static void
add_box(cpSpace *space)
{
const cpFloat size = 10.0f;
const cpFloat mass = 1.0f;
cpVect verts[] = {
cpv(-size,-size),
cpv(-size, size),
cpv( size, size),
cpv( size,-size),
};
cpFloat radius = cpvlength(cpv(size, size));
cpVect pos = rand_pos(radius);
cpBody *body = cpSpaceAddBody(space, cpBodyNew(mass, cpMomentForPoly(mass, 4, verts, cpvzero, 0.0f)));
body->velocity_func = planetGravityVelocityFunc;
cpBodySetPosition(body, pos);
// Set the box's velocity to put it into a circular orbit from its
// starting position.
cpFloat r = cpvlength(pos);
cpFloat v = cpfsqrt(gravityStrength / r) / r;
cpBodySetVelocity(body, cpvmult(cpvperp(pos), v));
// Set the box's angular velocity to match its orbital period and
// align its initial angle with its position.
cpBodySetAngularVelocity(body, v);
cpBodySetAngle(body, cpfatan2(pos.y, pos.x));
cpShape *shape = cpSpaceAddShape(space, cpPolyShapeNew(body, 4, verts, cpTransformIdentity, 0.0));
cpShapeSetElasticity(shape, 0.0f);
cpShapeSetFriction(shape, 0.7f);
}
void PhysicsBody::setAngularVelocity(float velocity)
{
if (!_dynamic)
{
CCLOG("physics warning: your can't set angular velocity for a static body.");
return;
}
cpBodySetAngularVelocity(_cpBody, velocity);
}
void RigidBody2D::CopyBodyData(cpBody* from, cpBody* to)
{
cpBodySetAngle(to, cpBodyGetAngle(from));
cpBodySetAngularVelocity(to, cpBodyGetAngularVelocity(from));
cpBodySetCenterOfGravity(to, cpBodyGetCenterOfGravity(from));
cpBodySetForce(to, cpBodyGetForce(from));
cpBodySetPosition(to, cpBodyGetPosition(from));
cpBodySetTorque(to, cpBodyGetTorque(from));
cpBodySetVelocity(to, cpBodyGetVelocity(from));
}
void RigidBody2D::CopyBodyData(cpBody* body)
{
cpBodySetAngle(m_handle, cpBodyGetAngle(body));
cpBodySetAngularVelocity(m_handle, cpBodyGetAngularVelocity(body));
cpBodySetCenterOfGravity(m_handle, cpBodyGetCenterOfGravity(body));
cpBodySetForce(m_handle, cpBodyGetForce(body));
cpBodySetPosition(m_handle, cpBodyGetPosition(body));
cpBodySetTorque(m_handle, cpBodyGetTorque(body));
cpBodySetVelocity(m_handle, cpBodyGetVelocity(body));
}
static int l_physics_setBodyAngularVelocity(lua_State* state)
{
l_tools_checkUserDataPlusErrMsg(state, 1, "You must provide a body");
l_physics_Body* body = (l_physics_Body*)lua_touserdata(state, 1);
float value = l_tools_toNumberOrError(state, 2);
cpBodySetAngularVelocity(body->body, value);
return 0;
}
void Slice::ClipPoly(cpSpace *space, cpShape *shape, cpVect n, cpFloat dist)
{
cpBody *body = cpShapeGetBody(shape);
int count = cpPolyShapeGetCount(shape);
int clippedCount = 0;
cpVect *clipped = (cpVect *)alloca((count + 1)*sizeof(cpVect));
for(int i=0, j=count-1; i<count; j=i, i++){
cpVect a = cpBodyLocalToWorld(body, cpPolyShapeGetVert(shape, j));
cpFloat a_dist = cpvdot(a, n) - dist;
if(a_dist < 0.0){
clipped[clippedCount] = a;
clippedCount++;
}
cpVect b = cpBodyLocalToWorld(body, cpPolyShapeGetVert(shape, i));
cpFloat b_dist = cpvdot(b, n) - dist;
if(a_dist*b_dist < 0.0f){
cpFloat t = cpfabs(a_dist)/(cpfabs(a_dist) + cpfabs(b_dist));
clipped[clippedCount] = cpvlerp(a, b, t);
clippedCount++;
}
}
cpVect centroid = cpCentroidForPoly(clippedCount, clipped);
cpFloat mass = cpAreaForPoly(clippedCount, clipped, 0.0f)*DENSITY;
cpFloat moment = cpMomentForPoly(mass, clippedCount, clipped, cpvneg(centroid), 0.0f);
cpBody *new_body = cpSpaceAddBody(space, cpBodyNew(mass, moment));
cpBodySetPosition(new_body, centroid);
cpBodySetVelocity(new_body, cpBodyGetVelocityAtWorldPoint(body, centroid));
cpBodySetAngularVelocity(new_body, cpBodyGetAngularVelocity(body));
cpTransform transform = cpTransformTranslate(cpvneg(centroid));
cpShape *new_shape = cpSpaceAddShape(space, cpPolyShapeNew(new_body, clippedCount, clipped, transform, 0.0));
// Copy whatever properties you have set on the original shape that are important
cpShapeSetFriction(new_shape, cpShapeGetFriction(shape));
}
static cpSpace *
init(void)
{
// Create a rouge body to control the planet manually.
