[LIBGDX学习]LibGDX代码详解（二十一）Box2D 子弹穿透

package com.mygdx.game.box2d;

import com.badlogic.gdx.Input;
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.EdgeShape;
import com.badlogic.gdx.physics.box2d.FixtureDef;
import com.badlogic.gdx.physics.box2d.PolygonShape;
import com.badlogic.gdx.physics.box2d.World;

public class VerticalStack extends Box2DTest {
static final int e_columnCount = 5;
static final int e_rowCount = 16;

Body m_bullet;
Body[] m_bodies = new Body[e_rowCount * e_columnCount];
int[] m_indices = new int[e_rowCount * e_columnCount];

@Override
protected void createWorld (World world) {
{
BodyDef bd = new BodyDef();
Body ground = world.createBody(bd);

EdgeShape shape = new EdgeShape();
shape.set(new Vector2(-40, 0), new Vector2(40, 0));
ground.createFixture(shape, 0.0f);

shape.set(new Vector2(20, 0), new Vector2(20, 20));
ground.createFixture(shape, 0);
shape.dispose();
}

float xs[] = {0, -10, -5, 5, 10};

for (int j = 0; j < e_columnCount; j++) {
PolygonShape shape = new PolygonShape();
shape.setAsBox(0.5f, 0.5f);

FixtureDef fd = new FixtureDef();
fd.shape = shape;
//fd.density = 1.0f;
//fd.friction = 0.3f;
fd.density = 1.0f;
fd.friction = 100f;

for (int i = 0; i < e_rowCount; i++) {
BodyDef bd = new BodyDef();
bd.type = BodyType.DynamicBody;

int n = j * e_rowCount + i;
m_indices
= n;

float x = 0;
//bd.position.set(xs[j] + x, 0.752f + 1.54f * i);
bd.position.set(xs[j] + x, 0.752f + 1.001f * i);
Body body = world.createBody(bd);
body.setUserData(n);// ???

m_bodies
= body;
body.createFixture(fd);

}
shape.dispose();
}

for(Body b:m_bodies){
System.out.print(" "+b.getUserData());// setUserData这样用？
}
System.out.println();

m_bullet = null;
}

// 发射子弹
@Override
public boolean keyDown (int keyCode) {
if (keyCode == Input.Keys.COMMA) {
if (m_bullet != null) {
world.destroyBody(m_bullet);
m_bullet = null;
}

{
CircleShape shape = new CircleShape();
shape.setRadius(0.25f);

FixtureDef fd = new FixtureDef();
fd.shape = shape;
fd.density = 20.0f;
fd.restitution = 0.05f;

BodyDef bd = new BodyDef();
bd.type = BodyType.DynamicBody;
bd.bullet = true;// 精确检测
bd.position.set(-31, 5);

m_bullet = world.createBody(bd);
m_bullet.createFixture(fd);

//m_bullet.setLinearVelocity(new Vector2(400, 0));
m_bullet.setLinearVelocity(new Vector2(1600, 0));
}
}

if (keyCode == Input.Keys.SPACE) {
world.dispose();
world= new World(new Vector2(0, -10), true);
createWorld(world);
}
4000

return false;
}

public void render () {

super.render();

// if (renderer.batch != null) {
// renderer.batch.begin();
// // renderer.batch.drawText(renderer.font, "Press: (,) to launch a bullet", 0, Gdx.app.getGraphics().getHeight(),
// // Color.WHITE);
// renderer.batch.end();
// }
}
}