我正在使用Libgdx测试最新的Box2d Testbed。看起来他们没有工作，需要知道是否有其他人有同样的问题。第一个叫做传送带，https://github.com/ansman/box2d/blob/master/Testbed/Tests/ConveyorBelt.h
我转换为：
package com.badlogic.gdx.tests.box2d;
import com.badlogic.gdx.InputProcessor;
import com.badlogic.gdx.Input.Keys;
import com.badlogic.gdx.graphics.OrthographicCamera;
import com.badlogic.gdx.math.Vector2;
import com.badlogic.gdx.physics.box2d.Body;
import com.badlogic.gdx.physics.box2d.BodyDef;
import com.badlogic.gdx.physics.box2d.BodyDef.BodyType;
import com.badlogic.gdx.physics.box2d.joints.FrictionJointDef;
import com.badlogic.gdx.physics.box2d.Box2DDebugRenderer;
import com.badlogic.gdx.physics.box2d.Contact;
import com.badlogic.gdx.physics.box2d.EdgeShape;
import com.badlogic.gdx.physics.box2d.Fixture;
import com.badlogic.gdx.physics.box2d.FixtureDef;
import com.badlogic.gdx.physics.box2d.Manifold;
import com.badlogic.gdx.physics.box2d.PolygonShape;
import com.badlogic.gdx.physics.box2d.Transform;
import com.badlogic.gdx.physics.box2d.World;
import com.badlogic.gdx.tests.utils.GdxTest;
public class ConveyorBelt extends Box2DTest {
Body m_body;
Fixture platform;
@Override
protected void createWorld (World world) {
world.setGravity(new Vector2(0, -10));
/** amount of bounce when colliding */
float k_restitution = 0.4f;
Body ground;
{ /** x,y of entire shapes */
BodyDef bd = new BodyDef();
bd.position.set(0, 20);
ground = world.createBody(bd);
PolygonShape shape = new PolygonShape();
shape.setAsEdge(new Vector2(-20.0f, 0.0f), new Vector2(20.0f, 0.0f));
ground.createFixture(shape, 0.0f);
shape.dispose();
}
// Platform
{
BodyDef bd = new BodyDef();
bd.position.set(-5.0f, 5.0f);
Body body = world.createBody(bd);
PolygonShape shape = new PolygonShape();
shape.setAsBox(10.0f, 0.5f);
FixtureDef fd = new FixtureDef();
fd.shape = shape;
fd.friction = 0.8f;
platform = body.createFixture(fd);
}
// Boxes
for (int i = 0; i < 5; ++i)
{
BodyDef bd = new BodyDef();
bd.type = BodyType.DynamicBody;
bd.position.set(-10.0f + 2.0f * i, 7.0f);
Body body = world.createBody(bd);
PolygonShape shape = new PolygonShape();
shape.setAsBox(0.5f, 0.5f);
body.createFixture(shape, 20.0f);
}
}
/* void PreSolve(Contact contact, Manifold oldManifold)
{
Test extends PreSolve(contact, oldManifold);
Fixture fixtureA = contact.getFixtureA();
Fixture fixtureB = contact.getFixtureB();
if (fixtureA == platform)
{
contact.setTangentSpeed(5.0f);
}
if (fixtureB == platform)
{
contact.setTangentSpeed(-5.0f);
}
}
void Step(Settings settings)
{
Test extends Step(settings);
}
static Test Create()
{
return new ConveyorBelt;
}
Fixture platform;*/
}
这是通过将其与其他Box2D测试结合使用，但我注意到了一些事情。
Libgdx在其Contact.java类中没有setTangentSpeed方法
设置必须使用org.jbox2d.common导入
无法将测试解析为类型
我也尝试过使用Breakable，https://github.com/ansman/box2d/blob/master/Testbed/Tests/Breakable.h
已转换为
package com.badlogic.gdx.tests.box2d;
import com.badlogic.gdx.math.MathUtils;
import com.badlogic.gdx.math.Vector2;
import com.badlogic.gdx.physics.box2d.Body;
import com.badlogic.gdx.physics.box2d.BodyDef;
import com.badlogic.gdx.physics.box2d.BodyDef.BodyType;
import com.badlogic.gdx.physics.box2d.CircleShape;
import com.badlogic.gdx.physics.box2d.Contact;
import com.badlogic.gdx.physics.box2d.ContactImpulse;
import com.badlogic.gdx.physics.box2d.EdgeShape;
import com.badlogic.gdx.physics.box2d.Fixture;
import com.badlogic.gdx.physics.box2d.FixtureDef;