cpSpace *space = cpSpaceNew();
cpSpaceSetIterations(space, 20);
planetBody = cpSpaceAddBody(space, cpBodyNewKinematic());
cpBodySetAngularVelocity(planetBody, 0.2f);
for(int i=0; i<30; i++){
add_box(space);
}
cpShape *shape = cpSpaceAddShape(space, cpCircleShapeNew(planetBody, 70.0f, cpvzero));
cpShapeSetElasticity(shape, 1.0f);
cpShapeSetFriction(shape, 1.0f);
cpShapeSetFilter(shape, NOT_GRABBABLE_FILTER);
return space;
}
ETERM *body_set_angular_velocity(ETERM *fromp, ETERM *argp) {
// get the args
ETERM *space_refp = erl_element(1, argp);
ETERM *idp = erl_element(2, argp);
ETERM *angular_vel = erl_element(3, argp);
erlmunk_space *s;
int space_id = ERL_REF_NUMBER(space_refp);
HASH_FIND_INT(erlmunk_spaces, &space_id, s);
int body_id = ERL_INT_VALUE(idp);
erlmunk_body *b;
HASH_FIND_INT(s->bodies, &body_id, b);
if (b == NULL)
return NULL;
cpBodySetAngularVelocity(b->body, ERL_FLOAT_VALUE(angular_vel));
// DEBUGF(("body_set_angular_velocity(%f) has succeeded",
// ERL_FLOAT_VALUE(angular_vel)));
return NULL;
}
void RigidBody2D::SetAngularVelocity(float angularVelocity)
{
cpBodySetAngularVelocity(m_handle, ToRadians(angularVelocity));
}
void RigidBody2D::SetAngularVelocity(const RadianAnglef& angularVelocity)
{
cpBodySetAngularVelocity(m_handle, angularVelocity.value);
}
cpSpace *Buoyancy::Init()
{
ChipmunkDemo::Init();
space = cpSpaceNew();
cpSpaceSetIterations(space, 30);
cpSpaceSetGravity(space, cpv(0, -500));
// cpSpaceSetDamping(space, 0.5);
cpSpaceSetSleepTimeThreshold(space, 0.5f);
cpSpaceSetCollisionSlop(space, 0.5f);
cpBody *body, *staticBody = cpSpaceGetStaticBody(space);
cpShape *shape;
// Create segments around the edge of the screen.
shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(-320,-240), cpv(-320,240), 0.0f));
cpShapeSetElasticity(shape, 1.0f);
cpShapeSetFriction(shape, 1.0f);
cpShapeSetFilter(shape, NOT_GRABBABLE_FILTER);
shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(320,-240), cpv(320,240), 0.0f));
cpShapeSetElasticity(shape, 1.0f);
cpShapeSetFriction(shape, 1.0f);
cpShapeSetFilter(shape, NOT_GRABBABLE_FILTER);
shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(-320,-240), cpv(320,-240), 0.0f));
cpShapeSetElasticity(shape, 1.0f);
cpShapeSetFriction(shape, 1.0f);
cpShapeSetFilter(shape, NOT_GRABBABLE_FILTER);
shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(-320,240), cpv(320,240), 0.0f));
cpShapeSetElasticity(shape, 1.0f);
cpShapeSetFriction(shape, 1.0f);
cpShapeSetFilter(shape, NOT_GRABBABLE_FILTER);
{
// Add the edges of the bucket
cpBB bb = cpBBNew(-300, -200, 100, 0);
cpFloat radius = 5.0f;
shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(bb.l, bb.b), cpv(bb.l, bb.t), radius));
cpShapeSetElasticity(shape, 1.0f);
cpShapeSetFriction(shape, 1.0f);
cpShapeSetFilter(shape, NOT_GRABBABLE_FILTER);
shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(bb.r, bb.b), cpv(bb.r, bb.t), radius));
cpShapeSetElasticity(shape, 1.0f);
cpShapeSetFriction(shape, 1.0f);
cpShapeSetFilter(shape, NOT_GRABBABLE_FILTER);
shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(bb.l, bb.b), cpv(bb.r, bb.b), radius));
cpShapeSetElasticity(shape, 1.0f);
cpShapeSetFriction(shape, 1.0f);
cpShapeSetFilter(shape, NOT_GRABBABLE_FILTER);
// Add the sensor for the water.
