我正在尝试制作一个简单的 java 处理游戏，我可以在其中从某个形状射击子弹，但它们似乎没有射击

Question

他我是编码和创建城堡防御游戏的初学者。

我正在尝试在我的代码中添加子弹射击，但我很难将它实施到我的项目中。

这是我想出的用于在 void draw() function 中向下射击子弹的代码

float bulletY = DefenderY; //bullet being set in player x position
  float bulletX= DefenderX; //bullet set in player y postion
  
  
  rect(bulletX, bulletY, 8, 8); //creating the bullet
  text("score: ", countA, 20, 80);    //score counter not implimented yet
  if (keyPressed && key==CODED && key == 's')// if the space bar is pressed //key press detection, 
  {
    dropping = true;     //boolean is now true when previously flase
    
  }
  if(dropping == true){ if (bulletY<=400)    // checking if the bullet is still within the frame
    bulletY= bulletY + 1;} //boolean true then the rectangle should move from the player position
    }
    
    if(bulletY>=400){dropping = false; //when bullet hits game borders reset to player position
    bulletY=DefenderY;
    bulletX=DefenderX;}

但是矩形子弹没有从（DefenderY，DefenderY）position 移动，它与播放器保持连接，将不胜感激，

如果对我的问题有帮助，我还将在下面发布整个代码，谢谢。

class attackers{
float max = 400;
float min = 1;
float posx = (int)Math.floor(Math.random()*(max-min+1)+min);
float posy = 400;
float speed = 1;
}
attackers one, two, three, four;
 
 float DefenderX= 100; 
float DefenderY=100;

void setup()
{
  one = new attackers();
  two = new attackers();
  three = new attackers();
  four = new attackers();
  
  size(400,400); //fairly large relative to objects
  rectMode(CENTER); //set rect x,y to be the centre.
}



float gunX=40;
boolean dropping = false;
int countA = 0;



void draw()
{
  
  
  
  background(#0000FF);  //clear background
  ellipse(DefenderX,DefenderY,20,20);//Draw player  current position (x,y)
  if ( abs(DefenderX - one.posx)<20 && abs(DefenderY-one.posy )<20 ||
       abs(DefenderX - two.posx)<20 && abs(DefenderY-two.posy )<20 ||
       abs(DefenderX - three.posx)<20 && abs(DefenderY-three.posy )<20 ||
       abs(DefenderX - four.posx)<20 && abs(DefenderY-four.posy )<20
  )//are they close together?
  {
   print ("GAMEOVER!");
   
  }
float bulletY = DefenderY;
  float bulletX= DefenderX;
  
  
  rect(bulletX, bulletY, 8, 8);
  text("score: ", countA, 20, 80);
  if (keyPressed && key==CODED && key == 's')// if the space bar is pressed
  {
    dropping = true;
    print("its working");
    if (bulletY<=400)
    bulletY= bulletY + 1;
  }
  if(dropping == true){
    }
    
    if(bulletY>=400){dropping = false;
    bulletY=DefenderY;
    bulletX=DefenderX +30;}
    
  int randomattack, randomattack1, randomattack2, randomattack3;
  
  
   randomattack = (int)Math.floor(Math.random()*(two.max-two.min+1)+two.min);
  ellipse(one.posx,one.posy, 10,10);   //draw ball at current position : x, y fixed at 125!
  one.posy = one.posy - 1;
  
  
  if (abs(one.posy -1 )<1 )
  {one.posy = one.posy+ 400;
  one.posx = randomattack;}
  randomattack1 = (int)Math.floor(Math.random()*(two.max-two.min+1)+two.min);
  
  
ellipse(two.posx,two.posy, 10,10);   //draw ball at current position : x, y fixed at 125!
  two.posy = two.posy - 1;
  if (abs(two.posy -1 )<1 )
  {two.posy = two.posy+ 400;
  two.posx = randomattack1;}
  
  randomattack2 = (int)Math.floor(Math.random()*(two.max-two.min+1)+two.min);
 ellipse(three.posx,three.posy, 10,10);   //draw ball at current position : x, y fixed at 125!
  three.posy = three.posy - 1;
if (abs(three.posy -1 )<1 )
  {three.posy = three.posy+ 400;
  three.posx = randomattack2;}
    
    
randomattack3 = (int)Math.floor(Math.random()*(one.max-one.min+1)+one.min);
 ellipse(four.posx,four.posy, 10,10);   //draw ball at current position : x, y fixed at 125!
  four.posy = four.posy - 1;
if (abs(four.posy -1 )<1 )
  {four.posy = four.posy+ 400;
  four.posx = randomattack3;}
}void keyPressed()
{
  if (key==CODED)
  {
    if (keyCode == LEFT)
    {  DefenderX = DefenderX - 5; }
    if (keyCode == RIGHT)
    {  DefenderX = DefenderX + 5; } 
   
    
    
  
}
}

Answer 1

这是绘制项目符号的代码部分：

float bulletY = DefenderY;
float bulletX = DefenderX;
  
rect(bulletX, bulletY, 8, 8);

您将子弹 position 设置为 Defender position 然后立即绘制它。

稍后您有一些代码可以调整子弹 position，但它不会有任何效果，因为您已经在原始 position 的屏幕上绘制了子弹。

另请注意， draw function 运行每一帧，所以你可能不想像这样每帧都重置子弹 position，否则很难让它移动到任何地方。 在draw之外声明子弹 position 的变量，并且仅在子弹最初发射时重置它们。