import com.badlogic.gdx.physics.box2d.PolygonShape;
import com.badlogic.gdx.physics.box2d.World;
import com.badlogic.gdx.physics.box2d.joints.RevoluteJointDef;
import com.badlogic.gdx.backends.gwt.*;
public class Breakable extends Box2DTest {
Body body1;
Vector2 m_velocity;
float m_angularVelocity;
PolygonShape m_shape1;
PolygonShape m_shape2;
Fixture m_piece1;
Fixture m_piece2;
boolean m_broke;
boolean m_break;
/**
* @see org.jbox2d.testbed.framework.TestbedTest#initTest()
*/
@Override
protected void createWorld (World world) {
world.setGravity(new Vector2(0, -10));
Body ground;
// Ground body
{
BodyDef bd = new BodyDef();
ground = world.createBody(bd);
PolygonShape shape = new PolygonShape();
shape.setAsEdge(new Vector2(-40.0f, 0.0f), new Vector2(40.0f, 0.0f));
ground.createFixture(shape, 0.0f);
shape.dispose();
}
// Breakable dynamic body
{
BodyDef bd = new BodyDef();
bd.type = BodyType.DynamicBody;
bd.position.set(0.0f, 40.0f);
bd.angle = 0.25f * MathUtils.PI;
body1 = world.createBody(bd);
m_shape1 = new PolygonShape();
m_shape1.setAsBox(0.5f, 0.5f, new Vector2(-0.5f, 0.0f), 0.0f);
m_piece1 = body1.createFixture(m_shape1, 1.0f);
m_shape2 = new PolygonShape();
m_shape2.setAsBox(0.5f, 0.5f, new Vector2(0.5f, 0.0f), 0.0f);
m_piece2 = body1.createFixture(m_shape2, 1.0f);
}
m_break = false;
m_broke = false;
}
void PostSolve(Contact contact, ContactImpulse impulse)
{
if (m_broke)
{
// The body already broke.
return;
}
// Should the body break?
int count = contact.getManifold().pointCount;
float maxImpulse = 0.0f;
for (int i = 0; i < count; ++i)
{
maxImpulse = MathUtils.max(maxImpulse, impulse.normalImpulses[i]);
}
if (maxImpulse > 40.0f)
{
// Flag the body for breaking.
m_break = true;
}
}
void Break()
{
// Create two bodies from one.
Body body1 = m_piece1.getBody();
Vector2 center = body1.getWorldCenter();
body1.destroyFixture(m_piece2);
m_piece2 = null;
BodyDef bd = new BodyDef();
bd.position = body1.getPosition();
bd.angle = body1.getAngle();
Body body2 = world.createBody(bd);
m_piece2 = body2.createFixture(m_shape2, 1.0f);
}
}
// Compute consistent velocities for new bodies based on
// cached velocity.
Vector2 center1 = body1.getWorldCenter();
Vector2 center2 = body2.getWorldCenter();
Vector2 velocity1 = m_velocity.add(Vector2.crs(m_angularVelocity, center1.sub(center)));
Vector2 velocity2 = m_velocity.add(Vector2.crs(m_angularVelocity, center2.sub(center)));
body1.setAngularVelocity(m_angularVelocity);
body1.setLinearVelocity(velocity1);
body2.setAngularVelocity(m_angularVelocity);
body2.setLinearVelocity(velocity2);
}
void Step(Settings settings)
{
if (m_break)
{
Break();
m_broke = true;
m_break = false;
}
// Cache velocities to improve movement on breakage.
if (m_broke == false)
{
m_velocity = body1.getLinearVelocity();
m_angularVelocity = body1.getAngularVelocity();
}
Test = Step(settings);
}
static Test Create()
{
return new Breakable;
}
Body m_body1;
}
我注意到了：
Libgdx在Manifold.java中没有pointCount。一个快速解决方法是更改为getWorldManifold但没有做任何好的
Vector2.java不包含crs（float x，Vector2 v），其中m_velocity的Vectors不允许
设置不存在，除非我使用com.jbox2d.common import
如果不包含这些方法，如何让它们在Libgdx中运行？ Libgdx不再更新了吗？我想使用这些，但它似乎落后于移植。我甚至在Contact.java中注意到他在setTangentSpeed的代码之前停止了。我已经在我的测试中添加了gwt罐子而没有任何好处。
答案 0 :(得分：0)
如果您需要2.2.1版本的jbox2d，可以从trunk获取版本。它几乎已经准备好发布了，我只需要做一些优化和内联。
编辑：看起来libgdx使用它自己的包装器来实现Box2D的本机C ++实现。这在性能方面绝对是可取的，希望他们会更新他们的库。