cpConstraint.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 struct cpConstraintClass cpConstraintClass;

typedef void (*cpConstraintPreStepImpl)(cpConstraint *constraint, cpFloat dt);
typedef void (*cpConstraintApplyCachedImpulseImpl)(cpConstraint *constraint, cpFloat dt_coef);
typedef void (*cpConstraintApplyImpulseImpl)(cpConstraint *constraint);
typedef cpFloat (*cpConstraintGetImpulseImpl)(cpConstraint *constraint);

struct cpConstraintClass {
  cpConstraintPreStepImpl preStep;
  cpConstraintApplyCachedImpulseImpl applyCachedImpulse;
  cpConstraintApplyImpulseImpl applyImpulse;
  cpConstraintGetImpulseImpl getImpulse;
};

typedef void (*cpConstraintPreSolveFunc)(cpConstraint *constraint, cpSpace *space);
typedef void (*cpConstraintPostSolveFunc)(cpConstraint *constraint, cpSpace *space);


struct cpConstraint {
  CP_PRIVATE(const cpConstraintClass *klass);
  
  cpBody *a;
  cpBody *b;
  
  CP_PRIVATE(cpSpace *space);
  
  CP_PRIVATE(cpConstraint *next_a);
  CP_PRIVATE(cpConstraint *next_b);
  
  cpFloat maxForce;
  cpFloat errorBias;
  cpFloat maxBias;
  
  cpConstraintPreSolveFunc preSolve;
  
  cpConstraintPostSolveFunc postSolve;
  
  cpDataPointer data;
};

void cpConstraintDestroy(cpConstraint *constraint);
void cpConstraintFree(cpConstraint *constraint);

static inline void cpConstraintActivateBodies(cpConstraint *constraint)
{
  cpBody *a = constraint->a; if(a) cpBodyActivate(a);
  cpBody *b = constraint->b; if(b) cpBodyActivate(b);
}

#define CP_DefineConstraintStructGetter(type, member, name) \
static inline type cpConstraint##Get##name(const cpConstraint *constraint){return constraint->member;}

#define CP_DefineConstraintStructSetter(type, member, name) \
static inline void cpConstraint##Set##name(cpConstraint *constraint, type value){ \
  cpConstraintActivateBodies(constraint); \
  constraint->member = value; \
}

#define CP_DefineConstraintStructProperty(type, member, name) \
CP_DefineConstraintStructGetter(type, member, name) \
CP_DefineConstraintStructSetter(type, member, name)

CP_DefineConstraintStructGetter(cpBody*, a, A);
CP_DefineConstraintStructGetter(cpBody*, b, B);
CP_DefineConstraintStructProperty(cpFloat, maxForce, MaxForce);
CP_DefineConstraintStructProperty(cpFloat, errorBias, ErrorBias);
CP_DefineConstraintStructProperty(cpFloat, maxBias, MaxBias);
CP_DefineConstraintStructProperty(cpConstraintPreSolveFunc, preSolve, PreSolveFunc);
CP_DefineConstraintStructProperty(cpConstraintPostSolveFunc, postSolve, PostSolveFunc);
CP_DefineConstraintStructProperty(cpDataPointer, data, UserData);

// Get the last impulse applied by this constraint.
static inline cpFloat cpConstraintGetImpulse(cpConstraint *constraint)
{
  return constraint->CP_PRIVATE(klass)->getImpulse(constraint);
}


#define cpConstraintCheckCast(constraint, struct) \
  cpAssertHard(constraint->CP_PRIVATE(klass) == struct##GetClass(), "Constraint is not a "#struct)

#define CP_DefineConstraintGetter(struct, type, member, name) \
static inline type struct##Get##name(const cpConstraint *constraint){ \
  cpConstraintCheckCast(constraint, struct); \
  return ((struct *)constraint)->member; \
}

#define CP_DefineConstraintSetter(struct, type, member, name) \
static inline void struct##Set##name(cpConstraint *constraint, type value){ \
  cpConstraintCheckCast(constraint, struct); \
  cpConstraintActivateBodies(constraint); \
  ((struct *)constraint)->member = value; \
}

#define CP_DefineConstraintProperty(struct, type, member, name) \
CP_DefineConstraintGetter(struct, type, member, name) \
CP_DefineConstraintSetter(struct, type, member, name)

#include "cpPinJoint.h"
#include "cpSlideJoint.h"
#include "cpPivotJoint.h"
#include "cpGrooveJoint.h"
#include "cpDampedSpring.h"
#include "cpDampedRotarySpring.h"
#include "cpRotaryLimitJoint.h"
#include "cpRatchetJoint.h"
#include "cpGearJoint.h"
#include "cpSimpleMotor.h"