JME基础教程代码分析8 碰撞
package com.hello;
import com.jme3.app.SimpleApplication;
import com.jme3.collision.CollisionResult;
import com.jme3.collision.CollisionResults;
import com.jme3.font.BitmapText;
import com.jme3.input.KeyInput;
import com.jme3.input.controls.ActionListener;
import com.jme3.input.controls.KeyTrigger;
import com.jme3.input.controls.MouseButtonTrigger;
import com.jme3.material.Material;
import com.jme3.math.ColorRGBA;
import com.jme3.math.Ray;
import com.jme3.math.Vector3f;
import com.jme3.scene.Geometry;
import com.jme3.scene.Node;
import com.jme3.scene.shape.Box;
import com.jme3.scene.shape.Sphere;
/** Sample 8 - how to let the user pick (select) objects in the scene
* using the mouse or key presses. Can be used for shooting, opening doors, etc. */
public class HelloPicking extends SimpleApplication {
public static void main(String[] args) {
HelloPicking app = new HelloPicking();
app.start();
}
Node shootables;
Geometry mark;
@Override
public void simpleInitApp() {
initCrossHairs(); // a "+" in the middle of the screen to help aiming
initKeys(); // load custom key mappings
initMark(); // a red sphere to mark the hit
/** create four colored boxes and a floor to shoot at: */
//用一个节点加载了4个Cube，一个地板对象
shootables = new Node("Shootables");
rootNode.attachChild(shootables);
shootables.attachChild(makeCube("a Dragon", -2f, 0f, 1f));
shootables.attachChild(makeCube("a tin can", 1f,-2f, 0f));
shootables.attachChild(makeCube("the Sheriff", 0f, 1f,-2f));
shootables.attachChild(makeCube("the Deputy", 1f, 0f,-4f));
shootables.attachChild(makeFloor());
}
/** Declaring the "Shoot" action and mapping to its triggers. */
//发射动作监听
private void initKeys() {
inputManager.addMapping("Shoot",
new KeyTrigger(KeyInput.KEY_SPACE), // trigger 1: spacebar
new MouseButtonTrigger(0)); // trigger 2: left-button click
inputManager.addListener(actionListener, "Shoot");
}
/** Defining the "Shoot" action: Determine what was hit and how to respond. */
private ActionListener actionListener = new ActionListener() {
@Override
public void onAction(String name, boolean keyPressed, float tpf) {
if (name.equals("Shoot") && !keyPressed) {
// 1. Reset results list.
//碰撞结果集
CollisionResults results = new CollisionResults();
// 2. Aim the ray from cam loc to cam direction.
//从cam位置到cam瞄准的目标的射线
Ray ray = new Ray(cam.getLocation(), cam.getDirection());
// 3. Collect intersections between Ray and Shootables in results list.
//收集shootables节点和射线之间碰撞的结果集列表，这是节点操作概念的体现之一。
shootables.collideWith(ray, results);
// 4. Print the results.
//后台打印了结果集
System.out.println("----- Collisions? " + results.size() + "-----");
for (int i = 0; i < results.size(); i++) {
// For each hit, we know distance, impact point, name of geometry.
float dist = results.getCollision(i).getDistance();
Vector3f pt = results.getCollision(i).getContactPoint();
String hit = results.getCollision(i).getGeometry().getName();
System.out.println("* Collision #" + i);
System.out.println(" You shot " + hit + " at " + pt + ", " + dist + " wu away.");
}
// 5. Use the results (we mark the hit object)
//结果集中有焦点就把红球设置在最近碰撞点的位置上
if (results.size() > 0){
// The closest collision point is what was truly hit:
CollisionResult closest = results.getClosestCollision();
// Let's interact - we mark the hit with a red dot.
mark.setLocalTranslation(closest.getContactPoint());
rootNode.attachChild(mark);
} else {
// No hits? Then remove the red mark.
rootNode.detachChild(mark);
}
}
}
};
/** A cube object for target practice */
protected Geometry makeCube(String name, float x, float y, float z) {
Box box = new Box(new Vector3f(x, y, z), 1, 1, 1);
Geometry cube = new Geometry(name, box);
Material mat1 = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md");
mat1.setColor("Color", ColorRGBA.randomColor());
cube.setMaterial(mat1);
return cube;
}
/** A floor to show that the "shot" can go through several objects. */
protected Geometry makeFloor() {
Box box = new Box(new Vector3f(0,-4,-5), 15,.2f,15);
Geometry floor = new Geometry("the Floor", box);
Material mat1 = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md");
mat1.setColor("Color", ColorRGBA.Gray);
floor.setMaterial(mat1);
return floor;
}
/** A red ball that marks the last spot that was "hit" by the "shot". */
protected void initMark() {
Sphere sphere = new Sphere(30, 30, 0.2f);
mark = new Geometry("BOOM!", sphere);
Material mark_mat = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md");
mark_mat.setColor("Color", ColorRGBA.Red);
mark.setMaterial(mark_mat);
}
/** A centred plus sign to help the player aim. */
protected void initCrossHairs() {
guiNode.detachAllChildren();
guiFont = assetManager.loadFont("Interface/Fonts/Default.fnt");
BitmapText ch = new BitmapText(guiFont, false);
ch.setSize(guiFont.getCharSet().getRenderedSize() * 2);
ch.setText("+"); // crosshairs
ch.setLocalTranslation( // center
settings.getWidth()/2 - guiFont.getCharSet().getRenderedSize()/3*2,
settings.getHeight()/2 + ch.getLineHeight()/2, 0);
guiNode.attachChild(ch);
}
}