/*
* Chipmunk2d::Constraint#max_bias=(max_bias)
* @param [Float] max_bias
*/
static mrb_value
constraint_set_max_bias(mrb_state *mrb, mrb_value self)
{
cpConstraint *constraint;
mrb_float max_bias;
mrb_get_args(mrb, "f", &max_bias);
constraint = mrb_data_get_ptr(mrb, self, &mrb_cp_constraint_type);
cpConstraintSetMaxBias(constraint, (cpFloat)max_bias);
return mrb_nil_value();
}
void physics_add_top_down_friction(cpBody *body, cpBody *control, float friction, cpConstraint **out_pivot, cpConstraint **out_gear) {
//emulates linear friction
cpConstraint *pivot = cpSpaceAddConstraint(game.space, cpPivotJointNew2(
control,
body,
cpvzero,
cpvzero
));
cpConstraintSetErrorBias(pivot, cpBodyGetMass(body) * friction);
cpConstraintSetMaxForce(pivot, cpBodyGetMass(body) * friction);
//emulates angular friction
cpConstraint *gear = cpSpaceAddConstraint(game.space, cpGearJointNew(
control,
body,
0, 1
));
cpConstraintSetMaxBias(gear, 0);
cpConstraintSetMaxForce(gear, friction / cpBodyGetMass(body) / 10);
if (out_pivot) *out_pivot = pivot;
if (out_gear) *out_gear = gear;
}
static cpSpace *
init(void)
{
ChipmunkDemoMessageString = "Control the crane by moving the mouse. Press the down arrow to release.";
space = cpSpaceNew();
cpSpaceSetIterations(space, 30);
cpSpaceSetGravity(space, cpv(0, -100));
cpSpaceSetDamping(space, 0.8);
cpBody *staticBody = cpSpaceGetStaticBody(space);
cpShape *shape;
shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(-320,-240), cpv(320,-240), 0.0f));
cpShapeSetElasticity(shape, 1.0f);
cpShapeSetFriction(shape, 1.0f);
cpShapeSetLayers(shape, NOT_GRABABLE_MASK);
// Add a body for the dolly.
dollyBody = cpSpaceAddBody(space, cpBodyNew(10, INFINITY));
cpBodySetPos(dollyBody, cpv(0, 100));
// Add a block so you can see it.
cpSpaceAddShape(space, cpBoxShapeNew(dollyBody, 30, 30));
// Add a groove joint for it to move back and forth on.
cpSpaceAddConstraint(space, cpGrooveJointNew(staticBody, dollyBody, cpv(-250, 100), cpv(250, 100), cpvzero));
// Add a pivot joint to act as a servo motor controlling it's position
// By updating the anchor points of the pivot joint, you can move the dolly.
dollyServo = cpSpaceAddConstraint(space, cpPivotJointNew(staticBody, dollyBody, cpBodyGetPos(dollyBody)));
// Max force the dolly servo can generate.
cpConstraintSetMaxForce(dollyServo, 10000);
// Max speed of the dolly servo
cpConstraintSetMaxBias(dollyServo, 100);
// You can also change the error bias to control how it slows down.
//cpConstraintSetErrorBias(dollyServo, 0.2);
// Add the crane hook.
cpBody *hookBody = cpSpaceAddBody(space, cpBodyNew(1, INFINITY));
cpBodySetPos(hookBody, cpv(0, 50));
// Add a sensor shape for it. This will be used to figure out when the hook touches a box.
shape = cpSpaceAddShape(space, cpCircleShapeNew(hookBody, 10, cpvzero));
cpShapeSetSensor(shape, cpTrue);
cpShapeSetCollisionType(shape, HOOK_SENSOR);
// Add a slide joint to act as a winch motor
// By updating the max length of the joint you can make it pull up the load.
winchServo = cpSpaceAddConstraint(space, cpSlideJointNew(dollyBody, hookBody, cpvzero, cpvzero, 0, INFINITY));
// Max force the dolly servo can generate.
cpConstraintSetMaxForce(winchServo, 30000);
// Max speed of the dolly servo
cpConstraintSetMaxBias(winchServo, 60);
// TODO cleanup
// Finally a box to play with
cpBody *boxBody = cpSpaceAddBody(space, cpBodyNew(30, cpMomentForBox(30, 50, 50)));
cpBodySetPos(boxBody, cpv(200, -200));
// Add a block so you can see it.
shape = cpSpaceAddShape(space, cpBoxShapeNew(boxBody, 50, 50));
cpShapeSetFriction(shape, 0.7);
cpShapeSetCollisionType(shape, CRATE);
cpSpaceAddCollisionHandler(space, HOOK_SENSOR, CRATE, (cpCollisionBeginFunc)HookCrate, NULL, NULL, NULL, NULL);
return space;
}
// float SG_CALL sgPhysicsConstraintGetErrorBias(SGPhysicsConstraint* constr);
void SG_CALL sgPhysicsConstraintSetMaxBias(SGPhysicsConstraint* constr, float max)
{
cpConstraintSetMaxBias(constr->handle, max);
}
void CCJoint::setMaxBias(cpFloat maxBias)
{
cpConstraintSetMaxBias(this->m_constraint, maxBias);
}