jmonkeyengine運動速度太快，無法進行碰撞檢測

我正在使用JMonkeyEngine製作Java遊戲，並且我在他們的網站上按照教程在牆上拍攝了球（子彈）。我知道一切都是如何運作的，但是當我提高子彈的速度時，它會直接穿過牆壁。jmonkeyengine運動速度太快，無法進行碰撞檢測

現在我知道發生這種情況的原因（因爲子彈移動速度太快，每幀衝突到註冊）。我也知道如何解決這個問題，並在他們的網站上找到了以下方法（JMonkeyEngine）。

setCcdMotionThreshold(0f)

但誰能告訴我這是如何實現或在哪裏可以找到使用這個人的樣本？

來源

2013-05-02 heyred

介紹
連續碰撞檢測（CCD）涉及子彈VS紙問題。如果一個快速移動的物體在一個時間步中是一個薄物體的一側，並且在下一個時間步的另一側導致物理引擎相信完全沒有發生碰撞。另一方面，連續碰撞檢測根本不使用時間步驟。它會在時間步的整個時間段內創建一個掃描卷，並查找該掃描卷是否與任何事物發生衝突。這既昂貴又不準確（因爲使用簡單的圓形碰撞形狀而不是完整的碰撞形狀）。

使用
連續碰撞檢測是在每個對象的基本設置，你可以使用CCD，並且在同一時間不要在同一場景中對象的對象，CCD被設置在一個物理對象如下圖所示

RigidBodyControl physicsObject = new RigidBodyControl(mass); 
physicsObject.setCcdMotionThreshold(expectedWidthOfThinObject); 
physicsObject.setCcdSweptSphereRadius(radiusOfSphereThatWillFullyContainObject);

你要設置expectedWidthOfThinObject高達你可以得到遠 ;請記住ccd是昂貴且不準確的。將其設置爲零會變成CCD關閉
你要設置radiusOfSphereThatWillFullyContainObject儘可能小，而完全包含對象

完整的示例
下面的源代碼將展示如何用連續碰撞之間的區別檢測並使用標準碰撞檢測。它發射兩組球，一個快一個慢，並以5秒的間隔打開和關閉ccd。慢速球總是與紙張發生碰撞，只有當ccd打開時纔會發生快速碰撞。

import com.jme3.app.SimpleApplication; 
import com.jme3.bullet.BulletAppState; 
import com.jme3.bullet.control.RigidBodyControl; 
import com.jme3.font.BitmapText; 
import com.jme3.material.Material; 
import com.jme3.math.ColorRGBA; 
import com.jme3.math.Vector3f; 
import com.jme3.scene.Geometry; 
import com.jme3.scene.shape.Box; 
import com.jme3.scene.shape.Sphere; 

public class BulletTest extends SimpleApplication { 

    public static void main(String args[]) { 
    BulletTest app = new BulletTest(); 
    app.start(); 
    } 

    /** Prepare the Physics Application State (jBullet) */ 
    private BulletAppState bulletAppState; 

    /** Prepare Materials */ 
    Material wall_mat; 
    Material slow_mat; 
    Material fast_mat; 
    Material floor_mat; 


    private RigidBodyControl brick_phy; 
    private static final Box box; 
    private static final Sphere sphere; 
    private RigidBodyControl floor_phy; 
    private static final Box floor; 

    /** dimensions used for wall */ 
    private static final float brickLength = 2f; 
    private static final float brickWidth = 0.015f; 
    private static final float brickHeight = 1f; 

    static { 
    /** Initialize the cannon ball geometry */ 
    sphere = new Sphere(32, 32, 0.1f, true, false); 
    /** Initialize the brick geometry */ 
    box = new Box(brickWidth, brickHeight, brickLength); 
    /** Initialize the floor geometry */ 
    floor = new Box(10f, 0.1f, 5f); 

    } 

    @Override 
    public void simpleInitApp() { 
    /** Set up Physics Game */ 
    bulletAppState = new BulletAppState(); 
    stateManager.attach(bulletAppState); 
    //bulletAppState.getPhysicsSpace().enableDebug(assetManager); 

    /** Configure cam to look at scene */ 
    cam.setLocation(new Vector3f(0, 4f, 6f)); 
    cam.lookAt(new Vector3f(2, 2, 0), Vector3f.UNIT_Y); 

