/** 创建多边形物体 */
private void createBody() {
// 定义物体的形状是多边形形状
PolygonShape shape = new PolygonShape();
shape.set(vecs, edge);
// 设置多边形物体的一些固定的物理属性
FixtureDef fd = new FixtureDef();
fd.shape = shape;
// 固定设置参数
fd.density = 5.0f; // 密度
fd.friction = 0.3f; // 摩擦系数
fd.restitution = restitution; // 恢复系数
BodyDef bd = new BodyDef();
bd.position.set(x, y);
bd.type = BodyType.DYNAMIC;
bd.angle = angle;
bd.allowSleep = true;
bd.setAwake(true);
// 根据bodyDef创建物体到世界中
body = world.createBody(bd);
// 设置好物体的固定属性
body.createFixture(fd);
}
@Test
public void testIsWoundCorrectly() {
PolygonShape shape = new PolygonShape();
Vec2 lineVertices[] = new Vec2[] {new Vec2(-1.0f, -1.0f), new Vec2(1.0f, 1.0f)};
shape.set(lineVertices, lineVertices.length);
assertFalse(GeometryVerifier.IsWoundCorrectly(shape));
Vec2 boxVertices[] =
new Vec2[] {
new Vec2(0.25f, 0.25f),
new Vec2(-0.25f, 0.25f),
new Vec2(-0.25f, -0.25f),
new Vec2(0.25f, -0.25f)
};
shape.set(boxVertices, boxVertices.length);
assertTrue(GeometryVerifier.IsWoundCorrectly(shape));
Vec2 miswoundBoxVertices[] =
new Vec2[] {
new Vec2(0.25f, -0.25f),
new Vec2(-0.25f, -0.25f),
new Vec2(-0.25f, 0.25f),
new Vec2(0.25f, 0.25f)
};
shape.set(miswoundBoxVertices, miswoundBoxVertices.length);
assertFalse(GeometryVerifier.IsWoundCorrectly(shape));
Vec2 potatoVertices[] =
new Vec2[] {
new Vec2(4.0f, 4.0f),
new Vec2(5.0f, 3.0f),
new Vec2(4.0f, 1.0f),
new Vec2(2.0f, 2.0f),
new Vec2(3.0f, 3.0f),
new Vec2(2.0f, 5.0f)
};
shape.set(potatoVertices, potatoVertices.length);
assertFalse(GeometryVerifier.IsWoundCorrectly(shape));
}
/**
* Create a convex hull from the given array of points. The count must be in the range [3,
* Settings.maxPolygonVertices].
*
* @warning the points may be re-ordered, even if they form a convex polygon
* @warning collinear points are handled but not removed. Collinear points may lead to poor
* stacking behavior.
*/
public final void set(final Vec2[] vertices, final int count) {
set(vertices, count, null, null);
}
/**
* Rozbije objekt. Upravi objekt world tak, ze vymaze triesteny objekt a nahradi ho fragmentami na
* zaklade nastaveneho materialu a clenskych premennych.
*
* @param dt casova dlzka framu
*/
public void smash(float dt) {
if (contact == null) { // riesi sa staticky prvok, ktory ma priliz maly obsah
b1.setType(BodyType.DYNAMIC);
return;
}
World w = b1.m_world;
Shape s = f1.m_shape;
Polygon p = f1.m_polygon;
if (p == null) {
switch (s.m_type) {
case POLYGON:
PolygonShape ps = (PolygonShape) s;
Vec2[] vertices = ps.m_vertices;
p = new Polygon();
for (int i = 0; i < ps.m_count; ++i) {
p.add(vertices[ps.m_count - i - 1]);
}
break;
case CIRCLE:
CircleShape cs = (CircleShape) s;
p = new Polygon();
float radius = cs.m_radius;
double u = Math.PI * 2 / CIRCLEVERTICES;
radius =
(float) Math.sqrt(u / Math.sin(u))
* radius; // upravim radius tak, aby bola zachovana velkost obsahu
Vec2 center = cs.m_p;
for (int i = 0; i < CIRCLEVERTICES; ++i) {
double j = u * i; // uhol
float sin = (float) Math.sin(j);
float cos = (float) Math.cos(j);
Vec2 v = new Vec2(sin, cos).mulLocal(radius).addLocal(center);
p.add(v);
}
break;
default:
throw new RuntimeException("Dany typ tvaru nepodporuje stiepenie");
}
}
float mConst = f1.m_material.m_rigidity / normalImpulse; // sila v zavislosti na pevnosti telesa
boolean fixA = f1 == contact.m_fixtureA; // true, ak f2 je v objekte contact ako m_fixtureA
float oldAngularVelocity =
fixA ? contact.m_angularVelocity_bodyA : contact.m_angularVelocity_bodyB;
Vec2 oldLinearVelocity = fixA ? contact.m_linearVelocity_bodyA : contact.m_linearVelocity_bodyB;
b1.setAngularVelocity(
(b1.m_angularVelocity - oldAngularVelocity) * mConst + oldAngularVelocity);
