2 * Copyright (C) 2008 Patrik Gornicz, Gornicz_P (at) hotmail (dot) com.
4 * This program is free software: you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation, either version 3 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program. If not, see <http://www.gnu.org/licenses/>.
18 #include "collisionManager.h"
23 #include "Entities/Ball.h"
24 #include "Entities/PhysicsEntity.h"
26 #include "CollisionInfo.h"
28 /// ***** Private Class Header *****
30 /// ***** Private Method Headers *****
33 void placeEntity(PhysicsEntity* p);
34 void updateEntities();
36 void applyCollision(PhysicsEntity* p1, PhysicsEntity* p2);
37 void applyCollision(Ball* b1, Ball* b2);
39 bool getInfo(Ball* b1, Ball* b2, CollisionInfo* cInfo);
41 /// ***** Private Variables *****
43 const int xDivisions = 20;
44 const int yDivisions = 16;
46 setPhys divisions[xDivisions][yDivisions];
48 /// ***** Initializers/Cleaners *****
50 void collision::init()
54 void collision::clean()
59 /// ***** Public Methods *****
61 void collision::update(setPhys& sp)
65 for( setPhys::iterator it = sp.begin();
75 /// ***** Private Methods *****
87 divisions[x][y].clear();
92 void placeEntity(PhysicsEntity* p)
94 Ball* b = dynamic_cast<Ball*>(p);
98 DPF(0, "ENTITY TYPE NOT SUPPORTED BY placeEntity()!!");
102 const float& xb = b->positionRaw().x;
103 const float& yb = b->positionRaw().y;
104 const float& rad = b->radius;
106 for( int x = (int)(xb - rad);
110 if(x < 0 || xDivisions <= x)
113 for( int y = (int)(yb - rad);
117 if(y < 0 || yDivisions <= y)
120 divisions[x][y].insert(p);
125 void updateEntities()
135 for( setPhys::iterator it1 = divisions[x][y].begin();
136 it1 != divisions[x][y].end();
139 for( setPhys::iterator it2 = divisions[x][y].begin();
140 it2 != divisions[x][y].end();
145 applyCollision(*it1, *it2);
153 void applyCollision(PhysicsEntity* p1, PhysicsEntity* p2)
155 Ball* b1 = dynamic_cast<Ball*>(p1);
156 Ball* b2 = dynamic_cast<Ball*>(p2);
158 if( b1 != NULL && b2 != NULL )
160 applyCollision(b1, b2);
164 DPF(0, "ENTITY TYPE NOT SUPPORTED BY applyCollision()!!");
167 void applyCollision(Ball* b1, Ball* b2)
171 if(!getInfo(b1, b2, &cInfo))
174 // a few values to simplify the equations
175 const Vector2& normal = cInfo.normal;
176 const Vector2& point = cInfo.point;
181 float e = (b1->CoR + b2->CoR) / 2;
183 Vector2 v1 = b1->velocityRaw();
184 Vector2 v2 = b2->velocityRaw();
187 float iTop = -(e + 1) * (v1 - v2).dot(normal);
189 // otherwise the collision happened and we do the math the below assumes
190 // collisions have no friction
192 float impulse = iTop / (normal.dot(normal) * (1 / m1 + 1 / m2));
194 b1->applyImpulse(impulse / m1 * normal, point);
195 b2->applyImpulse(-impulse / m2 * normal, point);
198 bool getInfo(Ball* b1, Ball* b2, CollisionInfo* pcInfo)
200 // a few values to simplify the equations
201 float r1 = b1->radius;
202 float r2 = b2->radius;
204 Vector2 p1 = b1->positionRaw();
205 Vector2 p2 = b2->positionRaw();
206 Vector2 v1 = b1->velocityRaw();
207 Vector2 v2 = b2->velocityRaw();
209 // quick binding box check
210 if (p1.x - r1 > p2.x + r2
211 || p1.x + r1 < p2.x - r2
212 || p1.y - r1 > p2.y + r2
213 || p1.y + r1 < p2.y - r2)
216 // test if not touching
217 if ((p1 - p2).sqrLength() >= (r1 + r2)*(r1 + r2))
220 // test if they are moving apart in some way if they aren't it's likely
221 // that they collided last frame and are still overlapping
223 if ((v1 - v2).dot(p1 - p2) >= 0)
226 pcInfo->point = p1 - (p1 - p2) * r1 / (r1 + r2);
227 pcInfo->normal = p1 - p2;