如何讓我的角色在Java中跳躍？

Question

我在YouTube上觀看新波士頓的教程，所以現在我正在創建「Bucky's Land」。這段代碼目前可以讓我的角色左右移動，上下移動。它根據他如何移動來改變玩家的側面。我是java的初學者，我想知道如何讓我的角色跳躍。任何幫助，將不勝感激！

package javagame; 

import org.newdawn.slick.*; 
import org.newdawn.slick.state.*; 

public class Play extends BasicGameState{ 

Animation bucky, movingUp, movingDown, movingLeft, movingRight; 
Image worldMap; 
boolean quit = false; 
int[] duration = {200,200}; 
float buckyPositionX = 0; 
float buckyPositionY = 0; 
float shiftX = buckyPositionX + 320; 
float shiftY = buckyPositionY + 160; 
boolean jumping = false; 
float verticalSpeed = 0.0f; 

public Play(int state){ 
} 

public void init(GameContainer gc, StateBasedGame sbg) throws SlickException{ 
    worldMap = new Image("res/world.png"); 
     Image[] walkUp = {new Image("res/buckysBack.png"), new Image("res/buckysBack.png")}; 
     Image[] walkDown = {new Image("res/buckysFront.png"), new Image("res/buckysFront.png")}; 
     Image[] walkLeft = {new Image("res/buckysLeft.png"), new Image("res/buckysLeft.png")}; 
     Image[] walkRight = {new Image("res/buckysRight.png"), new Image("res/buckysRight.png")}; 

     movingUp = new Animation(walkUp, duration, false); 
     movingDown = new Animation(walkDown, duration, false); 
     movingLeft = new Animation(walkLeft, duration, false); 
     movingRight = new Animation(walkRight, duration, false); 
     bucky = movingDown; 
    } 

public void render(GameContainer gc, StateBasedGame sbg, Graphics g) throws SlickException{ 
    worldMap.draw(buckyPositionX, buckyPositionY); 
    bucky.draw(shiftX, shiftY); 
    g.drawString("Buckys X: "+buckyPositionX+"\nBuckys Y: "+buckyPositionY, 400, 20); 

    if(quit==true){ 
     g.drawString("Resume (R)", 250, 100); 
     g.drawString("Main Menu (M)", 250, 150); 
     g.drawString("Quit Game (Q)", 250, 200); 
     if(quit==false){ 
      g.clear(); 
     } 
    } 
} 

public void update(GameContainer gc, StateBasedGame sbg, int delta) throws SlickException{ 
    Input input = gc.getInput(); 
    if(input.isKeyDown(Input.KEY_UP)){ 
     bucky = movingUp; //change bucky to up image 
     buckyPositionY += delta * .1f; //increase the Y coordinates of bucky (move him up) 
     if(buckyPositionY>162){ 
      buckyPositionY -= delta * .1f; //dont let him keep going up if he reaches the top 
     } 
     } 
     if(input.isKeyDown(Input.KEY_DOWN)){ 
     bucky = movingDown; 
     buckyPositionY -= delta * .1f; 
     if(buckyPositionY<-600){ 
      buckyPositionY += delta * .1f; 
     } 
     } 
     if(input.isKeyDown(Input.KEY_LEFT)){ 
     bucky = movingLeft; 
     buckyPositionX += delta * .1f; 
     if(buckyPositionX>324){ 
      buckyPositionX -= delta * .1f; 
     } 
     } 
     if(input.isKeyDown(Input.KEY_RIGHT)){ 
     bucky = movingRight; 
     buckyPositionX -= delta * .1f; 
     if(buckyPositionX<-840){ 
      buckyPositionX += delta * .1f; 
     } 
     } 
     //when they hit escape 
     if(quit==true){ 
     if(input.isKeyDown(Input.KEY_R)){ 
      quit = false; 
     } 
     if(input.isKeyDown(Input.KEY_M)){ 
      sbg.enterState(0); 
      try{ 
       Thread.sleep(250); 
      }catch(InterruptedException e){ 
       e.printStackTrace(); 
      } 
     } 
     if(input.isKeyDown(Input.KEY_Q)){ 
      System.exit(0); 

     } 
    } 
} 

public int getID(){ 
    return 1; 
    } 
} 

Answer 1

你需要一點物理知識。這個想法是，例如當有人按空格鍵時，你將字符的速度設置爲例如5。每秒你減去1並將其加到角色的高度，直到他再次擊中地面。你可能也想限制速度到（5，-5）