| 215 | | /** Determines the side (left, front, ...) of a rigid body with a box |
| 216 | | * collision shape that has a given contact point. |
| 217 | | * \param body The rigid body (box shape). |
| 218 | | * \param contact_point The contact point (in local coordinates) of the |
| 219 | | * contact point. |
| 220 | | */ |
| 221 | | Physics::CollisionSide Physics::getCollisionSide(const btRigidBody *body, |
| 222 | | const Vec3 &contact_point) |
| 223 | | { |
| 224 | | if(contact_point.getX()>0) |
| 225 | | return COL_RIGHT; |
| 226 | | else |
| 227 | | return COL_LEFT; |
| 228 | | |
| 229 | | btVector3 aabb_min, aabb_max; |
| 230 | | static btTransform zero_trans(btQuaternion(0, 0, 0)); |
| 231 | | body->getCollisionShape()->getAabb(zero_trans, aabb_min, aabb_max); |
| 232 | | btVector3 extend = 0.5f*(aabb_max - aabb_min); |
| 233 | | |
| 234 | | CollisionSide result = COL_LEFT; |
| 235 | | if(contact_point.getX()>0) // --> right side |
| 236 | | { |
| 237 | | if(contact_point.getZ()>0) // --> front or right side |
| 238 | | { |
| 239 | | result = fabsf(extend.getX() - contact_point.getX()) < |
| 240 | | fabsf(extend.getZ() - contact_point.getZ()) ? COL_RIGHT |
| 241 | | : COL_FRONT; |
| 242 | | } |
| 243 | | else // getZ()<0 --> back or right side |
| 244 | | { |
| 245 | | result = fabsf( extend.getX() - contact_point.getX()) < |
| 246 | | fabsf( extend.getZ() + contact_point.getZ()) ? COL_RIGHT |
| 247 | | : COL_BACK; |
| 248 | | } |
| 249 | | } |
| 250 | | else // getX() < 0 --> left side |
| 251 | | { |
| 252 | | if(contact_point.getZ()>0) // --> front or left side |
| 253 | | { |
| 254 | | result = fabsf(extend.getX() + contact_point.getX()) < |
| 255 | | fabsf(extend.getZ() - contact_point.getZ()) ? COL_LEFT |
| 256 | | : COL_FRONT; |
| 257 | | } |
| 258 | | else // --> back or left side |
| 259 | | { |
| 260 | | result = fabsf(extend.getX() + contact_point.getX()) < |
| 261 | | fabsf(extend.getZ() + contact_point.getZ()) ? COL_LEFT |
| 262 | | : COL_BACK; |
| 263 | | } |
| 264 | | } |
| 265 | | |
| 266 | | return result; |
| 267 | | } // getCollisionSide |
| 268 | | |
| 269 | | //----------------------------------------------------------------------------- |