shape = cpSpaceAddShape(space, cpBoxShapeNew2(staticBody, bb, 0.0));
cpShapeSetSensor(shape, cpTrue);
cpShapeSetCollisionType(shape, 1);
}
{
cpFloat width = 200.0f;
cpFloat height = 50.0f;
cpFloat mass = 0.3*FLUID_DENSITY*width*height;
cpFloat moment = cpMomentForBox(mass, width, height);
body = cpSpaceAddBody(space, cpBodyNew(mass, moment));
cpBodySetPosition(body, cpv(-50, -100));
cpBodySetVelocity(body, cpv(0, -100));
cpBodySetAngularVelocity(body, 1);
shape = cpSpaceAddShape(space, cpBoxShapeNew(body, width, height, 0.0));
cpShapeSetFriction(shape, 0.8f);
}
{
cpFloat width = 40.0f;
cpFloat height = width*2;
cpFloat mass = 0.3*FLUID_DENSITY*width*height;
cpFloat moment = cpMomentForBox(mass, width, height);
body = cpSpaceAddBody(space, cpBodyNew(mass, moment));
cpBodySetPosition(body, cpv(-200, -50));
cpBodySetVelocity(body, cpv(0, -100));
cpBodySetAngularVelocity(body, 1);
shape = cpSpaceAddShape(space, cpBoxShapeNew(body, width, height, 0.0));
cpShapeSetFriction(shape, 0.8f);
}
cpCollisionHandler *handler = cpSpaceAddCollisionHandler(space, 1, 0);
handler->preSolveFunc = (cpCollisionPreSolveFunc)WaterPreSolve;
handler->userData = this;
return space;
}
cpBool Buoyancy::WaterPreSolve(cpArbiter *arb, cpSpace *space, void *ptr)
{
CP_ARBITER_GET_SHAPES(arb, water, poly);
cpBody *body = cpShapeGetBody(poly);
// Get the top of the water sensor bounding box to use as the water level.
cpFloat level = cpShapeGetBB(water).t;
// Clip the polygon against the water level
int count = cpPolyShapeGetCount(poly);
int clippedCount = 0;
#ifdef _MSC_VER
// MSVC is pretty much the only compiler in existence that doesn't support variable sized arrays.
cpVect clipped[10];
#else
cpVect clipped[count + 1];
#endif
for(int i=0, j=count-1; i<count; j=i, i++){
cpVect a = cpBodyLocalToWorld(body, cpPolyShapeGetVert(poly, j));
cpVect b = cpBodyLocalToWorld(body, cpPolyShapeGetVert(poly, i));
if(a.y < level){
clipped[clippedCount] = a;
clippedCount++;
}
cpFloat a_level = a.y - level;
cpFloat b_level = b.y - level;
if(a_level*b_level < 0.0f){
cpFloat t = cpfabs(a_level)/(cpfabs(a_level) + cpfabs(b_level));
clipped[clippedCount] = cpvlerp(a, b, t);
clippedCount++;
}
}
// Calculate buoyancy from the clipped polygon area
cpFloat clippedArea = cpAreaForPoly(clippedCount, clipped, 0.0f);
cpFloat displacedMass = clippedArea*FLUID_DENSITY;
cpVect centroid = cpCentroidForPoly(clippedCount, clipped);
cpDataPointer data = ptr;
DrawPolygon(clippedCount, clipped, 0.0f, RGBAColor(0, 0, 1, 1), RGBAColor(0, 0, 1, 0.1f), data);
DrawDot(5, centroid, RGBAColor(0, 0, 1, 1), data);
cpFloat dt = cpSpaceGetCurrentTimeStep(space);
cpVect g = cpSpaceGetGravity(space);
// Apply the buoyancy force as an impulse.
cpBodyApplyImpulseAtWorldPoint(body, cpvmult(g, -displacedMass*dt), centroid);
// Apply linear damping for the fluid drag.
cpVect v_centroid = cpBodyGetVelocityAtWorldPoint(body, centroid);
cpFloat k = k_scalar_body(body, centroid, cpvnormalize(v_centroid));
cpFloat damping = clippedArea*FLUID_DRAG*FLUID_DENSITY;
cpFloat v_coef = cpfexp(-damping*dt*k); // linear drag
// cpFloat v_coef = 1.0/(1.0 + damping*dt*cpvlength(v_centroid)*k); // quadratic drag
cpBodyApplyImpulseAtWorldPoint(body, cpvmult(cpvsub(cpvmult(v_centroid, v_coef), v_centroid), 1.0/k), centroid);
// Apply angular damping for the fluid drag.
cpVect cog = cpBodyLocalToWorld(body, cpBodyGetCenterOfGravity(body));
cpFloat w_damping = cpMomentForPoly(FLUID_DRAG*FLUID_DENSITY*clippedArea, clippedCount, clipped, cpvneg(cog), 0.0f);
cpBodySetAngularVelocity(body, cpBodyGetAngularVelocity(body)*cpfexp(-w_damping*dt/cpBodyGetMoment(body)));
return cpTrue;
}
void RCPBody::setAngularVelocity(float v)
{
if (mBody) {
cpBodySetAngularVelocity(mBody, v);
}
}
