com.almasb.fxgl.physics.box2d.dynamics.Fixture Maven / Gradle / Ivy
/*
* FXGL - JavaFX Game Library. The MIT License (MIT).
* Copyright (c) AlmasB ([email protected]).
* See LICENSE for details.
*/
package com.almasb.fxgl.physics.box2d.dynamics;
import com.almasb.fxgl.core.math.Vec2;
import com.almasb.fxgl.physics.HitBox;
import com.almasb.fxgl.physics.box2d.collision.AABB;
import com.almasb.fxgl.physics.box2d.collision.RayCastInput;
import com.almasb.fxgl.physics.box2d.collision.RayCastOutput;
import com.almasb.fxgl.physics.box2d.collision.broadphase.BroadPhase;
import com.almasb.fxgl.physics.box2d.collision.shapes.MassData;
import com.almasb.fxgl.physics.box2d.collision.shapes.Shape;
import com.almasb.fxgl.physics.box2d.collision.shapes.ShapeType;
import com.almasb.fxgl.physics.box2d.common.Transform;
import com.almasb.fxgl.physics.box2d.dynamics.contacts.Contact;
import com.almasb.fxgl.physics.box2d.dynamics.contacts.ContactEdge;
/**
* A fixture is used to attach a shape to a body for collision detection. A fixture inherits its
* transform from its parent. Fixtures hold additional non-geometric data such as friction,
* collision filters, etc. Fixtures are created via Body::CreateFixture.
* Note: you cannot reuse fixtures.
*
* @author daniel
*/
public final class Fixture {
private final Filter filter = new Filter();
private final Body body;
private final Shape shape;
private Object userData;
private HitBox hitBox;
private float density;
private float friction;
private float restitution;
private boolean isSensor;
private FixtureProxy[] proxies;
private int proxyCount = 0;
Fixture(Body body, FixtureDef def) {
this.body = body;
shape = def.getShape().clone();
userData = def.getUserData();
density = def.getDensity();
friction = def.getFriction();
restitution = def.getRestitution();
isSensor = def.isSensor();
filter.set(def.getFilter());
// Reserve proxy space
int childCount = shape.getChildCount();
proxies = new FixtureProxy[childCount];
for (int i = 0; i < childCount; i++) {
proxies[i] = new FixtureProxy();
}
}
/**
* @return the parent body of this fixture
*/
public Body getBody() {
return body;
}
/**
* You can modify the child shape, however you should not change the number
* of vertices because this will crash some collision caching mechanisms.
*
* @return child shape
*/
public Shape getShape() {
return shape;
}
/**
* @return the type of the child shape. You can use this to down cast to the concrete shape.
*/
public ShapeType getType() {
return shape.getType();
}
/**
* @return the contact filtering data
*/
public Filter getFilterData() {
return filter;
}
/**
* Set the contact filtering data.
* This will not update contacts until the next time step when either parent body is awake.
* This automatically calls refilter.
* This is an expensive operation and should not be called frequently.
*
* @param filter filter
*/
public void setFilterData(final Filter filter) {
this.filter.set(filter);
refilter();
}
/**
* The same as in the fixture definition, unless explicitly changed.
* Use this to store your application specific data.
*
* @return user data
*/
public Object getUserData() {
return userData;
}
/**
* Set the user data.
* Use this to store your application specific data.
*
* @param data user data
*/
public void setUserData(Object data) {
userData = data;
}
public HitBox getHitBox() {
return hitBox;
}
public void setHitBox(HitBox hitBox) {
this.hitBox = hitBox;
}
public float getDensity() {
return density;
}
public void setDensity(float density) {
this.density = density;
}
public float getFriction() {
return friction;
}
/**
* This will NOT change the friction of existing contacts.
*/
public void setFriction(float friction) {
this.friction = friction;
}
public float getRestitution() {
return restitution;
}
/**
* This will NOT change the restitution of existing contacts.
*/
public void setRestitution(float restitution) {
this.restitution = restitution;
}
/**
* @return true if the fixture / shape is a sensor (non-solid)
*/
public boolean isSensor() {
return isSensor;
}
/**
* Set if this fixture is a sensor.