b1.setLinearVelocity(
b1.m_linearVelocity.sub(oldLinearVelocity).mulLocal(mConst).addLocal(oldLinearVelocity));
if (!w.isFractured(f2)
&& b2.m_type == BodyType.DYNAMIC
&& !b2.m_fractureTransformUpdate) { // ak sa druhy objekt nerozbija, tak sa jej nahodia
// povodne hodnoty (TREBA MODIFIKOVAT POHYB OBJEKTU,
// KTORY SPOSOBUJE ROZPAD)
oldAngularVelocity =
!fixA ? contact.m_angularVelocity_bodyA : contact.m_angularVelocity_bodyB;
oldLinearVelocity = !fixA ? contact.m_linearVelocity_bodyA : contact.m_linearVelocity_bodyB;
b2.setAngularVelocity(
(b2.m_angularVelocity - oldAngularVelocity) * mConst + oldAngularVelocity);
b2.setLinearVelocity(
b2.m_linearVelocity.sub(oldLinearVelocity).mulLocal(mConst).addLocal(oldLinearVelocity));
b2.setTransform(
b2.m_xf0.p.add(b2.m_linearVelocity.mul(dt)),
b2.m_xf0.q.getAngle()); // osetruje jbox2d od posuvania telesa pri rieseni kolizie
b2.m_fractureTransformUpdate = true;
}
Vec2 localPoint = Transform.mulTrans(b1.m_xf, point);
Vec2 b1Vec = b1.getLinearVelocityFromWorldPoint(point);
Vec2 b2Vec = b2.getLinearVelocityFromWorldPoint(point);
Vec2 localVector = b2Vec.subLocal(b1Vec);
localVector.mulLocal(dt);
Polygon[] fragment;
try {
fragment = m.split(p, localPoint, localVector, normalImpulse); // rodeli to
} catch (RuntimeException ex) {
return;
}
if (fragment.length == 1) { // nerozbilo to na ziadne fragmenty
return;
}
// definuje tela fragmentov - tie maju vsetky rovnaku definiciu (preberaju parametre z povodneho
// objektu)
BodyDef bodyDef = new BodyDef();
bodyDef.position.set(b1.m_xf.p); // pozicia
bodyDef.angle = b1.m_xf.q.getAngle(); // otocenie
bodyDef.fixedRotation = b1.isFixedRotation();
bodyDef.angularDamping = b1.m_angularDamping;
bodyDef.allowSleep = b1.isSleepingAllowed();
FixtureDef fd = new FixtureDef();
fd.friction = f1.m_friction; // trenie
fd.restitution = f1.m_restitution; // odrazivost
fd.isSensor = f1.m_isSensor;
fd.density = f1.m_density;
// odstrani fragmentacne predmety/cele teleso
ArrayList<Fixture> fixtures = new ArrayList<>();
if (f1.m_polygon != null) {
for (Fixture f = b1.m_fixtureList; f != null; f = f.m_next) {
if (f.m_polygon == f1.m_polygon) {
fixtures.add(f);
}
}
} else {
fixtures.add(f1);
}
for (Fixture f : fixtures) {
b1.destroyFixture(f);
}
if (b1.m_fixtureCount == 0) {
w.destroyBody(b1);
}
// prida fragmenty do simulacie
MyList<Body> newbodies = new MyList<>();
for (Polygon pg : fragment) { // vytvori tela, prida fixtury, poriesi konvexnu dekompoziciu
if (pg.isCorrect()) {
if (pg instanceof Fragment) {
Polygon[] convex = pg.convexDecomposition();
bodyDef.type = BodyType.DYNAMIC;
for (Polygon pgx : convex) {
Body f_body = w.createBody(bodyDef);
pgx.flip();
PolygonShape ps = new PolygonShape();
ps.set(pgx.getArray(), pgx.size());
fd.shape = ps;
fd.polygon = null;
fd.material = f1.m_material.m_fragments; // rekurzivne stiepenie
f_body.createFixture(fd);
f_body.setAngularVelocity(b1.m_angularVelocity);
f_body.setLinearVelocity(b1.getLinearVelocityFromLocalPoint(f_body.getLocalCenter()));
newbodies.add(f_body);
}
} else {
fd.material = f1.m_material.m_fragments; // rekurzivne stiepenie
bodyDef.type = b1.getType();
Body f_body = w.createBody(bodyDef);
PolygonFixture pf = new PolygonFixture(pg);
f_body.createFixture(pf, fd);
f_body.setLinearVelocity(b1.getLinearVelocityFromLocalPoint(f_body.getLocalCenter()));
f_body.setAngularVelocity(b1.m_angularVelocity);
newbodies.add(f_body);
}
}
}
// zavola sa funkcia z fraction listeneru (pokial je nadefinovany)
FractureListener fl = w.getContactManager().m_fractureListener;
if (fl != null) {
fl.action(m, normalImpulse, newbodies);
}
}