = 255;

		// z is not symetric
		j = (-gEnt->r.mins[2]);
		if (j<1)
			j = 1;
		if (j>255)
			j = 255;

		// and z maxs can be negative...
		k = (gEnt->r.maxs[2]+32);
		if (k<1)
			k = 1;
		if (k>255)
			k = 255;

		gEnt->s.solid = (k<<16) | (j<<8) | i;
	} else {
		gEnt->s.solid = 0;
	}

	// get the position
	origin = gEnt->r.currentOrigin;
	angles = gEnt->r.currentAngles;

	// set the abs box
	if ( gEnt->r.bmodel && (angles[0] || angles[1] || angles[2]) ) {
		// expand for rotation
		float		max;
		int			i;

		max = RadiusFromBounds( gEnt->r.mins, gEnt->r.maxs );
		for (i=0 ; i<3 ; i++) {
			gEnt->r.absmin[i] = origin[i] - max;
			gEnt->r.absmax[i] = origin[i] + max;
		}
	} else {
		// normal
		VectorAdd (origin, gEnt->r.mins, gEnt->r.absmin);	
		VectorAdd (origin, gEnt->r.maxs, gEnt->r.absmax);
	}

	// because movement is clipped an epsilon away from an actual edge,
	// we must fully check even when bounding boxes don't quite touch
	gEnt->r.absmin[0] -= 1;
	gEnt->r.absmin[1] -= 1;
	gEnt->r.absmin[2] -= 1;
	gEnt->r.absmax[0] += 1;
	gEnt->r.absmax[1] += 1;
	gEnt->r.absmax[2] += 1;

	// link to PVS leafs
	ent->numClusters = 0;
	ent->lastCluster = 0;
	ent->areanum = -1;
	ent->areanum2 = -1;

	//get all leafs, including solids
	num_leafs = CM_BoxLeafnums( gEnt->r.absmin, gEnt->r.absmax,
		leafs, MAX_TOTAL_ENT_LEAFS, &lastLeaf );

	// if none of the leafs were inside the map, the
	// entity is outside the world and can be considered unlinked
	if ( !num_leafs ) {
		return;
	}

	// set areas, even from clusters that don't fit in the entity array
	for (i=0 ; i<num_leafs ; i++) {
		area = CM_LeafArea (leafs[i]);
		if (area != -1) {
			// doors may legally straggle two areas,
			// but nothing should evern need more than that
			if (ent->areanum != -1 && ent->areanum != area) {
				if (ent->areanum2 != -1 && ent->areanum2 != area && sv.state == SS_LOADING) {
					Com_DPrintf ("Object %i touching 3 areas at %f %f %f\n",
					gEnt->s.number,
					gEnt->r.absmin[0], gEnt->r.absmin[1], gEnt->r.absmin[2]);
				}
				ent->areanum2 = area;
			} else {
				ent->areanum = area;
			}
		}
	}

	// store as many explicit clusters as we can
	ent->numClusters = 0;
	for (i=0 ; i < num_leafs ; i++) {
		cluster = CM_LeafCluster( leafs[i] );
		if ( cluster != -1 ) {
			ent->clusternums[ent->numClusters++] = cluster;
			if ( ent->numClusters == MAX_ENT_CLUSTERS ) {
				break;
			}
		}
	}

	// store off a last cluster if we need to
	if ( i != num_leafs ) {
		ent->lastCluster = CM_LeafCluster( lastLeaf );
	}

	gEnt->r.linkcount++;

	// find the first world sector node that the ent's box crosses
	node = sv_worldSectors;
	while (1)
	{
		if (node->axis == -1)
			break;
		if ( gEnt->r.absmin[node->axis] > node->dist)
			node = node->children[0];
		else if ( gEnt->r.absmax[node->axis] < node->dist)
			node = node->children[1];
		else