Hi, this is a basic question. But I'm just starting and I'm stuck. I wanted to create a basic space invader type game were a shot is fired when the user hits the mouse.

I've been able to get a square "shot" to move when the user hits the mouse. I created an object called "Shot" and have an array of them on my main program. When I hit the mouse one shot fires.

So far so good. My problem is that when ever I hit the mouse again, It appears to erase the shot that is currently on the screen, and replace it with a new shot. I want both (or many) to be on the screen at once:

The code is below:

// Global variables
// Intializing Shot object
// Why does shoting a new shot stop the old instance from displaying?
//-------------------------------------------------
Shot[] shot = new Shot[12];

boolean mouseCheck = false;
int totalShots = 0;

void setup()
{
 size(400,400);
 for(int i = 0; i < shot.length; i++)
 {
   shot[i] = new Shot(random(0,375));
   println("shot instance name is: shot" + i);
 }
}

void draw()
{
 background(150);

 if(mouseCheck)
 {
   shot[totalShots].display();
   shot[totalShots].move();
   println("shot instance display name is: shot" + totalShots);
 }

}

void mousePressed()
{
 totalShots++;
 mouseCheck = true;

 //println("Mouse has been pressed 2");
}

// Shot class

class Shot
{
 float shotX;
 int shotY;
 int shotWidth;
 int shotHeight;
 int speed;


 Shot(float tempShotX)
 {
 shotX = tempShotX;  
 shotY = 375;
 shotWidth = 25;
 shotHeight = 25;
 speed = 1;
 }

 void move()
 {
 shotY--;
 }

 void display()
 {
   //Display rectangle
   rect(shotX, shotY, shotWidth, shotHeight);
   //println("Mouse has been pressed 1");
 }

}

I played with your code a bit, mostly just adding a loop to go through your shots objects ... and added some properties to give you a hint of what you could do ...

Shot[] shot = new Shot[12];

boolean mouseCheck = false;
int totalShots = 0;

void setup()
{
 size(400,400);
 for(int i = 0; i < shot.length; i++)
 {
   shot[i] = new Shot(random(0,375));
   println("shot instance name is: shot" + i);
 }
}

void draw()
{
 background(150);

 // if(mouseCheck) // redundant ... you should loop through the shots objects regardless ...

 for (int l=0; l<shot.length; l++){
   {
     if (shot[l].fired){
     shot[l].display();
     shot[l].move();
     }
 
    // println("shot instance display name is: shot" + totalShots);
   }
 }

}

void mousePressed()
{
 totalShots++;
 totalShots %= shot.length;
 shot[totalShots].shotY = mouseY;
 shot[totalShots].shotX = mouseX;
 shot[totalShots].fired = true;
 //mouseCheck = true;
}

//println("Mouse has been pressed 2");


// Shot class

class Shot
{
 float shotX;
 int shotY;
 int shotWidth;
 int shotHeight;
 int speed;
 boolean fired; // also indicates if the bullet should be displayed or not ...

 Shot(float tempShotX)
 {
   shotX = tempShotX;  
   shotY = 375;
   shotWidth = 5;
   shotHeight = 25;
   speed = 1;
   fired = false;
 }

 void move()
 {
     shotY--;
   if (shotY < 0) {
     fired = false;
     shotY = 375;
   }
 }

 void display()
 {
   //Display rectangle
   rect(shotX, shotY, shotWidth, shotHeight);
   //println("Mouse has been pressed 1");
 }
}