java为什么我不能移动我的角色？

Question

我正在尝试制作一个角色可以向上（而不是跳跃）、向左、向右和向下移动的游戏。我是lwjgl的新手，所以如果您发现任何其他错误，或者您有任何建议给我，请不要犹豫

我的代码：

public class Player {

public float x, y, xspeed, yspeed, delta;
public long lastFrame;

public Player(){

    x=350;
    y=250;
    xspeed=1;
    }

public void drawPlayer(Texture tex, float x, float y, float width, float height) {
    this.x=x;
    this.y=y;
    tex.bind();

    glPushMatrix();

    glTranslatef(x,y,0);
    glBegin(GL_QUADS);
    glTexCoord2f(0,0);
    glVertex2f(0,0);
    glTexCoord2f(1,0);
    glVertex2f(width,0);
    glTexCoord2f(1,1);
    glVertex2f(width,height);
    glTexCoord2f(0,1);
    glVertex2f(0,height);
    glEnd();
    glLoadIdentity();
 }

public void playerMovement(){


    while(Keyboard.next()){

        float delta= getDelta();

        if(Keyboard.isKeyDown(Keyboard.KEY_D))
        xspeed = Math.max(-5, xspeed-1); 
        xspeed*=0.9;


        if (Keyboard.getEventKey()==Keyboard.KEY_W && Keyboard.getEventKeyState())
            x++;
            xspeed=Math.min(5, xspeed+1);

        if (Keyboard.getEventKey()==Keyboard.KEY_A && Keyboard.getEventKeyState())
            x++;
            xspeed=Math.min(5, xspeed+1);

        if (Keyboard.getEventKey()==Keyboard.KEY_S && Keyboard.getEventKeyState())
            x++;
            xspeed=Math.min(5, xspeed+1);
    }
  }

public float getDelta(){

    long currentTime= getTime();
    float delta=(float)(currentTime - lastFrame);
    lastFrame=getTime();

    return delta;
}

public long getTime(){

    return (Sys.getTime() *1000 ) / Sys.getTimerResolution();

}

public void update(int xspeed, int yspeed ){

    x+=xspeed;
    y+=yspeed;

 }
}

Answer 1

我要说的是，如果在球员运动中的陈述是没有意义的

   if(Keyboard.isKeyDown(Keyboard.KEY_D))
      xspeed = Math.max(-5, xspeed-1); 
      xspeed*=0.9;

这里，只有第一个赋值取决于键D，而不是乘法。因此，在（！）之后的最后一次X速度分配最后一个if总是“赢”

   if(Keyboard.isKeyDown(Keyboard.KEY_D)) {
      xspeed = Math.max(-5, xspeed-1);
      xspeed*=0.9;
   }

下面的if语句也是如此