    /** Initialize the scene, materials, and physics space */ 
    initMaterials(); 
    initWall(); 
    initFloor(); 
    setUpHUDText(); 
    } 

    public static final float FIREPERIOD=0.5f; 
    double fireTimer=0; 

    public static final float SWEEPPERIOD=5f; 
    double sweepTimer=0; 
    boolean continuouslySweeping=true; 


    @Override 
    public void simpleUpdate(float tpf) { 
     fireTimer+=tpf; 
     sweepTimer+=tpf; 

     if (sweepTimer>SWEEPPERIOD){ 
      sweepTimer=0; 
      continuouslySweeping=!continuouslySweeping; 
     } 

     hudText.setText("ContinouslySweeping=" + continuouslySweeping + "(" + (int)(SWEEPPERIOD-sweepTimer) + ")"); 

     if (fireTimer>FIREPERIOD){ 
      fireTimer=0; 
      makeCannonBall(new Vector3f(-4,3,0),new Vector3f(6,4,0),slow_mat,continuouslySweeping); //slow arcing ball 
      makeCannonBall(new Vector3f(-4,3,-0.5f),new Vector3f(10,1,0),fast_mat,continuouslySweeping); //fast straight ball 
     } 
    } 

    public BitmapText hudText; 

    private void setUpHUDText(){ 
     hudText = new BitmapText(guiFont, false);   
     hudText.setSize(guiFont.getCharSet().getRenderedSize());  // font size 
     hudText.setColor(ColorRGBA.White);        // font color 
     hudText.setText("ContinouslySweeping=true");    // the text 
     hudText.setLocalTranslation(300, hudText.getLineHeight(), 0); // position 
     guiNode.attachChild(hudText); 
    } 

    /** Initialize the materials used in this scene. */ 
    public void initMaterials() { 
    wall_mat = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md"); 
    wall_mat.setColor("Color", ColorRGBA.Blue); 

    fast_mat = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md"); 
    fast_mat.setColor("Color", ColorRGBA.Red); 

    slow_mat = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md"); 
    slow_mat.setColor("Color", ColorRGBA.Green); 

    floor_mat = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md"); 
    floor_mat.setColor("Color", ColorRGBA.Gray); 
    } 

    /** Make a solid floor and add it to the scene. */ 
    public void initFloor() { 
    Geometry floor_geo = new Geometry("Floor", floor); 
    floor_geo.setMaterial(floor_mat); 
    floor_geo.setLocalTranslation(0, -0.1f, 0); 
    this.rootNode.attachChild(floor_geo); 
    /* Make the floor physical with mass 0.0f! */ 
    floor_phy = new RigidBodyControl(0.0f); 
    floor_geo.addControl(floor_phy); 
    bulletAppState.getPhysicsSpace().add(floor_phy); 
    } 

    /** This loop builds a wall out of individual bricks. */ 
    public void initWall() { 

     Vector3f location=new Vector3f(2,2,0); 
     Geometry brick_geo = new Geometry("brick", box); 
     brick_geo.setMaterial(wall_mat); 
     rootNode.attachChild(brick_geo); 
     /** Position the brick geometry */ 
     brick_geo.setLocalTranslation(location); 

     //paper thin objects will fall down, mass 0 clamps it in position 
     brick_phy = new RigidBodyControl(0); 

     /** Add physical brick to physics space. */ 
     brick_geo.addControl(brick_phy); 
     bulletAppState.getPhysicsSpace().add(brick_phy); 
    } 


    public void makeCannonBall(Vector3f startPoint, Vector3f initialVelocity, Material material, boolean continuouslySwept) { 
     /** Create a cannon ball geometry and attach to scene graph. */ 
     Geometry ball_geo = new Geometry("cannon ball", sphere); 
     ball_geo.setMaterial(material); 
     rootNode.attachChild(ball_geo); 
     /** Position the cannon ball */ 
     ball_geo.setLocalTranslation(startPoint); 
     /** Make the ball physcial with a mass > 0.0f */ 
     RigidBodyControl ball_phy = new RigidBodyControl(1f); 
     /** Add physical ball to physics space. */ 
     ball_geo.addControl(ball_phy); 
     bulletAppState.getPhysicsSpace().add(ball_phy); 
     /** Accelerate the physcial ball to shoot it. */ 
     ball_phy.setLinearVelocity(initialVelocity); 

     if (continuouslySwept){ 
      ball_phy.setCcdMotionThreshold(0.015f); 
      ball_phy.setCcdSweptSphereRadius(0.01f); 
     } 

    } 


}

隨着對兩組滾珠連續檢測彈跳如預期（滾珠從左上角的進入）：
enter image description here