CollisionRegion.h

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/*
 
CollisionRegion.h
 
Collision regions are used to group entities which may potentially collide, to
reduce the number of collision checks required.
 
Oolite
Copyright (C) 2004-2013 Giles C Williams and contributors
 
This program 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.
 
This program 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 this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
MA 02110-1301, USA.
 
*/
 
#import "OOCocoa.h"
#import "OOMaths.h"
 
 
#define COLLISION_REGION_BORDER_RADIUS  32000.0f
#define COLLISION_MAX_ENTITIES          128
#define MINIMUM_SHADOWING_ENTITY_RADIUS 75.0
 
@class Entity, OOSunEntity;
 
 
@interface CollisionRegion: NSObject
{
@private
    BOOL                isUniverse;         // if YES location is origin and radius is 0.0f
    
    int                 crid;               // identifier
    HPVector                location;           // center of the region
    GLfloat             radius;             // inner radius of the region
    GLfloat             border_radius;      // additiønal, border radius of the region (typically 32km or some value > the scanner range)
 
    unsigned            checks_this_tick;
    unsigned            checks_within_range;
 
    NSMutableArray      *subregions;
    
    BOOL                isPlayerInRegion;
    
    Entity              **entity_array; // entities within the region
    unsigned            n_entities;     // number of entities
    unsigned            max_entities;   // so storage can be expanded
    
    CollisionRegion     *parentRegion;
}
 
- (id) initAsUniverse;
- (id) initAtLocation:(HPVector) locn withRadius:(GLfloat) rad withinRegion:(CollisionRegion*) otherRegion;
 
- (void) clearSubregions;
- (void) addSubregionAtPosition:(HPVector) pos withRadius:(GLfloat) rad;
 
// collision checking
- (void) clearEntityList;
- (void) addEntity:(Entity *)ent;
- (BOOL) checkEntity:(Entity *)ent;
 
- (void) findCollisions;
- (void) findShadowedEntities;
 
// Description for FPS HUD
- (NSString *) collisionDescription;
 
- (NSString *) debugOut;
 
@end
 
/* Given a region centred at e1pos with a radius of e1rad, the depth
 * of shadowing cast by e2 from the_sun is recorded in outValue, with
 * >1 = no shadow, <1 = shadow */
BOOL shadowAtPointOcclusionToValue(HPVector e1pos, GLfloat e1rad, Entity *e2, OOSunEntity *the_sun, float *outValue);