コード例 #1
0
  public double energy() {
    double dx, dy, dz, distance;
    double e = 0.0;

    for (int i = 0; i < bodies.length; ++i) {
      Body iBody = bodies[i];
      e +=
          0.5
              * iBody.getMass()
              * (iBody.getVX() * iBody.getVX()
                  + iBody.getVY() * iBody.getVY()
                  + iBody.getVZ() * iBody.getVZ());

      for (int j = i + 1; j < bodies.length; ++j) {
        Body jBody = bodies[j];
        dx = iBody.getX() - jBody.getX();
        dy = iBody.getY() - jBody.getY();
        dz = iBody.getZ() - jBody.getZ();

        distance = Math.sqrt(dx * dx + dy * dy + dz * dz);
        e -= (iBody.getMass() * jBody.getMass()) / distance;
      }
    }
    return e;
  }
コード例 #2
0
  public void advance(final double dt) {

    for (int i = 0; i < bodies.length; ++i) {
      Body iBody = bodies[i];

      for (int j = i + 1; j < bodies.length; ++j) {
        Body jBody = bodies[j];
        double dx = iBody.getX() - jBody.getX();
        double dy = iBody.getY() - jBody.getY();
        double dz = iBody.getZ() - jBody.getZ();

        double dSquared = dx * dx + dy * dy + dz * dz;
        double distance = Math.sqrt(dSquared);
        double mag = dt / (dSquared * distance);

        iBody.setVX(iBody.getVX() - (dx * jBody.getMass() * mag));
        iBody.setVY(iBody.getVY() - (dy * jBody.getMass() * mag));
        iBody.setVZ(iBody.getVZ() - (dz * jBody.getMass() * mag));

        jBody.setVX(jBody.getVX() + (dx * iBody.getMass() * mag));
        jBody.setVY(jBody.getVY() + (dy * iBody.getMass() * mag));
        jBody.setVZ(jBody.getVZ() + (dz * iBody.getMass() * mag));
      }
    }

    for (Body body : bodies) {
      body.setX(body.getX() + dt * body.getVX());
      body.setY(body.getY() + dt * body.getVY());
      body.setZ(body.getZ() + dt * body.getVZ());
    }
  }
コード例 #3
0
 /**
  * Fires the weapon, if it has passed it's cooldown interval.
  *
  * @param body the body of the firing entity.
  */
 public void fire(Body body, EntityType whoFired) {
   if (System.currentTimeMillis() - lastFireTime >= FIRE_INTERVAL) {
     lastFireTime = System.currentTimeMillis();
     Bullet bullet = new Bullet(whoFired);
     bullet.body.setPos(body.getX(), body.getY());
     bullet.body.setVectorX(0);
     if (whoFired == EntityType.PLAYER) {
       bullet.body.setVectorY(10);
     } else {
       bullet.body.setVectorY(-10);
     }
     EntityManager.addBullet(bullet);
   }
 }
コード例 #4
0
ファイル: WorldTest.java プロジェクト: skolotienko/notreal2d
  @Test
  public void testMovement() throws Exception {
    int iterationCountPerStep = Defaults.ITERATION_COUNT_PER_STEP;
    int stepCountPerTimeUnit = 10;

    World world = new World(iterationCountPerStep, stepCountPerTimeUnit);

    Body body = new Body();
    body.setForm(new CircularForm(1.0D));
    body.setMass(1.0D);
    world.addBody(body);

    body.setPosition(0.0D, 0.0D);
    body.setVelocity(1.0D, 0.0D);

    for (int i = 1; i <= 1000; ++i) {
      world.proceed();
      Assert.assertEquals(
          "Simple movement. Illegal 'x' after step " + i + '.',
          0.1D * i,
          body.getX(),
          world.getEpsilon());
      Assert.assertEquals(
          "Simple movement. Illegal 'y' after step " + i + '.',
          0.0D,
          body.getY(),
          world.getEpsilon());
    }

    body.setPosition(0.0D, 0.0D);
    body.setVelocity(1.0D, 0.0D);
    body.setMovementFrictionFactor(0.1D);

    double expectedPositionX = 0.0D;
    double expectedVelocityX = 1.0D;

    for (int i = 1; i <= 1000; ++i) {
      for (int j = 0; j < stepCountPerTimeUnit; ++j) {
        expectedPositionX += 0.01D * expectedVelocityX;
        expectedVelocityX = max(expectedVelocityX - 0.001D, 0.0D);
      }

      world.proceed();
      Assert.assertEquals(
          "Movement with ground friction. Illegal 'x' after step " + i + '.',
          expectedPositionX,
          body.getX(),
          world.getEpsilon());
      Assert.assertEquals(
          "Movement with ground friction. Illegal 'y' after step " + i + '.',
          0.0D,
          body.getY(),
          world.getEpsilon());
    }

    body.setPosition(0.0D, 0.0D);
    body.setVelocity(1.0D, 0.0D);
    body.setMovementFrictionFactor(0.0D);
    body.setMovementAirFrictionFactor(0.1D);

    expectedPositionX = 0.0D;
    expectedVelocityX = 1.0D;

    for (int i = 1; i <= 1000; ++i) {
      for (int j = 0; j < stepCountPerTimeUnit; ++j) {
        expectedPositionX += 0.01D * expectedVelocityX;
        expectedVelocityX *= pow(1.0D - 0.1D, 0.01D);
      }

      world.proceed();
      Assert.assertEquals(
          "Movement with air friction. Illegal 'x' after step " + i + '.',
          expectedPositionX,
          body.getX(),
          world.getEpsilon());
      Assert.assertEquals(
          "Movement with air friction. Illegal 'y' after step " + i + '.',
          0.0D,
          body.getY(),
          world.getEpsilon());
    }
  }