我在这个游戏中的相机跟随y轴和角色的x轴我只希望它跟随y轴

Question

我试过改变'worldMap.draw（playerPositionX，playerPositionY）;' 'worldMap.draw（playerPositionX，0）;'但后来我的家伙只是不能跳一切正常，但我希望相机只跟随字符的x轴这是使用slick2d库

package lib;

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

public class Play extends BasicGameState {

Animation Player, movingLeft, movingRight, notMoving, notMoving1;
Image worldMap;
boolean quit = false;
boolean isJumping = false;
int[] duration = { 200, 200, 200, 200, 200, 200, 200 };

float playerPositionX = 0;
float playerPositionY = 0;
float shiftX = playerPositionX + 384;
float shiftY = playerPositionY + 384;

//gameplay constants, adjust these to get desired behaviour
final float JUMP_VELOCITY = 20.0f;
final float JUMP_BOOST = 1.0f;
final float GRAVITY = 0.1f;

float velocityY = 0;

public Play(int state) {

}

public void init(GameContainer gc, StateBasedGame sbg)
        throws SlickException {
    worldMap = new Image("res/worldMap.png");
    Image[] walkLeft = { new Image("res/playerL1.png"),
            new Image("res/playerL2.png"), new Image("res/playerL3.png"),
            new Image("res/playerL4.png"), new Image("res/playerL5.png"),
            new Image("res/playerL6.png"), new Image("res/playerL7.png") };
    Image[] walkRight = { new Image("res/playerR1.png"),
            new Image("res/playerR2.png"), new Image("res/playerR3.png"),
            new Image("res/playerR4.png"), new Image("res/playerR5.png"),
            new Image("res/playerR6.png"), new Image("res/playerR7.png") };
    Image[] stopWalking = { new Image("res/playerR1.png"),
            new Image("res/playerR1.png"), new Image("res/playerR1.png"),
            new Image("res/playerR1.png"), new Image("res/playerR1.png"),
            new Image("res/playerR1.png"), new Image("res/playerR1.png") };
    Image[] stopWalking1 = { new Image("res/playerL1.png"),
            new Image("res/playerL1.png"), new Image("res/playerL1.png"),
            new Image("res/playerL1.png"), new Image("res/playerL1.png"),
            new Image("res/playerL1.png"), new Image("res/playerL1.png") };
    movingLeft = new Animation(walkLeft, duration, false);
    movingRight = new Animation(walkRight, duration, false);
    notMoving = new Animation(stopWalking, duration, false);
    notMoving1 = new Animation(stopWalking1, duration, false);
    Player = notMoving;

}

public void render(GameContainer gc, StateBasedGame sbg, Graphics g)
        throws SlickException {
    worldMap.draw(playerPositionX,playerPositionY);
    Player.draw(shiftX, shiftY);

    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 {
    Player.update(delta);
    Input input = gc.getInput();
    String lastKeyPressed = null;

    if (input.isKeyDown(Input.KEY_W)) {
        if (!isJumping) {
            velocityY = JUMP_VELOCITY;
            isJumping = true;
            playerPositionY += velocityY*delta * .1f;
        } 
    }

    if (isJumping) {
        playerPositionY += velocityY * delta * .1f;
        velocityY -= delta * GRAVITY;

        if (playerPositionY <=0.0f) { //this checks for collision with the ground
            isJumping = false;
            playerPositionY = 0.0f;
        }
    }

    if (input.isKeyDown(Input.KEY_A)) {
        Player = movingLeft;
        playerPositionX += delta * .1f;
        lastKeyPressed = "A";
    }

    if (input.isKeyDown(Input.KEY_D)) {
        Player = movingRight;
        playerPositionX -= delta * .1f;
        lastKeyPressed = "D";
    }

    if ((lastKeyPressed == "A")
            && (!input.isKeyDown(Input.KEY_A) && (!input
                    .isKeyDown(Input.KEY_D)))) {
        Player = notMoving1;
    }

    if ((lastKeyPressed == "D")
            && (!input.isKeyDown(Input.KEY_A) && (!input
                    .isKeyDown(Input.KEY_D)))) {
        Player = notMoving;
    }

    if (input.isKeyDown(Input.KEY_ESCAPE)) {
        quit = true;
    }

    if (quit == true) {
        if (input.isKeyDown(Input.KEY_R)) {
            quit = false;
        }
        if (input.isKeyDown(Input.KEY_M)) {
            sbg.enterState(0);
        }
        if (input.isKeyDown(Input.KEY_Q)) {
            System.exit(0);
        }
    }
}

public int getID() {
    return 1;
}

}