static void
make_leg(cpSpace *space, cpFloat side, cpFloat offset, cpBody *chassis, cpBody *crank, cpVect anchor)
{
cpVect a, b;
cpShape *shape;
cpFloat leg_mass = 1.0f;
// make leg
a = cpvzero, b = cpv(0.0f, side);
cpBody *upper_leg = cpSpaceAddBody(space, cpBodyNew(leg_mass, cpMomentForSegment(leg_mass, a, b, 0.0f)));
cpBodySetPosition(upper_leg, cpv(offset, 0.0f));
shape = cpSpaceAddShape(space, cpSegmentShapeNew(upper_leg, a, b, seg_radius));
cpShapeSetFilter(shape, cpShapeFilterNew(1, CP_ALL_CATEGORIES, CP_ALL_CATEGORIES));
cpSpaceAddConstraint(space, cpPivotJointNew2(chassis, upper_leg, cpv(offset, 0.0f), cpvzero));
// lower leg
a = cpvzero, b = cpv(0.0f, -1.0f*side);
cpBody *lower_leg = cpSpaceAddBody(space, cpBodyNew(leg_mass, cpMomentForSegment(leg_mass, a, b, 0.0f)));
cpBodySetPosition(lower_leg, cpv(offset, -side));
shape = cpSpaceAddShape(space, cpSegmentShapeNew(lower_leg, a, b, seg_radius));
cpShapeSetFilter(shape, cpShapeFilterNew(1, CP_ALL_CATEGORIES, CP_ALL_CATEGORIES));
shape = cpSpaceAddShape(space, cpCircleShapeNew(lower_leg, seg_radius*2.0f, b));
cpShapeSetFilter(shape, cpShapeFilterNew(1, CP_ALL_CATEGORIES, CP_ALL_CATEGORIES));
cpShapeSetElasticity(shape, 0.0f);
cpShapeSetFriction(shape, 1.0f);
cpSpaceAddConstraint(space, cpPinJointNew(chassis, lower_leg, cpv(offset, 0.0f), cpvzero));
cpSpaceAddConstraint(space, cpGearJointNew(upper_leg, lower_leg, 0.0f, 1.0f));
cpConstraint *constraint;
cpFloat diag = cpfsqrt(side*side + offset*offset);
constraint = cpSpaceAddConstraint(space, cpPinJointNew(crank, upper_leg, anchor, cpv(0.0f, side)));
cpPinJointSetDist(constraint, diag);
constraint = cpSpaceAddConstraint(space, cpPinJointNew(crank, lower_leg, anchor, cpvzero));
cpPinJointSetDist(constraint, diag);
}
void PhysicsJointDistance::setDistance(float distance)
{
cpPinJointSetDist(_cpConstraints.front(), PhysicsHelper::float2cpfloat(distance));
}