*/
public void setSensor(boolean sensor) {
if (sensor != isSensor) {
body.setAwake(true);
isSensor = sensor;
}
}
public int getProxyCount() {
return proxyCount;
}
public int getProxyId(int index) {
return proxies[index].proxyId;
}
/**
* Call this if you want to establish collision that was previously disabled by
* ContactFilter::ShouldCollide.
*/
public void refilter() {
// Flag associated contacts for filtering.
ContactEdge edge = body.getContactList();
while (edge != null) {
Contact contact = edge.contact;
Fixture fixtureA = contact.getFixtureA();
Fixture fixtureB = contact.getFixtureB();
if (fixtureA == this || fixtureB == this) {
contact.flagForFiltering();
}
edge = edge.next;
}
World world = body.getWorld();
if (world == null) {
return;
}
// Touch each proxy so that new pairs may be created
BroadPhase broadPhase = world.getContactManager().broadPhase;
for (int i = 0; i < proxyCount; ++i) {
broadPhase.touchProxy(proxies[i].proxyId);
}
}
/**
* Test a point for containment in this fixture.
* This only works for convex shapes.
*
* @param p a point in world coordinates
*/
public boolean containsPoint(Vec2 p) {
return shape.testPoint(body.m_xf, p);
}
/**
* Cast a ray against this shape.
*
* @param output the ray-cast results
* @param input the ray-cast input parameters
*/
public boolean raycast(RayCastOutput output, RayCastInput input, int childIndex) {
return shape.raycast(output, input, body.m_xf, childIndex);
}
/**
* Get the mass data for this fixture.
* The mass data is based on the density and the shape.
* The rotational inertia is about the shape's origin.
*/
public void getMassData(MassData massData) {
shape.computeMass(massData, density);
}
/**
* This AABB may be enlarged and/or stale.
* If you need a more accurate AABB, compute it using the shape and the body transform.
*
* @return the fixture's AABB
*/
public AABB getAABB(int childIndex) {
return proxies[childIndex].aabb;
}
/**
* Compute the distance from this fixture.
*
* @param p a point in world coordinates.
* @return distance
*/
public float computeDistance(Vec2 p, int childIndex, Vec2 normalOut) {
return shape.computeDistanceToOut(body.getTransform(), p, childIndex, normalOut);
}
// These support body activation/deactivation.
void createProxies(BroadPhase broadPhase, final Transform xf) {
// Create proxies in the broad-phase.
proxyCount = shape.getChildCount();
for (int i = 0; i < proxyCount; ++i) {
FixtureProxy proxy = proxies[i];
shape.computeAABB(proxy.aabb, xf, i);
proxy.proxyId = broadPhase.createProxy(proxy.aabb, proxy);
proxy.fixture = this;
proxy.childIndex = i;
}
}
void destroyProxies(BroadPhase broadPhase) {
// Destroy proxies in the broad-phase.
for (int i = 0; i < proxyCount; ++i) {
FixtureProxy proxy = proxies[i];
broadPhase.destroyProxy(proxy.proxyId);
proxy.proxyId = BroadPhase.NULL_PROXY;
}
proxyCount = 0;
}
private final AABB pool1 = new AABB();
private final AABB pool2 = new AABB();
private final Vec2 displacement = new Vec2();
void synchronize(BroadPhase broadPhase, Transform transform1, Transform transform2) {
if (proxyCount == 0) {
return;
}
for (int i = 0; i < proxyCount; ++i) {
FixtureProxy proxy = proxies[i];
// Compute an AABB that covers the swept shape (may miss some rotation effect).
AABB aabb1 = pool1;
AABB aabb2 = pool2;
shape.computeAABB(aabb1, transform1, proxy.childIndex);
shape.computeAABB(aabb2, transform2, proxy.childIndex);
proxy.aabb.combine(aabb1, aabb2);
displacement.x = transform2.p.x - transform1.p.x;
displacement.y = transform2.p.y - transform1.p.y;
broadPhase.moveProxy(proxy.proxyId, proxy.aabb, displacement);
}
}
// The proxies must be destroyed before calling this.
void destroy() {
proxies = null;
}
/**
* This proxy is used internally to connect fixtures to the broad-phase.
*/
static class FixtureProxy {
final AABB aabb = new AABB();
Fixture fixture = null;
int proxyId = BroadPhase.NULL_PROXY;
int childIndex;
// only we can create these
private FixtureProxy() { }
}
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