cpArbiter.h

/* Copyright (c) 2007 Scott Lembcke
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */


typedef cpBool (*cpCollisionBeginFunc)(cpArbiter *arb, cpSpace *space, void *data);
typedef cpBool (*cpCollisionPreSolveFunc)(cpArbiter *arb, cpSpace *space, void *data);
typedef void (*cpCollisionPostSolveFunc)(cpArbiter *arb, cpSpace *space, void *data);
typedef void (*cpCollisionSeparateFunc)(cpArbiter *arb, cpSpace *space, void *data);

struct cpCollisionHandler {
  cpCollisionType a;
  cpCollisionType b;
  cpCollisionBeginFunc begin;
  cpCollisionPreSolveFunc preSolve;
  cpCollisionPostSolveFunc postSolve;
  cpCollisionSeparateFunc separate;
  void *data;
};

typedef struct cpContact cpContact;

#define CP_MAX_CONTACTS_PER_ARBITER 4

typedef enum cpArbiterState {
  // Arbiter is active and its the first collision.
  cpArbiterStateFirstColl,
  // Arbiter is active and its not the first collision.
  cpArbiterStateNormal,
  // Collision has been explicitly ignored.
  // Either by returning false from a begin collision handler or calling cpArbiterIgnore().
  cpArbiterStateIgnore,
  // Collison is no longer active. A space will cache an arbiter for up to cpSpace.collisionPersistence more steps.
  cpArbiterStateCached,
} cpArbiterState;

struct cpArbiterThread {
  // Links to next and previous arbiters in the contact graph.
  struct cpArbiter *next, *prev;
};

struct cpArbiter {
  cpFloat e;
  cpFloat u;
  cpVect surface_vr;
  
  CP_PRIVATE(cpShape *a);
  CP_PRIVATE(cpShape *b);
  CP_PRIVATE(cpBody *body_a);
  CP_PRIVATE(cpBody *body_b);
  
  CP_PRIVATE(struct cpArbiterThread thread_a);
  CP_PRIVATE(struct cpArbiterThread thread_b);
  
  CP_PRIVATE(int numContacts);
  CP_PRIVATE(cpContact *contacts);
  
  CP_PRIVATE(cpTimestamp stamp);
  CP_PRIVATE(cpCollisionHandler *handler);
  CP_PRIVATE(cpBool swappedColl);
  CP_PRIVATE(cpArbiterState state);
};

#define CP_DefineArbiterStructGetter(type, member, name) \
static inline type cpArbiterGet##name(const cpArbiter *arb){return arb->member;}

#define CP_DefineArbiterStructSetter(type, member, name) \
static inline void cpArbiterSet##name(cpArbiter *arb, type value){arb->member = value;}

#define CP_DefineArbiterStructProperty(type, member, name) \
CP_DefineArbiterStructGetter(type, member, name) \
CP_DefineArbiterStructSetter(type, member, name)

CP_DefineArbiterStructProperty(cpFloat, e, Elasticity);
CP_DefineArbiterStructProperty(cpFloat, u, Friction);
CP_DefineArbiterStructProperty(cpVect, surface_vr, SurfaceVelocity);

cpVect cpArbiterTotalImpulse(const cpArbiter *arb);
cpVect cpArbiterTotalImpulseWithFriction(const cpArbiter *arb);
cpFloat cpArbiterTotalKE(const cpArbiter *arb);


void cpArbiterIgnore(cpArbiter *arb);

static inline void cpArbiterGetShapes(const cpArbiter *arb, cpShape **a, cpShape **b)
{
  if(arb->CP_PRIVATE(swappedColl)){
    (*a) = arb->CP_PRIVATE(b), (*b) = arb->CP_PRIVATE(a);
  } else {
    (*a) = arb->CP_PRIVATE(a), (*b) = arb->CP_PRIVATE(b);
  }
}
#define CP_ARBITER_GET_SHAPES(arb, a, b) cpShape *a, *b; cpArbiterGetShapes(arb, &a, &b);

static inline void cpArbiterGetBodies(const cpArbiter *arb, cpBody **a, cpBody **b)
{
  CP_ARBITER_GET_SHAPES(arb, shape_a, shape_b);
  (*a) = shape_a->body;
  (*b) = shape_b->body;
}
#define CP_ARBITER_GET_BODIES(arb, a, b) cpBody *a, *b; cpArbiterGetBodies(arb, &a, &b);

static inline cpBool cpArbiterIsFirstContact(const cpArbiter *arb)
{
  return arb->CP_PRIVATE(state) == cpArbiterStateFirstColl;
}

static inline int cpArbiterGetCount(const cpArbiter *arb)
{
  return arb->CP_PRIVATE(numContacts);
}

typedef struct cpContactPointSet {
  int count;
  
  struct {
    cpVect point;
    cpVect normal;
    cpFloat dist;
  } points[CP_MAX_CONTACTS_PER_ARBITER];
} cpContactPointSet;
cpContactPointSet cpArbiterGetContactPointSet(const cpArbiter *arb);

cpVect cpArbiterGetNormal(const cpArbiter *arb, int i);
cpVect cpArbiterGetPoint(const cpArbiter *arb, int i);
cpFloat cpArbiterGetDepth(const cpArbiter *arb, int i);